REPORT OF THE DIRECTOR 1920-21 37 



was favored to an appreciable extent at least by cool weather pre 

 venting the plants from readily outgrowing the injuries by wireworms 



Codling moth. Field studies of the codling moth have been con- 

 tinued by the Entomologist in cooperation with the Bureau of Plant 

 Industry of the State Department of Farms and Markets. L. F. 

 Strickland succeeded, through the cooperation of George W. Mead 

 of Barker, in securing exact records of evening temperatures as well 

 as the maxima and minima. The accuracy of this work was 

 materially increased, as was the case last year, by the cooperation 

 of the United States Weather Bureau in loaning thermographs and 

 providing for the supervision and setting up of the instruments. The 

 intimate relations existing between evening temperatures and codling 

 moth oviposition are graphically represented in a chart by Mr Strick- 

 land, who was also responsible for observations upon egg deposition 

 in the orchard. The demonstration of this relationship is a necessary 

 preliminary to the solving of the vexatious problem of codling moth 

 control in the western part of the State. 



The series of experiments to determine the relative efficiency of 

 the several sprays for the control of the codling moth in the western 

 part of the State has been continued. The most marked results, 

 as was to be expected, were obtained with the first or calyx spray 

 and under the conditions obtaining in the experimental orchard the 

 past season, the figures would appear to indicate an increased 

 infestation on trees sprayed twice as compared with those receiving 

 but one application. These data must be interpreted or erroneous 

 conclusions may be drawn. The real explanation is that the 

 apparently higher percentage of infested fruit on the plot sprayed 

 twice is due to the smaller crop on these trees rather than to an 

 increase in the number of apple worms. Complications of this 

 character are almost unavoidable in experimental work and when 

 the cause is not known may vitiate results. 



A comparatively rare apple pest. The rose leaf beetle, a rather 

 common feeder upon roses and widely distributed in the State, 

 appeared in a somewhat unfamilar role the past season on account 

 of its feeding upon and somewhat seriously injuring young apples. 

 In some instances 10 to 20 per cent of the fruit was affected so 

 seriously that most of the apples dropped or were badly deformed. 



Shade tree insects. Shade trees, as a rule, were comparatively 

 free from serious insect damage, though the elm leaf beetle was 

 locally abundant and injurious, especially in the upper Hudson 

 valley and the lower portion of the Mohawk valley. The com- 

 parative scarcity of this insect in many of the cities and villages 



