|Morrison Jr, John|
Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/1996
Publication Date: N/A
Interpretive Summary: Farmers who plant field crops in the South and Southeastern states of the USA have been becoming aware that under some conditions, the planted seed is being eaten by the red imported fire ant, Solenopsis invicta. This occurs before the seed has time to germinate and the seedlings emerge from the soil. Severe fire any damage causes financial hardship because of the necessity of replanting a damaged crop. We studied the potential damage by fire ants to the planted dry seed of wheat, corn, sorghum, cotton, and soybean crops. The results were that imported fire ants heavily damaged wheat, corn, and sorghum seed. Cotton and soybean seed damage was at such a low level that it would be difficult to detect in the field. Fire ant damage was reduced by the commercial bag-treatment insecticides which are typically applied to purchased seed, but if germination was slow due to dry soil, then the damage could be substantial. The results indicate that effective repellents or insecticidal treatments are needed on the dry seed when planted in regions which are infested with red imported fire ants.
Technical Abstract: Red imported fire ants (RIFA) have been documented as a predator to planted field crop seed. The RIFA eat into the seed before the germination process can foster plant establishment. When conservation/sustainable tillage systems are used in RIFA-infested regions, the ant colonies are disturbed less than with conventional tillage and may constitute a stronger threat to successfulcrop stand establishment. Five predominate field crop seed, wheat, corn, grain sorghum, cotton, and soybean, were tested as potential food sources for RIFA. The seed were at air-dry moisture condition, as typically sown by farmers. Tested corn, sorghum, and cotton seed were with and without typical bag-treatment insecticides. The wheat was raw, untreated seed and the soybeans were with and without typical farmer-treated inoculant. RIFA do feed on dry wheat, corn, and sorghum seed and to some extent on cotton and soybean seed. Typical bag-treatment insecticides tested did reduce RIFA feeding, but if damage exceeded 20-30%, as seen for treated sorghum, then there would still be a substantial risk of crop stand failure during extended dry soil, slow germination conditions. Raw, untreated, wheat seed was the most heavily damaged, and yet farmers in the RIFA-infested region of the USA routinely plant untreated wheat seed. From the results, RIFA damage to the plant stand of the tested five crops may vary from insignificant to a failure depending upon exposure time to RIFA, seed type, and seed bag-treatment.