Effect of Storage Technologies on Postharvest Insect Pest Control and Seed Germination in Mexican Maize Landraces

Insecticidal and Repellent Activity of Plant Powders on the Weevil (Sitophilus zeamais) in Stored Corn Grains in a Rural Community of Oaxaca, Mexico

The bioinsecticidal and repellent effect of four plant powders (Chenopodium ambrosioides, Piper auritum, Laurus nobilis, and Origanum vulgare) was evaluated in the control of Sitophilus zeamais adults in corn grains stored in the rural community of Santa María Zacatepec, Oaxaca, Mexico. Using completely randomized experimental designs, concentrations of 1%, 2%, and 3% by mass of corn grains infested with adults of S. zeamais were tested; the controls were corn without powder and aluminum phosphide. The analysis was performed using ANOVA with Tukey's post hoc and Student's t-tests. The highest mortality (>80%) and repellent effect (Repellent Index < 0.3) that were statistically significant were obtained with C. ambrosioides and P. auritum at 3%. Both plant species have the potential for weevil control in stored corn and represent a friendly alternative for the environment and public health in the rural community where the study was conducted.

Impact of storage technologies and duration on insect pest population, post-harvest losses, and seed quality of stored chickpea in Ethiopia

Chickpea (Cicer arietinum L.) is the most important winter season food legume in Ethiopia. Despite being a major producer and consumer of chickpeas, Ethiopia experiences lower yields due to biotic and abiotic stresses, particularly insect pest infestations during storage. This study aimed to evaluate the impact of different storage technologies and durations on the losses of stored chickpea seeds in terms of both quantity and quality. The experiment involved five storage technologies and three durations, spanning a period of 6 months, with data collected at 2-month intervals. The results showed that the Purdue Improved Crop Storage (PICS) and Super GrainPro (SGP) bags effectively maintained intergranular temperature, seed moisture content, and relative humidity throughout the storage period, followed by the modified hermetic metal silo. In contrast, traditional bags exhibited a significant increase in these parameters. The PICS and SGP bags also exhibited the lowest numbers of total insect pests after 6 months, while the jute bags had the highest infestation. Common insect species found in the stored chickpea seeds were Callosobruchus chinensis (L.), Sitophilus oryzae (L.), and Tribolium confusum (duVal). Furthermore, hermetic bags (PICS and SGP) demonstrated the least grain damage and weight loss, while jute bags had relatively higher values. Seed viability was well maintained in hermetic bags but significantly decreased in traditional bags. Overall, hermetic storage technologies, such as the PICS and SGP bags, effectively suppressed insect development, reduced losses, and preserved seed viability without the need for insecticides. It is recommended that farmers use these hermetic storage bags after proper drying to enhance food security and income generation. By implementing these recommendations, Ethiopia can enhance its chickpea storage practices, reduce post-harvest losses, and contribute to improved food security and economic sustainability in the chickpea sector. © 2023 Society of Chemical Industry.

Insecticidal property of Ocimum essential oil embedded polylactic acid packaging films for control of Sitophilus oryzae and Callosobruchus chinensis

Naturally derived essential oils (EOs) from Ocimum basilicum (OB) and Ocimum gratissimum (OG) were incorporated in polylactic acid (PLA) matrix with concentration of 2.5 % and 5 % respectively by solvent casting method, with an aim to develop insecticidal polymer pouches (insect proof polymer pouches). The major components following GC-MS analysis revealed the presence of EOs as estragole (69.998 %) in OB and thymol (29.843 %) in OG. The developed films with EOs showed remarkable insecticidal activity with 100 % and 80 % mortality rate for OB and OG respectively at 2.5 % concentration against rice weevil (Sitophilus oryzae). While, both OB and OG EOs observed 100 % mortality against pulse beetle (Callosobruchus chinensis) after 96 h exposure in presence of grain conditions and the insecticidal efficacy was equivalent to the commercial hermetic bags (CSB). The physical property of film showed increase in the film thickness in EO-PLA films whereas the mechanical properties of EO-PLA films matrix have increased the polymer flexibility with decreasing tensile strength (TS) and Youngs modulus (EM) as TS OB 5 %, OG 5 % - 15.64 MPa, 17.66 MPa respectively. While, water vapour transmission rate (WVTR) was reduced to 0.015 g/m2.hr, optical characteristics showed slight significant change in colour and FTIR spectra exhibited a change in -OH stretching compared to blank PLA matrix. The surface morphology of the blank and EO embedded PLA films visualized by SEM depicted a complete homogenization of essential oils in the PLA matrix.

Landrace and GM maize cultivars' selection choices among rural farming households in the Eastern Cape Province, South Africa

Maize plays a significant role among rural farming households in South Africa. The study therefore estimated the drivers of maize cultivars' selection choices among rural farming households focusing on the commonly grown cultivars from the study area (Landrace and genetically modifies [GM] maize). A cross-sectional survey of 650 respondents randomly selected from Port St Johns and King Sabata Dalindyebo Local Municipalities of the Eastern Cape Province of South Africa were used. Descriptive results revealed that a significant number of the respondents from the study area (65%) were growing Landrace maize cultivars, followed by GM maize (31%), improved OPVs (3%) and conventional hybrids (1%). Multivariate Probit regression estimates show that GM maize cultivars' selection is positively influenced by the amount of rainfall (1% level), household size (5% level), education (1% level), size of arable land (10% level) and access to cell phones (5% level), whilst negatively influenced by the employment status (5%). Conversely, the selection of Landrace maize cultivars is negatively influenced by the of amount rainfall (1% level), education (1% level), income (10% level), access to cell phone (10% level) and radio (10% level) whilst positively influenced by the number of livestock (5% level). The study therefore argues that GM maize cultivars may be meaningfully promoted in high rainfall areas, focusing on arable land sizes and targeted awareness campaigns. The promotion of Landrace maize cultivars may be targeted in low rainfall areas in a mixed farming setting to enhance the complementarity of maize and livestock.