Abstract:
Laboratory experiments were conducted to understand the influence of host-finding
behaviour of Apanteles subandinus Blanchard and Orgilus lepidus Muesebeck, two
endoparasitoids of the potato tuber moth (PTM) Phthorimaea operculella Zeller (Lepidoptera:
Gelechiidae), in a successful biological control of the pest. Responses of the two
parasitoids to their host and to three host plants of the PTM were investigated in a wind
tunnel individually. The results suggested that host-finding by both parasitoids is stimulated
by a combination of chemicals. Females of both species discriminate between the
volatiles of a mechanically damaged plant and those of PTM larvae-damaged plant. The
combination of odours originating from plant host on which the host is feeding play a crucial
role in the foraging behavior of these parasitoids. Developmental experience during
larval stages and experience of adults to host plant influence their foraging for host. The
implications of parasitoid response towards plant volatiles and their importance in biological
control are discussed. Additional experiments are necessary to isolate and identify
the nature of the volatile chemicals released from the host-plant complex and use them to
improve the biological control of the pest.
