GRAPEVINE ROOT WORM 33 



with Fidia grubs and possibly preys on them. The larva of an 

 aphis lion, Chrysopa species, was observed by the writer investi- 

 gating under loose bark where eggs were present, and it is not 

 at all improbable that these insects destroy many. 



REMEDIAL. MEASURES 



It was felt when this study was undertaken that there was a 

 lack of definite knowledge regarding methods of controlling this 

 insect and it was accordingly planned to make a thorough test 

 of those advised as well as to experiment in other directions. 

 Some of these investigations gave results which appear to have a 

 positive value, while others only proved certain measures com- 

 paratively useless. 



Destroying the pupae. There is no doubt as to the benefits of 

 cultivating vineyards for the purpose of destroying the pupae, 

 if the operations are properly carried out. In the first place, 

 plan to have a moderately high ridge of firm earth about the base 

 of the vines the latter part of May, so that the grubs will come 

 well above the roots before transforming to the pupal or '^ turtle '^ 

 stage. Then adjust operations so that horse-hoeing away from 

 the vines will come early in June, thus avoiding special cultiva- 

 tion for the purpose of destroying the insects. It may be found, 

 however, that some adjustment of the cultivator, so that it will 

 work a little deeper, or a little extra care in keeping the im- 

 plement close to the vine, will materially increase the efficiency 

 of this operation. In 1902 our attention was called in the early 

 part of June to a vineyard where there were from 50 to 60 grubs 

 about many of the vines, while repeated search the latter part of 

 the same month failed to discover more than three or four pupae 

 under a vine and in many cases not a specimen. In the interval 

 this vineyard had been carefully cultivated for the purpose of 

 destroying the pupae, and we are of the opinion that this prac- 

 tice was largely responsible for the scarcity of the insects. This is 

 further substantiated by our cage experiments in 1903 [see p. 27] 

 which show that from 50,^ to 75^ or more of the pupae can be killed 

 by cultivation no more thorough than that given by horse im- 

 plements. These data lead us to believe that much can be ac- 

 complished by planning cultural operations so that the vineyard 

 will be horse-hoed at the time when the majority of the insects 



