Entomopathogenic nematodes application for controlling Lobesia botrana in grapevine and their impact on grapevine quality
Entomopathogenic nematodes (EPN) are well-known biological control agents combined with specific adjuvants that now allow their use against aerial pests. Lobesia botrana (Lepidoptera: Tortricidae) is one of the major harmful pests detected in worldwide vineyards. Previous studies demonstrated that the EPNs Steinernema feltiae and S. carpocapsae could control L. botrana. The hypothesis was that the best combination of EPN-adjuvant/timing (season/temperatures) will support the use of EPN in the vineyard against L. botrana with no impact on the grape performance. The aims of this study were to select the best EPN-adjuvant mix for their use against L. botrana and determine whether this application can imply any change in the grape quality. Overall, the adjuvant Maximix resulted in the best candidate for the combination with S. feltiae and S. carpocapsae. Compared with the no-application treatment, Maximix combined with EPN increased their killing against L. botrana L3 larvae on grapes and leaves with a significant reduction of the damage. In the trunk bark system at 22 ºC, 14 ºC, and 10 ºC, pupae mortality caused by EPN decreased with temperature, from ~60 % at 22 ºC to values ~20 % at 10ºC, and the use of Maximix in this scenario did not improve their efficacy. The volatile composition of the grapes did not show significant differences among treatments however, a trend to increase different families of volatiles (terpenes and C13-norisoprenoids) was observed when S. feltiae was combined with the adjuvant Maximix. Further validation in field conditions is necessary for their full implementation.
Issue: ICGWS 2023
1Instituto de Ciencias de la Vid y del Vino (ICVV), Consejo Superior de Investigaciones Científicas, Universidad de La Rioja, Gobierno de La Rioja, Ctra. Burgos km 6, La Grajera, 26007 Logroño, Spain