Effect of Early Foliar Disease Control on Wheat Scab Severity (Fusarium graminearum) in Argentina

Jorge David Mantecón

doi:10.1155/2013/956862

Abstract

Wheat scab is common in Argentina mainly durum wheat and some bread varieties. The epidemics occur every 5 to 7 years. During the 2007, 2008, and 2009 growing seasons, three trials were conducted at the INTA Balcarce Experimental Station. Each plot had six rows of 5 m long, spaced 0.15 m apart and was set up in a randomized complete block design with four replications. Trifloxystrobin plus cyproconazole was sprayed at Z3.1 stage. Treatments were sprayed at Z6.1 stage with tebuconazole, prochloraz, and metconazole to improve scab control. Artificial inoculations were made in Z6.1. Severity ofSeptorialeaf bloth and leaf rust was assessed in boot stage (Z3.9). Scab severity was rated at early dough stage (Z8.3). Yields were recorded each year. Fungicide only applied at Z3.1 stage did not reduce field scab severity but reduced the seeds infection and increased the yields. Early fungicide spray produced yield increase at about 22% and a decrease in seed infection of up to 40%. Yields increased in a 55.3% and in a 19.6% when compared with the inoculated and not inoculated check, respectively. The purpose of this study was to evaluate the effect of foliar disease control on scab, crop yield, and seed health.

Highlights

Head blight caused by Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schw.) Petch) occurs in humid wheat producing areas of the world [1, 2]
Based on field trials carried out over three consecutive years, fungicide spray at Z3.1 stage did not reduce significantly head blight infection and grain weight heavily reduce the percentage of infected kernels
On natural infections there was no difference between spray and not spray with fungicide at Z3.1 stage for all scab parameters analyzed

Summary

Introduction

Head blight (scab) caused by Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schw.) Petch) occurs in humid wheat producing areas of the world [1, 2]. Damage has been significant in south east of Buenos Aires province. In Argentina, the use of foliar fungicides on wheat is common, and it has increased considerably [7]. Near 30% of the crop area in SE of Buenos Aires is sprayed to control of foliar disease like rust and leaf blotch [8]. The control of scab by fungicide applications should be a preventive action because if fungicide applications are done when the symptoms appear, the disease control efficiency would be extremely low. The use of fungicide to control wheat scab is low compared with the use of fungicide for controlling foliar disease

Objectives

Methods

Results

Conclusion