Novel Approach for a Controlled Delivery of Essential Oils during Long-Term Maize Storage: Clove Bud and Pennyroyal Oils Efficacy to Control Sitophilus zeamais, Reducing Grain Damage and Post-Harvest Losses

SIMPLE SUMMARY: Sitophilus zeamais (Motschulsky) is one of the most destructive pests of stored maize grains worldwide. Synthetical chemical insecticides are applied for its control, but these can cause the development of resistant populations and have environmental implications. Essential oils can be a viable alternative to synthetic chemical insecticides, but their long-term effectiveness is still up for debate. The aim of this work was to evaluate the effectivity of Clove bud and Pennyroyal essential oils for long-term (twenty weeks) protection of maize, delivered with the aid of an innovative macro-encapsulation device. The blend of both compounds reduced losses by more than 45%, diminishing the survivability of S. zeamais by over 90%. This work demonstrates the potential application of this technology and solutions on the control of S. zeamais, describing and evaluating their effects on S. zeamais populations and their relation to the damages and losses of maize grains. ABSTRACT: Maize grains represent a significant contribution for assuring food safety all over the globe. Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), also known as the maize weevil, is one of the most destructive pests in stored maize, causing qualitative and quantitative losses. To control S. zeamais populations in maize storage sites, synthetical chemical insecticides are applied. However, these are often used wastefully, have environmental implications, and can induce the development of resistant populations. In this work, the insecticidal and grain protecting efficacy of an innovative macro-capsule delivery device, loaded with essential oils from Clove bud and Pennyroyal, as well as their combined solutions, was tested against naturally S. zeamais-infested maize grains. The blend of both compounds incorporated in a controlled release device reduced losses by more than 45% over a long storage period of twenty weeks, diminishing the survivability of maize weevils by over 90%. The usage of the blend at a concentration of [Formula: see text] with an antioxidant showed the best results, however, by halving the concentration [Formula: see text] , a significant control of S. zeamais populations was still achieved.