Wood vinegar and its inhibitory effect under laboratory conditions on fungal growth in coffee crop foliage

Abstract

Wood vinegar or pyroligneous acid is a complex mixture of water and organic compounds including ketones, alcohols, alkanes, esters, among others, which are obtained from the pyrolysis of wood. The objective of the study was to evaluate the efficacy and inhibition of pyroligneous acid on the growth of fungi that affects the foliage of coffee crops under laboratory conditions. Coffee leaves with symptoms of leaf spots caused by the fungi Colletotrichum sp and Cercospora sp were collected. The fungi were isolated by sowing infested tissue on potato dextrose agar culture medium. The effectiveness of pyroligneous acid was evaluated by inoculation with 6 mm diameter discs containing the pathogens on the surface of petri dishes containing potato dextrose agar medium with the doses of the product, after inoculation measurements were taken every 12 hours for a period of 144 hours, then the percentage formula for mycelial growth inhibition was applied. To calculate the inhibition of radial growth of phytopathogenic fungi, the calculation of the diameter growth of the fungus in relation to time was performed. Pyroligneous acid at a dose of 250 ml exhibits 100% efficacy in inhibiting mycelial growth and has a radial growth-inhibitory effect on Colletotrichum sp. and Cercospora sp. when both are present, and when only Cercospora sp. is present, the effective dose is 150 ml.