940 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Tussock moth [Notoloplnis (Orgyia) leucostigma). Very destructive 

 to shade trees of all kinds. Every leaf was taken from some trees. 



Elm-tree beetle {Galerucella xanthomelcena) did the usual amount 

 of damage to the English Elm throughout the State. 



Walnut-tree caterpillar (Datana integerrima) has almost defoliated 

 every black Walnut tree in the north part of the State. Also found on 

 Hickory, Apple, and Quince. 



Melon plant louse {Aphis gossypii) has ruined many hundred acres of 

 Melons. 



San Jose scale {Aspidiotus perniciosus) has been most conspicuous ; 

 68 new localities visited during the past year. 



Oyster-shell scale {Mytilaspis pomorum) has been very destructive to 

 Lilac. 



The report also states that the Harlequin Cabbage bug (Murgantia 

 histrionica), which did so much damage last season, has been almost 

 absent. 



The Asparagus beetle (Crioceris asparagi) has also been absent. 

 And the Colorado Potato beetle has not been abundant. — M. C. C. 



Insecticide Experiments, Some. By C. L. Marlatt {Bull. No. 30, 

 N.S., U.S. Dep. Agr., JJiv. Eiit., pp. 83-89 ; two plates). — The experi- 

 ments were made in the spring and early summer of 1900, and were 

 designed to test the efiect of various substances, chiefly against the San 

 Jose scale insect. They included (1) crude petroleum ; (2) refined 

 kerosene ; (3) lime, sulphur, and salt wash ; (4) hot water ; (5) Bordeaux 

 wash and kerosene emulsion ; and (6) kerosene and lime emulsion. 



Crude and Refined Petroleum. — A series of Plum, Apple, and Pear 

 trees were sprayed March 22 with crude petroleum (48 degrees Baume), 

 the applications being made thoroughly enough to completely wet the 

 bark. The Plum trees were thickly infested with Diaspis pentagona and 

 the Pear trees with the San Jose scale. Some of these trees had been 

 pruned back heavily, and others were straggling trees ten or twelve feet 

 in height. The application was made between 2 and 3 p.m. on a bright, 

 dry day. At the same time a block of trees was sprayed with kerosene or 

 refined petroleum. The weather continued fair and dry for four days, 

 and there was no rainfall of any amount prior to April 11. After the 

 second day the kerosene had very largely evaporated, the treated trees 

 showing only a very light discoloration. Trees treated with crude oil, 

 on the other hand, were still very wet and oily-looking. The full-grown 

 female scales of Diaspis pentagona were thoroughly soaked and were 

 permanently preserved, apparently, in the oil and had scarcely changed 

 colour and were not drying up. After six days a slight change in the 

 coloration of the female scale insects began to be observed, the colour 

 slightly altering from light lemon to light orange. This change in 

 coloration is a certain indication of the death and gradual drying up of 

 scale insects, which usually change from lemon to orange, and finally to 

 brown or black in the different states of drying after being killed by an 

 insecticide. Three weeks after the application the trees treated with the 

 crude oil were distinctly greasy in appearance and blackened by the 

 oil. Trees sprayed by the pure kerosene gave no indication of having 



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