Abstract
Benomyl wettable powder control of green mold of a very early ripening variety of mandarin orange, Satsuma, decreased to unacceptable levels for practical use against benzimidazole-resistant strains of Penicillium digitatum in orchards. Application of an iminoctadine triacetate liquid formulation that achieved a high fungicidal efficacy in vitro against benzimidazole-resistant and -sensitive strains of P. digitatum gave variable effects in the control of the disease under field conditions. When the disease incidence was severe, the efficacy of the iminoctadine triacetate application was significantly lower. However, simultaneous application of an iminoctadine triacetate liquid formulation and benomyl wettable powder improved the control efficacy to levels acceptable for practical use. Interestingly, the effect was not additive but synergistic. Although thiophanate-methyl wettable powder is also a benzimidazole like benomyl wettable powder, it was not as effective. In addition, no significant effect on application timing during 3 weeks before harvest and cumulative precipitation of up to 150 mm during the treatment period was detected.
