50 



INJURIOUS INSECTS OF 1903. 



KEY FOR ORCHARDISTS AND NURSERYMEN. 



The basis of the following key is taken from one compiled by 

 Mr. Lochhead, which appeared in the 33d Annual Report of the 

 Entomological Society of Ontario. It seemed necessary to re- 

 arrange the key to some extent, in conformity with Minnesota 

 conditions, eliminating some insects given in the original and 

 adding others not given, and it also appeared desirable to the 

 writer to append the best known remedy or remedies under most 

 of the pests. Insects affecting the Apple, Plum, Pear and Cherry 

 are here given (albeit there will be but little call for information 

 regarding pests of the last two), and it is hoped, in view of the 

 growing interest in horticulture in our state, that the key will be 

 of use to Minnesota orchardists and nurserymen in identifying in- 

 sects at work on their fruit trees. Many of the illustrations used 

 originated in this department. 



KEY TO APPLE INSECTS. 



A. Attacking the Roots: 



Causing knots or swellings on the smaller roots- 

 white mouldy lice. 



-bluish- 



WOOLLY APHIS. 



Fig. 19.— Woolly aphis, a, root of young tree illustrating deformation; b, section of 

 root with aphides clustered over it; c, root louse, female; a and b, natural size; 

 c, much enlarged. After Marlatt, Division of Entomology, Department of Agri- 

 culture. 



