EFFECTS OF HOST PLANT LEAF DAMAGE ON CABBAGE-LOOPER MOTH ATTRACTION AND OVIPOSITION

Mated female Trichoplusia ni (Hubner) moths, when presented a choice o f either undamaged cotton plants, Gossypium hirsutum L., or damaged pl ants (cut leaves or feeding T. ni larvae) in a flight tunnel, were mos t often attracted first to the damaged plants. However, these same mot hs oviposited primarily on the undamaged plants. In a similar test wit h cabbage plants, Brassica oleracea L., the presence of conspecific la rvae decreased both attraction and oviposition. Cuts to cabbage leaves had no significant effect on attraction or oviposition. When presente d one plant at a time, percentages of cabbage looper moths attracted w ere not affected by the presence of larvae on either cabbage or cotton plants, or by cuts to cabbage plant leaves. Percentages of moths attr acted were, however, higher using cotton plants with cut leaves. The r esults suggest an important role for damage induced plant volatiles in host location as well as host acceptance by T. ni.