Effect of relative humidity and essential oils on conidial germination of Colletotrichum gloeosporioides (Penz.) Sacc. causing mango anthracnose

Date

6-2016

Degree

Bachelor of Science in Agriculture

Major Course

Major in Plant Pathology

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Christian Joseph R. Cumagun

Restrictions

Restricted: Not available to the general public. Access is available only after consultation with author/thesis adviser and only to those bound by the confidentiality agreement.

Abstract

Anthracnose (Colletotrichum gloeosporioides (Penz.) Sacc.) is one of the major post harvest diseases of mango which reduces fruit production worldwide including the Philippines. With its economic importance, management of the disease is very crucial to attain higher yield. This study was conducted to investigate the effects of different levels of relative humidity on the conidial germination using modified glycerol-water chamber and the effects of essential oils of banana, pineapple and orange on the mycelial growth and conidial germination of C. gloeosporioides. The effect of essential oils on the disease incidence and severity of C. gloeosporioides in vivo was further evaluated. Extracellular enzymes produced by C. gloeosporioides grown on specific media were also tested. The results showed that conidial germination was inhibited at <90% RH, while no difference was observed on the conidial germination of 7 day old cultures and 14 day old cultures. Essential oils significantly reduced the mycelial growth and conidial germination (P<0.05). Highest mycelial growth inhibition was shown in banana essential oils with 7000 ppm concentration that caused 78.7% reduction followed by 5000 ppm of banana essential oils and 7000 ppm of pineapple essential oils with 69.9% and 41.0%, respectively. In addition, conidial germination significantly reduced by three essential oils. Results of in vivo studies showed that essential oils of banana and pineapple caused a high reduction of anthracnose incidence with only 22.2 and 33.3%, respectively, while the lowest disease severity was observed on pineapple essential oils followed by essential oils of banana and orange. On the other hand, banana essential oils showed phytotoxic effect on the fruit peel of mango. C. gloeosporioides showed negative results for amylase and lipase grown on Nutrient Agar (NA) and polyphenol oxidase grown on Malt extract-yeast extract (YEME).

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2016 A3 /G38

Document Type

Thesis

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