Diseases and Pests of the Apple and' Their Control 213 



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The best spray combination for this treatment is standard 

 lime-sulfur solution 1 to 8 plus 40 per cent nicotine sulfate 

 1 to 1066 (% pint to 50 gallons). The soap should not 

 be used when lime-sulfur is employed as they are not com- 

 patible. 



The above-ground, colonies of the woolly apple aphis 

 may best be treated in the summer by a drenching spray 

 of 10 per cent kerosene emulsion. The nicotine spray 

 does not penetrate the woolly covering of these lice as well 

 as the oil spray, otherwise the nicotine solution might be 

 used. As yet, no satisfactory method of combating the 

 woolly aphis on the roots has been found, but growing trees 

 on resistant stock, as the Northern Spy, is desirable in 

 regions in which this pest is troublesome. In spraying all 

 plant-lice it is important to remember that these are suck- 

 ing insects. 



Plum curculio (Conotrachelus nenuphar). 



The mature insect is a snout- 

 beetle which punctures the 

 young fruit in the early stages 

 and causes misshapen fruit. 

 Codlin-moth sprays serve to 

 check plum curculio although 

 control may not be entirely ef- 

 fective. Infestation is favored 

 when orchards are in sod or 

 grown up to weeds. Where 

 this pest is prevalent, an ar- 

 senical should be added to the 

 pink spray application. (See 

 Tig. 3.) 



Fig. 3. — Apple showing 

 the egg and feeding punc- 

 tures of the plum curculio 

 as well as the distorted 

 shape of the fruit attacked. 



