122 



large numbers of winged Aphids which also give rise to egg-laying 

 females. Early in October winged males appear on the wild pepper- 

 grass and migrating to the cherry mate with the females. 



The best remedy is thorough spraying with Black leaf 40 early in 

 spring as soon as all the eggs have hatched, when it is most 

 economically apphed in combination with the delayed lime-sulphur 

 dormant spray. 



Gibson (A.). Control of the Onion Maggot. — Canadian Horticulturist, 

 Toronto, xl, no. 12. December 1917, p. 312. 



The control of the imported onion maggot, Hylemyia antiqua, has 

 proved a difficult problem under field conditions, owing to the 

 prohibitive cost of such insecticides as hellebore, insect powder and 

 carboUc wash. During the last two seas'ons satisfactory tests have 

 been made with a poisoned bait spray composed of sodium arsenite 

 I oz., molasses 1 pint, boiling water 1 gal. ; the sodium arsenite is 

 first dissolved in the boiling water and the molasses added, the mixture 

 being ready for use when cool. Five apphcations of this were made 

 between 13th June and 16th July, the plants being about a foot high 

 on the latter date. The mixture was applied with a watering-can with 

 a small rose, the cost working out at a little less than five shillings an 

 acre, for ingredients and labour, and the time occupied being less than 

 ten minutes an acre. 



SwAiNE (J. M.). The False Tussock Caterpillars on Shade Trees. — 



Agric. Gaz. Canada, Ottawa, iv, no. 12, December 1917, 

 pp. 1043-1047. 



During the summer of 1917 a serious outbreak of defoliating cater- 

 pillars occurred on the shade trees of Eastern Canada, the most 

 abundant and widely distributed species being the false tussock 

 caterpillars. 



These included the hickory tussock moth, Halisidota caryae, Harr., 

 which lays its eggs to the number of about 100 in a patch on the 

 under-side of a leaf during early summer, its chief food-plants being 

 hickory, walnut, elm, butternut, hawthorn, rose, apple, ash, linden, 

 oak and locust The conspicuous black and white caterpillars feed 

 gregariously at first, defoliating whole branches during the latter part 

 of July, August and early September. They then pupate in oval, 

 hairy, greyish cocoons, from which the moth emerges the following 

 June. H. maculata, Harr. (spotted tussock) is a very similar species, 

 the larvae of which feed on alder, apple, willow, and Manitoba maple, 

 although it is usually recorded from the Eastern States as feeding 

 on oak. It rarely occurs in sufficient numbers to cause serious injury 

 or require control. H. tessehris, S. & A., is another similar species, 

 the larvae feeding on many native trees and shrubs. 



These caterpillars may be easily controlled by spraying the infested 

 foliage with lead arsenate or Paris green, the lead arsenate being used 

 at the rate of 2| lb. paste to 40 gals, water, or \\ lb. powdered lead 

 arsenate to the same quantity of water, while Paris green is employed 

 at the rate of 5 oz., mixed with 1 lb. freshly slaked limcj in 40 gals, 

 of water. They are heavily parasitised, especially by the common 



