DISEASES AND PESTS OP PLANTS. 53 



year, and they are known to feed on apple, plum, cherry, rose, thorn, willow, black- 

 berry, and other related plants. The common name given this insect very well 

 describes the peculiar shape and colour of the caterpillar. 

 Control. (See " Yellow-necked Apple-tree Caterpillar.") 



THE FALL WEB-WORM (Hyphantria cunea). 



The common fall web-worm is so named because of the web which it spins over 

 its food-plant during August and September. The moths emerge from over-wintering 

 pupae late in June. The eggs are laid by the female moths during the month of 

 July, and are deposited on the leaves of its food-plants in clusters of 400 to 500. 

 These usually hatch in about ten days. The young caterpillars immediately com- 

 mence to spin their webs over the foliage on which they are feeding. Within this 

 web the colony from one egg-mass feeds, enlarging the web as it becomes necessary. 

 The webs are usually started at the tips of the twigs, and first become noticeable 

 early in August. When the foliage in one web is entirely consumed the colony will 

 leave it and spin a fresh weT> upon a new branch. When the larvse are full-fed they 

 seek a place in which to pupate, usually under loose bark on the trees or rubbish at 

 its base; fence corners are also acceptable. 



Control. Cut off the webs containing the caterpillars and destroy them. 



THE TARNISHED PLANT-BUG (Lygus pratensis). 



A pest which is very troublesome in many countries and has proved particularly 

 injurious in orchards and truck-gardens in this Province. The adults hibernate over 

 winter and emerge in the first warm days of spring. They do extensive injury by 

 attacking the buds of fruit-trees, vines, canes, and plants. Later the young terminal 

 shoots are also attacked and injured. Their principal breeding-places are in meadows, 

 range land, and among weeds in and about the orchards and fields. 



Control. Although extensive experiments have been conducted over many years, 

 the control of this pest is as yet an unsolved problem. Clean culture has been recom- 

 mended by a number of writers, but has not proved effective. The insects are very 

 active creatures, and there is always a sufficient breeding area near by to produce 

 an abundance of bugs. 



The removal of all rubbish and waste material from the orchards and fields in 

 the fall will, to a great extent, remove hibernating-quarters for the insects on culti- 

 vated lands. This may check early invasion and permit the trees and plants to make 

 some development before injury is done. Keeping them in vigorous growth will over- 

 come much of the injury from this pest. 



THE PEAR-THRIPS (Euthrips pyri). 



This is a very serious insect pest and was first recorded in this Province in the 

 spring of 1915. It is believed to be confined to one locality in the Province as yet, 

 but it is thought advisable to warn the fruit-grower against this i>est on account of 

 its serious nature. 



The adult, which is the most destructive stage of the species, is a dark-brownish, 

 four-winded insect about Yso inch in length. The wings are long and narrow and are 

 delicately fringed with long hairs ; when at rest they lie horizontally along the back 

 of the insect and are very inconspicuous. The feeding of this insect causes much 

 damage to fruit-trees. The insects seek, preferably, the rudimentary flower and leaf 

 parts in the partially opened buds, but when the buds are more fully developed they 

 feed more or less openly on the stamens, pistils, petals, tender leaves, and appar- 

 ently on the secretions from the nectaries in the centre of the blossoms. 



If the thrips are numerous the injured buds become sticky with a brownish 

 liquid and cease to develop, while the blossom-clusters have a stunted, shrivelled, and 

 brownish appearance as if blasted. The effects of the attack of the thrips on fruit 

 yields depends on the number of blossom-buds destroyed. The period of activity of 



