Effects of different cover crops on grapevine properties and development of the vine mealybug in Mediterranean environment

The influence of complete cover cropping (inter- and intra-row) on grapevine growth, yield and must quality was evaluated during a three-year field trial in a commercial vineyard located in north-western Sardinia (Italy). Effects on developmental and reproductive parameters of the vine mealybug (Planococcus ficus) were also investigated. The experimental treatments were: natural covering, legume mixture, grass mixture, and conventional soil tillage, which served as the reference treatment. Sown cover crops reduce the grape production on average by 30%. However, different cover crops modify yield components in different ways. In addition, the total ground cover also influenced the must quality parameters in a positive way according to enological target intended. The grass cover increased the content of sugar, anthocyanins and polyphenols, thus improving the general quality of the must. The legume mixture and natural cover both reduced the total polyphenols and anthocyanins detected in the must at harvest. All the P. ficus biological parameters examined were affected by the ground management practices.Mealybugs reared on grapevines subjected to soil tillage and legume cover showed a faster development time and higher survival, fecundity and fertility than those developed on natural cover and grass plots.Utilizing competitive cover crops, while reducing yields, would improve must quality and reduce pest development.