Fungicide management strategies for the control of Fusarium head blight in southern Brazil

• Published in: Phytopathology Vol. 100; no. 6; p. S121
• Main Authors: Spolti, P, Simon, L, dos Santos, J, Barros, N, Guerra, D S, Del Ponte, EM
• Format: Journal Article
• Language: English
• Published: 01-06-2010
• Subjects: Fusarium graminearum; Triticum aestivum
• ISSN: 0031-949X

Effective management of Fusarium head blight (FHB) epidemics in wheat (caused by Fusarium graminearum) in Brazil may be achieved by using genetic and chemical control. Four non-inoculated field trials were conducted in 2009 at different locations with the aim to assess and compare the effect of two fungicides (mixture = metconazole + pyraclostrobin (BAS556) x metconazole (Caramba)); two dosages (0.5L/ha x 0.75L/ha) of the mixture; and number of applications (1 = flowering x 2 = flowering + 10 days later) on disease control and yield. A single and different wheat cultivar was used per location. FHB index varied from 5.1 to 7.3 in the two locations (with moderate resistant varieties) and from 10.1 to 31.2 in two locations (susceptible varieties). All treatments significantly reduced disease related to the unsprayed check. The use of two applications gave better results, and the use of mixture in highest dosage reduced around 92% and 76% of FHB index in susceptible and moderate resistant genotypes, respectively, and did not differ from the triazol. Fungicides had both neutral and positive effect in reducing infection by F. graminearum in grains. The better performance in disease control by using two applications of the mixture is possibly related to extended protection, which resulted in an average increase of 27% in test weight compared to metconazole. Mycotoxin analyses are underway and results will be presented together with other effects on yield components.