Optical Manipulations: An Advance Approach for Reducing Sucking Insect Pests

Insects use optical cues for host finding, flight orientation and navigation. Therefore, manipulation of these optical cues can interfere with host finding and dispersal of insect pests. Sucking insect pests, such as aphids, whiteflies and thrips, cause great economic losses for growers of agricultural crops worldwide. These pests cause direct feeding damages and often transmit viruses to crop plants. 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. Green-yellow color induces landing and favors settling (arresting) of these insects. High level of reflected sunlight (above 25% of sun radiation) also 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 mulches (below plants), to cladding materials (plastic sheets, nets and screens above plants) or to other objects elsewhere in the growing environment. The optical properties such as size, shape, and contrast of the color cue greatly affect the response of the insect. Non-persistent viruses can be transmitted only within minutes to a few hours after aphids acquired them. Thus, a delay of the viruliferous aphids with an arresting color can reduce the efficacy of viral transmission. Results of many studies indicate that optical manipulation can reduce infestation levels of sucking pests and the incidence of viral diseases they transmit. Future development of this technology must be compatible with the requirements for plant production and biocontrol. Optical manipulations can be a part of integrated pest management (IPM) programs for both open field and protected crops. This chapter includes a review of the published literature, results of our studies, and suggestions for future research and development of this technology.