LIBRARY 
STATE PLANT BOARD 
June 19^3 1-596 
TOUTED STATICS DEPARTMENT OP AGRICULTURE 
Agricultural Research Administration 
Bureau of Entomology and Plant Quarantine 
THE EUROPEAN CORN BORER AND ITS CONTROL IN DAHLIAS 
By C. H. Batchelder, D. D. Questel, and A. V. Cosenza, 
Division of Cereal and Forage Insect Investigations 
CONTENTS 
Introduction 1 
Dahlia "borers , native and introduced 
How to recognize European corn borer injuries in dahlias •• 2 
Source of corn borers in dahlias 3 
How corn borers get into dahlia plants 3 
Control of the corn borer with insecticides 3 
Insect icidal materials • h - 
Equipment for applying insecticides 
When to apply insecticides 6 
Supplementary control measures • 6 
Disbudding and disbranching 6 
Use of a tent 6 
Trimming root clumps 7 
INTRODUCTION 
The European corn borer ( Pyrausta nubilalls (Hbn. )) is a 
serious pest of dahlias in the northeastern part of the United 
States. 17 
As its name implies, the insect is most widely known as a 
pest of corn, although it also infests other cultivated crops, 
some weeds* and several ornamental garden plants. 
The European corn borer infests all types and varieties of 
dahlias. Certain varieties may sometimes show more infestation 
than others, owing to differences in the size and growth stage of 
the plants when the eggs of the insect were being laid. 
1/ The European corn borer in 19^2 was known to occur in 
Wisconsin, Missouri, Iowa, and eastward to Maine and North Carolina, 
as well as in Ontario, Ojuebec, and the Maritime Provinces of Canada* 
JUN 2 1 1943 
