INSECTICIDES ON GARDEN AND GREENHOUSE PESTS. 



745 



THE RESULTS OF SOME EXPERIMENTS WITH INSECTICIDES 

 ON SOME GARDEN AND GREENHOUSE PESTS. 



By R. Newstead, A.L.S., F.R.H.S., &c., Curator of the Grosvenor 



Museum, Chester. 



[Read November 12, 1901.] 



DuKiNG the last few years it has been my pleasure to conduct a number 

 of experiments with insecticides on various insects injurious to fruit-trees 

 and plants under cultivation, with a view, if possible, to discover some of 

 the more efi'ectual remedies. The insecticides selected were, for the 

 most part, those which have found most favour among horticulturists 

 during recent years ; some of which were originally discovered, after 

 much research, by the leading entomologists of the United States of 

 America and our Colonies. In my paper on " The Scale Insects and 

 Mealy Bugs of the British Isles," read before the Society in October 

 1899, a number of insecticides were dealt with at some length, and 

 I must ask the members of the Royal Horticultural Society to refer to 

 that article for information bearing upon coccids and allied pests. It 

 should be added, however, that recent experiments with the brown Peach 

 Scale [Lecaniwyi persiccE) have materially strengthened the advice then 

 given, and I shall therefore have occasion to refer to this pest. Some 

 attention has also been given to certain root-feeding coccids, which, as 

 pests, are practically new to this country. I have also to lay before you 

 the result of some extensive experiments with the " Pear-tree Slug- 

 worm," or " Saw-fly Grub," and the caterpillars of a small Tortrix Moth, 

 which are injurious to certain fruit-trees. 



In dealing with the Pear-tree Slugworm I have also entered into 

 some detail concerning the economy of this pest, giving some apparently 

 new and important facts concerning its life-history, which have a prac- 

 tical bearing upon the application of insecticides. The observations are 

 supplemented by photographic illustrations from life. 



Particulars concerning the life-history of the Tortrix pest have 

 already appeared in the Gardeners' Chronicle, but it has been thought 

 advisable to repeat the information there given, with due acknowledgment 

 to the editor, Dr. Maxwell T. Masters, who has also kindly supplied the 

 block illustrating the insect in its various stages (fig. 318). 



Paraffin and Soap, or " Kerosene Emulsion.'' 



In my former paper * I claimed that this emulsion had given the most 

 satisfactory results, and, further, that it had killed about 80 per cent, of the 

 larvae of the brown Peach Scale " {Lecanium persicce). Two additional 

 annual applications have since been made upon the same lot of trees, 

 with the result that this year very few females were found to have 

 survived the series of applications. I cannot, therefore, too stronglv 

 recommend this emulsion for all kinds of naked " scale " and " bug " or 



* Journal of the Royal Horticultural Society, vol. xxiii. pt. iii. 



