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

<p>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) (<i>Plutella xylostella</i>) larvae are an important pest of cruciferous crops in greenhouses, and <i>Cotesia vestalis</i>, a larval parasitoid of DBM, are found in the surrounding areas. Dispensers of HIPVs that attracted <i>C. vestalis</i> 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 <i>C. vestalis</i> and DBM were not significantly different in the untreated greenhouses, whereas the monthly incidence of <i>C. vestalis</i> was significantly higher than that of DBM in the treated greenhouses. Poisson regression analyses showed that, in both years, a significantly higher number of <i>C. vestalis</i> 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 <i>C. vestalis</i> in the treated greenhouses than in the untreated greenhouses.</p>