Abstract:

The paper aims to reveal the differences in sensitivity between Fusarium spp. after stress treatments and cultured under conventional condition to soil fumigants. We tested the fumigants’ control efficacy EC₅₀ of 3 kinds of fumigants (30% chloropicrin EC, 30% 1,3-dichloropropene OD, and 50% Calcium cyanamide Granules) to Fusarium spp. by a simple indoor dryer, and screened the fumigant with the smallest EC₅₀ to test the growth of Fusarium spp. previously cultured under different stress treatments, including different pH values, extreme temperatures and different salt stresses, after fumigation for 72 h, Fusarium spp. was then cultured under conventional condition (pH value was 7, salt concentration was 0, temperature was 28℃) for 120 h, and measured the diameter of the mycelium of Fusarium spp. by crossing method. The results showed that: among the 3 fumigants, 30% chloropicrin EC₅₀ was 0.21 mg/L which was the smallest; after different stresses, Fusarium spp. was fumigated with 30% chloropicrin EC, and then the regular inoculation was conducted for 120 h, the inhibition rate of 30% chloropicrin at different pH (5, 6, 7, 8, 9) treatments was 15.82%, 10.42%, 24.37%, 19.52%, 15.13%, respectively, the inhibition rate under different salt stresses (0, 10, 100, 200, 400, 800 mmol/L) was 27.04%, 28.84%, 15.60%, 21.33%, 14.38%, 11.12%, respectively, and the inhibition rate of 120 h after inoculation at 40℃ for 15, 10, 5 days and 4℃ for 15, 10, 5 days was 87.52%, 21.65%, 26.85%; 24.17%, 24.35%, 29.14%, respectively. It is found that there are differences in the sensitivity of Fusarium spp. treated with different stresses to the same concentration of fumigant, the sensitivity of Fusarium spp. to fumigant and the inhibition rate after stress treatment is lower than that of the control treatment.

Key words: Fusarium spp., Fumigant, Inhibition Rate, Stress Treatment, Sensitivity, Fumigation Effect