REPORT OF THE STATE ENTOMOLOGIST I909 'Jj 



plants. In the fall there is a return migration from the grasses 

 and grains and the deposit of winter eggs as mentioned above. 



Green apple aphis (Aphis mali Fabr.). This species, 

 like the preceding, passes the winter as black eggs which are un- 

 distinguishable from the above noticed form. The plant louse 

 has a pear-shaped, yellowish green, green or dark green body- 

 instead of the oval form of the European grain aphid. The eggs 

 of this widely distributed form hatch a little later in the season, 

 and the plant lice, like the preceding, frequently cause serious 

 curling of the foliage. This plant louse occurs upon the trees 

 throughout the season and, under conditions obtaining in New 

 Jersey, may produce six generations before the appearance of 

 the sexual forms and the deposition of eggs destined to hatch 

 the following season. 



Rosy apple aphis (Aphis malifoliae Fitch) . This 

 species is easily distinguished from the preceding by its larger 

 size, rounder shape and usually rosy color, though this latter 

 may vary from salmon to tan or even to slaty gray or black, the 

 body being dusted with whitish. This widely distributed aphid, 

 like the preceding, winters as eggs deposited on the trunk and 

 larger limbs. The young plant lice appear with the unfolding 

 of the leaves. There are about three generations produced be- 

 fore the trees are deserted for an unknown food plant. There 

 is a return migration in the fall and the deposition of eggs. 



Certain other aphid pests 



Cherry aphis (Myzus cerasi Fabr.). This species is 

 more or less abundant every year and, like some of its allies, 

 was excessively numerous the past season. It is easily recog- 

 nized as the black aphis so prevalent in early summer on sweet 

 cherry foliage, portions of the leaves sometimes being nearly 

 black with insects. Occasionally the attack is so severe as to 

 result in the entire destruction of the leaves for a foot or 2 feet 

 from the tips of the shoots. Such an outbreak means serious 

 injury to the trees. 



Hop aphis (P h o r o do n h u m u 1 i Schrk.). The hop louse 

 was locally abundant and is occasionally quite injurious to this 

 plant. It is one of the forms known to have two food plants. 

 The winter is passed as small, glossy, black eggs on various 

 species of Prunus or plum, both wild and cultivated. The eggs 

 hatch in early spring and three generations arc produced on the 



