Targeting diamondback moth in greenhouses by attracting specific native parasitoids with herbivory-induced plant volatiles

We investigated whether recruitment of specific parasitoids
using a specific blend of synthetic herbivory-induced plant
volatiles (HIPVs) could be a novel method of pest control in
greenhouses. In the Miyama rural area in
Kyoto, Japan,diamondback moth (DBM) (Plutella xylostella) larvae
are an important pest of cruciferous crops in greenhouses,
and Cotesia vestalis, a larval parasitoid of DBM, are
found in the surrounding areas. Dispensers of HIPVs that
attracted C. vestalis and honey feeders were set inside
greenhouses (treated greenhouses). The monthly incidence of DBM
in the treated greenhouses was significantly lower than that in the
untreated greenhouses across a two-year period. The monthly
incidences of C. vestalis and DBM were not significantly
different in the untreated greenhouses, whereas the monthly
incidence of C. vestalis was significantly higher than
that of DBM in the treated greenhouses. Poisson regression analyses showed
that, in both years, a significantly higher number of C.
vestalis was recorded in the treated greenhouses than in the
untreated greenhouses when the number of DBM adults increased. We
concluded that DBM was suppressed more effectively by C.
vestalis in the treated greenhouses than in the untreated
greenhouses.