INHIBITORY CONCENTRATION DETERMINATION OF FUNGI CAUSING POSTHARVEST DISEASES ON RAMBUTAN BY SOME CHEMICAL COMPOUNDS AND TWO STRAINS OF LACTIC BACTERIA

Abstract

The study surveyed on the inhibition of post-harvest fungi on rambutan by Presim, calcium lactate, Citribio,
potassium sorbate and two strains of Lactbacillus plantarum, Lactobaillus fermentum at 13oC and room temperature (28oC ± 2 ). The experiment was carried out by fungal culture method in the inhibitory
environment at the concentration range of 0.05% – 0.45% (for chemical compounds), and by co-cultivation method in a double medium between colony and spores fungal and lactic acid bacteria. The results
showed that 7 strains caused rambutan fruit rot to be harvested after harvesting include Lasiodiplodia psedotheobromae, Fusarium verticillioides, Phomopsis mali, Lasmenia sp., Gliocephalotrichum cylindrosporum, Pestalotiopsis virgatula voucher, Pestalotiopsis clavispora are inhibited by presim and triobio concentrations are from 0.05% to 0.15%. The two compounds are calcium lactate (concentrations of 0.15% – 0.45% and potassium sorbate (0.02% – 0.05%) did not show inhibition for these seven strains. L. plantarum and L. fermentum) are highly inhibitory to colony and spores of 7 fungal strains, of which L. planterum has a
stronger inhibition capacity than L. fermentum in diameter inhibition is 30 – 75 mm at 13oC At room temperature (28oC ± 2) L. Fermentum doesn’t inhibit G. cylindrosporum. Of the seven fungal strains,
there are five strains include F. verticillioides, P. mali, Lasmenia sp., G. cylindrosporum and P. virgatula voucher were inhibited with 2 strains of lactic bacteria higher than those of L. pseudotheobromae and P. clavispora.