40 



PAPEKS ON INSECTS AFFECTING VEGETABLES. 



September 15 the application was repeated. The older leaves were 

 still well coated with the poison from the first dose, but many new 

 leaves had been put out and these were unprotected. All were com- 

 pletely coated by the second spraying. At this date there were oc- 

 casional dead larvae, but they were not common. 



September 16 it was noted that some of the larvae were actuall} 7 

 entering the bud and that very few of them had been killed. 



Heav} 7 showers occurred September 18, 19, and 20, but the coat of 

 poison remained fairly good. At this latter date, most of the larva? 

 were in flourishing condition, and the experiment was considered a 

 failure. The plants were slightly burned, but no serious damage re- 

 sulted. One interesting point brought out by this experiment is that 

 the mixture was remarkably adhesive and not readily washed from 

 the foliage b}^ rains. 



Experiment No. 8. — Arsenate of lead,* 5 pounds, and whale-oil 

 soap, 10 pounds, in 100 gallons of water. 



October 12, 418 good-sized cabbage plants were sprayed. The 

 larA'ae were moderately common. All were deeply buried and ob- 

 viously beyond the reach of the poison. The mixture adhered well 

 and the plants were completely coated. These plants were examined 

 daily until October 19, but not a dead larva was found, and at that 

 date the experiment was abandoned as a complete failure. The 

 mixture did not burn the foliage. 



Expedient No. 4- — Paris green, 2 pounds, whale-oil soap, 8 

 pounds, and nicotine sulphate, 25 ounces, in 100 gallons of water. 



November 10, 410 good-sized moderately infested plants were 

 sprayed. These plants were kept under almost daily observation 

 until November 23, but not a dead larva was found. This mixture 

 did not burn the plants, and it completely wiped out plant-lice 

 (aphides) and several species of lepiclopterous larvae which were 

 exposed on the leaves. It was, however, ineffective against the well- 

 protected Hellula larva?. 



The experiments with insecticides may be summarized as follows: 



Experi- 

 ment 

 No. 



Date. 



Insecticide used. 



Effect on 

 larvae. 



Injury to 

 foliage. 



Remarks. 



1 



2 



1910. 

 Sept. 7 



Sept. 12 

 Oct. 12 

 Nov. 10 



Paris green, 2 pounds, and 

 whale-oil soap, 8 pounds, 

 in 100 gallons of water. 



Paris green, 5 pounds, lime, 

 5 pounds, and whale-oil 

 soap, 10 pounds, in 100 

 gallons of water. 



Arsenate of lead, 5 pounds, 

 and whale-oil soap, 10 

 pounds, in 100 gallons of 

 water. 



Paris green, 2pounds, whale- 

 oil soap, 8 pounds, and 

 nicotine sulphate, 25 

 ounces, in 100 gallons of 

 water. 



Ineffective . . 

 do 



Not worth 

 mention- 

 ing. 



do 



A few larvae, in folded 

 leaves, on small cabbage 

 plants were killed. None 

 were killed on large 

 plants. 



A few larvae, ir folded 



3 



4 



do 



do 



None 



do 



leaves, on small cabbage 

 plants were killed. 



Applied to large cabbage 

 plants. No larvae were 

 killed. 



Do. 



