Improved Management of Charcoal Rot of Strawberry in Australia with Soil Fumigation and Totally Impermeable Film

Abstract

Charcoal rot of strawberry [Fragaria ×ananassa (Duchesne)] caused by the soil-borne fungus Macrophomina phaseolina (Tassi) Goid results in significant plant losses each year in Australia. Before the current research, industry applied the soil fumigants 1,3-dichloropropene and chloropicrin in combination to the bed (strip fumigation) under low-density polyethylene film (LDPE) as the standard practice to manage the disease. We conducted column and field experiments to evaluate soil fumigation with 1,3-dichloropropene/chloropicrin under totally impermeable film (TIF) and broadacre application (treatment of beds and inter-rows) for control of M. phaseolina and charcoal rot compared with the previous standard practice. The results showed that treatment under TIF increased the concentration × time (CT) values of fumigants in soil by up to 38% compared with those of LDPE. Strip fumigation under TIF reduced DNA concentrations of M. phaseolina in soil (0–10 cm) by 65%, charcoal rot by 93%, and increased fruit yields by 37% compared with application under LDPE. Furthermore, broadacre fumigation reduced DNA concentrations of M. phaseolina by an average of 55%, charcoal rot by 65%, and increased fruit yields by 40% compared with those of strip fumigation under LDPE. This work demonstrates the effectiveness of improved fumigation practices for minimizing the impact of charcoal rot in strawberry.