Intercropping is one of the important cultural practices in pest management and is based on the principle of reducing insect pests by increasing the diversity of an ecosystem. On—farm experiments were conducted in villages of semi—arid tropical (SAT) India to identify the appropriate combination of castor (Ricinus communis L.) (Malpighiales: Euphorbiaceae) and intercropping in relation to pest incidence. The diversity created by introducing cluster bean, cowpea, black gram, or groundnut as intercrops in castor (1:2 ratio proportions) resulted in reduction of incidence of insect pests, namely semilooper (Achaea janata L.), leaf hopper (Empoasca flavescens Fabricius), and shoot and capsule borer (Conogethes punctiferalis Guenee). A buildup of natural enemies (Microplitis, coccinellids, and spiders) of the major pests of castor was also observed in these intercropping systems and resulted in the reduction of insect pests. Further, these systems were more efficient agronomically and economically, and were thus more profitable than a castor monocrop.

:Okra [Abelmoschus esculentus L. (Moench)] also known as lady's finger is an important vegetable crop valued for its immature, tender and green fruits in India.One of the major bottlenecks in successful production of okra is the damage caused by early season sucking pests and fruit borers. Among the sucking pests leafhoppers (Amrasca biguttula biguttula) is undoubtedly more severe and destructive on okra during early stage of the crop. At present, most of the commonly used insecticides are not able to suppress its population below economic thresholds probably because of development of resistance. Among the different insecticides tested for bioassay under laboratory conditions, thiamethoxam 25 WDG at 0.2 g per litre and flonicamid 50 WG at 0.3 g per litre showed the highest mortality and was followed by fipronil 5 SC at 1 ml per litre, dinotefuran 20 SG at 0.2 g per litre and acetamiprid 20 SP at 1 g per litre which proved to be superior over imidacloprid 17.8 SL at 0.3 ml per litre, diafenthiuron 50 WP at 1 g per litre, lamda-cyhalothrin 5 EC at 0.5 ml per litre, emamectin benzoate 5 SG at 0.2 g per litre, fenpyroximate 5 SC at 1ml per litre and acephate 75 SP at 1 g per litre.The concentration mortality response of nymphs to these chemicals under laboratory was evidenced through leaf dip bioassay and the LC 50 values for these chemicals were computed. The LC 50 value of thiamethoxam 25 WDG, flonicamid 50 WG, fipronil 5 SC, dinotefuran 20 SG and acetamiprid 20 SP were 4. 03, 4.50, 16.18, 7.60 and 16.40 ppm respectively.The different insecticides which were promising through laboratory were field evaluated and the results revealed that thiamethoxam 25 WDG at 25 g a. i. per hectare was found to be effective against the leafhoppers followed by flonicamid 50 WG at 75 g a. i. per hectare, fipronil 5 SC at 25 g a. i. per hectare, dinotefuran 20 SG at 20 g a. i. per hectare and acetamiprid 20 SP at 20 g a. i. per hectare. Whereas, acephate 75 SP at 375 g a. i. per hectare was least effective against the leafhoppers.How to view point the article : Rekha, Somasekhar, Prabhuraj, A., Hosamani, A.C. and Khan, Hasan (2017). Bioassay of insecticides against okra leafhopper Amrasca biguttula biguttula (Ishida). Internat. J. Plant Protec., 10(2) : 364-368,