Volatile blooms of Aleurodicus rugioperculatus Martin infested coconut and banana leaves attracting parasitoid Encarsia guadeloupae Viggiani

Abstract

Invasive whitefly species in coconut plantations have become a matter of concern in the last half a decade as they cause direct and indirect infestation on the palms. The Rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin infestation was high on Cocos nucifera L. (coconut) followed by Dypsis lutescens (H. Wendl.) (Butterfly palm) and Annona squamosa L. (custard apple). The coconut varieties Malayan Yellow Dwarf and Chowghat Orange Dwarf were observed with higher infestation index while that of West coast tall was the lowest. Higher RSW parasitization levels were observed on Musa paradisiaca L. (banana) and Canna indica L. (Indian shot), with 85.96 and 71.59% parasitization, respectively. Identification of volatile organic compounds (VOCs) between healthy and RSW-infested coconut plants revealed the emission of 56 VOCs from the healthy coconut plant and 47 VOCs from RSW infested plant.  22 VOCs were common in both samples, and 25 VOCs were unique to RSW-infested coconut plants. The presence of 42 VOCs was identified from the headspace extracts of RSW-infested bananas. Differences in the VOCs emitted from RSW-infested banana and coconut plants revealed higher emission of terpenoids like β-Caryophyllene, (E, Z)-2,6-dimethyl-2,4,6-Octatriene, Humulene, α-Pinene, Farnesane, α-Copaene and β-cis-Ocimene from RSW infested banana plants that proved to be more attractive to the parasitoid. Identifying specific blends of volatile compounds influencing Encarsia guadeloupae Viggiani could help to augment the parasitotic for RSW management in coconut plantations.