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United States Department of Agriculture

Agricultural Research Service

Title: Quantifying the Feeding Periods Required by Corn Flea Beetles to Acquire and Transmit Pantoea Stewartii

Authors
item Menelas, B - IOWA STATE UNIVERSITY
item Block, Charles
item Esker, P - IOWA STATE UNIVERSITY
item Nutter, F - IOWA STATE UNIVERSITY

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 30, 2005
Publication Date: March 1, 2006
Citation: Menelas, B., Block, C.C., Esker, P.D., Nutter, F.W. 2006. Quantifying the Feeding Periods Required by Corn Flea Beetles to Acquire and Transmit Pantoea Stewartii. Plant Disease. 90:319-324

Interpretive Summary: Stewart's disease of corn, or Stewart’s wilt, is caused by the bacterium Pantoea stewartii. The disease spreads from plant to plant by feeding of corn flea beetles (Chaetocnema pulicaria) which carry the bacteria. Controlling the overwintering and first generations of the beetles is a key step in preventing or limiting damage from this disease. The feeding times required for corn flea beetles to pick up and transmit P. stewartii were unknown and were investigated in this study. Field-collected beetles were fed for 3, 6, 12, 24, 36, 48, and 72 hr on corn seedlings that were infected with an antibiotic-resistant strain of P. stewartii. The shortest time for beetles to acquire the bacteria was between three and six hours. After 72 hr of feeding, more than 67% of the beetles were infested with bacteria. To measure transmission efficiency, infested corn flea beetles were allowed to feed on healthy seedlings for periods of 3, 6, 12, 24, 36, 48, and 72 hr. Transmission was considered positive if the P. stewartii isolate was successfully recovered from leaf tissue around the feeding sites. The minimum time for flea beetles to transmit P. stewartii to healthy plants was between zero and three hours. After 6 hours of feeding, transmission success ranged from zero to 33% for the three experiments. After 72 hrs, 58-71% of the beetles had infected a new plant. The predicted times for 50% of the infested corn flea beetles to transmit the pathogen in the three experiments were 29.3, 28.3, and 27.2 hrs, respectively. These results suggest that there is a small window of opportunity for seed and foliar-applied insecticides to control early season corn flea beetles and prevent a large scale infection. This is the first study to quantify the time it takes for corn flea beetles to acquire and transmit Pantoea stewartii and to estimate the relative transmission efficiency. These are key, and previously unknown, factors that should aid in developing better control and management strategies for Stewart’s disease of corn.

Technical Abstract: The feeding times required for corn flea beetles (Chaetocnema pulicaria) to acquire and transmit Pantoea stewartii were investigated in the Stewart’s disease of corn pathosystem. To quantify the effects of feeding time on the acquisition of P. stewartii, field-collected beetles were fed for 3, 6, 12, 24, 36, 48, and 72 hr on corn seedlings previously inoculated with a rifampicin and nalidixic acid-resistant strain of P. stewartii. Acquisition was considered positive if the P. stewartii resistant strain was recovered on selective media. The earliest measured acquisition occurred between three and six hours of feeding. After 72 hr of feeding, the percentage of infested beetles ranged from 68 to 94% in the three experiments. The average time for 50% of the beetles to become infested with P. stewartii was 36.5 ± 11.6 hr. To quantify the effect of feeding time on transmission, infested corn flea beetles were allowed to feed on healthy seedlings for periods of 3, 6, 12, 24, 36, 48, and 72 hr. Transmission was considered successful if the P. stewartii isolate was successfully recovered from leaf tissue near the feeding sites. The minimum time for C. pulicaria to transmit P. stewartii to healthy plants was between zero and three hours. After 6 hours of feeding, transmission success ranged from zero to 33% for the three experiments. After 72 hrs, the percentage transmission ranged from 58 to 71%. The predicted times for 50% of the P. stewartii-infested corn flea beetles to transmit the pathogen in the three experiments were 29.3, 28.3, and 27.2 hrs, respectively. These results suggest that there is a small window of opportunity for seed and foliar-applied insecticides to be effective in controlling early season corn flea beetles and prevent them from spreading P. stewartii to new plants.

Last Modified: 10/25/2014
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