Investigation of Scarring of Fruit by Apple Redbugs 207 



following day many nx'mphs were found hatching. On April 29 some 

 nymphs were still hatching. The first red spots on the leaves caused by 

 the feeding bugs were found on that date. The buds were now showing 

 pink on Rhode Island Greening a'nd Tompkins King trees and the time 

 was right to begin the first scab spray. 



On the following day, April 30, spraying was started. The usual spray 

 of arsenate of lead and lime-sulfur i to 40 w^as used, and to it was added 

 one quart of Black-leaf-40 to each 200-gallon tank of spray mixture. The 

 writer spent a day in following directly behind the sprayer while it emptied 

 five tanks, making careful observations on how and under what conditions 

 the bugs were killed. 



The nymphs of L. niendax were very numerous, each branch averaging 

 one insect to a bud and frequently several insects being found on a terminal 

 bud. The nymphs were most numerous on certain water-sprout growth 

 where the adults had been especially attracted to lay their eggs. In one 

 case eleven nymphs were counted on one terminal bud, with ten more 

 nymphs distributed on the two buds below. The nymphs were in the 

 first and second instars only, and all were hatched except a few stragglers. 

 The writer followed close behind the sprayer, and as soon as a limb was 

 sprayed he approached quickly and watched the effect on the bugs. 

 Nymphs that were hit directly died within one minute. Those that were 

 protected in curled leaves were found to die within from three to four 

 minutes when the spray covered* the leaves about them, this condition 

 being observed several times. A nymph chased out of a curled leaf and 

 forced to walk over a surface spattered with spray died within three 

 minutes. Another nymph which ran out of a curled leaf and got its 

 feet wet with spray died in two minutes. A branch containing live nymphs 

 was broken off and carried thru the mist from the sprayer, and it was 

 found that all the exposed nymphs died shortly but those in curled leaves 

 did not. It was observed that many bugs in the adjoining rows of trees 

 were killed by the drifting spray in advance of the machine. 



In view of the ease with which the bugs were killed, the quantity 

 of Black-leaf-40 was reduced to three-fourths of a quart to each 200- 

 gallon tank of spray mixture. This was equally effective in killing the 

 bugs where the spraying was thoroly done, but the nymphs that sought 

 protection in curled leaves were not killed in all cases. It was apparent 

 in these observations that it is not necessary to hit the young bugs with 

 the spray in order to kill them, for the fumes of the nicotine sulfate 

 will, if placed near enough, overcome the tender nymphs. Redbugs are 

 very tender in their early stages, much more so than plant lice. It was 

 noted that young plant lice died quickly when hit, but old ones often 

 survived when only lightly sprayed. The nymphs of redbugs could be 



V7 



