Repellency of mustard (Brassica juncea) and arugula (Eruca sativa) plants, and plant oils against the sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)

Authors: Legaspi, Jesusa; Miller, Neil; WOLAVER, DANIELLE - Florida A & M University; LAMBERT, KANGA - Florida A & M University; MUHAMMAD, HASEEB - Florida A & M University; ZANUNCIO, JOSE - Universidade Federal De Vicosa

Submitted to: Subtropical Agriculture and Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2016
Publication Date: 12/30/2016
Citation: Legaspi, J.C., Miller, N.W., Wolaver, D., Lambert, K., Muhammad, H., Zanuncio, J.C. 2016. Repellency of mustard (Brassica juncea) and arugula (Eruca sativa) plants, and plant oils against the sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae). Subtropical Agriculture and Environments. 67:28-34.

Interpretive Summary: The sweetpotato whitefly is an extremely destructive and serious pest of vegetable, fiber and ornamental crops worldwide and has proven resistant to many chemical insecticides. “Push – pull” pest management is an environmentally-friendly and sustainable strategy based on manipulating the behavior of insect pests and their natural enemies where the pests are repelled from a crop (the “push” component) and simultaneously attracted to a low-value trap crop (“pull” component) where they are subsequently removed. Scientists from the USDA, Agriculture Research Service, Center for Medical, Agricultural and Veterinary Entomology, Tallahassee, Florida, in collaboration with researchers from Florida A&M University, Tallahassee, Florida, conducted laboratory studies assessing insect movement towards or away from an odor source or color. A variety of colors and chemical extracts or entire plants were tested for attraction or repellent effects on the whitefly. In the first experiment, we found measurable movement of whitefly adults towards cucumber plants and the colors yellow and green. However, when mustard odors were added, whiteflies were no longer attracted, and at times were repelled. The second experiment showed highest total distances traversed and rate of insect movement in hot pepper wax, mustard oil and the cucumber controls. Time allocation analysis showed attraction towards cucumber and hot pepper wax, as well as aversion to garlic oil and mustard oil. A clean air control elicited no directional movement. These studies suggest mustard and mustard oil for use as “push” components in “push-pull” management. Finally, we suggest ways to improve the equipment and methods for future studies of this nature.

Technical Abstract: The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an economic complex of at least 36 cryptic species, comprising a highly polyphagous and serious pest of vegetable, fiber and ornamental crops. Sustainable alternative measures such as cultural controls can be effective in integrated pest management of Bemisia, but have received relatively little research effort. “Push – pull” strategies are a form of cultural control based on behavioral manipulation of insect pests and their natural enemies, wherein pests are repelled from a protected resource (“push” component) and simultaneously attracted to a trap crop (“pull” component) where they are subsequently removed, preferably through biological control or other appropriate means. In this study, we conducted laboratory studies using an olfactometer or odor-detecting equipment to determine the effect of volatiles from whole plants and plant oils to repel the sweetpotato whitefly. We used two types of olfactometers to measure responses of Bemisia tabaci adults to volatiles from putative repellent and attractive plants, as well as to repellent oils. In addition to volatiles, we tested responses to colors known to attract whitefly adults. Finally, we monitored whitefly behavior using a video recorder and behavioral analysis software in response to repellent oils. Results indicated measurable movement of whitefly adults towards attractants, such as cucumber plants and the colors yellow and green, and movement away from mustard plants (Caliente and giant red mustard varieties). Repellency was seen to odor of arugula and mustard plants. In addition, the highest total distances traversed and rate of insect movement were recorded in hot pepper wax, mustard oil and the cucumber controls. Time allocation analysis indicates attraction towards the cucumber control and hot pepper wax, as well as aversion to garlic oil and mustard oil. The clean air control elicited no directional movement. ). These studies indicated mustard and mustard oil for use as “push” components in “push-pull” management. Present results suggest garlic oil may also be a promising “push” candidate. Finally, we suggest modified olfactometers and the use of behavioral analysis software as alternative solutions to traditional Y-tube olfactometer studies.