Nanopartícula de óxido de cobre no controle da mancha aureolada do cafeeiro

Abstract

Bacterial Blight Spot (Pseudomonas syringae pv. garcae - Psg) is the main bacteriosis that affects coffee crops. Under favorable conditions, mild climate and crops exposed to wind and humidity, the disease causes damage to nurseries and adult plants. In areas with the presence this pathogen, the recommended control methods are the use of preventatives (copper based products) and curatives (antibiotics), but the successive use of these products can lead to long-term environmental contamination and also lead to the selection isolates resistant Psgs. Thus, research is being carried out in order to find more efficient formulations in terms of antimicrobial activity, such as copper nanoparticles. Thus, the objective of this study was to evaluate the efficiency of the copper oxide nanoparticle (CuO NP) in the control of Coffee Bacterial Blight Spot compared to conventional products. Two experiments were carried out: in the first one, the in vitro antibacterial effect of different concentrations of NP CuO (0, 25, 50, 100, 200, 400 mg.L-1) was evaluated against Psg isolates resistant and sensitive to CuSO4. In the second experiment, the isolates UFLA 52 and UFLA 103, respectively sensitive and resistant to copper nanoparticle in vitro, were inoculated in coffee seedlings previously treated with the most effective dose obtained in the in vitro test with three commercial products (Casumin®, Big Red® and Supera®). Exposures from concentrations of 25 mg.L-1 showed an inhibitory effect on the growth of the isolates, with a dose close to 200 mg.L-1 being the most efficient, with a reduction of 38.04% and 4.73% for UFLA 52 and UFLA 103 respectively. The effect of NP CuO on the efficiency of disease severity reduction was 27.82% for seedlings inoculated with the sensitive isolate, and 24.21% for seedlings inoculated with the resistant isolate NP CuO, therefore statistically similar to commercial products. These results suggest the need for further studies of different nanoparticles, as well as biological evaluations to enable their use as antibacterial formulations to protect the coffee crop against Bacterial Blight Spot.