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Pollinators play vital roles to the environment, biodiversity conservation, food security and several dimensions of global sustainable development. Honey bee is an important pollinator globally but has been exposed to increasing threats from diseases, pesticides and biotic stresses. This review paper highlights the role of honey bees as pollinators, addresses threats which influence decline of honey bees and assess pesticidal risk toxicity on non-target organisms. Decline of honey bee population is caused by several factors including habitat fragmentation, pesticidal toxicity, colony collapse disorder and climate change. Pesticidal residue and toxicity has an adverse effect which results in honey bee population decline, disturb foraging and contamination of bee products. Residues of agricultural pesticides like pyrethroid and neonicotinoid pose a serious threat on honey bee health further reducing agricultural production and diversity. Pesticidal risk assessments are carried out to study effects of pesticides on pollinators with an aim to provide measures to safeguard their abundance, diversity and health. Sustainable agriculture, effective policy and proper management can decrease pollinators' risk by helping to diversify the agriculture for pollen and nectars with reduced usage of pesticides and proper management.

This experiment was conducted in tomato field at Agriculture and Forestry University (AFU, Chitwan, Nepal) between October 2016 and May 2017 to evaluate effect of net house on invasive insect species of tomato moth, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). The trial was setup with two treatments inside net house and under open conditions and was designed with four replications. The adults of T. absoluta were observed significantly lower numbers inside the net house (1.41 adult/trap) compared to the open condition (24.84 adult/trap). The T. absoluta population increased with rainfall. The marketable yield was significantly higher inside the net house (100.91 ton/hec) due to reduction of damage to tomato fruit (4 ton/hec) by T. absoluta. The initial level of investment was found to be higher inside the net house when compared to open cultivation. In terms of economic analysis in long term aspect only, the net house is a suitable means of pest management against T. absoluta.

A survey and field experiment were conducted to evaluate the efficacy of commercial insecticides against tomato leaf miner [Tuta absoluta (Meyrick)(Lepidoptera: Gelechiidae)] under farmer’s field condition in Palpa, Nepal from February 2018 to April 2018. It consists of seven treatments replicated three times. The treatments included: Abamectin 0.15% EC (dose: 0.3ml/liter), Imidachloprid 17.8% SL (dose: 0.3ml/liter), Spinosad 45% SC (0.3ml/liter), Azadirachtin 300 ppm (5ml/liter), Chlorantraniliprole 18.5% SC (0.3ml/liter), Emamectin benzoate 5% SC (2gm/liter) and control. Treatments were applied two times at 12 days interval. From the farmer survey, Tuta absoluta was identified as the major production problem of the study area. The field experiment revealed that there was a significant effect of insecticides in larval mortality and damage reduction. The lowest percentage of leaves damage was obtained in spinosad followed by chlorantraniliprole and emamectin benzoate and the lowest fruits damage was obtained in chlorantraniliprole followed by spinosad and emamectin benzoate. Similarly, the lowest larval population in both leaves and fruits was observed in chlorantraniliprole followed by spinosad and emamectin benzoate. Average mining in infested leaves and fruits was found non-significant at all days of observation. The rate of larval population reduction over control was found highest in chlorantraniliprole followed by spinosad and emamectin benzoate. Thus, chlorantraniliprole, spinosad and emamectin benzoate were superior insecticides for management of Tuta absoluta in the field condition.

Plant clinics in Nepal has been started in 2008 and has coverage in more than 40 districts of Nepal. A study has been conducted in Chitwan district of Nepal to assess the changes on farmer’s knowledge attitude and practice due to implementation of plant clinics. Total of 175 clinic attendants and 175 non-attendants were selected by simple random sampling method and interviewed by using semi-structured questionnaire. By and large, this study found wider positive changes among clinic attendants than non-attendants especially on their knowledge and skills to identity pests and diseases with their causes and practice appropriate remedial measures against those problems. The study revealed positive impact to by increasing knowledge and skillset among attending farmers to assess the season of disease and pest occurrence, estimate economic threshold level as well as preventive and curative measures against the plant health problems. Plant clinic has made impressive positive changes on adoption of recommended dose of pesticides and organic control methods among attendants than non-attendants. The level of awareness and adoption of waiting period after pesticide use was found higher among attendants than non-attendants.