THE STATE ENTOMOLOGIST. 67 



time find enemies, and lose its acute power of doing liarm even in Europe, 

 is highl}' probable ; and M. Planehon has already noticed that the infested 

 ■vines in the later invaded departments of Gard and Herault retained a com- 

 paratively greener color than in that of Vaucluse, first invaded. Such has 

 been the history of the Hessian fly and a number of other insects imported 

 into this country. These are the explanations I venture, and whether they 

 be generally accepted or not, the facts remain. 



OUTWARD AND MORE VISIBLE EFFECTS OP THE ROOT DISEASE. 



As long as the lice are confined to the more fibrous roots which, in a 

 measure, are renewed each year, the vines show ho decided outward signs 

 of the malady, which ma}" then be considered in its incipient stage. As 

 the}' become multiiilicd and fasten on to the larger roots, their work 

 becomes more visible in a sicklj", yellowish appearance of the leaf; and a 

 reduced growth of the vine is the result. As the roots waste away these 

 symptoms become more acute, and at this stage of the disease the lice have 

 generally left, so that when the vine is about d3'ing it is often difficult to 

 find any trace of the cause of death. On the rotten roots little eight- 

 legged mites are frequently met with, and the}" are also to be found in the 

 galls. They may always be distinguished from the true lice by their white, 

 or dirty-white, color. 



PRACTICAL SUGGESTIONS. 



Last year, from the knowledge we then had of this insect in this 

 country, 1 recommended the destruction of the Clinton vine, where other 

 «,nd better varieties succeeded as well. This advice was given in order to 

 get rid of the galls, and wherever it has been followed it has had the desired 

 effect. It was given, however, under the impression that the lice 

 would not attack the roots except where the leaves were covered with 

 galls ; whereas, in truth, the roots would appear to be less affected (at least 

 during the growing season) where the leaf-galls are abundant than where 

 they ard scarce; while they may be absolutely ruined where no signs of 

 galls exist. Consequently there is no longer any urgent need of, or good 

 reasons for, destrojnng our Clinton vines. By doing so we may diminish 

 the number of galls, but Ave can jiever exterminate the root-lice. Future 

 experiments will no doubt show that good results will attend the grafting 

 of such varieties as are known to be most seriously affected, on to the roots 

 of less suscejjtible varieties. 



The insect should be especially watched, as it is apt to be most trouble- 

 some, on poor, gravelly or clayey soils. In deep, rich soils I think there is 

 less danger. In France it has been found to be less troublesome on sandy 

 soils, and in m}" studies I have always noticed that minute, soft-bodied 

 insects do poorly in sand.* The gi-eater the growth of vine the greater the 

 growth of root, and consequently, vines that are trained on walls and 

 which thus more nearly approach the wild state, or which are rendered vig- 

 orous by a rich soil, are least susceptible to the disease. 



* In examining vine roots this faU in sonii; parts of Nortliern Illinois , wliere sand formed a prom- 

 inent portion of the soil, I found very few root-lice, except on Cordifolia vines whose leaves had 

 been covered with galls. Even on these the general healthfulness of the roots, indicated that they 

 had not been infested during the summer, and that the lice had all come from the last galls of the 

 season . 



