New York Agricultural Experiment Station. 575 



Life History and Habits. 



Although this insect is being studied here at the Station, we 

 have not observed, up to the time of writing this report, all of 

 the transformations which take place during the life cycle. As 

 usually given by entomologists, however, its life history is,briefly, 

 as follows: 



The winged viviparous females appear late in the summer or 

 early in the fall. This female produces oviparous females. The 

 males are present at this time and the oviparous females produce 

 eggs, which will hatch the following season. These are 

 called winter eggs. In addition to these eggs, propagation is 

 jH-ovided for by hibernating larva3. These live on the roots or 

 above ground on the trunk or branches. This year, as previ- 

 ously stated, we found the lice hibernating in the very young 

 larva stage and in all gradations to a nearly full grown louse. 



The winter eggs hatch in the spring, producing agamic females. 

 Each female starts a colony, from which other colonies originate. 



Natural Enemies. 



Several species of parasitic insects are known to prey ui)on the 

 woolly aphis. Certain species of predaceous insect also prey 

 upon this insect. One of the most important of these is the root 

 louse syrphus fly, the larva of which was often found last season 

 among the colonies of the lice. 



Preventive and Remedial Measures. 



Preventive measures. — At present the only preventive measure 

 which we can suggest for both nurserymen and orchardists is to 

 refuse to accept trees which are infested with this insect. 



Growers of iiurser}' stock will find it of advantage either to 

 destroy old apple trees which may be in (lie vicinity of their 

 blocks of apple trees, or to have these trees kept free from the 

 woolly aphis. We have noticed several instances where the 

 nursery stock had undoubtedly become infested with this insect 

 from old infested apple trees near by. 



