April, ’18] 
CHILDS: CODLING MOTH IRREGULARITIES 
227 
immediately presents itself is: what factor or group of factors is respon¬ 
sible for this very marked variation. A study of the existing weather 
conditions during these years assists to a large degree in supplying the 
answer. v 
Owing to the fact that the writer did not arrive in Hood River until 
the middle of July, 1914, observations were not taken relative to the 
weather conditions during the early season. However, a study of the 
daily weather report indicates that the temperatures for April, May 
and June for this year were exceedingly mild, the mean average tem¬ 
perature being much higher than in any of the other three years under 
consideration, and this is largely due to the fact that the average mini¬ 
mum temperatures were uniformly higher during the three months. 
The result was that codling moths issued in large numbers early in the 
season. This was followed by favorable weather conditions for egg 
deposition and hatching. Mr. G. F. Moznette, who made observations 
at Hood River on the activities of the codling moth during the spring 
of 1914, found eggs hatching in large numbers in several orchards on 
June 5. On this date many of the worms had entered the fruits. 
Summer weather during July and August continued favorable for 
development. The first worms were found leaving the apples on June 
24; pupae were noted on July 7 and moths emerged July 19. On July 
27 the first eggs of the second brood were found on the fruit. The 
Station gave out, at this time, notices for growers to begin their spray¬ 
ing operations for the control of the second generation of worms. 
In 1915, during the months of April, May and June there was much 
more fluctuation in the daily temperatures than in the corresponding 
time during 1914. The average maximum temperature for 1915 was 
practically the same as for 1914 but the minimum temperatures were 
very much lower. In 1915, due to this fluctuating daily temperature, 
breeding cage observations seemed of little importance when correlated 
with timing of sprays for the control of the first generation of worms. 
The latter part of April and the first few days of May were very warm 
resulting in the emergence of numerous moths in the breeding cages on 
April 27 and the days immediately following. At the time the calyx 
spray was being applied in an orchard in which the writer was carrying 
on experimental work many moths were flushed from the trees when 
the spray was thrown into the foliage. Following the sixth of May and 
continuing throughout the remainder of the month rainy, cold weather 
occurred. The influence of these conditions not only prevented 
emerged moths from depositing eggs but checked—practically stopped 
—emergence which had begun on April 27. Eggs of the codling moth 
were not found until May 28, one month after the emergence of the first 
insects. These were found plentifully during the month of June and 
