Introduction

Grey mold is one of the main causes of post-harvest strawberry (Fragaria x ananassa Duch.) rot fruit, which is caused by Botrytis cinerea Pers.:fr fungus. The treatment with chemical fungicides is the main method for its control; however, its use cause health concerns and pollution. The above promote the research toward alternatives of control. The aim of the present research was to evaluate the chitosan-fatty acids composites effects on the B. cinerea infection in post-harvest strawberry fruits.

Method

In vitro bioassays were conducted to evaluate the chitosan, sodium octanoate and decanoic acid effect on the mycelial growth of B. cinerea. Likewise, in vivo bioassays were conducted to evaluate the compounds alone and in mixture effect on infection severity of grey mold in post-harvest strawberry fruits. The treatments were evaluated in a completely randomized design and the data were analyzed by means of analysis of variance (ANOVA) (p ≤ 0.05) and average comparison by Tukey´s test (p ≤ 0.05).

Results

The chitosan inhibited 100 % of the growth when it was applied in 10, 12.5 and 15 mg/mL concentrations, while the sodium octanoate reached the same inhibition percentage in 0.33 and 0.49 mg/mL concentrations. Finally, decanoic acid inhibited in 100 % to B. cinerea in 0.17, 0.34 and 0.51 mg/mL concentrations. In in vivo bioassays, the best results of strawberry fruits protection from B. cinerea infection were those in which the chitosan/sodium octanoate (12.5/0.49 y 15/0.49 mg/mL) were utilized, with absence of severity. Also highlight the chitosan (15 mg/mL), decanoic acid (0.51 mg/mL) and chitosan/decanoic acid composites (12.5/0.51 and 15/0.51 mg/mL) treatments, with severity degrees between 1 and 2.

Discussion or Conclusion

The chitosan, sodium octanoate and decanoic acid significantly inhibited the in vitro mycelial growth of B. cinerea. The chitosan/sodium octanoate composite have a greater protective effect of strawberry fruits, in relation to the compounds applied alone. The chitosan and decanoic acid presented a significantly protective effect of the fruits, applied alone as well as in composite. The above suggest that these compounds could be potentially used in the post-harvest control of B. cinerea.

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