Behavioral Responses of Aphis craccivora, Aphis gossypii and their Parasitoid, Binodoxys indicus to Volatiles from Undamaged, Aphid-Damaged and Jasmonic Acid-Treated Lablab purpureus subsp. bengalensis.

Aphis craccivora (AC) and Aphis gossypii (AG) are serious pests of Lablab purpureus subsp. bengalensis. Binodoxys indicus is a parasitoid of both aphids. Thus, it is interesting to observe the behavioral responses of both aphids and the parasitoid to volatiles of undamaged (UD), insect-damaged (ID, plants infested by each aphid for 48-120 h) and jasmonic acid (JA)-treated plants. In olfactometer bioassays, aphids preferred the volatiles from UD and ID plants, whereas the parasitoid preferred volatiles from ID plants. Aphids and the parasitoid preferred volatiles of ID 120 h plants over ID 48 h plants. Aphids and the parasitoid did not prefer the volatiles of JA-treated plants. GC-MS analysis of volatiles from UD, AC-infested, AG-infested and JA-treated plants demonstrated the presence of 23, 28, 29 and 27 compounds, respectively. To identify key volatile compounds responsible for the behavioral responses of aphids and the parasitoid, all individual synthetic compounds for each treatment were tested in olfactometer bioassays. AC and AG showed attraction to eight and seven individual compounds, respectively, resembling 120 h conspecific-damaged plants. The parasitoid, B. indicus, showed attraction to five and four individual compounds resembling 120 h AC- and AG-infested plants, respectively. The above eight and seven compound blends could be used as lures in baited traps to capture both aphids in Lablab fields, whereas the above five and four compound blends could be applied to intensify the foraging behavior of B. indicus during early infestation of these aphids in Lablab plants in integrated pest management strategies.