|Momol, M. timur|
Submitted to: Phytopathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/5/2007
Publication Date: 6/20/2007
Citation: Reitz, S.R., Maiorino, G., Ritchie, L., Olson, S., Sprenkel, R., Crescenzi, A., Momol, M. 2007. The effects of plant essential oils and particle films on tomato spotted wilt and thrips in tomatoes. Phytopathology. 97(7):S98. Interpretive Summary: The thrips-vectored Tomato spotted wilt virus is the primary pest problem facing tomato production in the southern USA. Because insecticides do not effectively control primary infection by thrips immigrating into crop fields, scientists with the Center for Medical, Agricultural and Veterinary Entomology, the University of Florida, and the Università degli Studi della Basilicata, Potenza, Italy are investigating biologically-based, sustainable alternatives to manage thrips and tomato spotted wilt. Field trials were conducted to determine the effects of three plant essential oils, geraniol, lemongrass oil and tea tree oil, and kaolin based particle films on the incidence of tomato spotted wilt and population dynamics of thrips. 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 insecticide 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.
Technical Abstract: Because the thrips-vectored Tomato spotted wilt virus is a limiting factor in tomato production in the southern USA, we are investigating novel control methods that would be effective and environmentally non-disruptive. In laboratory choice tests, we found that three plant essential oils, geraniol, lemongrass oil and tea tree oil were repellent to western flower thrips and repellency increased with the addition of kaolin. In two field trials we compared the effects of these essential oils (250 ppm per application, twice per week) and kaolin (28kg/ha) with a grower standard insecticide treatment (spintor rotated with baythroid and endosulfan) and a control on the population dynamics of thrips and incidence of tomato spotted wilt, in a 5x2 factorial design. Insect and disease pressure was much greater in the second year trial (mean tomato spotted wilt: 34% year 1 versus 82% year 2). The plant essential oils were more effective when combined with kaolin, because kaolin may reduce the volatility of the oils, thus increasing their effective time. Tea tree oil was the most effective essential oil. In each year, the tea trial + kaolin treatment was as effective as the standard synthetic insecticide treatments in terms of insect and disease control and yield. 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.