148 EXPERIMENT STATION KECORD. 



The germicidal properties of tannic acid (f'cnthl. Ikikt. u. Par., 15 {1894), No. 

 23, pp.S9l-SUi). 



The history and physiology of the copper question, C. MuLLEit {Ztschr. Pflan- 

 zenkrank., 4 {1S94), No. 3, pp. 142-144).— k historical rdsuiu^. 



Literature of fungus diseases, W. C. Sturgis {Connecticut State Sta. llpt. 1893, 

 pp. 253-285).— \iex>Y'uit fioni lUilletin 118 of the station (E. S. K., 5, p. 1078). 



_port of the mycologist, W. C. Sturgis {Connecticut State Sta. lijd. 1893, pp. 

 72-111). — This is a lejdiut from part ii of the Auuual Report of the station for 

 1893 (E. S. R., 5, pp. 866, 877). 



ENTOMOLOGY. 

 The pear midge, -J. B. Smith [New Jersey Sta. Bui. 99, pp. 14, Jigs. 4). 



Synopsis. — Illustrated description of the pear midge, with accounts of its life his- 

 tory, distribution, and ravages in the United States. Lawrence pears suffer most, 

 but other varieties are attacked. Top-dressing with kainit killeil the pup* 

 while wintering in the ground. 



The pear midge ( Diplosis pyrlrora) has been kllo^y]l and studied iu 

 Europe for half a century, but did not occur in the United States until 

 introduced from France to Connecticut in imported pear stocks in 1877. 

 The pest rapidly increased, and by 1893 had so spread as to be ahso 

 abundant and destructive in southern Xew York and jSTew Jersey. 



The adult is a grayish, long-legged ^j resembling a mosquito, with 

 its wings expanding less than one fifth inch. It apj)ears for a week or 

 10 days just before the pear blossoms open, and. piercing the corolla 

 with its ovipositor, lays from 10 to 30 eggs on the stamens. These hatch 

 in 3 or 4 days, and the larva pass at once into the core of the embryo 

 pear, before the opening flower has ex^wsed them to the sun. TJie 

 larva; become mature in early June and drop from the dwarfed, 

 deformed pears to the ground, into which they burrow an inch or two, 

 in the course of the summer spinning oval cocoons in which they pass 

 the winter, emerging in the spring. 



The seeds of the young pears are destroyed and the fruits grow 

 slowly, acquiring a peculiar knobby appearance, and decay and drop 

 fiom the trees in early summer. The Lawrence is the variet}' attacked 

 in preference, followed by the Bartlett and other varieties in the order 

 of the lateness of blossoming. In one orchard examined not a single 

 Lawrence pear escaped, and over 50 per cent of the Bartletts Avere 

 destroyed. 



As it is obviouslj^ impossible to prevent the midges from laying their 

 eggs in the blossoms or to destroy the larvae while in the young pears, 

 experiments were made of top-dressing the soil during the summer with 

 various chemicals in the hope of killing the larvte and pupte. Muriate 

 of potash, nitrate of soda, and kainit were applied with gratifying 

 results, the former two killing a majority of the insects, while after 

 treatment with the last not a single larva or pupa remained alive. 



