Effect of postharvest hot water and fungicide application on the severity of crown rot disease and quality of cavendish bananas (Musa spp.)
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Date
2005-11-01
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Abstract
Crown rot is a serious postharvest disease problem in all banana-producing areas of the world including Ghana. It causes severe losses in fruits shipped over long distances covering 10 days or more in transit. A study was conducted at the Department of Horticulture, KNUST Kumasi to evaluate the effect of hot water, fungicide concentration and time of dipping on crown rot disease, and to assess the banana fruit quality after treatment. Treatments were made up of three (3) levels of water temperature, i.e. water at 45 °C, 40 °C and ambient temperature (28±2 °C); three levels of fungicide concentration — 700 mg/l, 500 mg/i and 0 mg/I with three levels of dip time: 10 minutes, 20 minutes and 30 minutes. The experimental design used was a 3x3x3 Factorial in Complete Randomized Design.
Isolations were made from rotted banana crowns obtained from three (3) locations in the Ashanti region over a period of 8 months. In general, those fungi isolated were those previously reported to cause crown rot, with Colletotrichum musae, Botryodzlodia theobromae and Fusarium moniW’orme var subglutinans being the most common. These fungal isolates were used In a pathogenicity test (Koch’s postulates). Mature Cavendish bananas of export quality were inoculated with 7-14 day old spore suspensions of the isolates and dipped in the various treatments. The treated bananas were later assessed for crown rots and fruit quality. Quality attributes measured included pH, Total Titratable Acidity (TTA), Total Soluble Solids (TSS) and Peel Color. Twenty (20) volunteers were used in consumer-oriented tests. Analysis of Variance showed no significant differences (P<0.05) among treatment means for pH; TSS and TTA but there were significant differences (P<O.05) among treatment means for crown rot and peel color.
Results indicated that the treatments with higher water temperatures (45 °C) and higher fungicide concentration (700 mg/l) irrespective of dip time were the most effective against crown rot disease development. There were no adverse effects of all treatments on fruit quality, and consumer-oriented tests indicated that all the treated bananas were acceptable.
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A dissertation submitted to the School of Postgraduate
studies, KNUST, in partial fulfilment of the requirements for the award of a Master of Science (Msc.) degree in Postharvest Physiology, 2005