Food grains infestation by insect pests in stores is a severe challenge in food production around the globe, especially in wet and humid regions. In Bhutan, mung bean is commonly grown for consumption as a superior source of protein. However, severe cowpea weevil infestation is observed while in storage condition. Controlling with synthetic pesticides is associated with health risks due to toxic residues which intervene in safe and healthy protection methods. Protecting the grains in-store through organic approach is imperative for consumption and seed purposes. Some botanical plant extracts are known for their protective properties which need location-specific studies based on availability and suitability. Therefore, this study was conducted to evaluate the efficacy of eight treatments (Acorus calamus rhizome powder, mustard oil, garlic cloves, turmeric rhizome powder, wood ash, Vitex negundo leaf powder, super grain bag including untreated control) against cowpea weevil (Callosobruchus maculatus) in mungbean under storage condition. The experiment was laid in a randomized complete block design with three replications. The result revealed that the lowest mean number of grains perforated and percent grain perforated were recorded in grains treated with Acorus calamus rhizome powder (0.46 & 0.20 %) followed by mustard oil (1.05 & 0.47 %) and grains stored in super grain bag (5.74 & 2.49%), which were significantly lower (P<0.001) as compared to other treatments. The lowest number of adult cowpea weevils was also recorded in grains treated with Acorus calamus and mustard oil followed by grains stored in super grain bag. Germination percentage was found highest in wood ash followed by mustard oil, Acorus calamus and garlic-treated grains while the lowest was in super grain bag. Therefore, Acorus calamus rhizome powder and mustard oil were found to be effective in managing cowpea weevil without affecting seed germination and vigour.

In Bhutan, litchi production is constrained by insect pest damage. Among insect pests, the litchi fruit and shoot borer (Conopomorpha sinensis Bradley) is an emerging pest of economic importance in the subtropical regions of Bhutan. Up until now, there is documented research on its biology and management in Bhutan. Therefore, this study was undertaken to study the efficacy of two different management methods against litchi fruit borer infestation in three litchi varieties (Bhur litchi 1, Bhur litchi 2 & Hong houy). The management methods consisted of three treatments; T1-Azadirachtin followed by Imidacloprid, Azadirachtin and Cypermethrin; T2-Azadirachtin followed by Imidacloprid, Azadirachtin and Azadirachtin; T3-Untreated control. The result showed that the fruit infestation at harvest was significantly lower in management method T1 (34.74%) as compared to T2 (78.07%) and untreated control (89.98%). In terms of the variety, the lowest fruit infestation at harvest was observed for Hong houy (56.02%) as compared to Bhur Litchi 1 (73.28%) and Bhur Litchi 2 (73.45%). There were no significant differences in fruit drop percent and percent infestation of dropped fruits between the treatments and varieties tested. Heavy fruit drop was observed in the third week, due to unknown reasons, which then decreased over the fruit development stages. Fruit borer infestation seems to increase rapidly after the fifth and eighth weeks indicating that most of the fruit borer damage occurs at the fruit maturity stage after fruit colour break. Therefore, the last application of cypermethrin 10% EC at the fruit colour break stage was found necessary to reduce fruit infestation during this vulnerable pest infestation period besides scheduled application of Azadirachtin and Imidacloprid at the early fruit development period.