Development and promotion of news and enhanced biofertilizers, biostimulants and biopesticides for increased crop productivity: yeast application for biocontrol of postharvest pathogens of fruits and vegetables

Date

2015

Abstract

Postharvest decays of fruits and vegetables account for significant levels of postharvest losses. It is estimated that about 20-25% of the harvested fruits and vegetables are decayed by pathogens during postharvest handling. In recent years intensive efforts have been made to develop new control methods to manage the postharvest diseases. The use of biological control agents offers an alternative or supplemental way of reducing the use of chemicals in nature. The research objective is to study the potency of yeasts in controlling post harvest diseases. Antagonistic yeasts are recommended potential microbial agents for controlling the postharvest diseases of fruits and vegetables. Epiphytic yeasts were isolated from fruit sources such as grape, apple, banana, orange, mango and carrot. Total yeast isolates used for screening were 47, 7 from collection of the PNCM and 40 isolated from fruit sources. Twenty two of the 40 yeast isolates from fruit sources exhibited antagonistic activity against 11 fungal (Aspergillus flavus, Bipolaris maydis, Botryodiplodia sp., Colleotrichum gloeosporioides, C. musae, Curvularia inaequalis, Fusarium oxysporum, Penicillium digitatum, P. vexans, Rhizopus oligosporus and Rhizoctonia solani) and 6 bacterial (Bacillus cereus, Erwinia carotovora, Micrococcus luteus, Ralstonia solanacearum, Serratia marcescens and Xanthomonas oryzae) pathogens in in vitro tests. The yeast antagonists from fruit sources were identified as Pichia kluyveri, Hypopichia burtonii, Meyerozyma guilliermondii, and Pichia kudriavzevii. Known yeast species obtained from the PNCM collection were identified as Candida albicans, Bebaryo myces hansenii, Pichia anomala, Rhodotorula glutiinis, Saccharomyces cerevisiae, Kluyveromyces marxianus and Torulopsis candida. These isolates were assayed and showed antagonistic activity against 9 fungal (Bipolaris maydis, Botryodiplodia sp., Colletotrichum gloeosporioides, Colletotrichum musae, Fusarium oxysporum, Penicillium digitatum, Phomposis vexans, Rhizoctonia solani, Rhizopus oligosporus and 4 bacterial (Erwinia carotovora, Micrococcus luteus, Ralstonia solanacearum and Xanthomonas oryzae) pathogens in in vitro tests. Yeast biomass production was scaled up using sugar cane molasses medium. Formulation of the biocon agents was developed using talc as carrier and carboxymethyl cellulose and sodium alginate as adhesion promoters. Stability tests showed that the suitable storage condition for the yeast agents was at 11 +- 1 deg C (refrigerated temperature). Toxicity tests done using mice showed no disease, deformations or ill effects in the test animals indicating safetiness of the product. In vivo assays conducted showed that yeast isolates were effective as control agent against pathogens in a wide range of crops. P. kudriavzevii was effective in controlling C. musae in banana, R. solanacearum in tomato, P. digitatum in calamansi and A. flavus in garlic. S. cerevisiae gave significant result in the control of C. gloeosporioides in mango, P. digitatum in calamansi and A. flavus in nuts. D. hansenii was also a promising isolate in combating C. musae in banana, A. flavus in garlic, and in nuts. T. candida was effective against C. gloeosporioides in mango, A. flavus in garlic and nuts. K. ohmeri was a potent agent against C. gloeosporioides in mango, P. digitatum in calamansi, A. flavus in garlic and in onion. No isolate was able to control E. carotovora in tomato and in eggplant.

Language

English

Document Type

Article

Pages /Collation

59 leaves

En – AGROVOC descriptors

MUSA (BANANAS); GARLIC; CALAMONDINS; NUTS; MANGOES; ONIONS; AUBERGINES; YEASTS; BIOLOGICAL CONTROL; PATHOGENS; POSTHARVEST TECHNOLOGY; POSTHARVEST DECAY; EPIPHYTES; MICROBIAL PESTICIDES; POSTHARVEST LOSSES

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