WALNUT PESTS 



2015 



Pig. 2. Mouse Injury to Nut Tree. 



— H. R. Oossard. 



duced. Then more winged forms appear, 

 which produce true males and females. 

 The males have wings but the females 

 are wingless. Copulation takes place and 

 the overwinter eggs are deposited by the 

 females about the buds on the young 

 shoots. 



Remedies 



Spray with "Black Leaf-40" or kerosene 

 emulsion 10 per cent. 



Walnut Caterpillar 



Datana integerrima Gr. & Rob. 

 The walnut caterpillar does much in- 

 jury to the walnut, butternut, hickory and 

 pecan trees in the Mississippi states by 

 eating their leaves and in many cases 

 completely defoliating the trees. When 

 full grown, the caterpillar is about two 

 and one-half inches long, dark, nearly 

 black in color, and sparsely covered with 

 long, silky, white hairs. The eggs are of 

 dull white color, and are laid in masses 

 of from 200 to 300 on the undersides of 

 leaves. (Pig. 1.) The caterpillars feed 



in large numbers, clustered together. 

 They first work on one leaf, then on a 

 branch, completely cleaning them up as 

 they go. The moth has a body measuring 

 three-fourths of an inch long and wings 

 when spread measuring one and five- 

 eighths inches in the male to one and 

 seven-eighths in the female. The fore 

 wings are of light brown color crossed 

 by four darker brown lines; the hind 

 wings are of pale yellowish color, un- 

 marked. The winter is passed in the 

 chrysalid stage in the ground. 



Remedies 



While the caterpillars are still young 

 and feeding upon the leaves, they may be 

 destroyed by spraying with arsenate of 

 lead at the rate of from two to three 

 pounds to 50 gallons of water. After the 

 caterpillars have come down the tree and 

 clustered there to molt, the mass may be 

 burned or crushed. Parasites such as the 

 Tachina flies are efficient in killing great 

 numbers of this insect. The eggs of the 

 fly are laid upon the caterpillar and later 

 hatch into maggots, which feed upon their 

 host, causing its death. So effective are 

 these parasites that it is rare for the wal- 



Fis. 1. Egj? Mass of Walnut Moth, About 

 One-half Natural Size. (Original.) 



