VINEYARD SPRAYING AGAINST ROSE-CHAFER. 55 
a very ragged fruit cluster is the result. (See figs. 20-21.) By the 
time the berries have attained the size of buckshot, or even smaller, 
the danger has practically passed. This danger period covers about 
three weeks, dating from about June 13 to July 5. It is, however, 
from about June 15 to 25 that the beetles appear in maximum num- 
bers in the Lake Erie Valley, swarming into vineyards planted on 
light sandy soil from adjacent and rough sod lands and doing an 
immense amount of damage in a very short period. It is in the 
sandy soils of these pastures and rough sod lands along the lake 
shore that the insect breeds. Detached vineyards with general farm 
Fic. 18.—The rose-chafer (Macrodactylus subspinosus): a, Adult or beetle; 6, larva; 
c,d, mouthparts of larva; e, pupa; f, injury to leaves and blossoms of grape, with 
beetles at work. a, 6, e, Much enlarged; c, d, more enlarged; f, slightly reduced. 
(From Marlatt.) 
lands intervening are much more likely to suffer from serious infes- 
tation than where the vineyards are continuous and practically all 
of the soil is under clean cultivation. Thus there is an area in the 
township of North East, Pa., about 2 or 3 miles in length, lying 
parallel with the lake shore, where the soil is of a light gravel-and- 
sand composition, which in former years was badly infested by rose- 
chafers. Within the past few years practically all of the general 
farm lands of this area have been broken up and planted to vine- 
yards. These vineyards are now subject to clean culture, with the 
result that there has been no serious invasion by this pest over this 
area for several seasons. 
