Oviposition deterrence against Sitodiplosis mosellana (Diptera: Cecidomyiidae) in spring wheat (Gramineae)

Abstract

AbstractSpring wheats, Triticum aestivum L., previously identified as being lightly infested by eggs or larvae of wheat midge, Sitodiplosis mosellana (Géhin), were tested to determine if reduced infestation was the result of oviposition deterrence. Oviposition deterrence was measured as the number of eggs deposited on a wheat line relative to that on a check. Egg densities on some of these lines were 10% or less compared with the susceptible commercial cultivar 'Roblin' in choice tests and 20% or less in no-choice tests in the laboratory. These lines also deterred oviposition in the field, reducing egg densities by at least 50% in single-row and multi-row field plots. Other experimental lines showed levels of oviposition deterrence intermediate between the most deterrent lines and 'Roblin'. One of 12 commercial cultivars tested, 'AC Superb', also had low egg densities in the laboratory and in single-row field tests, but this possible oviposition deterrence was not consistently present in large plots or commercial fields. The most deterrent experimental lines showed a level of oviposition deterrence that would be agriculturally useful and desirable in combination with a previously described antibiotic resistance.