182 FRUIT INSECTS 



lower leaves of nursery trees, doing little real injury, but the 

 later broods, feeding on the tender terminal leaves of the grow- 

 ing shoots in the latter part of June, July and August, seriously 

 retard the growth and thus cause the production of stunted, 

 undersized trees. These hoppers are also an important factor 

 in the dissemination of fire blight among nursery trees. 



Remedial treatment. 



These leaf-hoppers can be most effectively combated during 

 their nymphal stages, for the adults are so well protected by 

 their wings that applications strong enough to kill them usually 

 injure the foliage. A 10 per cent kerosene emulsion or a solution 

 of whale-oil or any good soap (1 pound in 6 or 8 gallons of water) 

 will kill all the nymphs that are thoroughly hit. Efficient work 

 can also be done with '' Black Leaf 40 " tobacco extract, one 

 pint to 100 gallons of water. In the case of nursery stock it is 

 practically impossible to hit enough of the young hoppers in the 

 curled leaves to pay for the labor and expense involved. Dip- 

 ping the infested tips into pails or dippers containing a soap 

 solution, one pound in 8 gallons of water, kills practically all 

 the young hoppers and is an entirely satisfactory method of 

 controlling the insec^t on apple nursery stock. The dipping 

 should be done in the latter part of June and again about a 

 month later. At these times the maximum number of nymphs 

 will be found on the trees. 



Many of the adults can be captured as they jump and fly 

 away from the disturbed plants by holding near by a shield 

 covered with some sticky tanglefoot-like substance, 1 pound 

 of melted resin in 1 pint of castor oil or '' castorine." In Mis- 

 souri nurseries the hoppers are sometimes captured on sticky 

 shields mounted on a two-wheeled cart drawn by a horse. 



References 



Minn. Agr. Exp. Sta. Bull. 112, pp. 145-164. 1908. 

 Iowa Agr. Exp. Sta. Bull. 111. 1910. 



