226 



THE MONTHLY BULLETIN. 



tration very often means a bad wireworm infestation. During the last 

 two years which were unusually wet, the centers of infestation by 

 wire worms seemed to move from the low country near the ocean to 

 higher ground, in places where there was a choice. Before that, the 

 centers of infestation had usually been in the low areas. If these 

 observations are correct, we should look for the centers of infestation 

 (m the higher ground this j^ear. 



There seems to be considerable variation in the time the worms 

 become active in the spring in the different types of soil and in different 

 localities. During the spring of 1914, which was very cold and foggy, 

 the w^orms did considerable damage in the Camarillo district and even 

 as far inland as Somis. During the spring of 1915, which was unusu- 

 ally warm and sunshiny, practically no damage was done in the 

 Camarillo and Somis sections, and considerably less damage than usual 

 in the Oxnard district. On cold sandy ground, in some instances, 



Fig. 74. — Wireworms, the larvse of click-beetles, in a 

 potato. Slightly enlarged. (After Kssig, Inj. and Ben. 

 Insects of Cal., p. 232, State Hort. Com.) 



catch-crops failed to show any worms, but the beans were riddled when 

 planted. In another instance the beans germinated and grew for 

 several weeks before the worms became active. Soil temperature and 

 to some extent the moisture content are undoubtedly the controlling 

 factors in these cases. In fact, the worms seem to be very sensitive to 

 heat. They will live indefinitely in cold water, or may live half an 

 hour in pure distillate, but they are killed in five or ten minutes when 

 exposed to the warm sunshine or placed in lukewarm water, and drop- 

 })ing them througli raw steam kills them instantly. 



These different conditions are confusing and lead to a vast number 

 of erroneous ideas and conclusions on the part of the farmer. Many a 

 farmer has been led to believe that he has controlled the worms through 



