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MASS. EXPERIMENT STATION BULLETIN 353 



Walnut Caterpillar 



Datana integerrima G. & A. 



This native moth is known to be present from Maine to Florida and west to 

 Kansas. The caterpillars seem to prefer the foliage of the black walnut but also 

 attack pecan, butternut, English walnut, Japanese walnut, and hickory, and have 

 occasionally been reported on other trees. The feeding usually occurs about 

 midsummer. The caterpillars feed in clusters, often devouring all the leaves on 

 one limb before moving on to another. In severe attacks the whole tree may be 

 defoliated. Isolated trees or trees in small groups are more liable to be injured 

 than groves of the preferred host, or than trees located in woodlands. Often- 

 times when the caterpillars are disturbed the\' will characteristically raise both 

 ends of the body suddenly and remain motionless for a minute or so. 



Walnut Caterpillar 



1. Egg mass on leaf. Actual size. 



2. Mature caterpillar. Slightly enlarged. 



3. Pupa2X. 



4. Adult female moth. Actual size. 



5. Cluster of cast skins on tree trunk. 



Courtesy, Conn. Agr. Expt. Station. 



Description. The moths are heavy-bodied, with a wingspread of nearly 2 

 inches. The forewings are buff-colored, with darker lines running irregularly 

 across them. The hind wings are lighter in color and do not have the cross lines. 



