GRAPE INSECTS 449 



wards the last of Juno and in July. Normally the life-cycle 

 is completed in one year, but under adverse conditions, such as 

 compact clay soil or an insufficient supply of food, the larval 

 development may be so retarded that they require a second 

 season in which to reach maturity. In the latter case they go 

 into hibernation early, in August of the second year, and prob- 

 ably give rise to the earliest beetles the following spring. 



Treatment. 



As the grape root-worm beetles feed extensively on the upper 

 surface of the leaves before beginning to lay their eggs, an 

 excellent opportunity is presented to destroy them with an 

 arsenical spray. Arsenate of lead, 6 pounds in 100 gallons of 

 water, is the poison now used most extensively for this purpose, 

 replacing Paris green and arsenite of lime because of its greater 

 adhesiveness and owing to the fact that there is less danger 

 of foliage injury. The first application should be made very 

 soon after the first beetles appear, for it has been shown that 

 they eat the poison much more readily if they have never had 

 an opportunity to feed on unsprayed foliage. A second appli- 

 cation should be made about 10 days after the first. Recent 

 work in western New York has shown that the efficiency of 

 the poison can be greatly increased by adding 2 gallons of 

 molasses to each 100 gallons of the spray liquid. Unfortunately 

 the addition of molasses decreases the adhesiveness of the poison, 

 and the application should not be made just before a rain, 

 if it can be avoided. For satisfactory results in poisoning the 

 grape root-worm, it is important that the foliage be evenly 

 covered with a fine mist-like spray. Pumps should be used that 

 give a high and uniform pressure, and the nozzles should be so 

 arranged that not only the sides of the vines are hit, but the 

 uppermost nozzle should be carried out over the top of the 

 trellis and directed downward so as to reach the new growth, 

 where much of the feeding is done. 



As stated above, the majority of the overwintering grubs 

 2g 



