Cotrole biológico do bolor verde em laranja 'pêra'

Abstract

Citrus farming is a significant agricultural sector in the global economy and food security, however, one of the obstacles to citrus farming is the occurrence of diseases, mainly of fungal origin. Green mold caused by Penicillium digitatum is the main post-harvest disease of orange (Citrus sinensis) crops, with losses that can reach up to 90%. Chemical control, with the use of fungicides, is the most widely used method to minimize the effects of P. digitatum on Citrus spp.. Due to the risk of environmental contamination, biological control stands out as a promising alternative in the integrated management of plant diseases. The objective of this study was to determine the effect of commercial biological products on a) severity of green mold in ‘Pêra’ orange; b) in vitro control of P. digitatum; c) physicochemical quality of the fruits; and d) evaluation of resistance induction. The experiments were carried out at the Phytopathology Laboratory (LAFIT) located at the Federal University of Paraíba/CCA/Campus II, Areia-PB. The fungus P. digitatum used was isolated from C. sinensis fruits with typical symptoms of green mold. The treatments consisted of: T1: Sterilized Distilled Water (ADE); T2: Natucontrol® (Trichoderma harzianum); T3: Shocker® (Bacillus subtilis); T4: Bio-Imune® (Bacillus amyloliquefaciens e T. harzianum); T5: EcoTrich® (T. harzianum); T6: Tricho-Turbo® (Trichoderma asperellum); T7: Auin-Ce® (Beauveria bassiana); T8: Mac Café® (Cladosporium sp.); T9: Romeo SC® (Saccharomyces cerevisiae); T10: Fungicide (Thiabendazole- benzimidazole). In vitro control was performed by adding a fungal colony disk to the center of Petri dishes with potato-dextrose-agar medium and the diluted treatments, in which the mean colony diameter (MD), mycelial growth velocity index (MVI), percentage of growth inhibition (PIC) and percentage of sporulation inhibition (PIE) were evaluated. In vivo control was performed with previously wounded C. sinensis fruits inoculated with a disk from the P. digitatum colony. The fruits were subjected to a humid chamber for 24 hours and the severity of the green mold was evaluated daily. The physicochemical analyses were: weight loss, skin firmness, soluble solids content, titratable acidity, SS/AT ratio, pH and vitamin C. The enzymatic activity corresponded to the activity of Phenylalanine-ammonium lyase (PAL), Peroxidase (POX) and Polyphenoloxidase (PPO). The severity of green mold in treated fruits was reduced by up to 69%. The treatments increased the activity of PAL, PPO and POX. All treatments significantly decreased DM, IVCM, PIC and PIE, differing from the control. There were differences in pH and vitamin C values between treatments. Biological products did not alter postharvest quality parameters. Under in vitro and in vivo conditions, biological treatments controlled P. digitatum and reduced the severity of green mold in ‘Pêra’ orange.