Viral Threats to Fruit and Vegetable Crops in the Caribbean

Viruses pose major global challenges to crop production as infections reduce the yield and quality of harvested products, hinder germplasm exchange, increase financial inputs, and threaten food security. Small island or archipelago habitat conditions such as those in the Caribbean are particularly susceptible as the region is characterized by high rainfall and uniform, warm temperatures throughout the year. Moreover, Caribbean islands are continuously exposed to disease risks because of their location at the intersection of transcontinental trade between North and South America and their role as central hubs for regional and global agricultural commodity trade. This review provides a summary of virus disease epidemics that originated in the Caribbean and those that were introduced and spread throughout the islands. Epidemic-associated factors that impact disease development are also discussed. Understanding virus disease epidemiology, adoption of new diagnostic technologies, implementation of biosafety protocols, and widespread acceptance of biotechnology solutions to counter the effects of cultivar susceptibility remain important challenges to the region. Effective integrated disease management requires a comprehensive approach that should include upgraded phytosanitary measures and continuous surveillance with rapid and appropriate responses.

Microbiome-Mediated Strategies to Manage Major Soil-Borne Diseases of Tomato

The tomato (Solanum lycopersicum L.) is consumed globally as a fresh vegetable due to its high nutritional value and antioxidant properties. However, soil-borne diseases can severely limit tomato production. These diseases, such as bacterial wilt (BW), Fusarium wilt (FW), Verticillium wilt (VW), and root-knot nematodes (RKN), can significantly reduce the yield and quality of tomatoes. Using agrochemicals to combat these diseases can lead to chemical residues, pesticide resistance, and environmental pollution. Unfortunately, resistant varieties are not yet available. Therefore, we must find alternative strategies to protect tomatoes from these soil-borne diseases. One of the most promising solutions is harnessing microbial communities that can suppress disease and promote plant growth and immunity. Recent omics technologies and next-generation sequencing advances can help us develop microbiome-based strategies to mitigate tomato soil-borne diseases. This review emphasizes the importance of interdisciplinary approaches to understanding the utilization of beneficial microbiomes to mitigate soil-borne diseases and improve crop productivity.

Spore Dispersal Patterns of Colletotrichum fioriniae in Orchards and the Timing of Apple Bitter Rot Infection Periods

Bitter rot is a major disease of apple fruit in warm and humid regions. It is caused by various species in the Colletotrichum gloeosporioides and C. acutatum species complexes, of which C. fioriniae of the C. acutatum species complex is most common in the Mid-Atlantic region of the United States. While bitter rot management begins with good cultural practices, fungicides are generally used for consistent control. Fungicides should be applied before or during infection periods, but the timing of infection is unclear due to the hemibiotrophic lifestyle of the causal species. To determine when infection periods occur, we quantified C. fioriniae spore dispersal throughout three growing seasons and compared the temporal susceptibility of apples in two seasons of field trials. Spores were detected in rainwater from bud break to leaf drop, with the highest spore quantities in the summer and early fall correlating with optimal temperatures for C. fioriniae. Late-season-inoculated fruit had more bitter rot than early-season-inoculated fruit, but this was also positively correlated with periods of optimal temperatures and moisture for infection. In the context of previous experiments, these results suggest that infection periods are primarily determined by temperature and moisture rather than apple fruit phenology. Based on the relative numbers of spores and biotrophic and necrotrophic infections, only a tiny proportion of spores establish viable biotrophic infections, but a relatively high proportion of biotrophic infections switch to necrotrophy. We suggest bitter rot management should focus on preventing initial biotrophic infections by protecting apples during weather conditions that favor infection.

Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan

Foliar diseases caused by Stemphylium and Colletotrichum species are among the major biotic factors limiting Welsh onion production in Taiwan. Owing to concerns about the environment and the development of pathogen resistance to existing fungicides, biological control using endophytes is emerging as an eco-friendly alternative to chemical control. The aim of the present study was to isolate endophytes from healthy Welsh onion leaves and investigate their antagonistic potential against the major phytopathogenic fungi associated with Welsh onion plants in Taiwan. A total of 109 bacterial and 31 fungal strains were isolated from healthy Welsh onion leaves and assigned to 16 bacterial and nine fungal genera using morphological and molecular characterization based on DNA sequence data obtained from nuclear internal transcribed spacer (nrITS) (fungi) and 16S rRNA (bacteria). Evaluation of these endophytic isolates for biocontrol activity against leaf blight pathogens Colletotrichum spaethianum strain SX15-2 and Stemphylium vesicarium strain SX20-2 by dual culture assay and greenhouse experiments resulted in the identification of two bacterial isolates (GFB08 and LFB28) and two fungal isolates (GFF06 and GFF08) as promising antagonists to leaf blight pathogens. Among the four selected isolates, Bacillus strain GFB08 exhibited the highest disease control in the greenhouse study. Therefore, Bacillus strain GFB08 was further evaluated to understand the mechanism underlying its biocontrol efficacy. A phylogenetic analysis based on six genes identified Bacillus strain GFB08 as B. velezensis. The presence of antimicrobial peptide genes (baer, bamC, bmyB, dfnA, fenD, ituC, mlna, and srfAA) and the secretion of several cell wall degrading enzymes (CWDEs), including cellulase and protease, confirmed the antifungal nature of B. velezensis strain GFB08. Leaf blight disease suppression by preventive and curative assays indicated that B. velezensis strain GFB08 has preventive efficacy on C. spaethianum strain SX15-2 and both preventive and curative efficacy on S. vesicarium strain SX20-2. Overall, the current study revealed that healthy Welsh onion leaves harbour diverse bacterial and fungal endophytes, among which the endophytic bacterial strain, B. velezensis strain GFB08, could potentially be used as a biocontrol agent to manage the leaf blight diseases of Welsh onion in Taiwan.

Survey, Detection, Characterization of Papaya Ringspot Virus from Southern India and Management of Papaya Ringspot Disease

Papaya ringspot virus (PRSV) is a significant threat to global papaya cultivation, causing ringspot disease, and it belongs to the species Papaya ringspot virus, genus Potyvirus, and family Potyviridae. This study aimed to assess the occurrence and severity of papaya ringspot disease (PRSD) in major papaya-growing districts of Karnataka, India, from 2019 to 2021. The incidence of disease in the surveyed districts ranged from 50.5 to 100.0 percent, exhibiting typical PRSV symptoms. 74 PRSV infected samples were tested using specific primers in RT-PCR, confirming the presence of the virus. The complete genome sequence of a representative isolate (PRSV-BGK: OL677454) was determined, showing the highest nucleotide identity (nt) (95.8%) with the PRSV-HYD (KP743981) isolate from Telangana, India. It also shared an amino acid (aa) identity (96.5%) with the PRSV-Pune VC (MF405299) isolate from Maharashtra, India. Based on phylogenetic and species demarcation criteria, the PRSV-BGK isolate was considered a variant of the reported species and designated as PRSV-[IN:Kar:Bgk:Pap:21]. Furthermore, recombination analysis revealed four unique recombination breakpoint events in the genomic region, except for the region from HC-Pro to VPg, which is highly conserved. Interestingly, more recombination events were detected within the first 1710 nt, suggesting that the 5' UTR and P1 regions play an essential role in shaping the PRSV genome. To manage PRSD, a field experiment was conducted over two seasons, testing various treatments, including insecticides, biorationals, and a seaweed extract with micronutrients, alone or in combination. The best treatment involved eight sprays of insecticides and micronutrients at 30-day intervals, resulting in no PRSD incidence up to 180 days after transplanting (DAT). This treatment also exhibited superior growth, yield, and yield parameters, with the highest cost-benefit ratio (1:3.54) and net return. Furthermore, a module comprising 12 sprays of insecticides and micronutrients at 20-day intervals proved to be the most effective in reducing disease incidence and enhancing plant growth, flowering, and fruiting attributes, resulting in a maximized yield of 192.56 t/ha.

An in-field heat treatment to reduce Cercospora beticola survival in plant residue and improve Cercospora leaf spot management in sugarbeet

Introduction

Sugarbeets account for 55 to 60% of U.S. sugar production. Cercospora leaf spot (CLS), primarily caused by the fungal pathogen Cercospora beticola, is a major foliar disease of sugarbeet. Since leaf tissue is a primary site of pathogen survival between growing seasons, this study evaluated management strategies to reduce this source of inoculum.

Methods

Fall- and spring-applied treatments were evaluated over three years at two study sites. Treatments included standard plowing or tilling immediately post-harvest, as well as the following alternatives to tillage: a propane-fueled heat treatment either in the fall immediately pre-harvest or in the spring prior to planting, and a desiccant (saflufenacil) application seven days pre-harvest. After fall treatments, leaf samples were evaluated to determine C. beticola viability. The following season, inoculum pressure was measured by monitoring CLS severity in a susceptible beet variety planted into the same plots and by counting lesions on highly susceptible sentinel beets placed into the field at weekly intervals (fall treatments only).

Results

No significant reductions in C. beticola survival or CLS were observed following fall-applied desiccant. The fall heat treatment, however, significantly reduced lesion sporulation (2019-20 and 2020-21, P < 0.0001; 2021-22, P < 0.05) and C. beticola isolation (2019-20, P < 0.05) in at-harvest samples. Fall heat treatments also significantly reduced detectable sporulation for up to 70- (2021-22, P < 0.01) or 90-days post-harvest (2020-21, P < 0.05). Reduced numbers of CLS lesions were observed on sentinel beets in heat-treated plots from May 26-June 2 (P < 0.05) and June 2-9 (P < 0.01) in 2019, as well as June 15-22 (P < 0.01) in 2020. Both fall- and spring-applied heat treatments also reduced the area under the disease progress curve for CLS assessed the season after treatments were applied (Michigan 2020 and 2021, P < 0.05; Minnesota 2019, P < 0.05; 2021, P < 0.0001).

Discussion

Overall, heat treatments resulted in CLS reductions at levels comparable to standard tillage, with more consistent reductions across year and location. Based on these results, heat treatment of fresh or overwintered leaf tissue could be used as an integrated tillage-alternative practice to aid in CLS management.

The socio-economic challenges of managing pathogen evolution in agriculture

Genetic resistance forms the foundation of infectious disease management in crops. However, rapid pathogen evolution is causing the breakdown of resistance and threatening disease control. Recent research efforts have identified strategies for resistance gene deployment that aim to disrupt pathogen adaptation and prevent breakdown. To date, there has been limited practical uptake of such strategies. In this paper, we focus on the socio-economic challenges associated with translating applied evolutionary research into scientifically informed management strategies to control pathogen adaptation. We develop a conceptual framework for the economic valuation of resistance and demonstrate that in addition to various direct benefits, resistance delivers considerable indirect and non-market value to farmers and society. Incentives for stakeholders to engage in stewardship strategies are complicated by the uncertain timeframes associated with evolutionary processes, difficulties in assigning ownership rights to genetic resources and lack of governance. These interacting biological, socio-economic and institutional complexities suggest that resistance breakdown should be viewed as a wicked problem, with often conflicting imperatives among stakeholders and no simple cause or solution. Promoting the uptake of scientific research outcomes that address complex issues in sustainable crop disease management will require a mix of education, incentives, legislation and social change. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.

Past and Future Epidemiological Perspectives and Integrated Management of Rice Bakanae in Korea

In the past, rice bakanae was considered an endemic disease that did not cause significant losses in Korea; however, the disease has recently become a serious threat due to climate change, changes in farming practices, and the emergence of fungicide-resistant strains. Since the bakanae outbreak in 2006, its incidence has gradually decreased due to the application of effective control measures such as hot water immersion methods and seed disinfectants. However, in 2013, a marked increase in bakanae incidence was observed, causing problems for rice farmers. Therefore, in this review, we present the potential risks from climate change based on an epidemiological understanding of the pathogen, host plant, and environment, which are the key elements influencing the incidence of bakanae. In addition, disease management options to reduce the disease pressure of bakanae below the economic threshold level are investigated, with a specific focus on resistant varieties, as well as chemical, biological, cultural, and physical control methods. Lastly, as more effective countermeasures to bakanae, we propose an integrated disease management option that combines different control methods, including advanced imaging technologies such as remote sensing. In this review, we revisit and examine bakanae, a traditional seed-borne fungal disease that has not gained considerable attention in the agricultural history of Korea. Based on the understanding of the present significance and anticipated risks of the disease, the findings of this study are expected to provide useful information for the establishment of an effective response strategy to bakanae in the era of climate change.

Meloidogyne enterolobii risk to agriculture, its present status and future prospective for management

Meloidogyne enterolobii, commonly known as guava root-knot nematode, poses risk due to its widespread distribution and extensive host range. This species is recognized as the most virulent root-knot nematode (RKN) species because it can emerge and breed in plants that have resistance to other tropical RKNs. They cause chlorosis, stunting, and yield reductions in host plants by producing many root galls. It is extremely challenging for farmers to diagnose due to the symptoms' resemblance to nutritional inadequacies. This pathogen has recently been considered a significant worldwide threat to agricultural production. It is particularly challenging to diagnose a M. enterolobii due to the similarities between this species and other RKN species. Identified using traditional morphological and molecular techniques, which is a crucial first in integrated management. Chemical control, biological control, the adoption of resistant cultivars, and cultural control have all been developed and effectively utilized to combat root-knot nematodes in the past. The object of this study was to get about the geographical distribution, host plants, symptoms, identification, and control techniques of M. enterolobii and recommend future initiatives to progress its management.

Huanglongbing Pandemic: Current Challenges and Emerging Management Strategies

Huanglongbing (HLB, aka citrus greening), one of the most devastating diseases of citrus, has wreaked havoc on the global citrus industry in recent decades. The culprit behind such a gloomy scenario is the phloem-limited bacteria "Candidatus Liberibacter asiaticus" (CLas), which are transmitted via psyllid. To date, there are no effective long-termcommercialized control measures for HLB, making it increasingly difficult to prevent the disease spread. To combat HLB effectively, introduction of multipronged management strategies towards controlling CLas population within the phloem system is deemed necessary. This article presents a comprehensive review of up-to-date scientific information about HLB, including currently available management practices and unprecedented challenges associated with the disease control. Additionally, a triangular disease management approach has been introduced targeting pathogen, host, and vector. Pathogen-targeting approaches include (i) inhibition of important proteins of CLas, (ii) use of the most efficient antimicrobial or immunity-inducing compounds to suppress the growth of CLas, and (iii) use of tools to suppress or kill the CLas. Approaches for targeting the host include (i) improvement of the host immune system, (ii) effective use of transgenic variety to build the host's resistance against CLas, and (iii) induction of systemic acquired resistance. Strategies for targeting the vector include (i) chemical and biological control and (ii) eradication of HLB-affected trees. Finally, a hypothetical model for integrated disease management has been discussed to mitigate the HLB pandemic.

Reduction of Pythium Damping-Off in Soybean by Biocontrol Seed Treatment

Pythium spp. is one of the major groups of pathogens that cause seedling diseases on soybean, leading to both preemergence and postemergence damping-off and root rot. More than 100 species have been identified within this genus, with Pythium irregulare, P. sylvaticum, P. ultimum var ultimum, and P. torulosum being particularly important for soybean production given their aggressiveness, prevalence, and abundance in production fields. This study investigated the antagonistic activity of potential biological control agents (BCAs) native to the U.S. Midwest against Pythium spp. First, in vitro screening identified BCAs that inhibit P. ultimum var. ultimum growth. Scanning electron microscopy demonstrated evidence of mycoparasitism of all potential biocontrol isolates against P. ultimum var. ultimum and P. torulosum, with the formation of appressorium-like structures, short hyphal branches around host hyphae, hook-shaped structures, coiling, and parallel growth of the mycoparasite along the host hyphae. Based on these promising results, selected BCAs were tested under field conditions against six different Pythium spp. Trichoderma afroharzianum 26 used alone and a mix of T. hamatum 16 + T. afroharzianum 19 used as seed treatments protected soybean seedlings from Pythium spp. infection, as BCA-treated plots had on average 15 to 20% greater plant stand and vigor than control plots. Our results also indicate that some of these potential BCAs could be added with a fungicide seed treatment with minimum inhibition occurring, depending on the fungicide active ingredient. This research highlights the need to develop tools incorporating biological control as a facet of soybean seedling disease management programs. The harnessing of native BCAs could be integrated with other management strategies to provide efficient control of seedling diseases.

An Overview of Chili Leaf Curl Disease: Molecular Mechanisms, Impact, Challenges, and Disease Management Strategies in Indian Subcontinent

Leaf curl disease in a chili plant is caused mainly by Chili leaf curl virus (ChiLCV) (Family: Geminiviridae, Genus: Begomovirus). ChiLCV shows a widespread occurrence in most of the chili (Capsicum spp.) growing regions. ChiLCV has a limited host range and infects tomatoes (Solanum lycopersicum), potatoes (S. tuberosum), and amaranth (Amaranthus tricolor). The virus genome is a monopartite circular single-stranded DNA molecule of 2.7 kb and associated with α and β-satellites of 1.3 and 1.4 kb, respectively. The virus genome is encapsulated in distinct twinned icosahedral particles of around 18-30 nm in size and transmitted by Bemisia tabaci (Family: Aleyrodidae, Order: Hemiptera). Recently, bipartite begomovirus has been found to be associated with leaf curl disease. The leaf curl disease has a widespread distribution in the major equatorial regions viz., Australia, Asia, Africa, Europe, and America. Besides the PCR, qPCR, and LAMP-based detection systems, recently, localized surface-plasmon-resonance (LPSR) based optical platform is used for ChiLCV detection in a 20-40 μl of sample volume using aluminum nanoparticles. Management of ChiLCV is more challenging due to the vector-borne nature of the virus, therefore integrated disease management strategies need to be followed to contain the spread and heavy crop loss. CRISPR/Cas-mediated virus resistance has gained importance in disease management of DNA and RNA viruses due to certain advantages over the conventional approaches. Therefore, CRISPR/Cas system-mediated resistance needs to be explored in chili against ChiLCV.

Efficacy of Biorational Products for Managing Diseases of Tomato in Greenhouse Production

Gray mold (Botrytis cinerea), late blight (Phytophthora infestans), powdery mildew (Leveillula taurica), pith necrosis (Pseudomonas corrugata), and bacterial canker (Clavibacter michiganensis) are major diseases that affect tomato (Solanum lycopersicum L.) in greenhouse production in Mexico. Management of these diseases depends heavily on chemical control, with up to 24 fungicide applications required in a single season to control fungal diseases, thus ensuring a harvestable crop. While disease chemical control is a mainstay practice in the region, its frequent use increases the production costs, likelihood of pathogen-resistance development, and negative environmental impact. Due to this, there is a need for alternative practices that minimize such effects and increase profits for tomato growers. The aim of this study is to evaluate the effect of biorational products in the control of these diseases in greenhouse production. Four different treatments, including soil application of Bacillus spp. or B. subtilis and foliar application of Reynoutria sachalinensis, Melaleuca alternifolia, harpin αβ proteins, or bee honey were evaluated and compared to a conventional foliar management program (control) in a commercial production greenhouse in Central Mexico in 2016 and 2017. Disease incidence was measured at periodic intervals for six months and used to calculate the area under the disease progress curve (AUDPC). Overall, the analysis of the AUDPC showed that all treatments were more effective than the conventional program in controlling most of the examined diseases. The tested products were effective in reducing the intensity of powdery mildew and gray mold, but not that of bacterial canker, late blight, and pith necrosis. Application of these products constitutes a disease management alternative that represents cost-saving to tomato growers of about 2500 U.S. dollars per production cycle ha^-1, in addition to having less negative impact on the environment. The products tested in this study have the potential to be incorporated in an integrated program for management of the examined diseases in tomato in this region.

Recent advances in research on biocontrol of postharvest fungal decay in apples

Apple is the largest fruit crop produced in temperate regions and is a popular fruit worldwide. It is, however, susceptible to a variety of postharvest fungal pathogens, including Penicillium expansum, Botrytis cinerea, Botryosphaeria dothidea, Monilia spp., and Alternaria spp. Decays resulting from fungal infections severely reduce apple quality and marketable yield. Biological control utilizing bacterial and fungal antagonists is an eco-friendly and effective method of managing postharvest decay in horticultural crops. In the current review, research on the pathogenesis of major decay fungi and isolation of antagonists used to manage postharvest decay in apple is presented. The mode of action of postharvest biocontrol agents (BCAs), including recent molecular and genomic studies, is also discussed. Recent research on the apple microbiome and its relationship to disease management is highlighted, and the use of additives and physical treatments to enhance biocontrol efficacy of BCAs is reviewed. Biological control is a critical component of an integrated management system for the sustainable approaches to apple production. Additional research will be required to explore the feasibility of developing beneficial microbial consortia and novel antimicrobial compounds derived from BCAs for postharvest disease management, as well as genetic approaches, such as the use of CRISPR/Cas9 technology.

Manipulation of Vector Host Preference by Pathogens: Implications for Virus Spread and Disease Management

Some plant pathogens manipulate the behavior and performance of their vectors, potentially enhancing pathogen spread. The implications are evolutionary and epidemiological but also economic for pathogens that cause disease in crops. Here we explore with models the effects of vector manipulation on crop yield loss to disease and on the economic returns for vector suppression. We use two frameworks, one that simulates the proportional occurrence of the pathogen in the vector population with the option to eliminate vectors by a single insecticidal treatment, and one that includes vector population dynamics and the potential for multiple insecticidal sprays in a season to suppress vectors. We parameterize the models with published data on vector manipulation, crop yields as affected by the age of the plant at infection, commodity prices and costs of vector control for three pathosystems. Using the first framework, maximum returns for treating vectors are greater with vector manipulation than without it by approximately US$10 per acre (US$24.7/ha) in peas infected by Pea enation mosaic virus and Bean leaf roll virus, and approximately US$50 per acre (US$124/ha) for potatoes infected by Potato leaf roll virus. Using the second framework, maximum returns for controlling the psyllid vectors of Candidatus Liberibacter solanacearum are 50% greater (approximately US$400/acre, US$988/ha) but additional returns for multiple weekly sprays diminish more with vector manipulation than without it. These results suggest that the economics of vector manipulation can be substantial and provide a framework that can inform management decisions.

Current recommendations and novel strategies for sustainable management of soybean sudden death syndrome

The increase in food production requires reduction of the damage caused by plant pathogens, minimizing the environmental impact of management practices. Soil-borne pathogens are among the most relevant pathogens that affect soybean crop yield. Soybean sudden death syndrome (SDS), caused by several distinct species of Fusarium, produces significant yield losses in the leading soybean-producing countries in North and South America. Current management strategies for SDS are scarce since there are no highly resistant cultivars and only a few fungicide seed treatments are available. Because of this, innovative approaches for SDS management need to be developed. Here, we summarize recently explored strategies based on plant nutrition, biological control, priming of plant defenses, host-induced gene silencing, and the development of new SDS-resistance cultivars using precision breeding techniques. Finally, sustainable management of SDS should also consider cultural control practices with minimal environmental impact. © 2021 Society of Chemical Industry.

Characterization of Pestalotiopsis sp. causing gray leaf spot in coconut (Cocos nucifera L.) in Bangladesh

Coconut (Cocos nucifera L.) is one of the most important fruit trees in Bangladesh. This tree is susceptible to various pathogens. Among them, a fungus was consistently isolated from gray leaf spot symptom in coconut. This study aimed to isolate, characterize, and find the management strategies of the causal fungus of gray leaf spot disease in coconut. Both morphological and molecular characters identified the pathogen as Pestalotiopsis sp. for the first time in Bangladesh. Artificial inoculation of this fungus showed symptoms similar to those previously observed in the field. Cross-inoculation test suggests that Pestalotiopsis sp. has a wide host range. The infection process of Pestalotiopsis sp. started at 2 h after inoculation (hai) with the formation of germ tube followed by the formation of infection hyphae, which penetrated directly into the host at 6 hai. Gray leaf spot symptom was developed at 120 hai. Numerous conidia developed from the acervuli at 168 hai. These conidia acted as the source of inocula for secondary infection. The optimum temperature for the growth of Pestalotiopsis sp. was 25°C, however, the growth of Pestalotiopsis sp. ceased at 15°C and 35°C. This pathogen was completely inhibited by Autostin 50 WDG (carbendazim) at 100 ppm. Trichoderma viride (Pb-7) was found as the potential biocontrol agent against Pestalotiopsis sp. These findings could contribute to describing the disease cycle and epidemiology of Pestalotiopsis sp. that would ultimately require to undertake effective control measures against this pathogen.

Wheat Blast: A Disease Spreading by Intercontinental Jumps and Its Management Strategies

Wheat blast (WB) caused by Magnaporthe oryzae pathotype Triticum (MoT) is an important fungal disease in tropical and subtropical wheat production regions. The disease was initially identified in Brazil in 1985, and it subsequently spread to some major wheat-producing areas of the country as well as several South American countries such as Bolivia, Paraguay, and Argentina. In recent years, WB has been introduced to Bangladesh and Zambia via international wheat trade, threatening wheat production in South Asia and Southern Africa with the possible further spreading in these two continents. Resistance source is mostly limited to 2NS carriers, which are being eroded by newly emerged MoT isolates, demonstrating an urgent need for identification and utilization of non-2NS resistance sources. Fungicides are also being heavily relied on to manage WB that resulted in increasing fungal resistance, which should be addressed by utilization of new fungicides or rotating different fungicides. Additionally, quarantine measures, cultural practices, non-fungicidal chemical treatment, disease forecasting, biocontrol etc., are also effective components of integrated WB management, which could be used in combination with varietal resistance and fungicides to obtain reasonable management of this disease.

Green Strategies of Powdery Mildew Control in Hop: From Organic Products to Nanoscale Carriers

Humulus lupulus L. is a long-lived, perennial, herbaceous, and dioecious climbing plant. The foremost producers in the European Union are Germany, the Czech Republic, Poland, Slovenia, and Spain. The Spanish cultivated area is concentrated in the province of León. Powdery mildew, caused by Podosphaera macularis, menaces hop production and quality in all hop growing regions located in the Northern hemisphere, colonizing leaves, petioles, inflorescences, and finally cones. In this work, powdery mildew control was monitored, comparing nine fungicide strategies: five organics, two integrated disease management (IDM)-based, with and without Nutragreen^® nanoscale carrier, and two conventional treatments (CON) with and without Nutragreen^® nanoscale carrier. The organic treatments were able to diminish P. macularis on leaves, but no effect was observed in cones. CON treatments reduced the infection on leaves and cones and increased the cone quantity and quality. Likewise, IDM-based treatments provided satisfactory results as they diminished powdery mildew on leaves and cones. Finally, dose reduction using a Nutragreen^® nanoscale carrier showed beneficial effects in the control of powdery mildew compared to the commercial dose. Hence, the use of nanoscale carries permits a 30% reduction in pesticide dose, which optimizes yield and hop quality, reduces risks linked to pesticides, and aids in compliance with public and international policy demands.

Validation of a Decision Support System for Blueberry Anthracnose and Fungicide Sensitivity of Colletotrichum gloeosporioides Isolates

Blueberry is an increasingly important crop in Florida. Anthracnose fruit rot (AFR), caused mostly by Colletotrichum gloeosporioides, is favored by long wetness periods and temperatures from 15 to 27°C. Currently, the model in the Strawberry Advisory System (StAS) guides fungicide applications targeting strawberry AFR. Given the similarity between blueberry and strawberry AFR, we hypothesized that the model used in StAS could be used in a decision support system (DSS) built for blueberry AFR. There is no information on inhibition posed by fungicides on C. gloeosporioides isolates from blueberry. Our objectives were to demonstrate that the model used in the StAS could be used for blueberry AFR management in Florida and to assess the sensitivity of isolates to fungicides. Four trials were undertaken in blueberry fields in Florida during two seasons to compare the effectiveness of fungicide applications according to the model with that of the growers' standard calendar. Sensitivity of blueberry C. gloeosporioides isolates to azoxystrobin, benzovindiflupyr, penthiopyrad, pydiflumetofen, boscalid, thiophanate-methyl, fluazinam, and fludioxonil was evaluated. AFR incidence and yield were compared between treatments. Following recommendations from the model resulted in disease control as effective as the standard program and in some cases with fewer applications. All isolates were sensitive to benzovindiflupyr, penthiopyrad, fluazinam, and fludioxonil. Low frequency of in vitro inhibition of isolates by azoxystrobin, pydiflumetofen, boscalid, and thiophanate-methyl should raise concern about fungicide resistance. Our results indicate that the model used in StAS could be used in a DSS to help Florida growers to manage AFR in blueberry.

Assessing the Involvement of Selected Phenotypes of Pseudomonas simiae PICF7 in Olive Root Colonization and Biological Control of Verticillium dahliae

Pseudomonas simiae PICF7 is an indigenous inhabitant of the olive (Olea europaea L.) rhizosphere/root endosphere and an effective biocontrol agent against Verticillium wilt of olive (VWO), caused by the soil-borne fungus Verticillium dahliae. This study aimed to evaluate the potential involvement of selected phenotypes of strain PICF7 in root colonization ability and VWO biocontrol. Therefore, a random transposon-insertion mutant bank of P. simiae PICF7 was screened for the loss of phenotypes likely involved in rhizosphere/soil persistence (copper resistance), root colonization (biofilm formation) and plant growth promotion (phytase activity). Transposon insertions in genes putatively coding for the transcriptional regulator CusR or the chemotaxis protein CheV were found to affect copper resistance, whereas an insertion in fleQ gene putatively encoding a flagellar regulatory protein hampered the ability to form a biofilm. However, these mutants displayed the same antagonistic effect against V. dahliae as the parental strain. Remarkably, two mutants impaired in biofilm formation were never found inside olive roots, whereas their ability to colonize the root exterior and to control VWO remained unaffected. Endophytic colonization of olive roots was unaltered in mutants impaired in copper resistance and phytase production. Results demonstrated that the phenotypes studied were irrelevant for VWO biocontrol.

Quantification of Colletotrichum fioriniae in Orchards and Deciduous Forests Indicates It Is Primarily a Leaf Endophyte

Colletotrichum fioriniae of the C. acutatum species complex is an important hemibiotrophic pathogen of vegetables and fruits in temperate regions worldwide. In apple, it is one of the primary species responsible for bitter rot disease. Understanding the disease cycle is complicated because many broadleaf plants can be hosts of C. fioriniae. By detecting and quantifying rain-splashed C. acutatum species complex conidia in more than 500 samples from heavily bitter-rot-infected apple orchards and nearby forested woodlots over two summers, we show that conidial quantities were higher in the woodlots than in the orchards. Testing of more than 1,000 surface-disinfected leaves of apple and 24 different forest plant species showed that overall C. fioriniae was an abundant leaf endophyte, with high variation in leaf colonization area. Endophytic isolates from leaves were pathogenic on apples, and multilocus sequence analysis showed 100% identity between most isolates from leaves and diseased fruits. Apple leaves endophytically infected with C. fioriniae were present in a conventionally managed orchard and abundant in an untreated orchard. These lines of evidence, in the context of previously published research, lead us to hypothesize that the main ecological role of C. fioriniae is that of a leaf endophyte, which we present as a generalized C. fioriniae infection cycle that provides an updated framework for its integrated management in agricultural systems.

Global Plant Virus Disease Pandemics and Epidemics

The world's staple food crops, and other food crops that optimize human nutrition, suffer from global virus disease pandemics and epidemics that greatly diminish their yields and/or produce quality. This situation is becoming increasingly serious because of the human population's growing food requirements and increasing difficulties in managing virus diseases effectively arising from global warming. This review provides historical and recent information about virus disease pandemics and major epidemics that originated within different world regions, spread to other continents, and now have very wide distributions. Because they threaten food security, all are cause for considerable concern for humanity. The pandemic disease examples described are six (maize lethal necrosis, rice tungro, sweet potato virus, banana bunchy top, citrus tristeza, plum pox). The major epidemic disease examples described are seven (wheat yellow dwarf, wheat streak mosaic, potato tuber necrotic ringspot, faba bean necrotic yellows, pepino mosaic, tomato brown rugose fruit, and cucumber green mottle mosaic). Most examples involve long-distance virus dispersal, albeit inadvertent, by international trade in seed or planting material. With every example, the factors responsible for its development, geographical distribution and global importance are explained. Finally, an overall explanation is given of how to manage global virus disease pandemics and epidemics effectively.

Evaluation of a Small-Molecule Compound, N-Acetylcysteine, for the Management of Bacterial Spot of Tomato Caused by Copper-Resistant Xanthomonas perforans

Bacterial spot caused by Xanthomonas spp. is one of the major diseases in tomato. Xanthomonas perforans is the main pathogen of bacterial spot on tomato in Florida. Currently, application of copper fungicides is the primary measure used to manage this disease. However, the development of copper resistance in X. perforans and accumulation of copper in the environment are major concerns for excessive use of copper-based products in agriculture. Due to its antibacterial properties and low environmental impact, N-acetylcysteine (NAC), a small molecule commonly used in medicine for human bacterial diseases, has been studied in agriculture for the control of plant bacterial pathogens, including X. citri and Xylella fastidiosa. This study evaluated the effect of NAC alone and in combination with copper on a copper-resistant X. perforans strain in vitro and its ability to control bacterial spot of tomato under greenhouse and field conditions. In vitro, the minimum inhibitory concentration of NAC against the X. perforans strain was 2,048 mg liter^-1. NAC increased sensitivity of the copper-resistant X. perforans to copper in vitro when application of NAC was followed by copper application after 6 h. In greenhouse assays, NAC applied alone or in combination with copper significantly (P < 0.05) reduced the disease severity of bacterial spot on tomato compared with the untreated control. NAC at 100 mg liter^-1 + copper at 300 mg liter^-1 consistently exhibited synergistic effects against bacterial spot. In the field trials, NAC at 1,000 mg liter^-1 + copper at 150 mg liter^-1 significantly reduced disease severity compared with the untreated control. Results from this study demonstrated that NAC significantly reduced the disease severity of bacterial spot of tomato and enhanced the efficacy of copper against copper-resistant X. perforans, indicating that NAC could be applied for the effective management of bacterial spot of tomato.

Present Status and Future Management Strategies for Sugarcane Yellow Leaf Virus: A Major Constraint to the Global Sugarcane Production

Sugarcane yellow leaf virus (SCYLV) is a distinct member of the Polerovirus genus of the Luteoviridae family. SCYLV is the major limitation to sugarcane production worldwide and presently occurring in most of the sugarcane growing countries. SCYLV having high genetic diversity within the species and presently ten genotypes are known to occur based on the complete genome sequence information. SCYLV is present in almost all the states of India where sugarcane is grown. Virion comprises of 180 coat protein units and are 24-29 nm in diameter. The genome of SCYLV is a monopartite and comprised of single-stranded (ss) positive-sense (+) linear RNA of about 6 kb in size. Virus genome consists of six open reading frames (ORFs) that are expressed by sub-genomic RNAs. The SCYLV is phloem-limited and transmitted by sugarcane aphid Melanaphis sacchari in a circulative and non-propagative manner. The other aphid species namely, Ceratovacuna lanigera, Rhopalosiphum rufiabdominalis, and R. maidis also been reported to transmit the virus. The virus is not transmitted mechanically, therefore, its transmission by M. sacchari has been studied in different countries. SCYLV has a limited natural host range and mainly infect sugarcane (Sachharum hybrid), grain sorghum (Sorghum bicolor), and Columbus grass (Sorghum almum). Recent insights in the protein-protein interactions of Polerovirus through protein interaction reporter (PIR) technology enable us to understand viral encoded proteins during virus replication, assembly, plant defence mechanism, short and long-distance travel of the virus. This review presents the recent understandings on virus biology, diagnosis, genetic diversity, virus-vector and host-virus interactions and conventional and next generation management approaches.

Opportunities and Challenges in Studies of Host-Pathogen Interactions and Management of Verticillium dahliae in Tomatoes

Tomatoes (Solanum lycopersicum L.) are a valuable horticultural crop that are grown and consumed worldwide. Optimal production is hindered by several factors, among which Verticillium dahliae, the cause of Verticillium wilt, is considered a major biological constraint in temperate production regions. V. dahliae is difficult to mitigate because it is a vascular pathogen, has a broad host range and worldwide distribution, and can persist in soil for years. Understanding pathogen virulence and genetic diversity, host resistance, and plant-pathogen interactions could ultimately inform the development of integrated strategies to manage the disease. In recent years, considerable research has focused on providing new insights into these processes, as well as the development and integration of environment-friendly management approaches. Here, we discuss the current knowledge on the race and population structure of V. dahliae, including pathogenicity factors, host genes, proteins, enzymes involved in defense, and the emergent management strategies and future research directions for managing Verticillium wilt in tomatoes.

Verticillium Wilt of Olive and its Control: What Did We Learn during the Last Decade?

Verticillium (Verticillium dahliae Kleb.) wilt is one of the most devastating diseases affecting olive (Olea europaea L. subsp. europaea var. europaea) cultivation. Its effective control strongly relies on integrated management strategies. Olive cultivation systems are experiencing important changes (e.g., high-density orchards, etc.) aiming at improving productivity. The impact of these changes on soil biology and the incidence/severity of olive pests and diseases has not yet been sufficiently evaluated. A comprehensive understanding of the biology of the pathogen and its populations, the epidemiological factors contributing to exacerbating the disease, the underlying mechanisms of tolerance/resistance, and the involvement of the olive-associated microbiota in the tree's health is needed. This knowledge will be instrumental to developing more effective control measures to confront the disease in regions where the pathogen is present, or to exclude it from V. dahliae-free areas. This review compiles the most recent advances achieved to understand the olive-V. dahliae interaction as well as measures to control the disease. Aspects such as the molecular basis of the host-pathogen interaction, the identification of new biocontrol agents, the implementation of "-omics" approaches to unravel the basis of disease tolerance, and the utilization of remote sensing technology for the early detection of pathogen attacks are highlighted.

Role of Fungicide Applications on the Integrated Management of Wheat Stripe Rust

First described in Europe in 1777, stripe rust (SR) caused by Puccinia striiformis Westend. f. sp. tritici Erikss (Pst) is one of the most important and destructive diseases of wheat worldwide. Until 2000, SR was mainly endemic to cooler regions, but since then, new aggressive strains have emerged, spread intercontinentally, and caused severe epidemics in warmer regions across the world. This has put SR as a disease that poses a threat to the world food security. At present, the preferred strategy for control of SR is the access to wheat cultivars with adequate levels of SR resistance. However, wheat breeding programs are not sufficiently advanced to cope with the recently emerged Pst strains. Under this scenario, foliar fungicide applications have become an important component of SR management, but information on the effects of fungicide applications on SR control and wheat cultivar yield response is scarce. This review seeks to provide an overview of the impact and role of fungicides on SR management. With focus on wheat management in the major wheat-growing regions of the world, the review addresses: (a) the efficacy of different fungicide active ingredients, optimal fungicide timing and number of applications in controlling SR, and (b) the impact of fungicide on wheat grain yield response. Inclusion of fungicides in an integrated crop management approach is discussed.

Current Knowledge on Pathogenicity and Management of Stemphylium botryosum in Lentils (Lens culinaris ssp. culinaris Medik)

Stemphylium blight (SB) caused by Ascomycete, Stemphylium botryosum Wallr. has been a serious threat to lentil cultivation, mainly in Bangladesh, Nepal, India, and Canada since its first outbreak in Bangladesh in 1986. The genus Stemphylium Wallr., a dematiaceous hyphomycete, comprises up to 150 species, and is pathogenic on a wide range of plants infecting leguminous as well as nonleguminous crops. In recent years, studies indicated overlapping in morphological characters among the different species under the genus Stemphylium, making the identification and description of species difficult. This necessitates different molecular phylogenetic analysis in species delimitation. Therefore, a detailed understanding of spatial diversity and population structure of the pathogen is pertinent for producing source material for resistance breeding. The role of different weather variables as predisposing factors for the rapid spread of the pathogen necessitates devising a disease predictive model for the judicial application of fungicides. A dearth of information regarding spore biology, epidemiology, race diversity, host-pathogen interaction, and holistic disease management approach necessitates immediate attention towards more intensive research efforts. This is the first comprehensive review on the current state of knowledge and research efforts being made for a better understanding of the SB resistance through cognizing biology, ecology, and epidemiology of S. botryosum and effective disease management strategies to prevent widespread outbreaks of SB. The information regarding the biology and epidemiology of S. botryosum is also crucial for strengthening the "Integrated Disease Management" (IDM) programme. The need for a regional research network is advocated where the disease is becoming endemic.

Global Dimensions of Plant Virus Diseases: Current Status and Future Perspectives

Viral diseases provide a major challenge to twenty-first century agriculture worldwide. Climate change and human population pressures are driving rapid alterations in agricultural practices and cropping systems that favor destructive viral disease outbreaks. Such outbreaks are strikingly apparent in subsistence agriculture in food-insecure regions. Agricultural globalization and international trade are spreading viruses and their vectors to new geographical regions with unexpected consequences for food production and natural ecosystems. Due to the varying epidemiological characteristics of diverent viral pathosystems, there is no one-size-fits-all approach toward mitigating negative viral disease impacts on diverse agroecological production systems. Advances in scientific understanding of virus pathosystems, rapid technological innovation, innovative communication strategies, and global scientific networks provide opportunities to build epidemiologic intelligence of virus threats to crop production and global food security. A paradigm shift toward deploying integrated, smart, and eco-friendly strategies is required to advance virus disease management in diverse agricultural cropping systems.

Wheat blast: from its origins in South America to its emergence as a global threat

Wheat blast was first reported in Brazil in 1985. It spread rapidly across the wheat cropping areas of Brazil to become the most important biotic constraint on wheat production in the region. The alarming appearance of wheat blast in Bangladesh in 2016 greatly increased the urgency to understand this disease, including its causes and consequences. Here, we summarize the current state of knowledge of wheat blast and aim to identify the most important gaps in our understanding of the disease. We also propose a research agenda that aims to improve the management of wheat blast and limit its threat to global wheat production.

The Effect of Integration of Self-Management Web Platforms on Health Status in Chronic Obstructive Pulmonary Disease Management in Primary Care (e-Vita Study): Interrupted Time Series Design

Background

Worldwide nearly 3 million people die from chronic obstructive pulmonary disease (COPD) every year. Integrated disease management (IDM) improves quality of life for COPD patients and can reduce hospitalization. Self-management of COPD through eHealth is an effective method to improve IDM and clinical outcomes.

Objectives

The objective of this implementation study was to investigate the effect of 3 chronic obstructive pulmonary disease eHealth programs applied in primary care on health status. The e-Vita COPD study compares different levels of integration of Web-based self-management platforms in IDM in 3 primary care settings. Patient health status is examined using the Clinical COPD Questionnaire (CCQ).

Methods

The parallel cohort design includes 3 levels of integration in IDM (groups 1, 2, 3) and randomization of 2 levels of personal assistance for patients (group A, high assistance, group B, low assistance). Interrupted time series (ITS) design was used to collect CCQ data at multiple time points before and after intervention, and multilevel linear regression modeling was used to analyze CCQ data.

Results

Of the 702 invited patients, 215 (30.6%) registered to a platform. Of these, 82 participated in group 1 (high integration IDM), 36 in group 1A (high assistance), and 46 in group 1B (low assistance); 96 participated in group 2 (medium integration IDM), 44 in group 2A (high assistance) and 52 in group 2B (low assistance); also, 37 participated in group 3 (no integration IDM). In the total group, no significant difference was found in change in CCQ trend (P=.334) before (–0.47% per month) and after the intervention (–0.084% per month). Also, no significant difference was found in CCQ changes before versus after the intervention between the groups with high versus low personal assistance. In all subgroups, there was no significant change in the CCQ trend before and after the intervention (group 1A, P=.237; 1B, P=.991; 2A, P=.120; 2B, P=.166; 3, P=.945).

Conclusions

The e-Vita eHealth-supported COPD programs had no beneficial impact on the health status of COPD patients. Also, no differences were found between the patient groups receiving different levels of personal assistance.

Trial Registration

Netherlands Trial Registry NTR4098; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4098 (Archived by WebCite at http://www.webcitation.org/6sbM5PayG)

Impact of a Post-Discharge Integrated Disease Management Program on COPD Hospital Readmissions

BACKGROUND

Readmission following a hospitalization for COPD is associated with significant health-care expenditure.

METHODS

A multicomponent COPD post-discharge integrated disease management program was implemented at the Cleveland Clinic to improve the care of patients with COPD and reduce readmissions. This retrospective study reports our experience with the program. Groups of subjects who were exposed to different components of the program were compared regarding their readmission rates. Multivariate logistic regression analysis was performed to build predictive models for 30- and 90-d readmission.

RESULTS

One hundred sixty subjects completed a 90-d follow-up, of which, 67 attended the exacerbation clinic, 16 subjects received care coordination, 51 subjects completed both, and 26 subjects did not participate in any component despite referral. Thirty- and 90-d readmission rates for the entire group were 18.1 and 46.2%, respectively. Thirty- and 90-d readmission rates for the individual groups were: exacerbation clinic, 11.9 and 35.8%; care coordination, 25.0 and 50.0%; both, 19.6 and 41.2%; and neither, 26.9 and 80.8%, respectively. The model with the best predictive ability for 30-d readmission risk included the number of hospitalizations within the previous year and use of noninvasive ventilation (C statistic of 0.84). The model for 90-d readmission risk included receiving any component of the post-discharge integrated disease management program, the number of hospitalizations, and primary care physician visits within the previous year (C statistic of 0.87).

CONCLUSIONS

Receiving any component of a post-discharge integrated disease management program was associated with reduced 90-d readmission rate. Previous health-care utilization and lung function impairment were strong predictors of readmission.

High Level of Integration in Integrated Disease Management Leads to Higher Usage in the e-Vita Study: Self-Management of Chronic Obstructive Pulmonary Disease With Web-Based Platforms in a Parallel Cohort Design

Background

Worldwide, nearly 3 million people die of chronic obstructive pulmonary disease (COPD) every year. Integrated disease management (IDM) improves disease-specific quality of life and exercise capacity for people with COPD, but can also reduce hospital admissions and hospital days. Self-management of COPD through eHealth interventions has shown to be an effective method to improve the quality and efficiency of IDM in several settings, but it remains unknown which factors influence usage of eHealth and change in behavior of patients.

Objective

Our study, e-Vita COPD, compares different levels of integration of Web-based self-management platforms in IDM in three primary care settings. The main aim of this study is to analyze the factors that successfully promote the use of a self-management platform for COPD patients.

Methods

The e-Vita COPD study compares three different approaches to incorporating eHealth via Web-based self-management platforms into IDM of COPD using a parallel cohort design. Three groups integrated the platforms to different levels. In groups 1 (high integration) and 2 (medium integration), randomization was performed to two levels of personal assistance for patients (high and low assistance); in group 3 there was no integration into disease management (none integration). Every visit to the e-Vita and Zorgdraad COPD Web platforms was tracked objectively by collecting log data (sessions and services). At the first log-in, patients completed a baseline questionnaire. Baseline characteristics were automatically extracted from the log files including age, gender, education level, scores on the Clinical COPD Questionnaire (CCQ), dyspnea scale (MRC), and quality of life questionnaire (EQ5D). To predict the use of the platforms, multiple linear regression analyses for the different independent variables were performed: integration in IDM (high, medium, none), personal assistance for the participants (high vs low), educational level, and self-efficacy level (General Self-Efficacy Scale [GSES]). All analyses were adjusted for age and gender.

Results

Of the 702 invited COPD patients, 215 (30.6%) registered to a platform. Of the 82 patients in group 1 (high integration IDM), 36 were in group 1A (personal assistance) and 46 in group 1B (low assistance). Of the 96 patients in group 2 (medium integration IDM), 44 were in group 2A (telephone assistance) and 52 in group 2B (low assistance). A total of 37 patients participated in group 3 (no integration IDM). In all, 107 users (49.8%) visited the platform at least once in the 15-month period. The mean number of sessions differed between the three groups (group 1: mean 10.5, SD 1.3; group 2: mean 8.8, SD 1.4; group 3: mean 3.7, SD 1.8; P=.01). The mean number of sessions differed between the high-assistance and low-assistance groups in groups 1 and 2 (high: mean 11.8, SD 1.3; low: mean 6.7, SD 1.4; F1,80=6.55, P=.01). High-assistance participants used more services (mean 45.4, SD 6.2) than low-assistance participants (mean 21.2, SD 6.8; F1,80=6.82, P=.01). No association was found between educational level and usage and between GSES and usage.

Conclusions

Use of a self-management platform is higher when participants receive adequate personal assistance about how to use the platform. Blended care, where digital health and usual care are integrated, will likely lead to increased use of the online program. Future research should provide additional insights into the preferences of different patient groups.

Trial Registration

Nederlands Trial Register NTR4098; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4098 (Archived by WebCite at http://www.webcitation.org/6qO1hqiJ1)

Management of Powdery Mildew in Squash by Plant and Alga Extract Biopesticides

Although many fungicides are registered for use to control powdery mildew on cucurbits, management of resistance to fungicides in pathogen populations still remains a major challenge. Two biopesticides Regalia SC and HMO 736 were evaluated in the greenhouse and field for their efficacy against powdery mildew in squash. In greenhouses, Regalia SC alone significantly (P < 0.05) reduced powdery mildew compared to the nontreated control, and was as effective as the chemical standard Procure 480SC (triflumizole). In alternation with Procure 480SC, Regalia SC demonstrated greater or equivalent effects on reducing the disease. HMO 736 alone showed varying levels of disease control, but alternating with Procure 480SC significantly improved control efficacy. In addition, application of Regalia SC or HMO 736 each in alternation with Procure 480SC significantly increased the chlorophyll content in leaves and the total fresh weight of squash plants, when compared with the water control, Regalia SC and HMO 736 alone. In field trials, application of Regalia SC and HMO 736 each alone significantly reduced disease severity in one of two field trials during the early stage of disease development, but not during later stages when disease pressure became high. Both Regalia SC and HMO 736 each applied in alternation with Procure 480SC significantly improved the control efficacy compared to Procure 480SC alone. Results from this study demonstrated that an integrated management program can be developed for powdery mildew in squash by integrating the biopesticides Regalia SC, HMO 736 with the chemical fungicide Procure 480SC.

An eHealth Platform to Manage Chronic Disease in Primary Care: An Innovative Approach

The number of individuals with chronic illness and multimorbidity is growing due to the rapid ageing of the population and the greater longevity of individuals. This causes an increasing workload in care, which results in a growing need for structural changes of the health care system. In recent years this led to a strong focus on promoting "self-management" in chronically ill patients. Research showed that patients who understand more about their disease, health, and lifestyle have better experiences and health outcomes, and often use less health care resources; the effect is even more when these patients are empowered to and responsible for managing their health and disease. In addition to the skills of patients, health care professionals need to shift to a role of teacher, partner, and professional supervisor of their patients. One way of supervising patients is by the use of electronic health (eHealth), which helps patients manage and control their disease. The application of eHealth solutions can provide chronically ill patients high-quality care, to the satisfaction of both patients and health care professionals, alongside a reduction in health care consumption and costs.

Development of an Integrated Approach for Managing Bacterial Wilt and Root-Knot on Tomato Under Field Conditions

A 2-year field study was conducted to develop a field application method using thymol as a preplant soil treatment for controlling bacterial wilt and root-knot nematode on tomato (Lycopersicon esculentum). In addition, acibenzolar-S-methyl (ASM), which induces plant systemic resistance, was applied in conjunction with thymol to determine whether combining these tactics could improve bacterial wilt management. The test sites were artificially infested with Ralstonia solanacearum and Meloidogyne arenaria, and thymol was applied as preplant fumigation through drip irrigation lines under polyethylene mulch at a rate of 73 kg/ha in both 2004 and 2005. ASM was applied primarily as foliar spray at a concentration of 25 mg/liter. Application of thymol significantly reduced incidence of bacterial wilt on tomato in both years of the trial. In thymol-treated plots, 26.0 and 22.6% of the plants wilted in 2004 and 2005, respectively; whereas, in untreated plots, more than 95% of the plants wilted in each year. Number of root-knot nematode juveniles was significantly reduced in field plots treated with thymol and ASM for both years. The combined use of thymol and ASM provided the greatest reduction of root galling among the treatments. Tomato yield (cv. FL47) was evaluated only in the 2005 trial; thymol-treated plots produced significantly higher marketable yield than untreated plots, and the thymol treatment in combination with ASM significantly increased tomato yield compared with thymol or ASM alone. These results indicate that use of thymol and ASM was beneficial in controlling bacterial wilt and root-knot. We developed an effective method for applying thymol through drip irrigation lines for managing these diseases in tomato production.

Effects of Reduced Tillage, Resistant Cultivars, and Reduced Fungicide Inputs on Progress of Early Leaf Spot of Peanut (Arachis hypogaea)

Field experiments were conducted in 2000 and 2001 on Georgia Green, Florida MDR-98, and C-99R peanut (Arachis hypogaea) cultivars in Tifton, GA, to determine the effects of tillage practices on early leaf spot (Cercospora arachidicola) epidemics under standard fungicide regimes and fungicide regimes with fewer applications. Leaf spot epidemics were suppressed in reduced tillage (strip-till) plots compared with conventional tillage plots and were suppressed in MDR-98 and C-99R cultivars compared with the standard runner-type cultivar, Georgia Green. Within tillage and cultivar combinations, leaf spot intensity typically was lower in plots treated with fungicides at standard intervals (seven total applications) than in those treated at extended intervals (four total applications). However, in most cases, leaf spot control in extended interval treatments in the strip-till system was comparable to that in the standard interval treatments in conventional tillage. Based on these results, the number of fungicide applications could be reduced without compromising control of leaf spot when reduced tillage is used, especially if combined with moderately resistant cultivars. Suppression of leaf spot epidemics in the strip-till plots did not coincide with higher yields in either year. In 2001, yields were lower in strip-till plots than in conventional tillage plots. Yields were typically higher in the cultivar C-99R than in Georgia Green, regardless of the tillage treatment.

Effect of Growth Stage on Susceptibility of Grape Berry and Rachis Tissues to Infection by Phomopsis viticola

Intact 'Seyval' grape clusters in the greenhouse and 'Catawba' clusters in the field were inoculated with conidia of Phomopsis viticola at seven Eichorn-Lorenz growth stages between 12 (prebloom) and 35 (véraison) in 1998. Five pots (10 clusters) were used per inoculation, and the experiment was repeated three times. Also, 10 to 20 randomly selected Catawba clusters were inoculated in the field for each of three replications at each growth stage. Studies were repeated in 1999. In addition, Chambourcin clusters were also inoculated at four growth stages in the greenhouse in 1999. Results obtained in the greenhouse and field during both years and for all cultivars indicate that berry and rachis infections can occur at all growth stages between 12 and 35 with no evidence of decreasing susceptibility over time. Results disagree with some literature reports that indicate that berry infection occurs primarily during bloom and shortly after bloom, and susceptibility decreases as fruit matures.

Evaluation of a Disease Warning System for Downy Mildew of Grapes

An electronic warning system for grape downy mildew- based on models for the infection of leaves of Vitis lambrusca, production of sporangia by Plasmopara viticola in lesions, and sporangial survival-was tested over 7 years in Ohio. Grapevines were sprayed with metalaxyl plus mancozeb (Ridomil MZ58) when the warning system indicated that environmental conditions were favorable for sporulation and subsequent infection. Over the 7 years, plots were sprayed from one to four times according to the warning system, and from four to 10 times according to the standard calendar-based schedule (depending on the date of the initiation of the experiment). The warning system resulted in yearly reductions of one to six sprays (with median of three sprays). Disease incidence (i.e., proportion of leaves with symptoms) in unsprayed plots at the end of the season ranged from 0 to 86%, with a median of 68%. Incidence generally was very similar for the warning-system and standard-schedule treatments (median of 7% of the leaves with symptoms), and both of these incidence values were significantly lower (P < 0.05) than that found for the unsprayed control, based on a generalized-linear-model analysis. Simplifications of the disease warning system, where sprays were applied based only on the infection or sporulation components of the system, were also effective in controlling the disease, although more fungicide applications sometimes were applied. Effective control of downy mildew, therefore, can be achieved with the use of the warning system with fewer sprays than a with a standard schedule.