MANEJO DE FUNGICIDAS E INFLUÊNCIA DO pH DE CALDA PARA O CONTROLE DE FERRUGEM ASIÁTICA

Abstract

The soybean crop, in the last decades has suffered more and more with the damages caused by Asian rust, being one of the main diseases of the crop. The objective was to evaluate the efficiency of different fungicides in the control of soybean rust and to highlight the interference of PH in the efficiency of these products. Therefore, two experimental trials were conducted at the Innovation and Technology Center - CIT GAPES, in the city of Rio Verde - GO, during the 2018/2019 harvest period. A randomized block design with 6 treatments and 4 repetitions. The treatments evaluated were the fungicide Azoxystrobin + Benzovindiflupir 200 g ha-1 submitted to five different pH ranges and a control without application. And another randomized block design with 17 treatments in 4 repetitions using the cultivar M7739. Product efficacy assessments carried out according to the severity of the disease, defoliation, productivity in bags per hectare and phytotoxicity. High values ​​of AACPD were observed for soybean plants that did not receive fungicide application to control Asian rust. Higher defoliation values ​​were observed for soybean plants without fungicide application, plants sprayed with fungicides in R1 and R5.1 and with no fungicide application in R5.4. The sprayed soybean plants that did not receive fungicide treatment in R5.4 (2) showed the lowest values ​​(69.19%) of Asian rust control. The soybean plants sprayed with fungicides (Elatus) at the R1 stage showed a phytotoxicity of (25%). The highest yields were observed for plants sprayed with (3), (5), (11) and (12). It was possible to conclude that all the fungicides used showed good control rates for Asian soybean rust.