-8- 



THE APHIDS ON APPLE II 



Apple Grain Aphid 



The apple grain aphid causes very little damage to foliage and no damage 

 to fruit. And yet, usually, it is the most abundant aphid on apple buds, spur 

 leaves and blossom clusters until shortly after bloom. 



Many times, growers spend money for materials and labor to control this 

 harmless aphid. And often such applications are too late to prevent losses from 

 any rosy apple aphids which may be present. 



The effective, preventive programs for rosy aphid, outlined. in the November - 

 December issue of Fruit Notes, will eliminate grain aphid infestations completely. 

 Worry and unnecessary expenditures also should be eliminated by carrying out these 

 "insurance" programs. 



More About the Aphid Itself 



Last fall, during September and October, v/inged females produced on grains 

 and g^rcaea left those plants and migrated to apple. Here they produced living 

 progeny which were wingless females. After having been mated with winged males 

 from grain and grass host plants these females laid overwintering eggs. 



The eggs resemble those of the rosy apple aphid. The tiny, black ovals are 

 found now (December) tucked into crevices around buds on slow growing terminals, 

 on fruit spurs, and wherever there is rough bark along the branches. 



Hatching starts early, even before any green tissue is showing. Literally 

 hundreds of young apple grain aphids may be found clustering on swollen buds in 

 the Silver Tip and Green Tip stages of bud development. Normally hatching is 

 completed within 7 to 10 days. 



The nymphs feed on the sap of leaves, flower buds and bud stems but do not 

 cause distortion of these parts. 



The growth of these first generation nymphs into stem mothers is completed 

 in about 2 weeks, sometime early in the Up~to-Pink stage. Stem mothers are 

 yellowish green with a distinct row or band of diamond- shaped, darker green 

 areas extending lengthwise along the mid-line of the back. 



Sometime before Pink the stem mothers, without mating, start to produce 

 living young, 2 to 3 per day for up to a month. Under favorable conditions 

 enormous populations may be present during bloom and shortly after. 



Most of the second generation nymphs, and all of those in the third genera- 

 tion on apple, develop into winged females which migrate to grains or grasses and 

 there produce living young, which represent the first of a series of summer broods 

 on these host plants. 



Here again is a complicated life cycle involving two host plant types, one 

 egg laying generation, three winged forms, and many broods in which are found only 

 the non-mating females capable of producing living young. 



