Fosfitos e produtos à base de extratos vegetais no controle da ferrugem do trigo

Abstract

There are several diseases that attack the crop, and the rust, caused by Puccinia recondita f . sp. tritici most common, occurring in almost all regions of Brazil. Alternative products have been used for the control of various diseases, can be considered a form of rust control. The objective of this study was to evaluate the effect of phosphites and products based on vegetal extracts in controlling leaf rust in wheat. The experiment was conducted at the Universidade Federal do Pampa - Campus Itaqui, following a randomized blocks design whit ten treatments and four replicates. For the execution of this work was used to cultivate wheat TBIO Iguaçu, due to being a cultivar moderately susceptible to rust. The treatments was Reforce Cu® (Cu + Potassium phosphite), Reforce Zn® (Zn phosphite), Fortaleza® (Potassium phosphite + compound citric), Nutriphite® (Potassium phosphite), Fulland® (phosphite copper), GreenForce S® (Product based extract by product of coffee plantations), Green Force V® (based product extract byproduct of coffee plantations) and Green FOS® (potassium phosphite), and control (with and without fungicide application). The applications were initiated 60 days after seeding, which held a spray every 20 days, totaling three applications. Evaluations started 75 days after sowing and were weekly evaluating the severity and incidence ten whole plants and ten flag leaf per plot, totaling 5 ratings. To assess the severity scale was used diagrammatic COBB. With the data of severity was determined the area under disease progress curve (AUDPC). Data were subjected to analysis of variance by F test and the averages grouped by Scott & Knott test at 5 % probability using Sisvar statistical program. The fungicide was more effective in controlling the disease followed by treatments with Fortaleza® , Reforce Zn® , Green Force S® and Fulland® . These products can be used as an alternative to conventional pesticides.