Effect of living (buckwheat) and UV reflective mulches with and without imidacloprid on whiteflies, aphids and marketable yields of zucchini squash

Abstract

The silverleaf whitefly, B biotype of the sweetpotato whitefly, Bemisia tabaci Gennadius also known as B. argentifolii Bellows and Perring, and the melon aphid, Aphis gossypii Glover, are key pests of zucchini squash in Florida. The use of mulches, living or synthetic, is one of the tactics that could be used to suppress whitefly and aphid populations and their associated transmitted viruses. Buckwheat, Fagopyrum esculentum Moench – a living mulch, and a synthetic, UV reflective mulch, were evaluated alone or in combination with a reduced-risk insecticide, imidacloprid Admire® 2F in two field experiments carried out during the Autumn of 2005 and 2006. Four 80-m2 plots were used for each treatment with standard white mulch as a control in a randomized complete block design. Imidacloprid was applied at planting and buckwheat mulch was planted approximately 2 weeks before the squash was seeded. Addition of imidacloprid to the mulches significantly reduced the number of whiteflies and apterous aphids in 2005 but not in 2006. In 2005, there were treatment differences on natural enemies' abundances where more natural enemies were recorded within buckwheat mulch than reflective mulch. Squash within synthetic mulches resulted in significantly higher yields than those grown with living mulch. We conclude that imidacloprid can be used with the mulches to manage whiteflies and aphids in zucchini squash when the pest populations are high, but this may not necessarily translate in economic benefits in terms of yields.