Postharvest Benomyl and Thiabendazole Treatments, Alone and With Scald Inhibitors, to Control Blue and Gray Mold in Wounded Apples1

Abstract

Abstract Benomyl and thiabendazole (TBZ), at concn of 1,000 ppm, were compatible with commercial scald inhibitors (2,700 ppm ethoxyquin or 2,000 ppm diphenylamine). No injury was observed on ‘ Delicious’ or ‘Stayman’ apples given combined treatments and stored 5 months at 0°C plus 6 or 7 days at 21°C. Effectiveness of fungicide and scald inhibitor was not altered when combined. Both benomyl and TBZ used as 10-15 sec dip treatments at 500 ppm controlled decay due to blue mold (Penicillium expansum) and gray mold (Botrytis cinerea) at puncture wounds in inoculated apples. They were less effective in controlling decay at bruises unless suspensions were heated in a range of 29°-45°C (84°-l 13°F) and used as a 2-min dip. Unheated benomyl was more effective than unheated TBZ in reducing blue mold at bruises. TBZ was less effective in controlling decay at punctures when treatment was delayed 24 hr after inoculation. TBZ added to water contaminated with blue mold spores, as in a dump tank, controlled decay at skin punctures but not at bruises during subsequent storage. Neither benomyl nor TBZ controlled Alternaria rot, which often developed at punctures when blue and gray mold rot were controlled.