IG T5.C. Entomological Society. 



strengths of lime-sulphur + arsenate of lead, and to recover if transferred to fresh 

 foliage within a few days. 



Very young cateriJillars placed on twigs freshly sprayed with lime-sulphur 1-30 

 died within two or three days, but, as they did not feed, death must have resulted 

 from the gases given off. 



Very young caterpillars placed on twigs that had been sprayed with lime-sulphur 

 1-30 and allowed to stand refused to eat, and finally died from starvation. 



Half-grown larvte iilaced on twigs sprayed with lime-sulphur did not feed like 

 larva; on unsprayed twigs, but did eat to some extent. After two weeks on lime- 

 sulphur sprayed twigs they were transferred to fresh-sprayed leaves, and finally 

 matured, pupated, and emerged in the adult stage. 



Lime-sulphur probably acts as a repellent to biting-insects in the same way that 

 Bordeaux does against the potato flea-beetles. Lime sprinkled or sprayed on the 

 foliage in the same proportions as found in a certain amount of lime-sulphur had 

 no effect. 



Mr. B. W. White : I have been delighted to listen to the address of Mr. Wilson. 

 I am sure we will all feel the benefit of his remarks. With our conditions here in 

 British Columbia, contrary to the Oregon conditions, we probably do not under 

 ordinary conditions need to apply more than two sprays annually — the first as the 

 buds show green with lime-sulphur and Black Leaf 40 for aphis, and the second 

 as the blossoms fall for scab and leaf-eating Insects. 



Jlr. Tom Wilson : Professor Wilson claims that aphis-eggs are not killed by 

 the use of winter aisplications of lime-sulphur. I may say that I believe this to 

 be quite true; I have failed to do so myself. By the addition of caustic soda the 

 necessary effect will be produced. For the woolly aphis I have seen the use of 

 lead paint advocated. 



Mr. Lyne : There is one item that occurs to me, and that is the burning effect 

 of sprays. AVhen applying the usual formulre, if we find the foliage suffering, I 

 find that the addition of lime will control the burning effect of lime-sulphur. 



Mr. Cunningham: By adding 6 lb. of lime to lime-sulphur 1-15 no damage 

 results on fruit or foliage. We can also apply a lime spray to control the burning 

 effect of lime-sulphur. 



Professor Wilson : All these points bear out our recommendations. We find 

 that lime-sulphur 1-10 can be applied without any Injury, but, on the other hand, 

 sometimes an application of 1-40 will result in injury. Consequently no recom- 

 mendation can be stable. 



Mr. L. L. Palmer : I notice in your paper that you have been carrying on your 

 experiments with the use of pure arsenicals. How can we as fruit-growers obtain 

 them? What firms sell them? 



I Professor Wilson : All our experiments in the past were based on commercial 

 sprays, and we find they vary. We believed that experiments previously carried on 

 by other experimental stations were unreliable, • as they never really knew with 

 what they were working. In our work, then, we believed it best to have a reliable 

 basis to work on, and our chemists at the station did this for us. I may say there 

 are two pure arsenates of lead on the market, but I am not at liberty to inform you 

 of the names of the satisfactory firms. The great variations that have taken place 

 in arsenical experiments in the past probably account for the variations in the 

 results. In our work, however, we carried on duplicate experiments with the 

 ordinary commercial sprays. There has been, I fancy, a great improvement in the 

 arsenates of lead during the past few years. 



Mr. Taylor: Sherwiu Williams arsenate of lead had no effect on cherry-slugs 

 at the rate of 1-40, but 1-20 killed the insects. 



Professor Wilson : Pyrethrum at the rate of l-.jO is a most satisfactory spray 

 for cherry-slugs. 



A member : Which would you advise us to use, the powdered or paste form of 

 arsenate of lead? 



