1942 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



Fig. 1. Strawberry Leaf Borer (Sesia rutilans) 

 adult moths. (Original.) 



west nearly everywhere the strawberry is 

 grown. The elongate, white larva, with 

 brown head and darker biting jaws, feeds 

 on the interior of the crown and tap root 

 of the strawberry plant, eating out the 

 entire heart. The plant, as a result, looks 

 sickly, and when pulled up will often 

 break just below the crown, exposing the 

 tunnel filled with frass and excrement and 

 often the larva itself. The adult insects 

 are clear-winged moths. (See Fig. 1.) 



Remedial Measures 



Dig up and destroy infested plants, 

 preferably in late fall or early spring. 



Fig. 2. Larva of Strawberry Root Borer. 



(Original) 



Strawberry Root Louse 



Aphis forhesi Weed 



Except for a brief time in the spring 

 when the young lice are working their 

 way down from the leaves, where they 

 hatch, to the crown of the plant, the 

 strawberry root louse spends most of its 

 time upon the roots of the strawberry, 

 whither they are carried by ants which 

 feed upon the sweet excretions of the 

 aphids. 



The presence of the lice may be de- 



tected by the failure of the plants to ma- 

 ture fruit and by the dying of plants in 

 spots in the beds. Suspicion should be 

 aroused also when numerous nests of 

 brown ants appear in the strawberry beds 

 after the first week in April. 



The aphids are very small, about one- 

 twentieth of an inch long, blue black in 

 color and pear-shaped, tapering toward 

 the head. 



Food Plants 



This species of aphis is found only on 

 the tame strawberry, not even the wild 

 strawberry in the neighborhod of infested 

 tame ones being attacked. 



Life History 



Sometime in late October or early No- 

 vember the root louse deposits its eggs 

 along the stems and ribs of the green 

 leaves, where they remain until the latter 

 part of March or April, when they begin 

 to hatch out. The eggs are very small 

 and shiny black, about one-thirty-fifth of 

 an inch long. The first brood feeds upon 

 the tender green leaves, slowly working 

 their way down to the crown of the straw- 

 berry. They reach their growth in about 

 15 days. 



Ants are largely responsible for the 

 presence of the aphids on the roots of the 

 plants. The aphids themselves do not 

 seem to be able to get to the roots. But 

 in late April ants begin to appear in the 

 strawberry bed and are seen busily car- 

 rying the young lice to the roots of the 

 plants, where they have provided quar- 

 ters by excavating galleries under the 

 crown of the plant, and along the radiat- 

 ing roots. The ants care for the aphids 

 all summer, sometimes carrying them 

 from one plant to another when they be- 

 come too thick on the roots of any plant. 



Distribution 



The insects are spread in three ways: 

 first, by the sale of plants which are al- 

 ready infested; second, by flight of the 

 winged aphids; third, by ants. 



IVatural Enemies 



This species of aphids has two natural 

 enemies: The common ladybird beetles 

 and their larvae which feed upon the 

 lice, and the parasitic fly which lays its 



