ORCHARD INSECTS OF THE PACIFIC NORTHWEST 



35 



form about these centers as the fruit grows result from the presence of 

 the eggs in the apples. Nicotine sulphate (40 percent nicotine), in the 

 proportion of 1 pint to 100 gallons of water, to winch is added several 

 pounds of soap in so- 

 lution or a pound of 

 casein spreader, will 

 effect some degree of 

 control if used when 

 the trees are in full 

 bloom; or the nico- 

 tine may be added to 

 the calyx spray. 



PEAR THRIPS 



The pear thrips 

 (Taeniothrips incon- 

 sequens Uzel) occurs 



On pears, DUt in tne p IGUEE 40.— Green fruit worm feeding on apple. Twice natural size. 



Pacific Northwest it 



is more serious as a prune pest, and it is therefore discussed under 

 that heading (p. 53). The recommendations given there also apply 

 to pear trees, except that where it is necessary to control scab, oil 

 should not be used, but nicotine sulphate (40 percent nicotine) 

 should be added to the delayed-dormant and pink-petal applications 

 of lime-sulphur at the rate of 1 pint to 100 gallons of spray material. 



APPLE LEAF HOPPERS 



The leaf hoppers injure apple trees in much the same manner as do 

 red spiders. They are sucking insects feeding exclusively on the foli- 

 age, and they withdraw the chlorophyll and other cell contents, 

 leaving the foliage with a whitened or mottled appearance. Leaf 

 hoppers are much larger than red spiders, and it does not require 

 many of them to cause serious injury; a half 

 dozen are able to remove most of the chloro- 

 phyll from a single leaf. Slight foliage injury 

 by leaf hoppers and red spiders is of no conse- 

 quence, but as soon as this injury reaches the 

 point where the foliage is reduced below the 

 amount required for the crop, the fruit 

 and buds are directly affected, the fruit 

 failing to reach normal size and the buds 

 being weakened so that they may not set fruit 

 the next season. It is therefore important to 

 guard against extensive injury. 



LIFE HISTORY 



Figure 41.— Holes in apple 

 made by eye-spotted bud 

 moth larvae. 



Two species of leaf hoppers are prevalent 

 in the Pacific Northwest, both native to the 

 United States. The more common and important of these is the 

 white apple leaf hopper (Typhlocyba pomaria McAtee), a slender, 

 active, whitish insect about one eighth inch long. It passes the 

 winter in the egg stage in the bark of the trees. The eggs hatch 



