The effects of temperature on the chronological distribution of Lobesia botrana life stages from egg to eclosion

Lobesia botrana, also known as the European grapevine moth (EGVM), is an invasive moth species that was first reported in Napa vineyards in 2009. EGVM larvae cause substantial damage to all the phenological stages of grapes resulting in economic loss. The possibility of introducing EGVM to unaffected areas of the US and other countries via grape exports is of concern. A study to document the effects of temperature on the chronological distribution of EGVM life stages from egg to eclosion was conducted at the Contained Research Facility at UC Davis. Head capsule measurements of sampled larvae were used to statistically differentiate instars. Mean developmental times and estimated rates of development for each life stage were determined at 16°C, 20°C, and 24°C. The results of this study can be used to determine the distribution of life stages at a precise time in the EGVM life cycle at which fumigation to post-harvested fruit is applied. Knowing the distribution and pinpointing EGVM’s most resistant stage when applying fumigation to grapes for export can help ensure the effectiveness of fumigation, containment of EGVM and continued trade.