igio 



The Cornell Reading-Courses 



Fig. 115. — Mature apple, showing 

 injury by redbugs 



spray for the codling moth. " Black leaf 40 " can be satisfactorily com- 

 bined with the dilute lime-sulphur and arsenate of lead used at these 



times. In this case the soap cannot be 

 added. These applications should be siiffi- 

 cient to control an ordinary infestation of 

 redbugs. In case, however, the insects are 

 present in great numbers, it is necessary to 

 use such large quantities of the spray liquid 

 that there is danger of foliage injury from 

 the lime-sulfur. Under such circumstances 

 the " black leaf 40 " spray should be applied 

 separately. It is necessary to spray for 

 redbugs at the times indicated, because a 

 little later, when the redbugs have become 

 larger, they are very resistant to the 

 sprays, and it is then much more difficult 

 to kill them. If the spraying is done too early some of the eggs will not 

 have hatched. 



In order to spray successfully for redbugs ver}^ thorough work must 

 be done. The insects have mouth parts of the sucking type, and it is 

 therefore necessary to hit every insect with the spray so as to wet it 

 thoroughly. Moreover, the yoimg nymphs are extremely agile and 

 readily dodge to the other side of a branch or take refuge among partly 

 expanded clusters of leaves. In order to be most effective the spraying 

 shoi-dd be done on a warm day when the yoimg bugs are most active, 

 for in cool weather they often secrete themselves in the curls of the 

 unopened leaves where it is impos- 

 sible to reach them with a spray. 

 A fairly coarse nozzle with a moderate 

 pressure, from 100 to 120 pounds, will 

 be found the most satisfactory. When 

 the nicotine solution is combined with 

 lime-sulfur and arsenate of lead, a 

 finer nozzle should be used. 



It is often desirable to determine 

 in advance of the spraying season 

 whether or not an orchard is infested. 

 This may be easily done by bringing 

 small branches indoors any time after 

 the first of March and by placing 

 them in dishes of water to force out the buds. If eggs are present on 

 these branches, the young redbugs wiU appear at the proper time and 



Fig. 116. — Apple scarred by egg-laying 

 punctures of the plum curcidio 



