Plant essential oils and particle films for the management of tomato spotted wilt on tomatoes

The thrips-vectored Tomato spotted wilt virus is a limiting factor in tomato production in the southern USA. Because insecticides do not effectively control primary infection by thrips immigrating into crop fields, we are investigating alternatives that would be effective and environmentally non-disruptive. We conducted a field trial to determine the effects of three plant essential oils, geraniol, lemongrass oil and tea tree oil as natural plant derived chemical repellent to thrips, and kaolin based particle films on the incidence of tomato spotted wilt and population dynamics of thrips. Plant essential oils were applied at 250 ppm twice per week and were compared with a grower standard insecticide treatment and an untreated control. All treatments were applied with and without kaolin, in a 5 x 2 factorial design. When combined with kaolin, the three plant essential oils controlled adult thrips and the incidence of tomato spotted wilt as well as the grower standard treatment. Kaolin significantly increased yield. When applied with kaolin, the plant essential oils produced yields similar to the grower standard. Kaolin may reduce the volatility of the oils, thus increasing their repellency to thrips. These findings indicate that naturally occurring products, such as plant essential oils and particle films, could be used successfully to reduce insecticide use on tomatoes.