Effects of ultraviolet-absorbing greenhouse plastic films on flight behavior of Bemisia argentifolii (Homoptera : Aleyrodidae) and Frankliniella occidentalis (Thysanoptera : Thripidae)

Several clear polyethylene film products, developed specifically for greenh ouse use, have high UV-absorbing abilities, while allowing high transmissio n of visible light. We examined the effects of these plastics on insect fli ght behavior. Four high UV-blocking products from 2 manufacturers were comp ared with their respective standard plastics. Insect species tested were th e whitefly, Bemisia argentifolii Bellows & Perring, and the western newer t hrips, Frankliniella occidentalis (Pergande). In choice experiments, when i nsects were released from a black box at the center of 2 tunnels, stick) tr aps caught 85-94% of released whiteflies and 90-98% of released thrips insi de standard tunnels when compared with UV-blocking tunnels. This indicates a distinct preference of both whiteflies and thrips to enter tunnels that t ransmit higher levels of UV light. In no-choice experiments, when insects w ere released at one end of a single tunnel covered with 1 type of plastic, there was no significant difference among types of plastic in the number of whiteflies or thrips caught, indicating that there was no obvious negative effect of UV-blocking plastic on the ability of insects to fly. These resu lts indicate that greenhouse plastics may have significant influence on the initial attraction of insects into greenhouses. It will be important to st udy these effects in more detail to understand the mechanisms underlying UV -light taxis and the application of this phenomenon to management of insect pests in greenhouse crops.