154 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



Dates of Emergence of Plies, Temperature and Precipitation 



in 191 5. 





Number of 



Maximum 



Minimum 





Date. 



flies. 



temperature. 



temperature. 



Precipitation. 



July 15 



1 



80 



56 





16 







83 



58 





17 







78 



57 



.11 



18 



9 



76 



60 



.24 



19 







89 



51 





20 



1 



81 ' 



59 





21 



2 



84 



55 





22 



14 



83 



49 





23 



9 



82 



56 





24 



11 



81 



49 





25 



5 



79 



51 





26 



5 



79 



57 





27 







82 



62 



.35 



28 



6 



85 



56 





29 







83 



58 



.47 



30 







73 



58 





31 



6 



76 



60 





August 1 



2 



83 



62 





2 







79 



62 



.64 



3 



3 



75 



48 



.05 



4 







78 



50 





5 



2 



72 



46 



.04 



6 







80 



67 





7 







78 



55 



.10 



8 







73 



58 





9 



1 



77 



58 





10 



1 



69 



60 



.17 



11 







85 



52 





12 







89 



58 





13 







87 



62 



.40 



14 



1 



82 



03 





In the season of 1914, the first fly issued on July 20, and the 

 last on August 15, under orchard conditions and on July 17, one 

 specimen was found dead below a baited plum tree in the resi- 

 dential section. In the season of 191 5, the first trypetid 

 emerged on July 15, and the last on August 14, under town 

 conditions. From these records it is evident that the first 

 application of the poisoned bait spray should be made on July 

 15, and the last treatment on August 15, providing that the 

 adults, which probably live until the apples are harvested, do 

 not invade the sprayed area from neglected trees. 



EXPERIMENTS WITH KINDS AND AMOUNTS OE POISONS. 



In view of the fact that a number of entomologists advocate 

 the use of soluble poisons in the bait to control various species 

 of Trypetidae, we conducted a series of experiments with dif- 

 ferent kinds and amounts of poisons to control the apple fruit- 

 fly. In Italy and France soluble poisons, such as potassium or 

 sodium arsenite and sodium arsenate, were used in a large num- 



