Experimental Treatment of Biopreparation Based on Pseudomonas Syringae pv. Tagetis for Weeds Control

Abstract

Cirsium arvense is one of the worst weeds in agriculture. As actual herbicides are not very effective and not accepted by organic farming or in order to reduce the cantity of herbicides used, possible biocontrol agents have been investigated since many decades. The work carried out aimed at obtaining and assessing the herbicidal potential of bacterial preparation based on Pseudomonas syringae pv. tagetis (PST) for biological control of Cirsium arvense (L.) Scop. Silibase 2848P, an organosilicone surfactant, was required to facilitate PST penetration into creeping thistle leaves. The experiments were conducted under controlled conditions (growth chamber) to determine the concentration of Silibase 2848P required for the maximum penetration of PST into creeping thistle leaves. As well as to evaluate disease incidence in emerging leaves, and to quantify the effects of inundative foliar application on fresh and dry weights of shoots. In field conditions, efficacy of PST applications was assessed in terms of disease incidence and effect on shoot height, number of flower buds and survival of C. arvense. Maximum disease severity were recorded when PST was applied at a concentration of 10 x 108 cfu/ml + Silibase 0.3%.