232 NEBRASKA STATE HORTICULTURAL SOCIETY 



exposure to the air and sunlight. Especially is this method valuable 

 in loose or sandy soils, where the pupal cells are so friable that they 

 are easily broken up by this cultivation. If a ridge of earth is thrown 

 beneath the trellis at the last cultivation of the previous summer, 

 the pupas will tend to form their cells in this ridge, well above the 

 roots of the vine thus facilitating their disturbance by cultivation 

 with minimum chances of injury to the roots of the vine with the 

 horse hoe. The ridge should not be thrown up in the spring, 

 because the leaves and trash which have accu^iulated under the trellis 

 during the winter will be thrown at the bottom of the ridge and there 

 will form a barrier through which the larvae will not penetrate when 

 Avorking upword in the soil to form their pupal cells, and they are 

 consequently not disturbed when the ridge is thrown back by the 

 hoe later in the spring. 



The above method of control by cultivation is especially success- 

 ful in normally moist springs and on loose soils. In seasons when 

 pupation comes unusually late the vineyardist is often reluctant to 

 postpone the first cultivation to so late a date, and quite reason- 

 ably so, because early and thorough cultivation is a very important 

 thing to do in the vineyard. Consequently, in some abnormally late 

 and dry seasons, it might be better management not to await the pupa- 

 tion period for cultivation but to cultivate at the usual time and 

 depend upon spraying to take care of the insects. Moreover, in dry 

 years it may be difficult to cultivate with a horse hoe as thoroughly 

 and deeply as is necessary to disturb the pupal cells, especially in 

 clay soils, if the cultivation is deferred until latter June. In such case^ 

 the vineyardist must use his best judgment, remembering that in 

 normal years the cultivation may be done at such a time and under 

 fcuch conditions as to prove an exceedingly valuable supplementary 

 aid to spraying, and one involving additional expense to him. 



The principal method of control is spraying with arsenical 

 poison so as to kill the beetles shortly after their emergence from 

 the soil and before they have laid their eggs. As the time for the 

 emergence of the beetle3 draw near, that is toward the end of June 

 and early in July, the vineyardist should make daily examinations 

 of his vines to ascertain exactly when the beetles begin to appear. 

 It will be found that considerable variation in tliis point occurs from 

 season to season, sometimes as much as two or three weeks in suc- 

 cessive seasons, so that no definite calender dates can be assigned, 

 but the time must be determined by field observations each year. 

 AVith the appearance of the first beetle all preliminary preparations 

 for spraying the vines should have been made, and actual spraying 

 operations should be started at once. It is highly essential that 

 the beetles be killed by their first feeding after emergence, when 

 they eat very freely, and before they have had an opportunity to 

 deposit their eggs. In spraying for these beetles arsenate of lead has 

 given the most satisfactory results, and it should be used at a strength 



