Biocontrol of tomato bacterial speck by natural extracts.

摘要

Biocontrol of Pseudomonas syringae pv. tomato, causal agent of tomato bacterial speck, is carried out by using cupric salts associated to appropriate agronomical practices such as seed certification, irrigation and fertilization. In nature there are a large number of antimicrobial compounds that play an important role in the biocontrol of different living organisms. Extracts of herbs, spices and their derivates are the most common plant materials used for this purpose. Due to the recent EU restriction on copper use in organic agriculture (Reg. EU no473/2002) as an alternative to copper compounds, different natural extracts have been recently studied. Here are reported the results obtained by using different combination of natural extracts (Lavandula sp., Allium sativum, Ficus carica, Punica granatum and lysozyme) to inhibit the growth, the survival and to reduce the damages caused by P. s. pv. tomato in open field. Natural extracts resulted able to control bacterial speck agent on phylloplane tomato plants at least for 10 days, even with respect to high bacterial contamination (106 cfu ml-1). Further studies are in progress to characterize the active principles of the extracts utilised as new strategies in biocontrol of tomato bacterial speck.