520 



Brittain (W. H.). The Green Apple Bug {Lygus inviius, Say) in Nova 

 Scotia. — MthAnn. Rept. Entoin. Soc. Ontario, 1915, Toronto, 191G, 

 pp. 65-78, 3 plates, 1 table. [Received lOth October 1916.] 



Lygus invitus, Say, is distributed throughout the fruit-growing 

 districts of Nova Scotia. At the present time pear trees are most 

 seriously injured, but damage to apples, although less severe, appears 

 to be increasing in many localities. This insect apparently oviposits 

 only on apple and pear, although adults have been observed feeding 

 on plum, and nymphs on couch grass, timothy, red clover, dandelions, 

 etc. During 1915, the first nymph emerging from overwintering eggs 

 was observed on 24th May and the last on 10th June, the period of 

 maximum emergence lying between 1st and 15th June inclusive. Trans- 

 formation into the adult stage was complete by 7th July. The average 

 duration of the nymphal stage was found to be 32 days and that of the 

 adult during July, 5'41 days. The length of the adult stage, however, 

 varies considerably, some females being found as late as 7th October. 

 Eggs are deposited beneath the tender bark of pears and apples, 

 especially of the latter, and were observed on 20th July and on sub- 

 sequent occasions. Young nymphs feed mainly on the foliage of apple 

 and pear, but occasionally puncture the shoots. In later stages the 

 blossoms and young fruit are exclusively attacked. The nymphs are 

 capable of very rapid movement ; when disturbed, they conceal 

 themselves in the leaf axils or drop to lower branches or to the ground. 

 In several instances they have been known to attack man and the larvae 

 of the fruit- worm. Xylina sp. In the adult stage great activity is shown 

 on sunny days. The powers of flight are considerable, and specimens 

 have been taken at a distance of a quarter of a mile from the point of 

 release. Predaceous habits, similar to those of the nymph, may be 

 exhibited in this stage. The preferred food is the fruit of pear, apples 

 being attacked less frequently. Injury to the foliage of apple by the 

 n3miphs causes the formation of purplish areas, accompanied by a 

 slight curling, and later of numerous small holes. Punctures in the 

 twigs cause the exudation of gum and the formation of a swelling which 

 may acquire a longitudinal crack. In cases of heavy infestation, 

 young twigs and blossoms may die off as the result of the loss of sap. 

 Injury to the fruit causes the exudation of gum, the formation of a 

 corky scar over the punctured area, and failure to develop normally. 

 The fruit often drops to the ground a few days after injury. In the 

 case of pears, the injury is similar, but results in the formation of a 

 black area around the punctures, the fruit becoming hard and unfit 

 for use. Damage to the fruit of plum occurs at the end away from the 

 stalk and causes a flow of gum. A list is given of the varieties of apple 

 in order of their susceptibility to attack. Among pears, the Bartlett 

 variety suffers most severely. Feeding experiments showed that 

 nymphs in the second and third instar were able to complete their 

 transformations on grape, elm, maple, sweet cherry, peach, red clover, 

 strawberry, or couch grass. Leaves and blossoms of strawberry died 

 as the result of attack, while couch grass showed evidence of wilting. 

 Examination of several orchards seemed to show that injury was most 

 severe in those which had been well sprayed and cultivated, but were, 

 at the same time, closely planted with thickly growing trees. 



The ant, Formica fu sea, and spiders were apparently the only natural 

 enemies of any importance. Spraying experiments were undertaken 



