https://krishi.icar.gov.in/jspui/bitstream/123456789/28711/1/Dr.%20Rajbir%20Singh_Biological%20Control.pdf

Biological control of postharvest diseases of fruits and vegetables by microbial antagonists: A review

Fungal diseases result in significant losses of fruits and vegetables during handling, transportation and storage. At present, post-production fungal spoilage is predominantly controlled by using synthetic fungicides. Under the global climate change scenario and with the need for sustainable agriculture, biological control methods of fungal diseases, using antagonistic microorganisms, are emerging as ecofriendly alternatives to the use of fungicides. The potential of microbial antagonists, isolated from a diversity of natural habitats, for postharvest disease suppression has been investigated. Postharvest biocontrol systems involve tripartite interaction between microbial antagonists, the pathogen and the host, affected by environmental conditions. Several modes for fungistatic activities of microbial antagonists have been suggested, including competition for nutrients and space, mycoparasitism, secretion of antifungal antibiotics and volatile metabolites and induction of host resistance. Postharvest application of microbial antagonists is more successful for efficient disease control in comparison to pre-harvest application. Attempts have also been made to improve the overall efficacy of antagonists by combining them with different physical and chemical substances and methods. Globally, many microbe-based biocontrol products have been developed and registered for commercial use. The present review provides a brief overview on the use of microbial antagonists as postharvest biocontrol agents and summarises information on their isolation, mechanisms of action, application methods, efficacy enhancement, product formulation and commercialisation.

Exploitation of microbial antagonists for the control of postharvest diseases of fruits: a review

Indigenous actinomycetes isolated from rhizosphere soils were assessed for in vitro antagonism against Colletotrichum gloeosporioides and Sclerotium rolfsii. A potent antagonist against both plant pathogenic fungi, designated SRA14, was selected and identified as Streptomyces hygroscopicus. The strain SRA14 highly produced extracellular chitinase and β-1,3-glucanase during the exponential and late exponential phases, respectively. Culture filtrates collected from the exponential and stationary phases inhibited the growth of both the fungi tested, indicating that growth suppression was due to extracellular antifungal metabolites present in culture filtrates. The percentage of growth inhibition by the stationary culture filtrate was significantly higher than that of exponential culture filtrate. Morphological changes such as hyphal swelling and abnormal shapes were observed in fungi grown on potato dextrose agar that contained the culture filtrates. However, the antifungal activity of exponential culture filtrates against both the experimental fungi was significantly reduced after boiling or treatment with proteinase K. There was no significant decrease in the percentage of fungal growth inhibition by the stationary culture filtrate that was treated as above. These data indicated that the antifungal potential of the exponential culture filtrate was mainly due to the presence of extracellular chitinase enzyme, whereas the antifungal activity of the stationary culture filtrate involved the action of unknown thermostable antifungal compound(s).

Antifungal potential of extracellular metabolites produced by Streptomyces hygroscopicus against phytopathogenic fungi.

Postharvest application of gum arabic and essential oils for controlling anthracnose and quality of banana and papaya during cold storage

The preservation of quality of fresh products is relevant for the industry due to its economic impact. This paper presents a comprehensive review of the use of different sources of calcium to preserve fresh fruits and vegetables in order to extend the shelf life and enhance the nutritional value. Emphasis is on discussing about the best sources of calcium, concentration, temperature and method of application, suitability of the commodities; and some hints for the cost/benefit analysis are presented.

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Calcium for extending the shelf life of fresh whole and minimally processed fruits and vegetables: a review

Colletotrichum gloeosporioides is the causal organism of anthracnose inCarica papaya L. (papaya, papaw). The effect of ammonium carbonate (3%) or sodium bicarbonate (2%) in aqueous solution or when incorporated into a wax formulation on anthracnose severity in inoculated or naturally infected fruits was examined. Both salts had significant effects, but that of ammonium carbonate was greater than that of sodium bicarbonate in controlling anthracnose. Ammonium carbonate (3%) incorporated into the wax formulation effectively reduced anthracnose incidence by 70% in naturally infected papaya and extended the storage life by maintaining the firmness, color and overall quality of the fruit in low temperature storage (13.5°C) and 95% r.h. for 21 days followed by 2 days under marketing conditions. The mode of action of ammonium carbonate on the control of anthroacnose appears to bevia complete inhibition of radial mycelial growth and conidia germination.

Effect of ammonium carbonate and sodium bicarbonate on anthracnose of papaya

Use of sodium bicarbonate and Candida oleophila to control anthracnose in papaya during storage

Trichoderma harzianum (TrH 40) isolated from soil samples from rambutan orchards (Nephelium lappaceum) had antagonistic effects against three postharvest pathogens of rambutan:Botryodiplodia theobromae, Colletotrichum gloeosporioides andGliocephalotrichum microchlamydosporum, causative fungi of stem end rot, anthracnose and brown spot, respectively. The effects were due to both antibiosis and mycoparasitism.T. harzianum (TrH 40) treatment, while reducing the occurrence of the three postharvest diseases, also retained the overall quality and color of the fruits.

Antagonistic effect of Trichoderma harzianum on postharvest pathogens of rambutan (Nephelium lappaceum.

The concentration of calcium and its distribution in different parts of the fruit were determined in Queen-type Mauritius and Cayenne-type Kew pineapple varieties. Calcium content was measured before and after storage for 17 days at 10 °C followed by 2 days at 28 °C. Total calcium concentrations were significantly (p < 0.05) higher in Kew than in Mauritius pineapple. This difference corresponded to a significantly (p < 0.05) lower incidence of chilling injury in the former. The calcium content in fruits at harvest was significantly (p < 0.05) higher in the shell region for both varieties. Browning symptoms associated with chilling injury were observed in the core and in the flesh adjacent to the core, where lower concentrations of calcium were recorded. Chilling injury was minimal in the flesh near the shell, where calcium concentrations were significantly (p < 0.05) higher. Following storage, calcium concentrations in the core and flesh regions decreased, while a significant (p < 0.05) increase in concentration was recorded in the shell region of the susceptible Mauritius variety. Copyright © 2003 Society of Chemical Industry

R.S. Wilson Wijeratnam

Papers

Effect of ammonium carbonate and sodium bicarbonate on anthracnose of papaya

Use of sodium bicarbonate and Candida oleophila to control anthracnose in papaya during storage

Antagonistic effect of Trichoderma harzianum on postharvest pathogens of rambutan (Nephelium lappaceum.

Fruit calcium concentration and chilling injury during low temperature storage of pineapple

Development of a formulation of Trichoderma asperellum to control black rot disease on pineapple caused by (Thielaviopsis paradoxa)