2ND-GENERATION OF GRAPE BERRY MOTHS, LOBESIA-BOTRANA (DEN. AND SCHIFF.) (LEP., TORTRICIDAE) AND EUPOECILIA-AMBIGUELLA (HB.) (LEP., COCHYLIDAE) - SPATIAL AND FREQUENCY-DISTRIBUTIONS OF LARVAE, WEIGHT-LOSS AND ECONOMIC INJURY LEVEL

Spatial and frequency distributions of grape berry moth larvae were st udied in vineyards of northeastern Italy. The larval density varied in relation to position of grape clusters within vines. For density valu es below 0.5 larval nests per cluster, the larvae were almost randomly distributed and fit the Poisson distribution, while above 0.5 larval nests per cluster were slightly aggregated and fit the negative binomi al distribution better. A new method to estimate cluster weight loss c ause by second generation of grape berry moths, based on weighing and counting of berries injured, was proposed. Therefore an estimate of ec onomic injury level based on this method was put forward.