594 



autumn and more or less throughout the summer, the sap being 

 extracted from the leaves, giving them a bleached and mottled 

 appearance. 



The stages of this Capsid are described. The bugs are abundant 

 from early summer to late autumn, when they either die off or seek 

 hibernation quarters at the base of their favourite food-plants or in 

 other protected spots. The eggs are deposited in the leaves and 

 petioles of the food-plants, the incubation period averaging 11 days. 

 The nymphs pass through five instars during an average period of 14 

 days, and the combined length of n3/mphal and adult stages is about 

 25 days. In South Carolina there are five or six generations annuall}'. 



The agility of the nymphs and adults protects them to a large extent 

 from natural enemies ; the earlier stage nymphs are, however, attacked 

 by the larva of a predaceous mite. The following egg-parasites are 

 recorded : Anaphes perdnbins, Gir., Gonatocertis sp., W estivoodella 

 americana, Ashm., Tetrastichns sp., Anagrus armatus nigriventris , 

 Gir., and Ahhella sithflava, Gir. 



Clean culture is the best remedial measure ; plants that remain 

 green late in the autumn and resume growth in the spring should be 

 cleared away and destroyed in autumn, as these are favourite hiber- 

 nation quarters. In cases of severe infestation, the crop should be 

 cut and removed, and the field sprayed with a 10 per cent, solution of 

 kerosene emulsion. 



Miller (D.). The Pear Leaf-curling Midge. Notes on the Auckland 



Infestation. — N.Z. Jl. Agric, Wellington, xxiii, no. 2, 20th 

 August 1921, pp. 84-92, 10 figs. 



The growing of young pear trees or nursery stock is impossible in 

 certain districts of Auckland owing to the extensive damage caused 

 by the pear-leaf midge. Whether the species concerned is the European 

 one {Perrisia pyri, Bch.) has not yet been determined. During the 

 infestation of 1920-21 there were at least six generations between 

 September and February, the maximum being reached when the 

 third and fourth generations overlapped. The eggs are deposited 

 between the folds of the young leaf as soon as it bursts from the bud. 

 As many as 35 may be laid at one time ; these hatch in about four 

 days. The infested leaf grows rapidly, but is unable to unfold, and 

 owing to the destructive action of the larvae combined with the 

 lateral growth, the leaf curls further inward from each side along 

 the midrib in the form of a double tube and rapidly turns black, 

 ultimately becoming hard and brittle as the larvae mature. The 

 latter then drop to the ground and pupate in the soil, the adults 

 emerging about 10 to 14 days later. The life-cycle from egg to adult 

 lasts from 25 to 30 days according to the season. Hibernation occurs 

 in the ground in the larval stage. 



All commercial varieties of pears are liable to attack, though vigorous 

 and early ones are, if anything, less severely injured. The Chinese 

 birch-leaf variety, used as stock, is practically immune, but the grafted 

 forms on the same stock are severel}' infested. The midge is often 

 distributed in infested soil, and once established the adults spread 

 rapidly on the wing or Iw the agency of the wind. 



One of the most important methods of control is the treatment 

 of the soil infested by larvae and emerging adults. This may be 

 done by means of chemicals or by cultivation. Covering the ground 

 to a depth of four inches with uninfested soil proved effective. 



