Effect of Crop Termination, Bed Fumigation, and Host Resistance Integration on Yield and Verticillium Wilt Incidence in California Strawberry Production

Verticillium wilt, caused by Verticillium dahliae, is a major disease affecting California strawberry production. Following the phaseout of methyl bromide, an integrated approach is necessary to alleviate disease pressure. Two field experiments were conducted to evaluate the effect of integrating sequential fumigant applications, crop termination, bed fumigation, and a moderately resistant cultivar on disease incidence and yields. For crop termination, metam potassium or metam sodium was utilized; for bed fumigation, either of the metam products or chloropicrin was utilized. ‘Seascape’ and ‘Valiant’ were utilized to evaluate the integration of genetic resistance following fumigation. In both trials, total and marketable yields were statistically similar between plots that were only bed fumigated and those sequentially crop terminated and bed fumigated. In trial 1, in which the initial V. dahliae inoculum and disease pressure were high, sequential crop termination with metam potassium followed by bed fumigation with chloropicrin produced the highest average total (21.8 ± 0.7 kg) and marketable (16.4 ± 0.7 kg) yields and significantly reduced disease incidence compared with the nontreated control. In contrast, trial 2 exhibited lower overall disease incidence due to reduced inoculum levels and cooler, wetter conditions; no significant yield differences were observed among treatments. Across both trials, Seascape produced higher average total yields than Valiant, but cultivar resistance did not consistently reduce disease incidence. These results indicate that fumigation remains most effective under high inoculum conditions, whereas the benefit of additional crop termination or genetic resistance is diminished under low disease pressure. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .