ORCHARD INSECTS OF THE PACIFIC NORTHWEST 



67 



keep this pest in check so that artificial control is unnecessary. 

 If these beneficial insects fail, the aphid may successfully be com- 

 bated with nicotine sulfate (40 percent nicotine), % pint to 100 

 gallons of water, to which is added soap or spreader, or a 2 percent 

 nicotine dust (2% pounds of nicotine sulfate to 47K pounds of hydrated 

 lime) mav be used. 



BENEFICIAL INSECTS 



Not all of the insects found in an orchard are harmful. Many are 

 of no importance, either because they are not sufficiently numerous, 

 or because they are not injuring the 

 trees or the cover crop. Many 

 others are entirely beneficial be- 

 cause they feed on some of the 

 insects that are harmful to the crops. 

 Fruit growers should be able to 

 recognize these beneficial insects in 

 order that they may not destroy 

 them, thinking them to be harmful. 

 The most conspicuous beneficial Figure 75 

 insects and the ones most often 

 found in an orchard are those that 

 prey on various species of aphids. 



These insects are very important factors in reducing the numbers of 

 aphids, and their work is most likely to be effective during warm 

 weather when they are active and are multiplying rapidly. 



The convergent lady- 

 beetle: a, Adult; b, pupa; c, larva. 

 X 3. 



Figure 76. — A ladybeetle, Stethorus picipes Figure 77. — Larva of a 



Casey, an enemy of red spiders. X 40. syrphus fly (Allograpta 



obliqua Say). X 5. 



Ladybeetles are nearly always abundant in orchards, and the beetles 

 and their young feed on the aphids which may be on the trees or in the 

 cover crops. There are many species, one of the commonest being the 

 convergent ladybeetle (Hippodamia conuergens Guer.) (fig. 75), a red 

 beetle with black head and black spots on the back. Some species are 

 plain red, others are black with two or more red spots, and there are 

 also small black ladybeetles (fig. 76) that feed chiefly on red spiders 



