New York Agricultural Experiment Station. 291 



be present in the vineyards. The normal time of entrance into 

 permanent hibernation quarters is from the latter part of October 

 until the early portion of December, depending on weather con- 

 ditions. Warm, sunny days during this time, or even during the 

 winter, cause the hoppers to fly about more or less. Since the 

 various hibernating places have a direct bearing on the infestation 

 of vineyards, considerable study was given to the habits of the 

 insect during this season. 



Green weeds or green grasses, except 

 where the upper portions are dead and 

 lodged, do not usually afford favorable places 

 for the wintering of the leaf-hoppers. How- 

 ever the grasses, such as the fox-tail grass 

 (Setaria glauca), that grow in abundance 

 during late summer on cultivated land and 

 which die and lodge either about large weeds 

 and corn stubble or about their own roots, 

 offer excellent shelters to the insects, and 

 large numbers of them exist in such situa- 

 tions. Plate IV, fig. 3, shows clumps of grass 

 which were sheltering many leaf-hoppers in 

 April after the very severe winter of 1911 — 

 12. Grassy headlands (Plate V, figs. 1-2), 

 grass and rubbish along ditches or fence rows 

 (Plate IV, figs. 1-2, and Plate VIII, figs. 2-3) are capital places for 

 the insects during the winter. Burdock has large flat leaves which 

 remain green during the winter and these shelter the pests. 

 Raspberry and blackberry patches (Plate VI) as well as woodland 

 or waste land which retain many leaves are favorite places for 

 hibernating hoppers. Old stumps which have had many holes 

 eaten into them by borers were found to shelter hundreds of leaf- 

 hoppers. The firmer leaves of trees when carried by the wind and 

 caught in the locations mentioned above are perhaps the most 

 powerful single influence in making these places favorable shelters 

 as they do not pack together tightly, but offer the insects many 

 safe hiding places. While the adults may be observed during the 

 months of November and December among various plants growing 

 in the vineyards, careful search during the spring has so far failed 



Fig. 16 — Adult Grape 

 Leaf-Hopper. 

 (Enlarged.) 



