Effects of induction by soybean looper, Chrysodeixis includes (Walker), (Lepidoptera:Noctuidae) on the feeding behavior of the green peach aphid, Myzus persicae (Hemiptera:Aphididae)

Insect vectored plant diseases limit agronomic production and the most important virus vectors are aphids, transmitting over 50% of all plant viruses.  Aphids are excellent virus vectors due to their host selection and feeding behaviors, such as reflexive probing and intracellular gustatory punctures.  By understanding how host plants respond to, and in turn, affect aphid feeding behavior, we can adapt pest management techniques to reduce virus transmission.  Induced resistance has been shown to affect herbivore feeding behavior and may be a viable way to reduce virus transmission.  In order to test this hypothesis, four soybean varieties; Davis (susceptible), Williams 82 (susceptible and inducible), Lyon (resistant and inducible), and Progeny 4906RR (unknown) were induced by allowing third instar soybean looper, Chrysodeixis includes (Walker), larvae to feed for 24 hr.  Three days post induction, green peach aphid, Myzus persicae (Sulzer), apterae feeding behavior was recorded on the top most trifoliate of induced and un-induced plants using the Electrical Penetration Graph (EPG) technique.  In Lyon and Williams82, no differences in feeding behavior were observed.  However, in Davis, probe duration and archlet numbers were reduced, and  in P4906RR, preprobe duration and time to first pd increased. This suggests that the inducible resistance mechanisms of different varieties vary in the specificity of the response to the herbivore causing the damage, or that soybean loopers are able to subvert these mechanisms in certain varieties.