Cultural control of Lobesia botrana on grapevines

Abstract: During 2007–2016, the effect of bunch-zone leaf removal (BZLR), performed at the beginning of Lobesia botrana (Den. & Schiff.) second flight, on the moth second and third generations was tested in north-eastern Italian vineyards. In addition, during 2015-2016, the mode of action of BZLR on L. botrana control was studied thorough some laboratory and field bioassays. In the laboratory, eggs and newly-hatched larvae were exposed to high temperatures (i. e., 35 °C to 43 °C). In the field, temperatures of sun-exposed berries were measured on differently oriented rows, and egg laying, hatching and larval settlement in sun-exposed and non-exposed bunches were compared. The results showed that BZLR reduced both carpophagous generation of around 50%. Temperatures from 40 °C and from 37 °C increased the mortality of eggs and newly-hatched larvae, respectively. In the field, the berry temperatures of sun-exposed bunches exceeded the temperatures that were lethal in the laboratory. On bunches exposed to sunlight, egg hatching and larval settlement were reduced without a lower number of eggs laid by females on these bunches. BZLR can be considered a valid cultural practice in the context of Integrated Pest Management.