VISUAL AND VOLATILE PREFERENCES OF THE GENERALIST HERBIVORE, LYGUS HESPERUS (HETEROPTERA: MIRIDAE)

Authors: Blackmer, Jacquelyn; Byers, John; RODRIGUEZ-SAONA, CESAR - PE MARUCCI CHATSWORTH, NJ

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/4/2006
Publication Date: 6/1/2006
Citation: Blackmer, J.L., Byers, J.A., Rodriguez-Saona, C.R. 2006. Visual and volatile preferences of the generalist herbivore, lygus hesperus (heteroptera: miridae). In P. Dugger and D. Richter, eds., Proc. National Cotton Council Beltwide Cotton Conference 1048-1052.

Interpretive Summary: The western tarnished plant bug (Lygus), is currently one of the most damaging pests in cotton. Plant visual and volatile cues play an important role in host-location in this species. Chemical profiles of a preferred host (alfalfa) were previously identified and included several green leaf volatiles, terpenes and flower-specific compounds. Release of these compounds was influenced by plant phenology, time of day and Lygus feeding damage. Visual cues, in the form of a green light-emitting diode (530 nm wavelength), were also found to enhance upwind responsiveness, with the combination of plant cues leading to a synergistic increase in upwind orientation. Several synthetic compounds have been tested in combination with the visual cue in a V-tube olfactometer and upwind responses exceeded 80% in some cases, indicating their utility as potential behavioral modifiers. Field and laboratory tests are now focused on determining the most effective trap design for maximizing Lygus capture while minimizing the capture of beneficial insects. The response of L. hesperus, several other herbivore species and key beneficial insects to hue (white, clear, black, yellow, orange, blue, purple, green, red) and value (black, white and two neutral grays) was examined in the field in a randomized block design (N=4 or 5 repeated 4 times over two seasons) using traps coated with Stickem. Hue (dominant wavelength) and possibly chroma (color purity), but not value (brightness or intensity) influenced Lygus trap catch. Trap colors that collected the highest number of Lygus (blue, black, clear and green) plus light yellow were subsequently presented with single or binary blends of two terpenes that were found to be attractive in laboratory bioassays. Selective trap design, orientation and placement relative to preferred and non-preferred hosts will be discussed.

Technical Abstract: Lygus hesperus, the western tarnished plant bug, is currently one of the most damaging pests in cotton. Plant visual and volatile cues play an important role in host-location in this species. Chemical profiles of a preferred host (alfalfa) were previously identified and included several green leaf volatiles, terpenes and flower-specific compounds. Release of these compounds was influenced by plant phenology, time of day and Lygus feeding damage. Visual cues, in the form of a green light-emitting diode (530 nm wavelength), were also found to enhance upwind responsiveness, with the combination of plant cues leading to a synergistic increase in upwind orientation. Several synthetic compounds have been tested in combination with the visual cue in a V-tube olfactometer and upwind responses exceeded 80% in some cases, indicating their utility as potential behavioral modifiers. Field and laboratory tests are now focused on determining the most effective trap design for maximizing Lygus capture while minimizing the capture of beneficial insects. The response of L. hesperus, several other herbivore species and key beneficial insects to hue (white, clear, black, yellow, orange, blue, purple, green, red) and value (black, white and two neutral grays) was examined in the field in a randomized block design (N=4 or 5 repeated 4 times over two seasons) using traps coated with Stickem. Hue (dominant wavelength) and possibly chroma (color purity), but not value (brightness or intensity) influenced Lygus trap catch. Trap colors that collected the highest number of Lygus (blue, black, clear and green) plus light yellow were subsequently presented with single or binary blends of two terpenes that were found to be attractive in laboratory bioassays. Selective trap design, orientation and placement relative to preferred and non-preferred hosts will be discussed.