I^II 



BETTER FRUIT 



Page 35 



ORCHARDS INJURED BY THE TUSSOCK MOTH 



SUMMARIZED BY F. M. HALL. FROM BULLETIN BY W. J. SCHOENE, NEW YORK EXPERIMENT STATION, GENEVA, NEW YORK 



THE white-marked tussock moth 

 has been, at intervals for nearly a 

 century, a noteworthy enemy of 

 fruit trees and shade trees. During 

 recent years it has become increasingly 

 prominent as a destroyer of foliage in 

 city parks and streets, and has made it 

 necessary for many cities and villages to 

 adopt vigorous repressive measures. The 

 attacks of the insect on fruit trees have 

 attracted attention less frequently, though 

 some of the caterpillars are found in 

 many orchards every year. In 1895 quite 

 a serious outbreak occurred in Ontario 

 and Yates Counties in this state, but 

 since that time the numbers of the cater- 

 pillars have remained about normal until 

 1908, when they increased alarmingly 

 over quite an area in Western New York, 

 particularly in the sections about Lock- 

 port, Ransomville and Middleport, in 

 Niagara County. Considerable damage 

 was done to the leaves, but more atten- 

 tion was attracted to the injury to fruit 

 caused by the young caterpillars. The 

 attack was usually upon the cheek of an 

 apple or pear, the skin only being eaten 



in some cases, though usually a cavity of 

 considerable depth was made. 



Attempts were made to control the 

 caterpillars by spraying with poison in 

 bordeaux mixture, but damage appeared 

 to increase for as much as a week after 

 the application of poison had been made. 

 Injury was .also quite common in the 

 orchards that had previously been given 

 sprayings for codling moth. These facts 

 led many orchardists to believe the tus- 

 sock-moth caterpillars immune to poison. 

 However, the failure to kill them is not 

 due to any peculiar resistance to poison, 

 but to the fact that the insects feed, . 

 after the first, within the apple and on 

 the lower sides of leaves in the interior 

 of the trees, where only most thorough 

 spraying will reach them. As long as the 

 caterpillars continued to feed in the pro- 

 tected spots they escaped death, but as 

 they changed feeding grounds with their 

 increasing size they took the poison, and 

 gradually died off. 



The extent of the injury varied greatly 

 with the individual trees, ranging from 

 wounds on possibly five per cent of the 



fruits to partial or almost complete 

 destruction of eighty-five per cent. This 

 variation is quite readily explained by 

 the wingless condition of the female 

 moth and the consequent limitation of 

 broods in successive years to rather nar- 

 row limits. 



SPRAY NOZZLES AND ATTACHMENTS 

 116, Brass Y; 117, Bordeaux nozzle; 118, 

 Angle Y; 119, Angle L; 120, Small Vapo 

 nozzle; 121, Large Vapo nozzle; 122, Brass 

 discs; 12:3, Steel discs; 145, Single Blizzard 

 nozzle: 116, Two-cluster Blizzard nozzle 



The caterpillars, especially in the last 

 two iir three of their four or five molts, 

 are strikingly marked, and, if we could 

 forget their association with crop destruc- 

 tion, even beautiful caterpillars. The 

 heads and two small tubercules on the 

 back are bright red, a long horn-like 

 pencil of black hairs projects forward 

 from each side of the head, and a similar 

 pencil back and upward from the rear of 

 the body, four very prominent brush-like 

 tufts of thickly crowded white hairs are 



