EXPERIMENT STATION EEPOKT. 599 



medium-sized bearing plum of irregular growth and with some of 

 the branches very badly infested. 



September 30th, none of the trees showed injury to foliage. The 

 apple had some fresh sets and some active larvae, but there had 

 been, undoubtedly, a material reduction. The first of the plum 

 trees showed very few active larvae, and such recent sets as ap- 

 jieared may have been there before the application. The second 

 of the plum trees showed quite a number of active larvse and fresh 

 sets. 



On the whole this mixture has not had a suflicient trial to make 

 it fair to s}>eak positively. It is made up in very small lots only 

 and varies a little in composition, but at the rate of 1 to 40 or 1 to 

 50, as advised, it will prove absolutely ineffective, simply because 

 no combination containing so small a percentage of petroleimi can 

 do any good. 



Meohanioal Emulsions. 



Very much to my surprise Mr. Dickerson found the mechanical 

 mixture of oil and water in high favor and very effective in all 

 CAses. He writes: "The oil and water mechanical mixture has 

 been much more extensively used than the undiluted oil, and, so 

 far as I know, the material was crude oil rather than kerosene, 

 applied with a Kerowater pump. I have seen both peach and apple 

 so sprayed in several localities with excellent results. Quite a 

 number of the peach growers w^ill continue to use the mixtures, and 

 others who did use it, but are now using limei, sulphur and salt, did 

 not change because they had not been successful, but because they 

 feared that injury might come from continued applications and 

 because they believed the lime-sulphur washes to be more bene- 

 ficial to the trees. The tendency, at least in spraying peach trees, 

 is to reduce the proportion of oil in the combination. At first 25 

 per cent. Avas used, but now 15 per cent, to 20 per cent, is generally 

 employed. An orchardist near Lambertville furnishes a good ex- 

 ample of what has been done with this material. He started to 

 spray five or six years ago with the 25 per cent, mechanical mix- 

 ture on both bearing apple and peach trees which were more or less 

 scaly. He felt, however, that he was getting too much oil on his 

 trees and reduced it to 20 per cent. This year he sprayed some 

 young peach trees with 15 per cent. I saw the peach orchard which 



