Efficacy of plant extracts to control fungal post-harvest ROT
Fungicides are widely used in conventional agriculture to control plant diseases. Prolonged usage often poses health problems as the modern society is becoming more healthconscious because of their harmful residual effects. The diseases are currently managed with synthetic fungicides but there is, h...
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Format: | Thesis |
Language: | English |
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Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42882/1/P.1-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/42882/2/Full%20Text.pdf |
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Summary: | Fungicides are widely used in conventional agriculture to control plant diseases. Prolonged usage often poses health problems as the modern society is becoming more healthconscious because of their harmful residual effects. The diseases are currently managed with synthetic fungicides but there is, however, a growing global interest on their
replacement with other alternatives such as with environment–friendly biopesticides, such
as use of botanicals or biological control. Penicillium digitatum, Aspergillius niger and
Fusarium Sp, the causal agents of citrus green mold, black rot and brown rot, are
important post-harvest pathogens that cause serious losses in citrus annually, besides
affections other commercial fruits. The current study tends to the application of botanical
as alternative to synthetic fungicides carrying out their antimicrobial screening, longevity
study, toxicology, post-harvest study included spraying plant extracts, resident effect,
wrapping and coating using different statistical analysis and ANOVA .The research also
focus on the selected plant extracts in control post-harvest fruit rot besides the costeffectiveness
for commercial purpose .Then selection of the best anti-fungal plant extract
on the isolation of its active anti-fungal compound using chromatography analysis. Ten
Ethanol extracts(concentrations 500-5000 ppm) of Cerbera odollam L.(Pong-pong),
Capsicum frutescence L.(Chili), Azadirachta indica L. (Neem), Cymbopogon nardus L.
(Lemon grass), Zingiber officinale L. (Ginger), Andrographis paniculata L . (Green
chirayta), Curcuma longa L. (Turmeric), Syzygyum aromaticum L. (Cloves), Murraya
koenigii L. (Curry leaf), Swietenia macrophyllai L. (Mahogani), were tested for their antifungal
activity for citrus green mold, black rot and brown rot and compared with the
control fungicide (Guazatine). Longevity of crude plant extracts was studied depending on
their anti-fungi activity under different storage conditions (Refrigerator, Room conditions,
and Outside) for four weeks. The best plant extracts were selected of plants under study
based their on anti-microbial activity showing more than 70-90% fungal inhibition and
longer stability and efficacy under different storage conditions. The toxicity (LC50) of the
best anti-fungal extracts was determined by the Brine Shrimp Test (BST).
Chromatography analysis GC-MS was used to determine the residual effect in fruits that
were sprayed with plant extracts. Efficacy of the selected best plant extract incooperated
with biodegradable materials wrappers (Polylactic acid, pectin and newspaper) was
determined during storage at room temperature (±25Co) to control fruit-pathogen decay
under modified atmosphere packaging (MAP) to increase shelf life and improve the fruit
quality and an another experiment in cooperating coating (chitosan, starch and oil paraffin)
with fruit wrappers to further increase the fruit quality . The plant extract that exhibited
best result to increase the shelf life and fruit quality was subjected to biocompond analysis
using chromatography LC-MS. Crude extracts from pong-pong and chili showed fungal
inhibition zone in PDA medium at 3000ppm (c.100%), while neem, lemon grass, ginger
recorded more than (70%) fungus inhibition; other plants showed low effect less than
(50%) for the same concentration. Longevity study showed the fresh extract solution for
all plants under study gave best effectiveness of crude plant extracts stored under different
conditions. Longevity study of fresh plant extracts under different condition recorded high
inhibition in PDA medium for 3 weeks when stored at 4oC, 1 week when stored at 25 oC,
and less than 1 week (3days) when samples were kept outside at ±32oC. In vivo, the fruits
sprayed with fresh plants extract of neem, pong-pong and chili completely prevented
infection at 4000 and 5000 ppm and increased shelf-life of fruit compared with untreated
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fruit by three week at room temperature. Five crude plant extracts from pong- pong, chili,
neem, lemon grass and Ginger were selected as the best plants based their on antimicrobial
activity showing more than 70-90% fungal inhibition and longer stability and
efficacy under different storage conditions. LC50 values below 2g/ml are considered to
be toxic and unsafe for human consumption. The LC50 values of the plant extracts were:
pong-pong was 5μg/ml (low but safe); chili: 20 g/ml (low but safe); neem: 30 g/ml
(safe); lemon grass: 473 g/ml (safe) and ginger: 495 g/ml (safe). Mass Spectrometry
analyses show low residual effect and not exceed maximum residue limits MRL values in
fruit treated with the best extracts after first, second and third week on the spray. Five
plants extracts namely pong-pong, chili, neem, lemon grass and ginger incooperated with
fruit wrappers fruit showed increased shelf life and decreased weigh loss for fruits stored
at room temperature compared with untreated fruit. Plant extract of pong-pong
incooperated with coating fruit (chitosan, starch and oil paraffin) showed decreased weigh
loss and increased shelf life for fruits stored at room temperature (±25oC) as compared
with untreated fruit. Cerebera produced the best results in the experiments and its extract
was selected for the identification of active anti-fungal biocompounds from. Alpha
Glycoside (4, 6 Benzylidene -1O-Methyl -2O-(2346 Tetra-O-Acetyl-Betad -Glucosyl), a
new compound from the leaf extract of Cerebra odollam L. was identified for its
antifungal action. |
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