ARS | Publication request: SETTLIN AND FEEDING RESPONSES OF PEA WEEVIL (COLEOPTERA: BRUCHIDAE) TO FLOWERS OF SELECTED PEA LINES.

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 1996
Publication Date: N/A

Interpretive Summary: AMERICAN FARMERS ARE BEING ASKED BY CONSUMERS AND ENVIRONMENTAL GROUPS TO REDUCE THEIR USE OF SYNTHETIC PESTICIDES AND USE MORE SUSTAINABLE APPROACHES TO MANAGE INSECT PESTS OF FOOD CROPS. ONE SUSTAINABLE APPROACH IS THE USE OF INSECT-RESISTANT CROP CULTIVARS. HOWEVER, BEFORE SCIENTISTS CAN DEVELOP PEST RESISTANT CULTIVARS, METHODS AND PROCEDURES MUST BE IN PLACE TO DISTINGUISH BETWEEN RESISTANT AND SUSCEPTIBLE PLANTS AMONG COLLECTIONS OF PLANT GERMPLASM. THIS RESEARCH, CONDUCTED BY TWO USDA ENTOMOLOGISTS AND A STATISTICIAN FROM WASHINGTON STATE UNIVERSITY, DETAILS THE DEVELOPMENT OF A PRACTICAL METHOD TO IDENTIFY PEA PLANTS WITH RESISTANCE TO PEA WEEVIL ATTACK. THIS INSECT IS A PEST OF FIELD PEAS IN EASTERN WASHINGTON AND NORTHERN IDAHO. THIS NEW METHOD IS BASED ON WEEVIL PREFERENCE FOR FLOWERS FROM PEA LINES STORED AT THE USDA-ARS PLANT INTRODUCTION STATION, PULLMAN, WA. THE OLD, MORE TIME-CONSUMING METHOD RELIED ON WEEVIL PREFERENCE FOR PEA PODS. THIS NEW PROCEDURE WILL EXPEDITE THE SEARCH FOR WEEVIL RESISTANCE IN PEA GERMPLASM.

Technical Abstract: THE HOST SELECTION AND FEEDING PREFERENCES OF FEMALE PEA WEEVILS (BRUCHUS PISORUM) FOR FLOWERS FROM PEA LINES VARYING IN THEIR SUSCEPTIBILITY TO PEA WEEVIL OVIPOSITION WAS INVESTIGATED IN A SERIES OF LABORATORY TESTS. A STATISTICAL METHOD BASED ON A MARKOV CHAIN MODEL WAS USED TO ANALYZE THE DATA FROM MULTIPLE CHOICE TESTS, IN WHICH REPEATED CATEGORICAL RESPONSES OF WEEVILS WERE RECORDED. WEEVILS CONSISTENTLY PREFERRED FLOWERS OF TWO VARIETIES (ALASKA AND GARFIELD) KNOW TO BE HIGHLY SUSCEPTIBLE TO PEA WEEVIL OVIPOSITION OVER FLOWERS OF TWO LINES (PI 196027 AND PI 263026) KNOWN TO PRODUCE PODS WITH ANTIXENOSIS RESISTANCE TO OVIPOSITING PEA WEEVILS. IN OTHER TESTS, FEMALE WEEVILS FAILED TO DISCRIMINATE BETWEEN FLOWERS OF ALASKA AND GARFIELD AND BETWEEN FLOWERS OF PI 196027 AND PI 263026. THE RESULTS SHOW THAT A LABORATORY BIOASSAY BASED ON WEEVIL PREFERENCE FOR FLOWERS CAN BE USED TO SCREEN PEA GERMPLASM FOR ANTIXENOSIS RESISTANCE. THIS STUDY ALSO DEMON- STRATES THE APPLICATION OF MARKOV CHAINS FOR ANALYZING DATA FROM PLANT/ INSECT INTERACTION STUDIES IN WHICH REPEATED CATEGORICAL RESPONSES OF TEST ORGANISMS ARE OBSERVED.