Does Background Odor in Tea Gardens Mask Attractants? Screening and Application of Attractants for Empoasca onukii Matsuda

Abstract

Plant volatiles help herbivores to locate their hosts, and therefore, they could be used to help develop pesticide-free pest management strategies. To develop an attractant for tea leafhopper (Empoasca onukii), we screened nine tea plant volatile compounds for their attractiveness using Y-tube olfactometer assays. Results indicated that tea leafhoppers significantly preferred ocimene, limonene, (Z)-3-hexenol, and (Z)-3-hexenyl acetate over clean air. These compounds were combined in a blend which lost its attractiveness at concentrations below 10-2 g/ml in liquid paraffin. In field tests, the blend was attractive to leafhoppers only in autumn, but not in summer. Analyses of the tea field background odor showed that all four components of the blend were present at much higher concentrations in summer (0.05-0.001 ng/liter) than in autumn (~10- to 25-fold lower). In field Y-tube bioassays, compared with the tea field background odor, the blend was attractive at a concentration of 10-1 g/ml in liquid paraffin, but not at 10-2 g/ml. These results suggest that field background odor can disrupt the attractiveness of an attractant based on plant volatiles to herbivores.

Chlorantraniliprole against the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae): From biochemical/physiological to demographic responses

“…When selecting insecticides, in addition to acute toxicity, chronic toxicity against target pests should also be closely considered, as chronic toxicity could result in reduced survival, lifespan, growth and development, fecundity, and population growth after exposure to low doses of the toxic substance 26,27 . Insecticides with different modes and mechanisms of action can be applied to generate various effects against targeted insects at low-lethal concentrations 28,29 . Moreover, sublethal effects of the same insecticide on different types of target pests can also be significantly different 21,30 .…”

Primary screening and application of repellent plant volatiles to control tea leafhopper, Empoasca onukii Matsuda

“…A typical example is the combination of a neem seed extract spray (repellent) with an attractive trap crop to protect cotton crops from Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) in Australia . Several attractants based on plant volatiles have been developed for tea leafhopper, and have been shown to be effective in field trials . If the attractant is not combined with an effective method to kill the attracted leafhoppers, it will not decrease the leafhopper density.…”

“…46 Several attractants based on plant volatiles have been developed for tea leafhopper, and have been shown to be effective in field trials. [47][48][49] If the attractant is not combined with an effective method to kill the attracted leafhoppers, it will not decrease the leafhopper density. The combination of a repellent, an attractant and a chemical insecticide or entomopathogenic fungus in plots would create a push-pull system to reduce the leafhopper population in tea plantations.…”

Susceptibility of Selected Tea Shoots to Oviposition by Empoasca onukii (Hemiptera: Cicadellidae) and Feasibility of Egg Removal with Harvesting

“…However, these applications represent increased costs for tea growers and can have adverse effects on the environment and on natural enemy populations which can result in pest resurgence [ 1 , 11 ]. Alternatively, numerous other control agents and methods against this pest have been proposed, including biological control [ 12 ], physical control [ 13 ], and chemical intervention [ 14 , 15 , 16 ]. However, the management of this pest remains challenging.…”