THE SKMITROPK'AL AHMY WORM. 67 



on the vines and only a few live ones, but the same conditions were 

 observed on the check rows. The experiment was an absolute failure. 



Eu'/ferinunf Xo. J J. — July 21), plants were sprayed with copper 

 arsenite mixture at the rate of 15 oinices to 50 gallons of water. In 

 this case 1] ounces of copper arsenite and 1 quart of thick lime were 

 used Avith 5 gallons of water. Two days later the spray showed belter 

 than in experiment No. 10 because of an abundance of lime and was 

 very finely and evenly a[)plied to the leaves. F'our larva* were dead 

 on a fcAv plants examined against 32 living Prodenia and 3 living 

 sweet-potato sphinx-moth larva^ {Phl^gethontius convolvuUlu.). 



August (), this spray still remained on the foliage, seeming to 

 adhere well, but the experiment was a failure in killing larva^. 



Experiment No. 12. — July 29, plants Avere sprayed with arsenate of 

 lead, 3 pounds to 50 gallons of water, applied as in previous experi- 

 ments with lead arsenate. There was no rain for 24 hours. On a fcAv 

 plants examined three days later 41 dead larA'a' were found and 40 

 living, an observed death rate of less than 50 per cent. It should be 

 pointed out at this time, however, that it is difficult to find dead larv?p, 

 as they sometimes dry up or craAvl aw\iy. 



August 2, the vines Avere almost free from larva\ The experiment 

 was pronounced Aery successful. 



Experiment No. 13. — July 30, arsenate of lead, 2 pounds to 50 gal- 

 lons of water, Avas used Avithout ensuing rain. In some roAvs exam- 

 ined August 1 about 20 per cent of the larA'a? Avere dead ; in others 48 

 per cent, 54 per cent, and CI per cent Avere killed in tAvo days. August 

 5, these roAvs appeared entirel}^ free from larA'a' unless closely in- 

 spected, Avhen only 5 or (5 could be found to a roAv. These might have 

 crawled from unsprayed Aveeds or other plants. 



Experimod No. l.!f. — July 30, arsenate of lead. 3 pounds to 50 gal- 

 lons of Avater, Avas used. Three days later 84 per cent of the larva> 

 under observation Avere destroyed, the roAVs being quite clean. Tn 

 both of these experiments, 13 and 14, many dead larA^a^ were found in 

 roAvs not sprayed, as many as fiA'^e roAvs away from the sprayed ones. 



Expetiment No. 16. — Augiist T, arsenate of lead, 2 pounds to 50 

 gallons of Avater. was sprayed by a laborer, under supervision. It 

 rained at 1 ]>. m.. but the spray remained on the leaA-es in large 

 amounts and, for having been applied by an inexperienced hand, Avas 

 Avell distributed. In this experiment, for some reason, the first four 

 roAvs sprayed at one filling of the tank produced (piite a number of 

 burned leaves. This Avas attributed to a possible mistake in Aveigh- 

 ing out the chemicals. It did not, hoAvcA'er, permanently injure the 

 plants. 



Caterpillars in the last 4 experiments, supposedly of the third gen- 

 eration, were A^ery small, not over one-fourth or one-third of an inch 

 in length. As a consequence they Avere quickly killed, large numbers 



