172 



which in some localities causes 50 per cent, of infestation in lucerne, 

 and Meromyza aynericana (greater wheat-stem maggot). It is believed 

 that two or three generations of this fly occur in a season and that 

 autumn wheat is more seriously injured than the plants attacked by 

 the earlier generation in June and July. 



RMgoletis pomonella (apple maggot) has been taken in considerable 

 numbers breeding in native snowberry {Symjjhoricarpus racemosa) and 

 probably occurs wherever this plant exists in British Columbia, but 

 has not been taken on apple. Cydia pomonella (codling moth), while 

 showing a general reduction in most localities, has broken out in certain 

 fresh orchards ; strenuous action will be necessary in 1919 to counter- 

 act this spread. 



Knight (H. H.), An Investigation of the Scarring of Fruit caused by 

 Apple Redbugs.— (7omeH Univ. Agric. Expt. Sta., Ithaca, N.Y., 

 Bull. no. 396, February 1918, pp. 187-208, 37 figs. [Received 

 10th February 1919.] ' 



The injuries produced in apples by the bug, Lygidea mendax, depend 

 largely on the kmd of apple, some varieties being more subject to 

 fatal injury than others, and also on the age of the fruit when the 

 puncture is made. If the core of the young apple is punctured, a 

 deep pit results m the mature fruit, but punctures made after the fruit 

 is I in h in diameter result in the formation of broad russet scars. 

 The healing of wounds made after the middle of July and usually 

 produced by the tussock moth [Hemerocampa?^ or the plum curculio 

 [Conotrachelus nenuphar] depends largely on the variety of apple. The 

 nymphs of L. mendax begin hatching just as the blossom-buds begin 

 to open and most of them have entered the fourth stage by the time 

 the petals have fallen, it being during the fourth and fifth instars that 

 the maximum damage is done. The adults, practically all of which 

 have appeared by 22nd June, feed on the fruits extensively for a week or 

 more, and then begin feeding on the tender developing shoots. Injuries 

 inflicted at this stage may resemble the work of apple maggot flies 

 [Rhagolct is pomonella] or of Syntomaspis drupanim (apple-seed Chalcid), 

 but in the latter case the larvae are to be found in the seeds. Under 

 certain conditions Afhis sorhi (rosy aphis) may develop and feed on 

 apples injured by red-bugs, with the result that the fruit is stunted and 

 badly misshapen. 



Heierocordylus mnlinus (dark apple red-bug) develops 7-10 days 

 earher than L. mendax, the nymphs hatching with the unfolding of 

 the leaves anfl feeding on the tender foliage and to a slight extent on 

 the fruit before reaching maturity, which occurs together with oviposi- 

 tion by the time the fruit is large enough to be injured. In western 

 New York the work of H. malinus in producing knotty fruit is very 

 limited or entirely absent on the standard varieties of apples. 



Conotrachelus nenuphar (plum curcuho) on emergence from hiber- 

 nation is a voracious feeder and attacks young apples as soon as they 

 are formed, these early-formed punctures not being usually accom- 

 panied by egg-laying. Later punctures together with oviposition 

 result in the formation of a characteristic crescent-shaped scar. 



Lime-sulphur spray, if the young fruit is drenched, will cause shght 

 burning and the injury may result in russet scars resembling in some 



