Effects of Soybean Looper Feeding and Jasmonic Acid Application on Green Peach Aphid Feeding Behavior in Soybean

Aphids are crop pests, reducing yields through photosynthate removal, and more importantly, are plant virus vectors, transmitting over 30% of all plant viruses.  Aphids are excellent virus vectors due to their host selection and feeding behaviors, including reflexive probing and intracellular gustatory punctures.  Factors that change aphid feeding behavior may be used to reduce virus transmission.  Induced resistance has been shown to affect herbivore feeding behavior and may be a viable way to reduce virus transmission.  Soybean variety Progeny 4906RR was induced by: (1) allowing third instar soybean looper, Chrysodeixis includes (Walker), larvae to feed for 24 hr, or (2) by spraying with 2mM JA.  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.  Plants treated with JA were probed more often than control plants and had longer pd subphase II-3 durations; behaviors indicative of increased virus transmission.  Plants induced by soybean looper had a shorter II-3 duration and fewer archlets than control plants, indicative of decreased virus transmission.  These results suggest that inducing host plant resistance using exogenous applications of JA could enhance plant virus transmission.