EXPERIMENT STATION BULLETINS. 413 



gallons) if pear psylla is still present. (Lime-sulpliur used at this time 

 or with the succeeding spray is quite apt to injure the foliage). 



Two weeks later apply another spray of bordeaux to which add II/2 

 pounds arsenate of lead powder to each 50 gallons. 



THE PEAR rSYLLA. 



The Pear Psylla is a serious and important insect regarding which 

 pear growers must be fully informed. It passes the winter in rubbish, 

 such as prunings left in or near the orchard, on the trunks of the trees, 

 in the cracks and crannies of the rough bark, and on the twigs among 

 the buds. It may be controlled by the following thorough treatment. 



1. Late in the fall, November or December, scrape the loose bark 

 from the trunks and large limbs and gather and burn or bury. Do not 

 leave on the ground. 



2. On a bright and fairly warm late fall day the insects will come 

 out of their hiding places and can then be killed with a contact spray. 

 Use some 40 per cent nicotine-sulphate solution at the rate of 1 pint in 

 100 gallons of water and to make it spread easily and quickly and so 

 go farther, add 3 pounds of dissolved soap. Any cheap soap will do. 

 Spray both sides of each tree, — the insects are lively and will dodge the 

 spray. The best possible job can be done by spraying both sides of each 

 tree at the same time, or at least by completing the job before any one 

 part of the sprayed trunk or limbs becomes dry. It is hoped that the 

 delayed dormant spray noted above will supercede this winter nicotine 

 spray and if the latter continues to show up as well as in 1921, it will 

 do so. 



FIRE BLIGHT. 



Fire blight is a bacterial disease of pears, apples, quinces and 

 plums. It attacks blossoms, — causing "blossom blight"; twigs, — caus- 

 ing ''twig blight" ; limbs, — causing "limb canker" ; and trunks . of 

 trees,— causing "body blight" and "collar blight." It characteristically 

 works rapidly in the cambium and bark, killing so quickly that the 

 leaves cling to the twigs, making the tree look as if scorched by fire. 



The common varieties of pear, except Kiefer, — ^^all varieties of 

 quince, — Tolman sweet, Jonathan, Transparent, Chenango apples, — 

 Transcendent and other crab varieties, — are especially susceptible. It 

 it a disease which does serious damage to young, rapidly growing trees. 

 Old trees and trees in sod, making slow growth, suffer less from blight. 

 Serious loss has come from "blossom blight" on Duchess, and from 

 collar blight with varieties on susceptible stocks (French crab). 



Spraying is not a preventive for this disease. Control measures con- 

 sist, (1), — in elimination of the hold-over cankers, (2), — in the prompt, 

 and consistent cutting out of blighted twigs in the orchard. 



The hold-over cankers arise from the blighted twigs of the previous 

 year and can be located readily in the winter. 



Pruning should be severe and each cut should be disinfected with 

 either formaldehyde 1-10 or with a 5 per cent wash of compound solution 

 of cresol or any standard coal-tar preparation of the sort. Prunings 

 should be collected and burned. 



In the growing season, especially in June and July, make frequent 

 and thorough inspections of the orchard and cut out all twig-blight 



