166 EXPERIMENT STATION RECORD. 



roots of the grapevine, and in this stage the insect is found in the ground for 

 the greater part of the year. In early June the full-grown larva makes an 

 earthen cell a few inches below the surface of the ground, within which it 

 pupates about the middle of June; the pupal stage lasts generally 20 days, 

 and the beetle or adult begins to emerge from the ground in late June or early 

 July, while a few belated beetles continue to appear in the early part of 

 August. On an average the beetle feeds for from 10 to 13 days on the grape 

 foliage before ovipositing. The eggs are laid beneath the loose bark on the 

 canes of the vines, and hatch on an average in 12 days ; the young larva drops 

 to the ground and soon finds its way to the roots of the vine; generally the 

 larva becomes three-fourths grown and sometimes attains its full growth in 

 the fall. Previous to wintering it penetrates deeper into the ground, below the 

 roots, and there constructs an earthen cell in which it passes the winter." A 

 diagram which shows the relative occurrence and time of transformation of 

 the grape root-worm in its various stages accompanies the account. 



Under the heading of natural enemies, mention is made of several predators, 



2 hymenopterous egg parasites (Fidiohia flavipes and Lathromeris [Bra- 

 chysticha] fldice), and an undetermined dipterous egg-parasite. Studies of the 

 life history and habits of F. flavipes show that it requires 10 days for the egg 

 and larval stages, 14 to 15 days for the pupal stage, or a total of 24 to 26 days 

 for the whole life cycle. By breeding the parasites 2 full generations and a 

 partial third were produced. The percentage of parasitized eggs in the field 

 was found to vary considerably in different sections of the grape belt as well 

 as in parts of the same vineyard. In 6 lots reported, the parasitism varied 

 from none on sprayed vines to 35 per cent on unsprayed. 



The vineyard conditions in the Lake Erie Valley are briefly described and 

 detailed accounts given of work with remedial measures. 



For the destruction of adult beetles, it is recommended that the first poison 

 spray application be made as soon as the first beetles are found upon the vines, 

 since observations indicate that the beetles feed much more freely immediately 

 after emerging from the soil than they do several days later, during the period 

 of egg deposition. " The beetles may be expected to appear on the foliage dur- 

 ing the last week or 10 days in June or the first few days in July, depending 

 on the earliness of the season. After June 20 vineyardists should keep a sharp 

 watch for their appearance and have their spray equipment in readiness to 

 make the first spray application. . . . Observations and experiments indicate 

 that, if these 2 applications are made promptly and thoroughly, this pest can 

 be reduced to such small numbers that it will not materially affect the vigor 

 of the vines." The spray formula recommended consists of arsenate of lead 



3 lbs., water 50 gal., copper sulphate 5 lbs., and fresh lump lime 5 lbs. 



As soon as pupfe are discovered, the soil beneath the trellis should be re- 

 moved by the horse hoe and the soil directly around the base of the vine 

 carefully and thoroughly stirred with the hand hoe. The efRciency of this 

 method of destroying the pupte may be increased by throwing up a ridge of 

 earth beneath the trellis during the last cultivation of the preceding summer, 

 as this will tend to encourage the insects to form their pupal cells above the 

 roots of the vine and thus admit of their destruction by cultivation without 

 serious injury to the roots of the vine by the horse hoe. • No effective measures 

 have as yet been developed for the destruction of the larvse or of the eggs. 

 " Experiments conducted against the larvte in the soil with oils, carbon bisul- 

 ]ihid, fertilizers, salt, etc., have proved ineffective, and in some cases injurious 

 to tlie grapevines ; and since the eggs are deposited beneath the bark of the 

 canes when the vines are in full foliage, it is practically impossible to reach 

 them with a spray application." Suggestions are given concerning the care 



