

ASSOCIATION OF PLANT HAIRS 

 AND INSECT RESISTANCE 



An Annotated Bibliography 



BvJames A. Webster, research entomologist. 



Cereal Leaf Beetle Laboratory. Agricultural Research Service. 



East Lansing. Mich. 



INTRODUCTION 



The primary known component of the resistance in wheat to the cereal 

 leaf beetle. Oulema melanopus (L.). is nonpreference for oviposition on plants 

 with pubescent leaf surfaces. Therefore, during studies of resistance caused by 

 pubescence, a bibliography was compiled of scientific publications reporting 

 on the relationship between hairs and insect resistance. 



Some plant hairs confer this resistance by interfering with such insect ac- 

 tivities as feeding and oviposition; other plants have hairs or glandular tri- 

 chomes that secrete material that is either toxic to the insect or impedes its 

 mobility. Some plants, however, have hairs that make the plant susceptible 

 to insect activity, and other more glabrous plants are insect resistant. Because 

 each insect-host interaction is a unique relationship, it is difficult to general- 

 ize further about plant hairs and insect resistance. Insect reactions to pubes- 

 cent plants reported in the publications in this bibliography are summarized 

 below. 



There are occasional discrepancies in the literature about plant hairs and 

 insect behavior. Thus, the summary may be used as a general guide, but 

 plant breeders and entomologists should make a thorough study of their in- 

 sect-host situation to avoid the possible release of a cultivar vulnerable to 

 another pest. 



