Use of acephate, benomyl and alginate encapsulation for eliminating culture mites and fungal contamination from in vitro cultures of hardy hibiscus (Hibiscus moscheutos L.)

Summary Shoot cultures of three Hibiscus moscheutos (L.) cultivars were infested with micro-arthropods (mites). Nodal segments (1 cm long) were excised from these cultures and encapsulated in a sodium alginate gelled Driver and Kuniyuki Walnut DKW medium containing 10, 50, or 100 mg l⁻¹ acephate (insecticide) or 10 mg l⁻¹ acephate plus 0, 50, or 100 mg l⁻¹ benomyl (fungicide), then placed in refrigerated (5°C) darkness for 4 wk. Acephate was tested alone if visible fungus was not touching the shoot masses and benomyl was tested if fungus was in contact with the proliferating shoots. Cold-stored encapsulated nodes were then placed on DKW medium with 0.1 μM thidiazuron for 6 wk for subsequent shoot development. The presence of acephate in the encapsulation medium completely eradicated or killed the mites, with 38–69% of cultures fungus-free; 12% of the fungal-contaminated nodes encapsulated with 100 mg l⁻¹ benomyl were fungus-free.