EFFECT OF DRENCHING COPTIS CHINENSIS FRANCH EXTRACT ON SOFT ROT OF ZANTEDESCHIA 'BLACK MAGIC'

Abstract

Calla lily (Zantedeschia sp.) is an important cut flower, pot plant or garden ornamental. However, bacterial soft rot (Pectobacterium carotovorum subsp. carotovorum) adversely affects the commercial viability of this crop. We conducted two field experiments to determine the effect of drench application of a formulated Coptis chinensis extract product on soft rot of Zantedeschia ‘Black Magic’. Three application rates of C. chinensis extract (0.625, 1.25 and 2.5 L/ha) were compared with copper hydroxide at 2 kg/ha, streptomycin at 100 ppm and water as control treatments in a randomized complete block design experiment with 3 replications. Pre-germinated tubers of Zantedeschia were planted on 1 m2 plots at a spacing of 20A—20 cm and drenched four times with the treatments at 14 days interval from either planting or at full foliage stage. Drenching of C. chinensis extract from planting significantly reduced soft rot incidence while drenching the extract at full foliage stage had no significant effect on incidence of the disease. Application of C. chinensis extract significantly suppressed the severity of soft rot with the highest rate (2.5 L/ha) consistently recording a lower percent disease index (PDI). Our results demonstrate the potential of C. chinensis extract to suppress soft rot of Zantedeschia.