Identification ofLathyrus sativusplant volatiles causing behavioral preference ofAphis craccivora

BACKGROUND The viviparous aphidAphis craccivoraKoch (Hemiptera: Aphididae) is a serious threat to the crop yield ofLathyrus sativusL. (Fabaceae), commonly known as grass pea. The synthetic insecticides applied to control this insect pest are not safe for the environment. Hence, it is necessary to find volatile organic compounds (VOCs) from two cultivars [BIO L 212 Ratan (BIO) and Nirmal B-1 (NIR)] ofL. sativusplants causing behavioral preference ofA. craccivora. RESULTS The VOCs from undamaged (UD), insect-damaged (ID) [plants on which 50 or 100 adults ofA. craccivorawere fed for 4 h (ID 50 or ID 100)], and mechanically damaged (MD) plants were identified and quantified by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses, respectively. Total VOCs were higher in ID plants compared to UD plants of each cultivar. However, total VOCs were higher in NIR cultivar compared to BIO cultivar for both UD and ID plants. Benzyl alcohol was predominant in volatile extracts of all treatments. In Y-tube olfactometer bioassays, females showed preference towards volatile extracts of UD, ID, and MD plants of each cultivar compared to the control solvent (CH2Cl2). Insects preferred certain synthetic blends comparable to volatile extracts of UD, ID, and MD plants of eachL. sativuscultivar against the control solvent. CONCLUSION Females preferred a synthetic blend of benzyl alcohol, 1,3-diethylbenzene, thymol, and 1-hexadecene at ratios of 142.49: 62.03:1.18:1 dissolved in 25 mu L of CH(2)Cl(2)in olfactometer bioassays, which could be used in developing lures to control this insect pest.

Automated summary

The viviparous aphid Aphis craccivora is a serious threat to the crop yield of Lathyrus sativus, and it is necessary to find volatile organic compounds (VOCs) from different cultivars of L. sativus plants causing behavioral preference of A. craccivora. The study found that females exhibit preference towards certain synthetic blends of VOCs, which could be used in developing lures to control this insect pest.