208 RErORT OF OFFICE OF EXPERIMENT STATIONS. 



TENT-CATERPILLARS. 



Motliods for controlling tlic ai)i)li'-tr('(' tcnt-catcriiilhir liavc hcon 

 stiulieil in various States. In Connect ic-ut " it was found that whore 

 early spray in*; is practiced no other remedy is re<|uired. Arsenate 

 of lead or Paris «rreen, with or without Bordeaux mixture, will kill 

 the caterpillars when applied to the folia«;e. If the caterpillars 

 begin feeding before the buds have fidly opened, the cokmies may 

 be brushed from the trees and the arsenicals de])ended upon to kill the 

 remainder of the caterpilhirs hiter. For spraying against the tent- 

 caterj)illar. one-half pound of Paris green or I) pounds of arsenate of 

 lead is reconnnended for each 50 gallons of water. 



During some seasons the forest tent-caterpillar appears in unusual 

 numbers and becomes a scourge of forest trees, especially maples. 

 This pest has been studied in several States, and in New York '' it was 

 found that if the insect appears in orchards, the egg masses may read- 

 ily be seen and may be collected and destroyed. For killing the cater- 

 pillars, it is sufficient to spray with an arsenical compound either 

 Paris green, arsenate of lead, or green arsenite. The caterpillars 

 may also be destroyed when they are collected in large clusters on the 

 trunks of the trees. 



RED SPIDERS. 



Considerable work has been done on methods of controlling red 

 spiders, especially at the California Station.'" As a result of the.se 

 experiments, it appears that the red spider of citrus trees while not 

 producing the spotting of the fruit, as has sometimes been thought, 

 does cause the fruit to drop and injures the leaves. In controlling this 

 pest, fumigation has been found of no value. Sulphur is of far less 

 value than for use against the red spider of deciduous fruit trees, 

 while the value of distillate oils in combating this pest still remains 

 somewhat uncertain. The best remedy for the red spider of citrus 

 trees wuh found to be sulphate of potash prej^ared according to a 

 formula calling for 32 pounds of potash, 87 i)ounds of finely ground 

 .sulphur, and 2 pounds of salt per 50 gallons of water. The stock 

 solution thus made is to be diluted about 100 times before spraying. 

 In spraying citrus trees for red spider, it appears to be necessary to use 

 extension rods so that the spray may be applied upward and outAvard 

 from the inside of the tree and also toward the center of the tree from 

 the outside. The red spider of deciduous fruit trees may be con- 

 trolled by the use of sulphur sprays. In preparing this insecticide 

 it is recommended that 1 pound of wheat flour be mixed with 1 gal- 



« Connecticut State Stn. Rul. ISO. 

 6 New York State Sta. Bui. l.".n. 

 c California Sta. Buls. 14.'j, 1.54. 



