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Description:
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Lygus hesperus is an important pest on different crops including cotton and alfalfa in the western U .S . Anaphes iole is a common parasitoid of Lygus spp . eggs in the U .S . and has potential as a biological control agent against L . hesperus in different crops . Its foraging behavior has been studied to a limited extent , but it is unknown whether A . iole females rely on plant volatiles to locate host habitats . L . hesperus feeding and oviposition are known to induce emission of plant volatiles in cotton and maize , but no studies have addressed the role of plant volatiles in the host searching behavior of A . iole . The objectives of this study were to evaluate the attraction of A . iole females toward volatiles derived from L . hesperus habitats and flight response of A . iole females toward cotton plants harboring L . hesperus eggs or treated with methyl jasmonate . Results from olfactometry bioassays showed that female wasps were attracted to odors emanating from different plant -L . hesperus complexes and from adult L . hesperus , while plants damaged by non -hosts or mechanically -damaged were not attractive . These findings suggested that A . iole females use specific plant volatiles released following L . hesperus feeding and oviposition to locate host habitats . In addition , in flight chamber tests A . iole females discriminated between cotton plants with moderate (41 eggs ) and high (98 eggs ) levels of L . hesperus infestations relative to uninfested plants , but not between plants with low (7 eggs ) infestations compared to uninfested plants . In larger scale experiments conducted in the greenhouse , female wasps responded to L . hesperus -infested plants but not to methyl jasmonate -treated plants under similar conditions . Overall , results from this study revealed that A . iole females employ volatile signals to locate its host s habitat and that they are attracted to plants damaged by L . hesperus feeding and oviposition . However , further research should seek to identify the chemical elicitors involved in the release of plant volatiles attractive to A . iole females . |