14 FARMERS' BULLETIN 845. 



may be almost completely exterminated. Native parasites and 

 predacious insects have done very little to check the increase of the 

 brown-tail moth. 



INTRODUCED PARASITES AND ENEMIES. 



The parasites and enemies already mentioned as being particularly 

 valuable for their work in destroying the gipsy moth, with the ex- 

 ception of the egg parasites, also attack the brown-tail moth. The 

 Calosoma beetle * and its larvae do valuable work each year in de- 

 stroying brown-tail caterpillars and pupae, and the insect parasites 

 also attack this species in considerable numbers. Another imported 

 parasite 2 has become established in this country and is doing ex- 

 cellent work. It attacks the brown-tail moth caterpillars, but not 

 those of the gipsy moth. 



Throughout the infested territory a marked decrease in the number 

 of moths has been noted during the last two or three years. The 

 work of the parasites has been a very important factor in this con- 

 nection. In some parts of the infested territory the mortality among 

 the caterpillars in the brown-tail webs has been very high during the 

 winter. 



HAND METHODS FOR CONTROLLING THE BROWN-TAIL MOTH. 



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 tree and left on the ground the caterpillars will emerge 

 and no benefit will result from the work which has been doixe. 



In orchard practice it is sometimes inadvisable to cut the winter 

 webs, for where an infestation is bad it is likely to leave a poorly 

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

 unless the infestation is very light, because the caterpillars, when 

 they occur in large numbers, do not allow the tree to put out suffi- 

 cient foliage to hold the spray material. The most effective method 

 is to spray the trees before the middle of August, using from 6 to 10 

 pounds of arsenate of lead to 100 gallons of water. Before spraying 

 operations of this sort are attempted care should be taken to deter- 

 mine whether the trees are well infested with egg masses of the 

 brown-tail moth, for if the infestation is very slight it will be more 

 satisfactory to cut and destroy the webs. If the infestation war- 

 rants, both shade, ornamental, and fruit trees may be sprayed to 

 advantage at this time. Caution should be used, however, in spray- 

 ing fruit trees, particularly if early fall varieties are to be treated. 

 If this is to be done, a somewhat weaker spray solution may be used, 

 provided it is applied as soon as the caterpillars begin to hatch. The 



i Calosoma sycophanta L. 2 Meteorus versicolor Wesm. 



