TRÊS ANOS DE MANEJO BIOLÓGICO INDICAM A MISTURA ENTRE Beauveria bassiana E SILICATO DE POTÁSSIO COMO PROMISSORA NO CONTROLE DE Thrips tabaci EM ALHO NOBRE

Abstract

Viruses transmitters, such as Thrips tabaci (Thysanoptera: Thripidae), prevent garlic plants from obtaining high yields in Brazil and worldwide. Sustainable and integrated control technologies, such as Beauveria bassiana and Potassium Silicate (K2SiO3), can combat this type of biotic stress synergistically. Such components are still underutilized in the phytosanitary management of garlic grown in Cerrado biome. The objective was to evaluate the effect, alone or in combination, of these technologies for the protection of garlic plants against Thrips tabaci and in phytotechnical parameters of this plant, for three consecutive agricultural crops (2017, 2018 and 2019). The treatments (T1) Beauveria bassiana - Bb, (T2) Potassium silicate - SilK, (T3) Clorfenapir - insecticide/acaricide, (T4) Bb + SilK (under binary mixture in tank) and (T5) absolute control (without spraying) were arranged in a DBC with four repetitions per crop. The experimental activities were carried out in a commercial production area (Fazenda Paineiras) of noble garlic (cv. Ito) located in the municipality of Campo Alegre de Goiás (southeastern Goiás state, Brazil). Thrips populations in garlic plants were sampled through yellow adhesive traps, biweekly, from the 25th day after the germination (DAG) of garlic until 100th DAG for each crop. Climatic parameters (temperature, relative humidity and wind speed) and planted area (hectares) were quantified and correlated with the total population of thrips sampled for each agricultural crop. Additionally, the angle between garlic central leaves was sampled during the development of the plants. Production parameters in quantity (kg ha-1) and quality (commercial bulb sizes) were also quantified, for each crop, depending on the treatments, at the end of the production cycle. Significant correlations were observed between the population of thrips with the climatic parameters, but lack of correlation with the planted area. The number of thrips plant-1 sampled differed between crops, treatments and with significant interaction between these two factors. The binary mixture between Bb+SilK was the only treatment, after three consecutive years of use, which managed to keep the population level of Thrips tabaci close to half of the value recommended for its control level established for garlic under field conditions in Brazil (20 thrips plant-1). This treatment also promoted adequate leaf angulation to reduce the support capacity of garlic plants against colonization of thrips, increase in production in quantity (ton ha-1) of garlic and, finally, increase in production in quality of garlic plants. Bb associated with products with synergistic potential (SilK) have great prospect of becoming part of the phytosanitary and cultural management routine for garlic producers in the Cerrado of Goiás.