Effect of Bordeaux mixture and alternative products in the management of late blight of tomato under organic system at the Southern Coast of Santa Catarina

Abstract

The effects of different types and concentrations of alternative products were evaluated for the
control of late blight of tomato in organic production. Citric acids, algae, bordeaux mixture, microorganism
solutions, vegetable extracts and silicates were tested in three experiments under field conditions at the Southern Coast of Santa Catarina. The disease was quantified by the area under the disease progress curve (AUDPC) and progress rate (r). The total and commercial yields were also determined. Experiments were conducted in completely
randomized design with four replications. Treatments were compared with Scott-Knott test (P < 0,05). Bordeaux mixture 0,5% reduced AUDPC by 67%, 35% and 49%, as well as disease progress rate were 50%, 16% and 30% compared with control in spring 2004, spring 2005 and autumn 2006, respectively. The yield was affected by the season of the year and Bordeaux mixture yielded 114% more compared to other treatments. None of the alternative
products influenced the yield and the control of the late blight of tomato.