Compatibility of Azospirillum brasilense with fungicide and insecticide and its effects on the physiological quality of wheat seeds

Abstract

Seed treatment is a practice that helps the initial establishment of the crop without the effects caused by pests and diseases. The association of diazotrophic bacteria with grasses has been used in the supply of nitrogen to plants; however, these microorganisms produce growth-promoting substances, which promote benefits in the growth and development of the crops. Thus, the objective of this study was to evaluate the compatibility of Azospirillum brasilense associated with the fungicide difenoconazole and the insecticide thiamethoxam by observing the effects on the quality of seed emergence of three wheat cultivars (Triticum aestivum L.). Three wheat cultivars, arranged in a 4 x 2 factorial system with four replicates, were tested. The treatments were the control; difenoconazole (Spectro® at a dose of 150 mL per 100 kg of seed); thiamethoxam (Cruiser® FS 350 at a dose of 200 mL per 100 kg seed) and difenoconazole + thiamethoxam, applied on wheat cultivars TBIO Mestre, TBIO Itaipu and TBIO Sinuelo. Bacteria from the Azospirillum genus were used in the inoculation. The wheat seed retains its quality when it checks the germination, vigor and independent accelerated aging, whether or not fungicide, insecticide and A. brasilense were used. The insecticide thiamethoxam increased the length of shoots and roots and provided compatibility with A. brasilense, and fungicide inhibited the length of shoots and roots and was antagonistic to the bacterium A. brasilense.

Impact of seed-applied fungicide and insecticide on Azospirillum brasilense survival and wheat growth-promoting ability

“…There are few reports related to the effect of pesticides on Azospirillum spp. While some pesticides such as benomyl, thiamethoxam and tebuconazole seemed to be compatible with A. brasilense (Pereyra et al 2009;Elslahi et al 2014;Munareto et al 2018) pyraclostrobin + thiophanate-methyl, were not (Munareto et al 2018;Vogel and Fey 2019;Pereira et al 2020;Santos et al 2020aSantos et al , 2020b. The compatibility depends on the tested pesticide, the sensitivity of the biological inoculant and the applied inoculation methodology.…”

Compatibility of Azospirillum brasilense with Pesticides Used for Treatment of Maize Seeds

“…Dartora et al [ 22 ] also found no effect of the fungicide fludioxonil-metalaxyl and of A. brasilense on the percentage of germination of maize seeds. Similarly, in wheat ( Triticum aestivum ), Muraneto et al [ 23 ] observed no differences in germination of seeds treated with fungicide, insecticide, and A. brasilense .…”

Combined Effects of Biological and Chemical Treatment on Rice Seed Physiological and Sanitary Quality

“…Fungicide application might have decreased the positive effects of T. harzianum inoculation and might even have affected plant responses to A. brasilense, B. subtilis, and P. fluorescens. A previous study showed that fungicides can have deleterious effects not only on fungi but also on bacteria and are not compatible with A. brasilense inoculated via seed treatment (Munareto et al, 2018).…”