MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 9 



Arsenate of lead held the codling moth to 98.74 per cent of fruit 

 free from worms, with no foliage injury resulting. Commercial 

 arsenate of lead No. 1 (triplumbic) produced 95.85 per cent free from 

 this insect, and the foliage was not injured. Arsenite of zinc powder 

 and arsenite of zinc paste were as effective against the codling moth 

 as arsenate of lead, but considerable foliage injury resulted from 

 their use, about 50 per cent of the leaves being burned on these plats. 



Arsenate of zinc, homemade, was effective, but fell somewhat below 

 arsenate of lead in its efficiency. The foliage was not in the least 

 injured from the use of this material. 



Arsenates of iron, chemically pure and homemade, did not burn 

 the foliage, but they were only moderately effective against the cod- 

 ling moth. As will be noted from the laboratory feeding tests with 

 this material, its killing effect is slow. 



Arsenate of calcium, chemically pure, 0.5 pound to 50 gallons, 

 held the codling moth to 86.88 per cent of fruit free from injury. 

 This fell somewhat below the efficiency of the standard arsenate of 

 lead. However, the use of a slightly increased strength of this mate- 

 rial would no doubt have been as effective as arsenate of lead, since 

 it proved to be an effective poison in the laboratory feeding tests. 

 Absolutely no burning resulted from its use, and its sticking qualities 

 were excellent, as was indicated by the abundance of the material 

 that could still be found on the foliage after several hard rains. 



Only 38.96 per cent of the fruit from the three trees of the unsprayed 

 plat was free from codling-moth injury. 



Experiment V. 



FOLIAGE INJURY TESTS OF VARIOUS ARSENICALS AND LIME-SULPHUR SOLUTION ON 

 FOLIAGE OF PEACH AND BEAN. 



A bean patch was planted in the laboratory yard, August 1, for 

 the purpose of testing the burning effect of the various poisons used 

 in the feeding tests. The leaves were sprayed with a large atomizer 

 August 31. One row containing about 30 plants was used for each 

 poison, one-third of the row being sprayed with the poison alone, 

 one-third with the poison combined with lime at the strength of 2 

 pounds to 50 gallons of spray, and the remaining third with the 

 poison combined with lime-sulphur, 1^ gallons to 50 gallons of spray. 

 The spray was prevented from blowing to other parts of the row 

 and to other rows by a canvas frame which was placed around the 

 part being sprayed. 



An experiment was also conducted on peach foliage on several 



trees in the laboratory yard. The poisons were used alone in all 



cases and were applied by means of an atomizer, using one peach 



limb for each poison. The spray was prevented from reaching other 



98119°— Bull. 278—15 2 



