Pathogenicity of four fungal strains, two of Beauveria bassiana (designated as BB-72 and BB-252), and two of Lecanicillium lecanii (designated as V-4 and CS-625) to green peach aphid, Myzus persicae Sulzer (Homoptera: Aphididae) was assessed. All treatments showed highly significant effects on the mortality of the aphid when applied as filtrate or conidia. The application methods did not have a significant effect on the mortality rate. The overall mortalities caused by both applications were statistically similar. The maximum overall mortality was caused by BB-72, followed by CS-625 in both application methods. On the other hand, (V-4) caused the minimum mortality rate, followed by (BB-252), which was statistically similar to those caused by V-4. The time also had significant effects on aphid mortality rates. The mortality was the minimum after 3 days reaching its maximum after 10 days. As the number of days increased, there was a corresponding increase in the mortality showing a direct relationship between mortality and time. The maximum mean individual mortality of 95% was caused by CS-625, followed by BB-72 (92%) after 10 days with the conidial application. Similarly, the combined effects of the three most virulent fungal strains showed highly significant differences on the mortality of peach aphid. The combination BB-72 + BB-252 showed the highest percent mortality, followed by BB-72 + BB-252 + CS-625. The combinations BB-72 + CS-625 and BB-252 + CS-625 had statistically similar effects of causing aphid mortality.

The Cucumber aphid (Myzus persicae), a destructive cucumber aphid usually managed by chemical pesticides, is responsible for enormous annual agricultural losses. A protein elicitor, PeBL1, was investigated in the present work for its ability to induce a defense response against M. persicae in cucumber. The rates of population growth (Intrinsic rate of increase) of M. persicae (second and third generations) decreased with PeBL1-treated cucumber seedlings as compared to positive (water) and negative 70.58 μg mL−1 controls (50 mM Tris-HCl, pH 8.0). In an assay on host selection, M. persicae had a preference for colonizing control plants as compared to the PeBL1-treated cucumber seedlings. The nymphal development time of the aphid was extended with the PeBL1-treated cucumber seedlings. Likewise, fecundity was reduced, with less offspring produced in the PeBL1-treated cucumber seedlings as compared to the positive (water) and negative 70.58 μg mL−1 controls (50 mM Tris-HCl, pH 8.0). The cucumber leaves treated with PeBL1 had a hazardous surface environment for M. persicae, caused by trichomes and wax formation. Jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) levels were significantly higher, exhibiting significant accumulation in the PeBL1-treated cucumber seedlings. The following results showed that PeBL1 considerably altered the height of the cucumber plant and the surface structure of the leaves to minimize M. persicae reproduction, and it prevented colonization. Defensive processes also included the activation of pathways (JA, SA, and ET). This study provides evidence of biocontrol for the use of PeBL1 in cucumber defense against M. persicae.

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Eggplant shoot and fruit borer (ESFB), Leucinodes orbonalis Guenee, a destructive pest of eggplant (Solanum melongena L.), adversely affects quality and yield of eggplant fruit throughout the world. Currently, its management is mainly relied on insecticides which are inimical to humans, livestock and environment. To get rid of the pernicious consequences of chemicals, use of alternative non-chemical approaches has been emphasized. Ergo, in the present study non-chemical methods viz. hoeing, clipping of damaged fruits and shoots and weeding at weekly intervals and a biocontrol agent Trichogramma chilonis individually and in combination were assessed for the management of ESFB. All the treatments though varied in their efficacies, caused significant reductions in infestation of ESFB and increased yield as compared to control. Combination of practices gave better results as compared to individual treatments with few exceptions. In general, the combined treatment (T. chilonis + hoeing + clipping) was found to be the most effective in reducing pest infestations and increasing yield followed by another combined treatment where hoeing, clipping and weeding were applied conjointly. Application of T. chilonis singly was the least effective treatment; however, incorporation of T. chilonis with other practices gave good results. Similarly, integration of hoeing with clipping of infested shoots and fruits at weekly intervals also proved satisfactory in reducing pest infestation and enhancing yield. It is concluded that integration of non-chemical approaches will help reduce infestation of ESFB significantly and will make a major contribution to both climate-change mitigation and sustainable crop production systems.

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