Abstract
Crown rot diseases have become increasingly important in strawberry production following the withdrawal of key pesticides due to environmental and human health concerns. The principal causal agents, Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae , can persist for extended periods in infected crown tissues and residual plant material in soil, serving as inoculum sources for subsequent crops. In some regions, crop termination using drip fumigants has been adopted to simultaneously destroy residual strawberry plants and the pathogens within them. In this study, we evaluated microwave heating as a non-chemical alternative for crop termination and pathogen suppression in strawberry. Pot experiments were used to quantify the thermal sensitivity of the two pathogens within infected crown tissue in microwave-heated soil. The estimated LD 50 and LD 90 temperatures for M. phaseolina were 63.1 °C and 86.2 °C, and for F. oxysporum f.sp. fragariae 72.3 °C and 87.3 °C, respectively. A field experiment showed that heating a strawberry crop to 80–90 °C using microwaves terminated plants as effectively as a herbicide treatment (glufosinate-ammonium + triclopyr). Microwave treatment also reduced the viability of M. phaseolina and F. oxysporum f.sp. fragariae in infected strawberry crowns by an average of 97%, decreased the emergence of the weed Senecio vulgaris by 73%, and reduced DNA concentrations of M. phaseolina and Pythium spp. (clades I and F) in soil by 95% and 80%, respectively. The results demonstrate the potential of microwaves as a non-chemical strategy for thermo-management of residual plant material and pathogen inoculum in strawberry production systems.