April, '21] herrick: codling moth 157 



only a third of the worms entered at the calyx. He also said "it was 

 noticed that spra\'ing was completely effective in the Pajaro Valley 

 when applied long after the calyx is closed and in the Sacramento 

 Valley good results followed when only two or three per cent of the cups 

 showed an appreciable amount of the spray." He concludes with this 

 significant statement "it will thus be seen that we do not know enough 

 of the facts to explain the reasons for the efficiency of the poison". 



Strickland (1920) has .shown that this side-worm injury is abundant, 

 and difficult to control in the apple region of Western New York in the 

 Ontario plain region. He says, "a large majority of the larvae enter 

 through the sides of the apple" and speaks of "this new factor of shallow 

 and deejj w^ork of the codling moth" and of the importance of it because 

 the defects will become more conspicuous when growers begin, as they 

 surely will, to make a uniform pack based on color, size, and smoothness 

 of fruit. He .suggests the importance of applications of spray material 

 subsequent to the calyx spray and seems to think emphasis should be 

 placed on these later sprayings. 



Childs (1920) says that during some seasons in Oregon "a very high 

 percentage of the worms enter through the calyx and during others the 

 reverse would be true." Apparently the proportion of worms entering 

 the calyx and sides varies also with the variety. For example, Childs 

 says, in an orchard of Spitzenburgs 66.96 per cent of the worms entered 

 the sides while only 33.04 per cent were calyx worms. In a block of 

 Newtowns G1.54 per cent were side worms and 38.48 per cent were calyx 

 worms. On the other hand, in a block of Arkansas Black 31.68 per cent 

 were side worms and 68.32 per cent were calyx worms. 



It is perfectly evident that we haven't all of the facts concerning the 

 larvae and their habits relative to their manner of entering the apple. 

 Moreover, it would appear that the habits of the larvae in attacking 

 the apple have an important bearing on the methods of control, especially 

 on the manner in which the poisons should be applied. There is also 

 another factor which I believe has an important bearing on this vexing 

 question of control and that is, the great variation in the time of appear- 

 ance of the codling moth in the spring from one season to another. 



In our work with the codling moth in 1911 and 1912 R. W. Braucher, 

 who carried out the work in the field, showed that the moths appeared 

 and laid their eggs fully two weeks earlier in 1911 than in 1912. Strick- 

 land (1920) points out that in the Ontario region of New York, "the egg 

 laying period for 1919 started ten days earlier than any other year since 

 1912" and the season of 1919 was what we may call a codling moth 

 year. It appears from a superficial view of the work of the insect that 

 in years in which it is abundant a greater proportion of the larvae enters 



