Potencial de compostos orgânicos voláteis para o recrutamento de coccinelídeos no manejo de diaspis echinocacti bouché, 1833 hemiptera: diaspididae na palma forrageira

Abstract

The semiarid region of Northeast Brazil is characterized by irregular rainfall, which interferes with the feeding of livestock in the region, especially livestock farming. It is the region with the largest area cultivated with forage palm to meet the forage needs of animals in periods of water scarcity. However, several pests are responsible for production losses, especially the scale insect Diaspis echinocacti (Bouché, 1833) (Hemiptera: Diaspididae). However, the use of resistant varieties, associated with biological control of pests in the recruitment of natural enemies, can contribute to the cultivation of this forage. Therefore, the objective of this work was to study the volatile organic compounds emitted from forage cactus varieties with and without infestation of D. echinocacti and the behavioral response of the natural enemies Coccidophilus citricola (Brèthes, 1905) (Coleoptera: Coccinellidae) and Zagreus bimaculosus (Mulsant) (Coleoptera: Coccinellidae) to the extracts of the infested plant. To collect the volatile organic compounds from the five forage cactus varieties with and without infestation by the pest, the aeration process was performed, followed by desorption by double-distilled hexane. Behavioral bioassays were also tested with the extracts of the infested plant in the response of predator recruitment. The identification of the compounds was performed by mass spectrometry (CG-EM) and subjected to multivariate analysis. The number of compounds identified for the varieties F8, redonda, sertânia, africana and miúda were 23, 13, 13, 18 and 23 VOCs, respectively. Behavioral bioassays proved that predators feel recruited by plants infested by scale insects. Multivariate analyses showed that forage cactus varieties emit VOCs in different concentrations. Keywords: Water scarcity; plant volatiles; Biological control.