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DAHLIA SOBERS, HA2IVE AKD IHTBODUCED 
In addition to the European corn "borer, a native insect known 
as the stalk borer ( Papalpoma nebris nitela (Quen.)) bores in the 
stems of dahlias in June and July, It has a light-tan head, a trans- 
Terse, dark-brown band near the middle of its body, and brown, inter- 
rupted, longitudinal stripes on its sides. This natire stalk borer 
is rarely as numerous as the European corn borer. The latter is a 
grayish-pink caterpillar with a dark-brown head, and when fully grown 
is about 1 inch in length. It attacks rarious parts of the plant and 
occurs on dahlias in greatest numbers during August and September* 
The treatments discussed in this circular are not recommended for 
control of the natire stalk borer. 
HOW TO BEOOGHIZB STJHOPEAH COHN BOBEB IHJTOIKS IK DAHLIAS 
Signs of infestation usually begin to appear late in July and 
early in August and continue to derelop until frost. The occurrence 
of egg masses of the corn borer on the under side of lower leares, as 
shown in figures 1 and 2, is a timely warning of impending infestation 
of dahlias. Later, one may obserre that some of the foliage and 
flower buds hare wilted. Infested buds turn black, and beside them 
one may find small masses of black, granular castings, called frass, 
which hare been pushed out by burrowing larvae. This condition, 
Illustrated in figure 3» i* followed by further wilting of other 
leares and buds on the affected branch or shoot. A borer, one-fourth 
to one-half inch in length, may be found in a small, discolored carity 
beneath the black frass. As a result of further excaration by these 
larvae, normal terminal bud growth is prevented, blooms are small and 
ill-shaped, and rarious parts of the plant become broken. 
Parts of the branches or stalks break off where the borer cuts 
a small hole from the inside, pushing out particles of sawdustlike 
material, as illustrated in figure 3t which cling to the edge of the 
opening and drop to parts of the plant below. In cases of serere in- 
festation, progressive wilting and breakage result in collapse of the 
plant before propagating roots are fully formed. 
When either roots or green plants are set out in advance of 
normal planting time, and show five or six sets of leaves by mid-June, 
dahlias are sometimes infested by the European corn borer in June. 
The injuries caused at this time are similar to those described above. 
