Integrating semiochemicals and trap crops towards developing an attract-and-kill strategy against tarnished plant bug, Lygus Lineolaris, (Hemiptera:Miridae) in cotton.

Authors: George, Justin; Reddy, Gadi V.P.; HALL, DAVID - Natural Resources Institute Finland (LUKE)

Submitted to: International Congress of Entomology
Publication Type: Abstract Only
Publication Acceptance Date: 3/22/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: In this study, we investigated the effect of integrating semiochemicals and trap crops towards developing an attract-and-kill strategy against tarnished plant bug, Lygus lineolaris, one of the major cotton pest worldwide. Different colored sticky cards were tested in cotton fields to determine their efficacy in attracting L. lineolaris. Red-colored sticky cards were more attractive to L. lineolaris adults than white, blue or yellow cards. Red sticky cards combined with blends of three potential pheromone components attracted significantly more L. lineolaris adults than sticky cards without a blend added. Traps baited with a blend of hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal in 4:10:7 ratio, respectively, caught a significantly higher number of L. lineolaris than those baited with 10:4:2 or 7:10:4 blends or an unbaited control in the first week of the experiment. The pheromone blend that attracted the most L. lineolaris was also tested with different trap colors to confirm there was no unexpected interaction of color and olfactory cues in order to provide an optimized trap and lure for monitoring L. lineolaris. Our results showed that these traps will be very useful in the early monitoring of tarnished plant bugs in the field and will contribute towards pest management decisions. This pheromone blend-red sticky card trap was further tested in combination with trap crops to attract the L. lineolaris to the less expensive mustard trap crop before killing them with insecticides. Planting trap crops significantly increased natural enemy populations and enhanced biological control of the different life stages of many cotton pests. Our preliminary results showed that a combination of semiochemicals with trap crops attracted significantly more Lygus to the trap crops and reduced the plant bug damage in nearby cotton rows. Also, no significant differences were observed in cotton yield between recommended insecticide applications compared to trap crops + pheromones with minimal insecticidal applications.

Technical Abstract: Visual and olfactory cues are used by tarnished plant bug, Lygus lineolaris, for mate finding and host location. The development of monitoring tools based on sensory cues is critical in the integrated management of this significant cotton pest. We investigated the synergistic effects of trap color and the addition of lures containing blends of pheromone components on catches of L. lineolaris on sticky traps under field conditions. Red-colored sticky cards were more attractive to L. lineolaris adults than white, blue or yellow cards. Red sticky cards combined with blends of three potential pheromone components attracted significantly more L. lineolaris adults than sticky cards without a blend added. Traps baited with a blend of hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal in 4:10:7 ratio, respectively, caught a significantly higher number of L. lineolaris than those baited with 10:4:2 or 7:10:4 blends or an unbaited control in the first week of the experiment. The pheromone blend that attracted the most L. lineolaris was also tested with different trap colors to confirm there was no unexpected interaction of color and olfactory cues in order to provide an optimized trap and lure for monitoring L. lineolaris. This pheromone blend-red sticky card trap was further tested in combination with trap crops to attract L. lineolaris to the less expensive mustard trap crop and can be killed by spraying insecticides. Planting trap crops significantly increases natural enemy populations and enhances biological control of the different life stages of many cotton pests. Our preliminary results show that a combination of semiochemicals with trap crops attracts significantly more Lygus to the trap crops and reduces the plant bug damage in nearby rows of cotton.