GYPSY AND BROWN-TAIL MOTHS AND THEIR CONTROL 33 



any comfort during the early summer if the caterpillars are abundant. 

 If clothing is hung on the line near badly infested trees, the hairs 

 frequently find lodgment and are brought into the houses, with 

 consequent poisoning of the inhabitants. 



NATIVE ENEMIES 



One of the important native enemies of the brown-tail moth is a 

 fungus disease (Entomophthora aulicae Reich.) which attacks the 

 caterpillars. It was first reported in this country by Roland Thaxter 

 in 1888. Like all diseases of this nature, the benefit derived from it 

 is regulated largely by weather conditions. This fungus sometimes 

 works to a slight degree on the small caterpillars in the fall, and is 

 found occasionally in the winter webs. As a rule, however, the 

 greatest mortality of caterpillars takes place in the spring, when they 

 are nearly full grown, and the pupae may, under the most favorable 

 conditions, be almost completely exterminated. 



Native parasites and predacious insects have done little to check 

 the increase of the brown-tail moth. 



INTRODUCED PARASITES AND OTHER ENEMIES 



Compsilura concinnata Meig., one of the species introduced as an 

 enemy of the gypsy moth, attacks the caterpillars of the brown-tail 

 moth freely, while two others, Apanteles lacteicolor Vier. and Sturmia 

 nidicola Towns., that were introduced from Europe at about the 

 same time are also important enemies of the insect. Other imported 

 enemies, Carcelia laxvfrons Vill., Meteorus versicolor Wesm., and 

 Eupteromalus nidulans Foerst., that have become established help to 

 reduce the numbers of the moth but are not usually of great importance. 



EFFECT OF LOW TEMPERATURES 



Extremely low temperatures in the winter often prove fatal to a 

 large proportion of the small caterpillars in the webs. When unpro- 

 tected by snow or other covering, they are usually killed by tempera- 

 tures below — 25° F. 



METHODS OF CONTROL 



The brown-tail moth can be controlled by cutting off the winter 

 webs and burning them before the caterpillars begin to emerge in 

 April. These webs should be destroyed by fire, for if they are simply 

 cut from the trees and left on the ground, the caterpillars will emerge 

 and no benefit will result from the work that has been done. 



In orchards it is sometimes inadvisable to cut the winter webs, for 

 where an infestation is heavy the cutting is likely to leave poorly 

 shaped trees. Spraying in the spring is not a satisfactory remedy 

 unless the infestation is very light, because large numbers of cater- 

 pillars do not allow the tree to put out sufficient foliage to hold the 

 spray material. 



An effective method in orchards is to spray the trees before the 

 middle of August, using 3 pounds of powdered lead arsenate to 100 

 gallons of water. Before doing so the orchardist should determine 

 to what extent the trees are infested with egg masses of the brown- 

 tail moth. In spraying fruit trees, particularly early fall varieties, 



