TONUI K JOSEPHAT MSC. STUDENT JKUAT

TONUI K JOSEPHAT
MSC. STUDENT
JKUAT- COHES
SUPERVISORS
DR. CHRISTINE BII (PhD)
DR. CIIRA KIIYUKIA (PhD)
2014
* Introduction
More
than 100, 000 moulds spp produce over 300
mycotoxins contaminanting food grains
Genera
Aspergillus, Penicillium, and Fusarium major
contaminants of maize
Produce
aflatoxins, ochratoxins and Fumonisins with toxic
and carcinogenic potential
Fungicides are chemical compounds against fungi
 They
affect fungal nucleic acid and sterol biosynthesis,
mitosis and cell division, respiration etc.
 Several bacterial and fungal antagonists have been
developed for the control of Mycotoxigenic fungi
*
 Mycotoxins cause health and economic problems in the
world affecting humans, animals and the environment
 Aspergillus flavus and A. parasiticus producing
Aflatoxins are a major problem in Kenya
Largest aflatoxicosis outbreak in 2004 resulted in 125
deaths & 317 cases in Eastern province, Kenya
Tones of maize grain yields have been destroyed
intermittently
*
Objectives
General objective
To determine the susceptibility of mycotoxigenic
fungi to some commercial fungicides as a potential
for the control of mycotoxin infestation in maize
Specific Objectives
1.To isolate and identify mycotoxigenic fungi
affecting maize grains from Machakos, Nairobi,
Mombasa, Kisumu and Kitale.
2.To determine the susceptibility of the
mycotoxigenic fungal isolates to Atracol, Milraz,
Mistress and Victory fungicides.
*
Materials and Methods
Study design
A laboratory based cross sectional study.
 A total of 138 maize samples from the five sites were collected
Conducted at KEMRI Center for Microbiology Research- Mycology
Laboratory
Procedures
 Fungicides diluted according to manufacturers instructions
 Fungicide was applied onto four maize Kernels and inoculated on SDA
media, incubated at 30oC for 72 hours for fungal growth.
Fungal growth identified morphologically
(Microscopic and
Macroscopic features) and scored to determine percentage Infestation

Activity of fungicides was determined by Disk Diffusion
*
Results
Percentage fungal infestation of maize from different
regions in Kenya following treatment of grains with
fungicides
*
Infestation
rates on
Type of fungicide used
MILRAZ
MISTRESS
VICTORY
ANTRACOL
CONTROL
% within type of
10%
26%
34%
14%
0%
fungicide used
n=14
N=35
N=47
N=19
N=0
% within type of
21%
27%
19%
24%
4%
fungicide used
N=29
N=37
N=26
N=33
N=5
% within type of
12%
12%
18%
15%
5%
fungicide used
N=17
N=17
N=25
N=21
N=7
% within type of
17%
14%
8%
8%
8%
fungicide used
N=23
N=19
N=11
N=11
N=11
% within type of
40%
22%
21%
39%
83%
fungicide used
N=55
N=30
N=29
N=54
N=115
Categories
maize
0
25
50
75
100
*
Plate A . Aspergillus niger
Plate C. Heavily infested untreated
control and treated maize
Plate B. Fusarium and A. flavus
Plate A . Aspergillus
flavus infested maize
*
*
Discussion
 Maize from the five regions were
contaminated by mycotoxin
producing moulds of the genera Aspergillus spp, Fusarium spp and
Penicillium spp.
There was a significant difference p<0.05 in the activity of the four
fungicides.
Generally, a significant percentage of maize treated with Mistress and
Victory (n=35) and (n=47) respectively were less infested.
The two fungicides were more effective in reducing the fungal
infestation on the treated maize samples.
 N=55 and N=54 samples treated with Milraz and Antracol respectively
had 100% infestation compared to those treated with Victory and Mistress
Fungicides (n=29) and (n=30) respectively.
*
Discussion Cont..
 Some
isolates of A. flavus, Fusarium spp and Penicillium
spp exhibited resistance to at least one of the test fungicides.
 Shown
by overgrowth of the mould on fungicide
impregnated disks and absence of a zone of inhibition
This
is indicative of emerging resistance to commercial
fungicides.
However,
more studies on the emerging resistance to more
fungicides country wide may be necessary.
*
 The four test fungicides were effective in reducing
fungal infestation of maize a potential for mycotoxin
control
 Further
evaluation
needed.
to
ascertain
their
 Some isolates showed resistance to the test
probably due to irrational use of fungicides.
field
fungicides
 Emerging triazole resistance in A. fumigatus linked
azole antifungals used in agriculture.
efficacy
to
 Calls for rational use of fungicides in agriculture to avoid
emerging resistance in clinical practice
*
We acknowledge Kenya Medical Research
Institute (KEMRI) for approval and funding for
this work under mycotoxin surveillance program.
We also acknowledge the Jomo Kenyatta
University of Agriculture and Technology (JKUAT)
for reviewing this work
*