Resumo

LILJESTHROM, Gerardo  e  ROJAS-FAJARDO, Gloria. Larval parasitism of Crocidosema (=Epinotia) aporema (Lepidoptera: Tortricidae) in north-eastern Buenos Aires province (Argentina). Rev. Soc. Entomol. Argent. [online]. 2005, vol.64, n.1-2, pp.37-44. ISSN 0373-5680.

In host-parasitoid interactions, parasitoid efficiency may be increased by different quantity and quality of plant signals. Crocidosema (=Epinotia) aporema (Walsingham) is a pest on soybean, with larvae feeding endophitically on various herbaceous leguminosae. In this study we analyzed larval parasitism of C. aporema on Melilotus albus Medikus, Galega officinalis L, Lupinus albus L and Glycine max Merrill in the north-east of the Buenos Aires province. Larval density was higher on L. albus (109,2 larvae/m²), than on the other leguminosae: 3,7; 6,9 y 11,3 on M. albus, G. officinalis and G. max, respectively. However, larval parasitism and the number of parasitoid species were lower on L. albus (9,5%, by the generalist ectoparasitoid Bracon sp.) than on M. albus (32,6%, Bracon sp. and the endoparasitoids Trathala sp.and Bassus sp.); G. officinalis and G. max (26,4% and 50,6% respectively, by Trathala sp. and Bracon sp. in both cases). Lupinus albus produced abundant sticky and odorous exudates in response to C. aporema larval feeding, which could have repelled the endoparasitoids. The much higher concentration of C. aporema on L. albus suggests this leguminosae could be used as a trap crop for control of C. aporema on soybean plots, method compatible with other tactics of conservative biological control.

Palavras-chave : Tritrophic interactions; Leguminosae; Crocidosema (=Epinotia) aporema; Ectoparasitoid; Endoparasitoid.

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