THE GRAPE CURCULIO. 15 



abdomen brown, the tips of antennae dark brown, and the bases of 

 antennae and the legs light brown. It runs rapidly over the ground 

 under infested grapevines, frequently crawling beneath fallen leaves 

 and into openings in the ground in search of curculio cocoons. When 

 one is found the parasite manifests much excitement and runs about 

 over the cocoon, with both antennae and ovipositor applied to the 

 surface, in search of a vulnerable point of attack. When such a point 

 is located the ovipositor is thrust viciously to its full length within 

 the cocoon, after which the insect remains quiet for a few seconds 

 while the egg is being deposited. The parasitic larva destroys the 

 curculio within the cocoon and issues as an adult within a short time. 

 Both this species and Microbracon mellitor were abundant in the 

 locality where the present investigation was carried out. A single 

 specimen of still another parasite, which has been determined by 

 Mr. R. A. Cushman as Triaspis curculionis Fitch, was reared from 

 the grape curculio in 1917. 



METHODS OF CONTROL. 



SPRAYING. 



The long period during which the curculio beetles feed freely on the 

 upper surface of the grape leaves renders them peculiarly susceptible 

 to arsenical sprays. In several cases practically complete freedom 

 from attack was obtained by applying two sprays of lead arsenate 

 at a strength of 3 pounds of the paste to 50 gallons of water, the first just 

 after the blossoms had dropped and the second three or four weeks 

 later. In August, 1917, a count of several thousand fruits of different 

 varieties of grape from sprayed vines showed that only a little more 

 than 1 per cent of the fruit was infested, while on unsprayed vines 

 in the same locality from 75 to 90 per cent of the fruit was punctured. 



On July 26 a Concord grapevine was sprayed with lead arsenate 

 at a strength of 3-50. As soon as the spray was dry a branch of the 

 vine bearing leaves and several bunches of sound fruit was inclosed in 

 a wire-screen cage in which 50 male and female curculio beetles had 

 been placed. Four days later, when the cage was removed, all the 

 beetles were dead. The grapes which had been in the cage contained 

 8 eggs and there were about 50 feeding marks on the leaves, indicating 

 that the death of the beetles resulted from a small amount of feeding. 

 At about the same time another grapevine was sprayed with a tobacco 

 extract containing 40 per cent of nicotine as sulphate at the rate of 1 

 pint to 800 gallons of water, and a fruiting branch inclosed with 40 

 beetles. At the end of 4 days 38 of the beetles were still alive in the 

 cage, 119 eggs had been deposited in the fruit, and 1,136 feeding 

 marks had been made on the leaves.' 



It is possible to destroy the beetles by spraying with arsenicals at 

 any time during the growing season of the fruit, or in the fall after the 

 fruit has been gathered. Preferably, however, a spray shuold be 



