April, '09] JOURNAL OF ECONOMIC ENTOMOLOGY , I59 



the fruit grower, coincides with the time when less injury is apt to be 

 done to the trees by the spray. 



This scheme of suggested treatment, it will be seen, reduces the 

 amount of arsenate of lead from the formula used in the experiment. 

 It seems probable, at least, that this amount of arsenical will bring 

 about successful results. Orchardists in some sections are using only 

 this amount of poison in their formulas against codling moth. 



None but the best grades of lead arsenate should be used and every 

 package purchased should be required to bear a certificate of analysis, 

 showing quality at least up to the standard established by the national 

 insecticide bill favored by this body for enactment before the coming 

 session of Cong-ress. 



'Mr. Slixgerland : What is your theory in regard to the way the 

 poison kills ? Does it kill the beetles, or don 't they like the spray ? 



Mr. Taylor : JNIy belief has always been that it kills the beetles, as 

 it is not supposed that arsenate of lead is a very strong repellent. 



Mr. Quaintance : The Bureau of Entomology has been interested 

 in this subject for several years, and I am glad to hear Mr. Taylor's 

 paper. It confirms results we got three or four years ago, especially 

 as to the high percentage of peaches which may be protected from the 

 curculio attack. As to the use of arsenate of lead on peach trees, 

 especially as to recommending its use to peach growers in the southern 

 states, I should think it would be unwise without explanations. The 

 effects of the lead on peach varies from year to year, and I think I have 

 never seen the same results twice. Some years there is but little if any 

 harm, and the next year the foliage is badly injured and much of the 

 fruit may fall. Tests of home-made arsenate of lead show but very lit- 

 tle difference. This question of injury- has been under investigation 

 by the Bureaus of Chemistry and Entomology, and it turns out that 

 arsenate of lead, after being applied to the trees, undergoes decompo- 

 sition, and the presence of lime or its absence, while entering materially 

 into the question, does not prevent burning. I want to urge that the 

 recommendation as to the use of arsenicals on peach in the southern 

 states be done with caution and that the grower know the risk he is tak- 

 ing. 



A Member : What time do you spray. ]\Ir. Quaintance ? 



]Mr. Quaintance: Just about as Mr. Taylor said, beginning as soon 

 as the petals are down. 



Mr. Taylor : I would like to ask ]\Ir. Quaintance if he has seen se- 

 vere injun' from the best grades of arsenate of lead where only a 



