The Role of Green Gram Plant Volatile Blends in the Behavior of Arctiid Moth, Spilosoma Obliqua

Abstract Larvae of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) feed on the leaves and flowers of green gram [Vigna radiata (L.) Wilczek] and reduce seed yield. Therefore, it is interesting to observe whether undamaged (UD) and insect-damaged (ID, plants after feeding by S. obliqua larvae) plants cause attraction of conspecific adult moths. Females showed attraction towards volatile blends of UD, ID and mechanically-damaged (MD) plants of three green gram cultivars [PDM 54 (PDM), Pusa Baisakhi (PUSA) and Samrat (SAM)] in Y-tube olfactometer bioassays. Females were more attracted towards volatile blends of ID plants of a particular cultivar than UD plants of the same cultivar. Total amount of volatiles was higher in ID plants than UD plants. Some herbivore-induced plant volatiles − 3Z-hexenal, 1-hexanol, 3Z-hexenyl acetate, 2-octanol and ocimene were attractive to the insect. Females were attracted towards three synthetic blends (µg in 25 µl CH2Cl2) comprised − 2.97 µg 3Z-hexenal, 4.92 µg 1-hexanol, 5.56 µg benzaldehyde, 9.76 µg 3Z-hexenyl acetate, 7.27 µg 2-octanol, 7.97 µg ocimene and 5.71 µg acetophenone resembling PDM, 4.68 µg 3Z-hexenal, 8.38 µg benzaldehyde, 7.66 µg 3Z-hexenyl acetate, 5.96 µg ocimene and 7.60 µg acetophenone resembling PUSA, and 3.39 µg 3Z-hexenal, 6.29 µg benzaldehyde, 8.74 µg 3Z-hexenyl acetate, 6.17 µg ocimene and 3.69 µg acetophenone resembling SAM in olfactometer and wind tunnel bioassays. Females could not distinguish between these three synthetic blends in olfactometer and wind tunnel bioassays, suggesting that these three synthetic blends could be used as lures in developing baited traps in integrated pest management strategies.