Elicitores de resistência no manejo de Fusarium sp. em milho

Abstract

Corn plants (Zea mays L.) stands out as one of the most cultivated and consumed cereals in the world. There are many factors that affect the productive success of the crop in the field, such as fungal diseases, especially the species of the genus Fusarium spp. The objective of this study was to determine the effect of different elicitors on the management of Fusarium sp. in purple creole corn seeds. The experiment was carried out at the Phytopathology Laboratory (LAFIT) of the Center for Agricultural Sciences, CCA-UFPB, Areia-PB. Seven treatments were used: Control (Sterile Distilled Water); Rocksil® (3 g L-1 ); Proagrim® (3 g L 1 ); Bion® (0.4 g L-1 ); Agrosilicon® (3 g L-1 ); Ecolife® (3 mL L-1 ) and Thiabendazole Fungicide (1.0 g L-1 ). A sanity test was performed, with 200 seeds divided into 20 repetitions. The effect of the elicitors on the physiological quality of the seeds was evaluated. In vitro test, which determined the mean diameter (DMC), mycelial growth rate index (IVCM), percentage of mycelial growth inhibition (PIC), sporulation (ESP.) and percentage of sporulation inhibition (PIE); the effect of elicitors on gas exchange, where the net CO2 assimilation (A), stomatal conductance (gs), intercellular space CO2 concentration (Ci), transpiration (E), water use efficiency, intrinsic efficiency were determined. water use, instantaneous carboxylation efficiency and leaf temperature (TF); and the activity of the enzymes peroxidase, polyphenoloxidase and phenialanine ammonia lyase were determined. The results showed that five fungal genera were identified: Fusarium sp. (49.5%), Aspergillus sp. (30.5%), Penicillium sp. (16%), Rhizopus sp. (11.5%) and Cladosporium sp. (1.5%) in the seeds. It was also observed that the treatments did not affect the physiological quality of the seeds. For in vitro tests, a fungistatic effect of Rocksil® , Ecolife® and Bion® elictors on Fusarium sp. was observed, For enzymatic activity, it was not possible to identify significant differences between treatments. Therefore, under the conditions tested, elicitors had no influence on the physiological quality of purple creole corn seeds. Rocksil® , Ecolife® and Bion® elicitors had a fungistatic effect on Fusarium spp. With the application of elicitors via seeds, there was no change in enzymatic activity.