Ben-Yakir, D., Institute of Plant Protection, ARO, Volcani Center, Bet-Dagan, Israel
Antignus, Y., Institute of Plant Protection, ARO, Volcani Center, Bet-Dagan, Israel
Offir, Y., Polysack Plastics Industries, Nir-Yitzhak-Sufa, Israel
Shahak, Y., Institute of Plant Protection, ARO, Volcani Center, Bet-Dagan, Israel

Insects use optical cues for host finding and flight orientation. The hue, brightness, size, shape and contrast of the visual cue affect the insect response. Manipulation of the natural optical cues can interfere with host finding and dispersal of insect pests. Sucking insect pests, such as aphids and whiteflies, cause great economic losses for growers of agricultural crops worldwide. These pests cause direct feeding damages and they often transmit viruses to crop plants. Nonpersistent viruses must be transmitted within minutes to 2 hours after aphids acquired them. These insects have receptors for UV light (peak sensitivity at 360 nm) and for green-yellow light (peak sensitivity at 520-540 nm). The absence of UV deters these pests and decreases their dispersal rate. Yellow color induces landing and favors settling of these insects. High level of reflected sunlight (above 25% of sun radiation) deters landing of these insects. Thus, optical cues can be used to divert pests away from crop plants. This can be achieved by incorporating optical additives to cladding materials (plastic sheets, nets and screens above plants). For non-persistent viruses, any delay of the infected aphids with an arresting color can reduce the efficacy of viral transmission. Results of our studies indicate that optical manipulation can reduce the infestation levels of aphids and whiteflies and the incidence of viral diseases they transmit by 2-10 folds. Thus, optical manipulations can be a part of integrated pest management programs for protected crops.