Surtos por Stomoxys calcitrans em gado de corte no Mato Grosso do Sul

Stable fly outbreaks in Brazil: a 50-year (1971-2020) retrospective

Over the last decades, stable fly (Stomoxys calcitrans) outbreaks associated with agricultural and/or livestock production systems have become a serious problem in some Brazilian locations. This article presents a survey on the history, evolution and mapping of such outbreaks in Brazil over five decades (1971-2020). Outbreaks (n= 579) were recorded in 285 municipalities from 14 states, mainly associated with by-products from the ethanol industry (82.7%), in natura organic fertilizers (12.6%) and integrated crop-livestock systems (3.1%). Few cases were reported until the mid-2000s, progressively increasing since then. Outbreaks associated with ethanol mills occurred in 224 municipalities, mainly in Southeast and Midwest states, while those associated with organic fertilizers (mainly poultry litter and coffee mulch) affected 39 municipalities, mostly in the Northeast and Southeast states. More recently, outbreaks in integrated crop-livestock systems during the rainy season have occurred in Midwest states. This survey highlights the magnitude of the problem of stable fly outbreaks in Brazil and its relationship with environmental public policies, agricultural production chains and regional trends. Specific public actions and policies are urgently needed to prevent their occurrence and impact in the affected regions.

Evaluation in vitro of the virulence of two entomopathogenic heterorhabditid nematodes in the control of Stomoxys calcitrans (Diptera: Muscidae) larvae in byproducts of the sugar and alcohol industry

Stomoxys calcitrans causes losses to livestock, mainly to cattle. This study aimed to determine the pathogenic potential of Heterorhabditis bacteriophora HP88 and H. baujardi LPP7 against S. calcitrans larvae after being exposed to byproducts of the sugar and alcohol industry. The efficacy of EPNs on stable fly larvae was evaluated in bioassays with vinasse at three temperatures (16, 25 and 35 °C) and concentrations (0, 50 and 100%), as well as in relation to larva age (4, 6 and 8 days) in filter cake and EPNs concentration (100, 300 and 500 IJs/larva) in sugarcane bagasse. H. bacteriophora showed higher efficacy than H. baujardi at all temperatures. Vinasse did not have a negative effect on the virulence of H. bacteriophora. The age of fly larvae did not affect the mortality rates caused by the EPNs. In bagasse, H. bacteriophora presented higher mortality rates than the control group. It is concluded that EPNs can be a potential component in integrated strategies of stable fly control and outbreak prevention in areas of sugar and alcohol production.

Semi-field evaluation of the predation of Macrocheles embersoni and Macrocheles muscaedomesticae (Acari: Mesostigmata: Macrochelidae) on the house fly and the stable fly (Diptera: Muscidae)

BACKGROUND

The house fly, Musca domestica L., and the stable fly, Stomoxys calcitrans (L.), are important and harmful organisms. The cosmopolitan house fly is not parasitic, but the adults are annoying and a known vector of several pathogens. The importance of the stable fly has increased in Brazil in the last 40 years, after major changes in sugarcane cultivation practices were implemented, including the widespread application of vinasse (byproduct in sugarcane mills) and the parallel reduction of sugarcane preharvest burning. These changes have favored the development of this fly, which can reach high populations, that can negatively affect cattle and other animals. The control of these flies relies heavily on the use of chemical products, which very often do not provide adequate population reduction. Predatory mites of the family Macrochelidae have been evaluated under laboratory conditions for the biological control of these organisms, especially of the house fly. The objective of this study was to examine the predation capacity of the macrochelids Macrocheles embersoni Azevedo, Castilho & Berto and Macrocheles muscaedomesticae (Scopoli) on the house fly and the stable fly, under semi-field conditions (screen-houses).

RESULTS

Reductions of 83 to 90% of the house fly and 66 to 73% of the stable fly populations were observed, with the release of 100 of these predators per square meter.

CONCLUSIONS

The number of adults of both fly species was much lower in the units where the predators had been released than in the others. However it is suggested that provisioning and or conserving alternative food sources for these macrochelids, such as free-living nematodes, could further improve biocontrol efficacy.

Retrospective analysis of the lifetime endocrine response of southern right whale calves to gull wounding and harassment: A baleen hormone approach

Physiological measurements are informative in assessing the relative importance of stressors that potentially impact the health of wildlife. Kelp Gulls, Larus dominicanus (KG), resident to the region of Península Valdés, Argentina, have developed a unique behavior of landing on the backs of southern right whale adults and calves, Eubalaena australis (SRW), where they feed on their skin and blubber. This parasitic behavior results in large open wounds on the dorsal surface of the whale. Coincidently, the SRW population off the coast of Península Valdés has experienced elevated calf mortality. We quantified levels of glucocorticoids and thyroid hormone extracted from baleen of dead calves to evaluate, retrospectively, the endocrine response of whale calves to gull wounding and harassment. Baleen accumulates hormones as it grows, allowing evaluation of long-term trends in physiological condition. While glucocorticoids (GCs) are known to increase in response to stressors such as disturbance, the metabolic hormone triiodothyronine (T₃) has been shown to decrease under sustained food deprivation but is largely unaffected by disturbance stress. We quantified lifetime patterns of GCs and T₃ in baleen recovered at necropsy from 36 southern right whale calves with varying severity of wounding from KGs. GC levels in baleen correlated positively with the degree of wounding, while T₃ levels remained stable irrespective of the severity of the wounding. Our results suggest no evidence of malnutrition in low vs. severely wounded whales. However, the positive correlation of GCs with wound severity indicates that heavily wounded calves are suffering high levels of physiological stress before they die. This suggests that KG wounding may have contributed to the high southern right whale calf mortality observed in the Península Valdés region of Argentina.

Stomoxys calcitrans (Diptera: Muscidae) outbreaks: current situation and future outlook with emphasis on Brazil

The stable fly (Stomoxys calcitrans) has historically been a pest of dairy cattle and feedlots due to the availability of decaying plant matter mixed with animal excrements in such production systems. In the last few decades, stable fly outbreaks have also been reported in pasture-raised beef cattle, usually associated with wastes accumulated from animal feeding during winter, the introduction of large-scale crop operations near cattle ranches, and/or the inadvertent use of organic fertilizers. Population explosions of Stomoxys flies may also have natural causes, affecting not only domestic and/or wild animals but also humans. This article compiles information on stable fly outbreaks in Brazil and abroad and discusses their causes and consequences.

Identification of stable fly attractant compounds in vinasse, a byproduct of sugarcane-ethanol distillation

The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is a worldwide pest of livestock. Recent outbreaks of stable flies in sugarcane fields in Brazil have become a serious problem for livestock producers. Larvae and pupae found inside sugarcane stems after harvesting may indicate that stable flies use these stems as potential oviposition or larval development sites. Field observations suggest that outbreaks of stable flies are associated with the vinasse and filter cake derived from biomass distillation in sugarcane ethanol production that are used as fertilizers in sugarcane fields. Adult stable flies are attracted to vinasse, which appears to present an ideal larval development site. The primary goal of the present study is to demonstrate the role of vinasse in influencing the sensory physiological and behavioural responses of stable flies, and to identify its associated volatile attractant compounds. Both laboratory and field studies showed that vinasse is extremely attractive to adult stable flies. Chemical analyses of volatiles collected revealed a wide range of carboxylic acids, alcohols, phenols and aldehydes as potential attractant compounds. These newly identified attractants could be used to develop a tool for the attractant-baited mass trapping of stable flies in order to reduce infestations.

Increased Wounding of Southern Right Whale (Eubalaena australis) Calves by Kelp Gulls (Larus dominicanus) at Península Valdés, Argentina

At least 626 southern right whale (Eubalaena australis) calves died at the Península Valdés calving ground, Argentina, between 2003 and 2014. Intense gull harassment may have contributed to these deaths. In the 1970s, Kelp Gulls (Larus dominicanus) began feeding on skin and blubber pecked from the backs of living right whales at Valdés. The frequency of gull attacks has increased dramatically over the last three decades and mother-calf pairs are the primary targets. Pairs attacked by gulls spend less time nursing, resting and playing than pairs not under attack. In successive attacks, gulls open new lesions on the whales' backs or enlarge preexisting ones. Increased wounding could potentially lead to dehydration, impaired thermoregulation, and energy loss to wound healing. The presence, number and total area of gull-inflicted lesions were assessed using aerial survey photographs of living mother-calf pairs in 1974-2011 (n = 2680) and stranding photographs of dead calves (n = 192) in 2003-2011. The percentage of living mothers and calves with gull lesions increased from an average of 2% in the 1970s to 99% in the 2000s. In the 1980s and 1990s, mothers and calves had roughly equal numbers of lesions (one to five), but by the 2000s, calves had more lesions (nine or more) covering a greater area of their backs compared to their mothers. Living mother-calf pairs and dead calves in Golfo Nuevo had more lesions than those in Golfo San José in the 2000s. The number and area of lesions increased with calf age during the calving season. Intensified Kelp Gull harassment at Península Valdés could be compromising calf health and thereby contributing to the high average rate of calf mortality observed in recent years, but it cannot explain the large year-to-year variance in calf deaths since 2000.

Reassessment of the potential economic impact of cattle parasites in Brazil

The profitability of livestock activities can be diminished significantly by the effects of parasites. Economic losses caused by cattle parasites in Brazil were estimated on an annual basis, considering the total number of animals at risk and the potential detrimental effects of parasitism on cattle productivity. Estimates in U.S. dollars (USD) were based on reported yield losses among untreated animals and reflected some of the effects of parasitic diseases. Relevant parasites that affect cattle productivity in Brazil, and their economic impact in USD billions include: gastrointestinal nematodes - $7.11; cattle tick (Rhipicephalus (Boophilus) microplus) - $3.24; horn fly (Haematobia irritans) - $2.56; cattle grub (Dermatobia hominis) - $0.38; New World screwworm fly (Cochliomyia hominivorax) - $0.34; and stable fly (Stomoxys calcitrans) - $0.34. The combined annual economic loss due to internal and external parasites of cattle in Brazil considered here was estimated to be at least USD 13.96 billion. These findings are discussed in the context of methodologies and research that are required in order to improve the accuracy of these economic impact assessments. This information needs to be taken into consideration when developing sustainable policies for mitigating the impact of parasitism on the profitability of Brazilian cattle producers.

Abundância de Stomoxys calcitrans (Diptera: Muscidae) em diferentes subprodutos canavieiros

Um aumento na abundância de Stomoxys calcitrans tem sido observado em áreas de produção sucroalcooleira devido aos subprodutos orgânicos resultantes desta atividade. O objetivo do presente estudo foi avaliar a abundância desta espécie em diferentes subprodutos da cana-de-açúcar. De janeiro a dezembro de 2011, a abundância de S. calcitrans foi monitorada em quatro subprodutos: bagaço, palha, torta de filtro (TF) e palha com vinhaça (PV), em uma usina sucroalcooleira no município de Angélica, Mato Grosso do Sul, Brasil. Mensalmente, 20 armadilhas de emergência foram distribuídas em cada substrato, mantidas ativas por quatro semanas. Durante todo o período de estudo, 4.049 espécimes de S. calcitrans foram coletados nos diferentes substratos, representando 9,22% do total de dípteros capturados nas armadilhas. Os quatro subprodutos amostrados apresentaram significativas diferenças em relação à abundância de S. calcitrans, sendo maior na TF (67,20%) e na PV (29,19%). Picos de abundância foram observados em junho (PV) e outubro (PV e TF). Maior produtividade de S. calcitrans foi observada na TF (55,8 moscas/mII) e na PV (24,2 moscas/mII), com produção média mensal de S. calcitrans na usina estimada em 37 mil e 24 milhões, respectivamente. A elevada capacidade de reprodução da S. calcitrans em subprodutos da usina explica as explosões populacionais desta espécie, ocorridas recentemente em fazendas pecuárias próximas a usinas sucroalcooleiras.

Sugarcane stems as larval habitat for the stable fly (Stomoxys calcitrans) in sugarcane plantations

Outbreaks of stable fly, Stomoxys calcitrans, cause losses for livestock producers located near sugarcane mills in Brazil, especially in southern Mato Grosso do Sul. The sugarcane mills are often pointed by local farmers as the primary source of these outbreaks; some mills also joined the farmers in combating the flies. Brazilian beef cattle production has great economic importance in similar level to bio-fuel production as ethanol. In this context, the wide-ranging knowledge on the biology and ecology of the stable fly, including larval habitats and their reproduction sites is extremely important for further development of control programs. This paper aims to report the occurrence and development of S. calcitrans larvae inside sugarcane stems in three municipalities of Mato Grosso do Sul. The sugarcane stems give protection against bad weather conditions and insecticide application. In this way, for sustainable sugarcane growth specific research concerning this situation should be conducted.