Complete insect mortality was achieved by 39-MHz treatments that raised grain temperatures to 40°C; whereas, grain temperatures of ca. 80°C were required for complete mortality in 2450-MHz treatments.
Insect mortalities from 39-MHz exposures were much greater 1 day after treatment than were those from 2450-MHz exposures producing comparable grain temperatures. The degree of injury and delayed mortality resulting from 39-MHz exposures also was much more severe than that resulting from 2450-MHz exposures. The results confirmed predictions, based on measurements of dielectric properties of adult rice weevils and wheat, that 39-MHz treatments should provide a much better opportunity for selectively heating the insects than would