Cell-free supernatant of Photorhabdus luminiscens was converted to nanoparticles (NPs) using a spray dryer fitted with ultrasonic nozzle. NPs were characterized by both scanning electron microscopy and zeta size analyser, and found to have average particle diameter of 89 nm. While converting to NPs, gum arabica @ 3% was used to eliminate hygroscopic property. Nanoparticulated supernatant exhibited superior pesticidal property against serious sucking pests of cotton, viz.

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Background: Pigeonpea is an important pulse-cum-grain legume crop of India. Major constraint in its production is the insects damage. Pod fly, Melanagromyza obtusa is of regular occurrence in South and Central India causing yield loss to the tune of 60 to 80 per cent particularly in late maturing pigeonpea crop. Due to its feeding habit as an internal borer, cultural, biological and mechanical methods are ineffective in reducing the damage due to pod fly and insecticides play a paramount role in managing their population under field conditions. Hence, present study have been aimed to evaluate the efficacy of different new pesticide chemistries against pod fly in pigeon pea ecosystem. Method: Two field experiments were conducted during Kharif 2019 and 2020 in RCBD using pigeonpea cv. GRG 811 with 14 treatments replicated twice. Two sprays were imposed at 15 days interval initiating from pod initiation stage. At maturity, number of damaged pods were recorded and expressed as percentage. Grain yield was recorded and benefit cost ratio was also worked out. Results: Among the screened insecticides, fipronil 4+thiamethoxam 4 SC @ 40+40 g a.i./ha followed by thiamethoxam 25 WG @ 50 g a.i./ha and fipronil 40+imidacloprid 40 WG @ 160+160 g a.i./ha provided better control of pod fly in terms of reduction in pod damage (69.54, 62.13 and 62.57%) and seed damage (72.51, 71.35 and 70.39%) respectively over untreated check. The average grain yield of 1577 kg/ha was highest in fipronil 4+thiamethoxam 4 SC @ 40+40 g a.i./ha followed by fipronil 40+imidacloprid 40 WG @ 160+160 g a.i./ha (1555.5 kg/ha) and thiamethoxam 25 WG @ 50 g a.i./ha (1536.5 kg/ha). Whereas, B: C was higher in fipronil 4+thiamethoxam 4 SC @ 40+40 g a.i./ha (2.84) and thiamethoxam 25 WG @ 50 g a.i./ha (2.83). Therefore these insecticides can be used for effective management of pod fly.

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Entomopathogenic fungi viz. Metarizhium anisoplae and Beauveria bassiana are well characterized in respect to pathogenicity to several insects and have been used for biological control of agriculture pests worldwide. Despite their potential, several factors like low resistance to elevated temperature have hindered widespread adoption of fungi as part of biological control regimes. In this study, five isolates of B. bassiana (Bb 01, Bb 02, Bb 03, Bb 04 and Bb 05) and two isolates of M. anisoplae (Ma 01 and Ma 02) were evaluated for thermotolerance capacity and bioefficacy against third instar of Spodoptera litura. Among the isolates studied, Bb 04 recorded the higher temperature tolerance up to 34oC with mean spore germination of 35.00 percent and mean dry mycelial weight of 443.38 mg. Further, in the bioassay studies, Bb 04 caused significantly (@ P<0.01%) higher percent mortality of S. litura larva at 1×108 spores ml-1 on fifth day (80.00 %) with LT50 value of 4.08 days and LC50 value of 2.07×104 conidia ml-1 at five days. Investigation results indicated that BB 04 is a suitable EPF isolate for management of S. litura where higher temperature prevails.