Abstract:

The best period to prevent and control wheat scab is on the preliminary stage of flowering. To explore the control efficacy on wheat scab and toxins when missing the preliminary stage of flowering, 13 wheat varieties in Jiangyan were selected for this experiment, and 48% cyanene·pentazolol SC was used to control the wheat scab. We designed three application methods: spraying 48% cyanene·pentazolol SC once after 6 days missing the preliminary stage of flowering, spraying 48% cyanene·pentazolol SC once at the preliminary stage of flowering, and spraying 48% cyanene·pentazolol SC once at the preliminary stage of flowering plus once after 6 days. The controlling efficacy of the 3 treatments against wheat scab, as well as their impact on the content of DON toxin in wheat grain were compared for each wheat variety. The results showed that the average control efficacy on diseased ear rate and the disease index and the reduction effect on DON toxin under spraying 48% cyanene·pentazolol SC once after 6 days missing the preliminary stage of flowering were 15.87%, 21.25% and 35.48% lower than those under spraying once at the preliminary stage of flowering respectively, and were 39.79%, 44.87% and 66.84% lower than those under spraying once at the preliminary stage of flowering plus once after 6 days. Therefore, the optimal first control time for scab is at the preliminary stage of flowering, while spraying 48% cyanene·pentazolol SC once after 6 days missing the preliminary stage of flowering has relatively poor control efficacy on scab and DON toxin. Spraying 48% cyanene·pentazolol SC once at the preliminary stage of flowering plus once after 6 days shows the best efficacy, and the performance trend of all the varieties are consistent.

Key words: wheat, wheat scab, DON toxin, cyanene·pentazolol, preliminary stage of flowering, pesticide application timing