Fig. 5.

The timing of application of J02 broth cultures mixing with 1% chitosan on the reduction of black spot caused by Alternaria brassicicola on the 28-old-day cabbage seedlings. J02 cultured in MRSSG (a modified De Man, Rogosa and Sharpe medium containing surimi and glycerol, pH 4.1) for 3 days was diluted 400×, mixed with 1% chitosan, and sprayed to cabbage seedlings. (A) Black spot symptoms on cabbage leaves. Seedlings were sprayed with water (control) or J02 broth and inoculated with spore suspensions (3 × 10⁴ spores/ml) of A. brassicicola at 0 h, 24 h before inoculation (hbi), or 24 h post inoculation (hpi). (B) Reduction of black spot severity on cabbage seedlings after applying J02 broth and chitosan at three different timing. (C) Effect of total applications on the reduction of black spot severity. J02 broth and chitosan were sprayed on to cabbage seedlings at day 28 (one application), days 21 and 28 (two applications), or days 14, 21, and 28 (three applications) and inoculated with spore suspensions of A. brassicicola at day 29. Plants were kept in a greenhouse for 7 days for lesion development. Seedlings sprayed with water (mock) or 2% lactic acid were used as the controls. Means followed by the same case letters in each panel were not significantly different (P ≤ 0.05).