]24 



Report of State Board of Horticulture. 



in the Pacific Northwest. Observations for the past six years have led me 

 to a different conclusion than that arrived at by my associates. Washburn* 

 states that there are at least four broods in Oregon. Aldricht reports three 

 broods in the section from Boise to Weiser and about Lewiston and part 

 of a fourth about Boise. SimpsonJ states that there are three broods about 

 Boise and the greater part of the bnake river valley. Parts of eastern 

 Oregon are similar to the sections of Idaho mentioned, and should the 

 conclusions of Aldrich and Simpson prove to be correct, three broods may 

 likewise be expected in the eastern part of the state. 



However, I have been entirely unable to find any evidence to support 

 Washburn's conclusions and I believe the others, likewise, will eventually 

 prove erroneous. In every instance, so far as I have been able to determine, 

 statements regarding third and fourth broods are based on inferences and 

 not on actual breeding records. Washburn, judging from his published 

 account, determined the length of time required for the development of 

 the first brood. Having done this by a process of simple division, he 

 showed "how easily four broods can appear during our long warm seasons." 



To make his ideas more easily understood he embodied them in the fol- 

 lowing table;* 



Moths emerge from cocoons 



Egg laying (when moths are about 10 

 days old) 



Hatching of eggs (5-10 days) 



Lifeof larvfe in apple (4 weeks) 



End of larvel and pupal stages in cocoon 

 (3 weeks) and emergence of moths 



Columns A, C and E are supposed to represent the broods which might 

 develop from moths that were assumed to have emerged June 1 and depos- 

 ited eggs June 10. Columns B and D represent the broods that should 

 develop from moths that emerged June 20 and deposited eggs June 30. 

 So far as the latter columns are concerned it may be assumed that they are 

 approximately correct except for the implied inference that at least a 

 partial brood of moths would appear November 5. The data furnished do 

 not support the conclusion he draws from columns A, C and E that "the 

 moth is at least four broods in Oregon." Moths are assumed to emerge 

 June 1 and deposit eggs June 11, but on the same page the statement is 

 made that eggs were found (June 28) long before any wormy apples were 

 found. Further, according to his calculations the moths that are to 

 deposit eggs for the third brood of larvae should issue about the middle of 

 October. There is no evidence, however, that he ever bred any moths at 



* Bui. 25, Or. Expt. Sta. 



t Bui. 21, Idaho Expt. Sta. 



% Bui. 30. New Series. Div. Ent. U. S. Dept. Agr. 



* See Bui. 25, Or. Expt. Sta. 



