66 THE EEPORT OF THE ' Xo. 36 



Seriousness of the Pest. 



Sufficient has already been written to indicate tliat this insect is a very serious 

 pest of both the apple and pear, but any estimate of the actual damage done 

 would, of course, be out of the question. However, it is safe to say that it is 

 one of the most serious insect pests of our orchards. In fact, there can be no doubt 

 that in orchards where it has become established, we have no pest to compare with 

 it, either in amount of damage done or in the difficulty of eradication. The pears 

 in certain orchards have for years been so scarred as to be scarcely merchantable, 

 and, in not a few apple orchards, the crop of fruit from susceptible varieties has 

 been greatly reduced or even destroyed. In one orchard visited, only one apple 

 <;ould be found among ten large Nonpareil trees, due entirely to the work of the 

 Oreen Apple Bug. 



Host Plants. 



x\s far as we have determined, the insect only breeds in the apple and pear. 

 It has been found feeding in the adult stage on plums, but has not been known 

 to oviposit in that plant. When shaken from the trees the nymphs have been ob- 

 served to feed upon coucli grass, timothy, red clover, dandelions and other plants 

 growing beneath the tree, but on reaching the adult stage they again seek the apple 

 .^nd pear trees for the purpose of feeding and depositing their eggs. 



The Insects. 



When the insect first appears it is light yellow in color, but as it develops it 

 becomes green. It somewhat resembles an aphis in appearance and was once de- 

 scribed by a farmer as a " new kind of long-legged aphis." Others speak of it as 

 the " horned aphis " on account of its long antennse. The adult is a small, delicate 

 insect, one quarter of an inch long. It is very pale on first emerging, but later 

 becomes a combination of light and dark brown. In appearance it resembles quite 

 closely the Tarnished Plant Bug (Lygiis praiensis). 



Life History. 



The maximum emergence of the nymphs from the egg state coincides with the 

 opening of the blossoms of the Gravenstein apple, but the beginning of the emerg- 

 ence is about five or six days earlier. They continue to hatch until the time the 

 blossom petals fall, when emergence is practically finished. In the season of 1915 

 the first n}Tnph to emerge was taken on May 24th and the last on June 10, the 

 period of maximum emergence being from June 1st to June 5th. The duration 

 of the first nymphal instar is 5.22 days (average of 52 individuals) ; of second, 

 5.43 days (average of 34 individuals) ; of the third, 6.66 days (average of 34 in- 

 dividuals) : of the fourth, 6.77 days (average of 24 individuals) ; and of the fifth, 

 6.83 days (average of 12 individuals). 



No nymphs were observed during the past summer after July 7th, all having 

 completed their transformations by that date. The length of the adult stage varies 

 greatly, single individuals having been taken in the orchard as late as the first week 

 in October. 



The following table gives the details of tlie life history of twelve individuals, 

 which were reared from the egg to the adult stage : — 



