Monoterpenes for Management of Field Crop Insect Pests

The control of different agricultural insect pests still relies mainly on the use of synthetic insecticides. However, excessive use of these chemicals cause many problems, including high residue levels, harmful effects on the environment and human health, and development of insect resistance. Therefore, new strategies for the management of agricultural insects are urgently needed. Plant-based natural products are promising alternatives to be applied for pest control, with remarkable and broad-spectrum biological activities. Among the plant secondary metabolites, essential oils, and their major constituents, mainly monoterpenes, have been widely studied for their application in insect control, food additives, perfumes and cosmetics. In this review, we focus on the studies describing the toxic effects of monoterpenes, including fumigant, contact and residual toxicities against insect pests attacking economic crops in fields. Furthermore, the effects of monoterpenes on insect behaviors (antifeedant and repellent activities) and insect growth regulation are also discussed.