766 EXPERIMENT STATION RECORD. 



soon as they leaf out. By summer the insects have gradually left other 

 plants and accumulated on the vines. The older and weaker insects 

 die off. reducing the numbers for a while; then about the first of June 

 the first brood reaches maturity, and from this time on the numbers 

 increase again. 



The injury to the plant is explained as due to the loss of water from 

 the continual leakage caused by the insect's punctures, which removes 

 the tension necessary to the growth of the plant, and causes premature 

 ripening and loss of the leaves. 



The remedies noted are turning sheep into the vineyard, destroying 

 leaves, plowing and rolling, winter spraying, summer spraying, jarring, 

 the use of the hopper dozer, and the net. The first and favorite remedy 

 is not thought worthy of recommendation. There is said to be no evi- 

 dence in favor of its employment. The second remedy is considered 

 equally worthless. The third may destroy a few, but the results will 

 not justify the expense. Winter spraying is worthless; summer spray- 

 ing, although effectual, scarcely pays when the difficulty and cost are 

 taken into consideration. In such spraying a strong wash, like kerosene 

 emulsion, must be used. Jarring is one of the best methods, and sev- 

 eral pieces of apparatus for use in this method are figured. In Califor- 

 nia the favorite apparatus resembles a large scoop with a net in front 

 and with the hind edge bent to receive the handle. The use of a large 

 insect net is also recommended. 



The plan of trying to exterminate the insects has been found by 

 repeated trials to be impracticable, and, since it is only the excessive 

 numbers of the insects that are injurious, the author proposes the plan 

 of merely trying to reduce the numbers below the danger line — about 

 50 per cent in the worst years. 



"According to the best estimate we could make by actual trial in the field of the 

 effect of the use of the net in the spring, it appeared that a much larger percentage 

 than that could lie destroyed — nearer 90 per rent, and this, to, while working at a rate 

 of about 5 acres a day. About half of a gang of men, green hands at the business, 

 part white and part Chinese, did almost as well as one skilled with the net. At the 

 rate of wages they were getting, the cost per acre would be between 15 and 20 cts. 

 This makes it a wonderfully cheap process. If it cost twice as much, and had to be 

 done a dozen times a year, it would not begin to cost as much as the loss to a crop 

 in a bad year. It seems to have been proven by actual test that a good percentage 

 of the hoppers can be taken and killed by the use of the net and at a cost per acre 

 that is nominal. There yet remains to be seen whether the vineyardist can develop 

 a judgment that is to be depended on as to when the insects are approaching the 

 danger point, and to set the nets going. According to this new theory of treatment, 

 it would appear that we have the true solution of the problem and that the net or 

 the palm-leaf fan are the means giving the greatest promise." 



Insects of the prune, A. B. Cordley (Oref/on Sta. Bid. 45, pp. 

 99-127, pis. .;, figs. ■/). — This bulletin was compiled to enable Oregon 

 fruit raisers to recognize the various insects that attack the prune. 

 Although prunes have been grown in Oregon for some years the insects 

 that affect the trees elsewhere are only beginning to be introduced. It 



