Author
|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/27/2010 Publication Date: 4/6/2010 Citation: Lee, J.C. 2010. Effect of methyl salicylate-based lures on beneficial and pest arthropods in strawberry. Environmental Entomology. 39:635-660. Interpretive Summary: When plants are attacked by pests, plants release volatile odors for defensive and signalling purposes. Methyl salicylate (MeSA) is a common volatile released that is also attractive to natural enemies. When synthetic MeSA is applied to crops, it has been demonstrated to increase natural enemies in vineyards and hop yards. In this study, I investigated the outcomes of applying MeSA to strawberry plants. In control plots of strawberries, no MeSA lures were applied. In other strawberry plots, two 30-day commercial MeSA lures were placed at the center. One lure was placed on the plant near the ground to attract ground dwelling predators, and another lure was hung 0.61 m aboveground over a sticky trap to attract flying insects. I monitored the natural enemies and pests in these control and MeSA plots over 31 days at the center of each plot, 5 m and 10 m radius. Pitfall traps were used to collect ground dwelling insects, sticky traps and visual inspection of leaves were used to monitor foliar insects. Overall positive responses to MeSA were found among green lacewings in July-August 2008 and minute pirate bugs in May-June 2009. Green lacewings also showed attraction to the point source but not at 5 m and 10 m. Ground dwelling predators collected in pitfall traps such as spiders and ground beetles did not appear to respond to MeSA. Abundance of natural enemies on leaves, and ladybugs, green lacewings, parasitic wasps, and spiders on sticky traps increased on certain dates in the presence of MeSA. This response was generally seen between 3-21 days after placing lures in the field. The application of MeSA did not clearly increase or decrease pest abundance. Technical Abstract: Methyl salicylate (MeSA) is a common herbivore-induced plant volatile that, when applied to crops, has the potential to enhance natural enemy abundance and pest control. The impacts of MeSA in the strawberry system were unknown and examined in this study. Strawberry plots contained no lures (control) or two 30-d MeSA lures (Predalure®) in the center—one lure 0.61 m aboveground over a sticky trap, and one lure on a plant near the ground. Insect abundance was monitored at the point source, 5 m and 10 m away over 31 days. Overall positive responses were found among Chrysopidae in July-August 2008 and Orius tristicolor (White) in May-June 2009 to MeSA based on white sticky trap captures. Chrysopidae showed attraction to the point source but not at 5 m and 10 m. Ground dwelling predators collected in pitfall traps such as Araneae, the carabid beetles, Pterostichus melanarius (Illiger) and Nebria brevicollis (Fabricius) did not appear to respond. Abundance of several natural enemy groups increased on certain dates between 3-21 days after placement of MeSA lures in the field based on sticky traps and visual inspection of leaves. There was no evidence that MeSA increased pest abundance. |
