INSECTS INJURIOUS TO THE APPLE AND PEAR 537 



Professor F. M. Webster* has observed this species on wheat in 

 Ohio, and states that in mild winters it remains on the wheat, 

 going down on the stems to just below the surface of the soil or 

 to the upper roots, as we have observed it in Texas. " Here they 

 go on reproducing when the temperature is favorable/' he says, 

 "the adults being apterous so far as observed by me, until spring, 

 when they ascend to the foliage, the adults after this being both 

 winged and wingless. On the stems and roots below the surface 

 of the ground they are of a greenish color, tinged with reddish- 

 brown, especially posteriorly, the full-grown individuals often 

 being wholly of a dark brown. It is during autumn that they 

 do their greatest injury to the wheat by sucking the juices from 

 the young plants, often, if on poor land and if in dry weather, 

 checking their growth and causing the foliage to turn yellow." 

 This species is seldom much in evidence on grains or grasses in 

 midsummer and rarely becomes very injurious to them. On 

 the apple it is abundant on the young foliage and particularly on 

 the flower buds and blossoms, where it is much more common than 

 the other species. It does not, however, curl the foliage nearly 

 as severely as the other species, due to its earlier migration. 



S-1 Control. It has been found in many places that by delaying 

 the lime-sulfur spray as applied for scale until the buds are 

 beginning to open in the spring the grower may effectively con- 

 trol the aphis, the spray killing at this time the over-wintering 

 eggs. It must be admitted, however, that there are times when 

 this treatment is not effective. Just why is not known. When 

 this spray is omitted or fails to kill the aphids, they may be 

 controlled by spraying with Blackleaf 40 at the rate of 1 to 1000, 

 four pounds of soap being added to the mixture if it is applied 

 without bordeaux or the arsenicals. Hodgkiss recommends a 

 spray called the nicotine-lime spray, made by adding two to 

 four pounds copper sulphate and six pounds lime to the 1 to 

 1000 solution of nicotine sulphate (Blackleaf 40). The above 

 amount for each 100 gallons of the spray. This acts to some 

 extent as a deterrent as well as an insecticide. Any spraying 

 done must be done before the leaves curl, since the insects must 

 be hit with the spray to be killed and when they are protected 

 by curled leaves it is impossible to hit any great number of them. 



*See Bulletin 51, Ohio Agr. Expt. Station, p. 111. 



