46 INSECTS AFFECTING VEGETATION 



The spraying must be thoroughly done and put on the trees when 

 the thrips appear in numbers, not waiting till many buds have been 

 destroyed. It is strongly advised to use power machines, and grow- 

 ers are urged to use them for all the spraying, and to have a tower 

 platform elevated over the tank so that one man can thoroughly 

 drench the tops of the trees. It is absolutely necessary to use high 

 pressure from 150 to 200 pounds and only angle nozzles should 

 be employed, and these must be held close to the bud clusters to 

 force the spray directly into the ends of the buds. This is absolutely 

 necessary to secure good penetration and get satisfactory results. 

 Plenty of material 3 to 5 gallons per tree for pears, depending on 

 the size of the tree should be used ; more liquid is required for large 

 prune trees ; large cherry trees may require 7 to 8 gallons per tree for 

 satisfactory results. 



In badly infested orchards three applications are necessary the 

 first year for controlling the pear thrips. Two of these sprayings 

 should be directed against the adults and one against the larvae, and 

 to obtain satisfactory results must be timed properly. The first spray- 

 ing should come as soon as the thrips can be found on the trees in 

 numbers. The second spraying, which is also for adults, should come 

 from four to ten days after the first, depending somewhat on variety 

 of fruit, stage of bud development, and rapidity of emergence of 

 thrips from the ground. On pears this will usually be just as the 

 earliest cluster buds are spreading, and on prunes and cherries when 

 the tips of the petals first begin to show. Both of these applications 

 are important and necessary to insure the production of a good crop 

 of uninjured blossoms. The nozzles should be held close to the bud 

 clusters and the spray directed into the ends of the buds. This makes 

 it necessary that the spraying be done mostly from above. The third 

 spraying is for larvae and properly comes just as most of the petals 

 are falling from the trees, depending somewhat upon the variety of 

 fruit. Those who can do so successfully are advised to irrigate and 

 plow in the fall. This is to be followed by thorough spraying the 

 following spring. (Cir. 131 B. of E. U. S. Dept. Agr.) 



The Pear Psylla. Occasionally we hear of trouble arising from 

 the pear psylia, an European insect, which was first noticed in Mich- 

 igan in 1891. The presence of this insect is usually indicated by a 

 general loss of vitality in the tree, early in the season. The young 

 growth droops, and sometimes considerable foliage and fruit drop 

 from the tree. The leaves are seen to be smeared with honey-dew, 

 which attracts ants and wasps, and which supports a black, sooty 

 fungus later in the season. 



The immature insects are very small, a little more than one-six- 

 teenth of an inch in size, yellow at first but afterward becoming 

 marked with black and red. They hatch from the eggs in May and 

 immediately commence sucking the juice of the leaves. The secre- 

 tion of honey-dew is so copious that the insects soon become sur- 

 rounded by small puddles of this sticky liquid, in which they sit and 

 grow. In about a month, they change to the adult, winged form, in 

 which stage they are provided with wings, and with strong jumping 



