156 MAIN!) AGRICULTURAL EXPERIMENT STATION. I916. 



moths, flies, ants, occasionally hymenopterous parasites, beetles, 

 etc., were picked up daily on the cheese cloth, and then the 

 leaves, bits of bark, twigs and wind-falls were swept off with 

 a broom. Rain fell on July n, 12 and 19, amounting to a total 

 of 1. 12 inches. On July 16 and 17, the fogs were so heavy that 

 droplets of water dripped from the wet leaves and probably 

 washed off some of the bait. On July 19, eight days after the 

 application of the spray, no dead insects were found on the 

 cheese cloth and the bait was now considered ineffective. 



Experiment II. In the second experiment instead of one 

 pound of potassium arsenate, one-half pound was used, the 

 proportions of the other ingredients being the same as in Illing- 

 worth's formula of 191 1. On July 11, one pint of the poisoned 

 bait was sprayed on the foliage of the lower branches of a large 

 Tolman Sweet. The results of the first experiment were prac- 

 tically the same as in this second experiment. 



ORCHARD EXPERIMENTS WITH POISONED BAIT. 



In order to give the various soluble poisons such as potassium 

 arsenate, sodium arsenate and sodium arsenite a most thorough 

 test under orchard and residential conditions, it was decided to 

 use 3-4, 1-2 or 1-4 of an ounce of these insecticides to every 

 three gallons of water and one pint of molasses. The different 

 kinds and amounts of soluble poisons burned the leaves, some 

 of which finally turned yellow and dropped from the trees. 

 Some of the owners were considerably alarmed on account of 

 the scorching of the leaves of their apple trees and we were 

 compelled to discontinue the use of soluble poisons and substi- 

 tute insoluble arsenicals. A remarkable peculiarity was the 

 fact that rarely was a dead specimen collected from the cheese 

 cloth with the use o:f Paris green or arsenite of lime in the 

 bait, and we are inclined to believe that the explanation rests 

 in the ability of some insects to strain out particles of insoluble 

 poisons from the diluted molasses. During the two seasons 

 cheese cloth was fastened to the ground below 29 apple trees 

 sprayed with different quantities of soluble or insoluble poisons 

 in diluted molasses, but not a single honey bee was found 

 among the dead insects. As no conclusion can be drawn on 

 the effectiveness of the poisoned bait, due to the fact that a 



