Influence of cover crop management systems on the development of the vine mealybug, Planococcus ficus, in a Mediterranean vineyard

Abstract: The vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), has become a serious pest in grape-growing areas in southern Europe and its development is affected by nitrogen fertilization. Cover crops are common cultural techniques in vineyards to manage soil fertility and plant vigour. The influence of different total ground cover crops on selected life-history parameters of the vine mealybugs (survival, development time, fecundity and fertility) was investigated in a multi-year interdisciplinary project. The soil management systems tested were: natural covering, grass and legume cover crops and soil tillage. To evaluate the vine response to ground management, crop yield and total soluble solids (sugar content) were recorded. The nitrogen content on grape leaves was indirectly assessed using a SPAD meter.Ground covers affected development time, fecundity and fertility of P. ficus in both years of observations. Enhanced reproductive and development parameters (i.e. lower development time and higher fecundity and fertility) were observed in tillage and legume covering plots. With regard to the grapevine response to soil management systems, in both years soil management significantly affected nitrogen concentration on plants, as SPAD values were higher in plants managed with tillage and legume covering. Cover crops modified the physiology of grapevines thereby affecting the development of the vine mealybug. The investigated ground covers also affected crop yield and quality of must. In particular, grass cover crops reduced the quantitative production and increased the concentration of sugar in the must. In conclusion, ground covers play an important role in vineyards and should also be considered when planning pest management programs.