7 research outputs found
Health Impact Assessment of Mangrove Vegetation in an Oil Spilled Site at the Bodo West Field in Rivers State, Nigeria
A post-impact health assessment of the mangrove vegetation of Bodo West
Field in Rivers State of Nigeria where three oil spillages occurred was
carried out to determine any major changes from the baseline profile of
the area 10yrs after spillage. The accidents resulted in the discharge
of a total of 1860 barrels of crude oil, which cut fire as it spilled
destroying the mangrove vegetation. Diseased plant samples were
collected from infected plants at 50m intervals to a distance of 300m
from the point of spillage along four transects in the East, West,
North and South directions. Results of laboratory diagnosis showed that
most of the plants especially plants along the South and East transects
were heavily infected with necrotic leafspots caused mainly by
Pesalotia and Phomopsis spp. Rhizophora mangle , Rhizophora
racemosa and Avicennia africana were the most heavily infected
plants. Other genera of fungal pathogens isolated were Alternaria ,
Aspergillus , Botrytis , Chaetonium , Colletotrichum , Dreschlera
, Fusarium Macrophomina , Penicillium , Phoma and Trichoderma .
No plant pathogenic bacteria or viruses were isolated. Oil pollution
predisposed the plant to fungal disease attack and also impacted the
soil and vegetation. @JASE
In vitro Seed-dressing Technique for the Control of Seed-borne Fungi of Rice variety Faro -29
Use of seed-dressing fungicides (Bavistin, Benlate, Fernasan-D, Apron
Plus 50 DS and Dithane\u2013 M45), and soaking and slurry methods at
various concentrations, for the control of seed-borne fungi of rice
variety Faro 29 in vitro, was investigated. The results obtained showed
that all the fungicides significantly inhibited the seed-borne fungi
associated with the seeds of the variety at concentrations of 40g/ml,
and 50mg/ml (P<0.05), in the soaking method, and at all the
concentrations in the slurry method (P<0.05).The mean percentage
seed germination , was not below 71%,at all the concentrations in the
two methods used . The relevance of this work to the production of rice
and food security in Nigeria is discussed
Effect of plant extracts on radial growth of Helminthosporium oryzae causative of Brown spot disease of rice under in-vitro
Brown spot disease, caused by Helminthosporium oryzae, is worldwide
problem capable of causing considerable damage to paddy in the nursery,
field or grain yield. The disease is seed borne, and thus can be
transmitted through infected seeds and crop residues, alternate hosts
and contaminated irrigation water. The objective of this study was to
evaluate the effect of plant extracts on radial growth of
Helminthosporium oryzae on rice plants. An in-vitro experiment was
conducted at the Plant Pathology Laboratory of National Root Crop
Research Institute, Umudike, Abia State, in Nigeria. Treatments
included water and alcohol extracts of Azardiractha indica (Neem
leaves), Piper guinensis (seeds), Garcinia cola (Bitter cola
seeds), Ocimum gratissimum (leaf) and Vernonia amygdalina (leaf);
and synthetic fungicide (Benomyl) at a concentrations of 10, 25 and 30%
of the extract applied to H. oryzae in culture. The test materials were
administered on Helminthosporium oryzae, sourced from rice seeds and
infected shoot system of rice. Alcohol extract of Piper guineensis had
the highest radial growth inhibition (89.89%) by the fifth day, but was
not significantly different from Azardiractha indica, which had an
inhibition value of 81.02%. The least effective plant extract was
Ocimum gratssimum with radial inhibition of 11.50%, which occurred also
on the fifth day. Plant extracts were as effective as the synthetic
fungicide in inhibiting growth of the test fungus. Therefore, the
effective extracts, all of which are readily available to the farmers,
should be promoted instead of the synthetic fungicides, which are in
limited supply and invariably expensive for rice farmers in Nigeria.La maladie des taches brunes, caus\ue9e par Helminthosporium oryzae
, est un probl\ue8me mondial susceptible de causer des dommages
consid\ue9rables au riz en p\ue9pini\ue8re, champ et en rendement
en grains. La maladie est transmise par les semences et peut donc
\ueatre transmise par des semences et des r\ue9sidus de culture
infect\ue9s, des h\uf4tes alternatifs et de l\u2019eau
d\u2019irrigation contamin\ue9e. L\u2019objectif de cette
\ue9tude \ue9tait d\u2019\ue9valuer l\u2019effet
d\u2019extraits de plantes sur la croissance radiale
d\u2019Helminthosporium oryzae sur les plants de riz. Une
exp\ue9rience in vitro a \ue9t\ue9 men\ue9e au laboratoire de
phytopathologie de l\u2019Institut national de recherche sur les
cultures racines, Umudike, \uc9tat d\u2019Abia, au Nig\ue9ria. Les
traitements comprenaient des extraits aqueux et alcooliques d\u2019
Azardiractha indica (feuilles de Neem), de Piper guinensis
(graines), de Garcinia cola (graines de cola amer), d\u2019 Ocimum
gratissimum (feuille) et de Vernonia amygdalina (feuille); et
fongicide synth\ue9tique (Benomyl) \ue0 des concentrations de 10,
25 et 30% de l\u2019extrait appliqu\ue9 sur H. oryzae en culture.
Les mat\ue9riaux d\u2019essai ont \ue9t\ue9 administr\ue9s sur
Helminthosporium oryzae, provenant de graines de riz et d\u2019un
syst\ue8me de pousses de riz infect\ue9. L\u2019extrait alcoolique
de Piper guineensis avait l\u2019inhibition de la croissance radiale
la plus \ue9lev\ue9e (89,89%) au cinqui\ue8me jour, mais
n\u2019\ue9tait pas significativement diff\ue9rente de celle
d\u2019Azardiractha indica, qui avait une valeur d\u2019inhibition de
81,02%. L\u2019extrait de plante le moins efficace \ue9tait Ocimum
gratssimum avec une inhibition radiale de 11,50%, qui s\u2019est
\ue9galement produite le cinqui\ue8me jour. Les extraits
v\ue9g\ue9taux \ue9taient aussi efficaces que le fongicide
synth\ue9tique pour inhiber la croissance du champignon
d\u2019essai. Par cons\ue9quent, les extraits efficaces, qui sont
tous facilement disponibles pour les agriculteurs, devraient \ueatre
encourag\ue9s \ue0 la place des fongicides synth\ue9tiques, qui
sont en quantit\ue9 limit\ue9e et invariablement co\ufbteux pour
les riziculteurs au Nigeria
Screening Colletotrichum gloeosporioides f.sp Manihotis isolates for virulence on cassava in Akwa Ibom state of Nigeria.
Six isolates of Colletotrichum gloeosporioides f.sp. manihotis obtained from anthracnose-infected cassava stems in six different cassava-growing locations of Akwa Ibom State were examined in the laboratory for morphological and physiological differences. The isolates were then screened in the greenhouse for virulence on cassava variety NR 8083 widely grown in Akwa Ibom State. Six-week old cassava plants were inoculated with 1ml of the spore suspension of each isolate of the pathogen at a concentration of 104 conidia/ml using a sterile hypodermal needle. One injection of inoculum was made at five different internodes of each cassava stem at an ambient temperature of 300C and relative humidity of 80%. Results of laboratory examinations showed that mycelial growth on potato dextrose agar (PDA) medium was fastest (10.65mm/day) in isolate CGM 2 from Ikono and slowest (7.29mm/day) in isolate CGM 6 from Uyo. Sporulation of the isolates on PDA medium under alternate light and dark regimes was highest (9.30 x 106 spores/ml) in isolate CGM 4 from Nsit Atai and lowest (1.23 x 106 spores/ml) in isolate CGM 5 from Oruk Anam. Percentage spore germination and conidia length were highest (85.64% and 23.55µm) respectively in isolates CGM 4 from Nsit Atai and CGM 1 from Essien Udim and lowest (49.86% and 13.75µm) in isolate CGM 3 from Itu and isolate CGM 2 from Ikono, respectively. Results of greenhouse inoculations showed variations in lesion size for the different isolates. The largest (15.30mm) lesion was produced by isolate CGM 4 from Nsit Atai, followed by isolate CGM 1 (12.60mm) from Essien Udim. There were no significant (p> 0.05) differences in lesion size for isolates CGM 3 (8.63mm) from Itu, CGM 2 (8.45mm) from Ikono and CGM 6 (8.41mm) from Uyo. Lesion size was smallest (5.00mm) in isolate CGM 5 from Oruk Anam. Isolate CGM 4 of C. gloeosporioides f.sp manihotis from Nsit Atai which showed the highest sporulation density and percentage spore germination, one of the longest conidia and largest lesion size on inoculated cassava stems, appeared to be the most virulent of the six isolates of the pathogen in Akwa Ibom State during this investigation.Key Words: Fungal variability, fungal virulence, Colletotrichum gloeosporioides f.sp. manihotis, cassava, anthracnos
In vitro Seed-dressing Technique for the Control of Seed-borne Fungi of Rice variety Faro -29
Use of seed-dressing fungicides (Bavistin, Benlate, Fernasan-D, Apron
Plus 50 DS and Dithane– M45), and soaking and slurry methods at
various concentrations, for the control of seed-borne fungi of rice
variety Faro 29 in vitro, was investigated. The results obtained showed
that all the fungicides significantly inhibited the seed-borne fungi
associated with the seeds of the variety at concentrations of 40g/ml,
and 50mg/ml (P<0.05), in the soaking method, and at all the
concentrations in the slurry method (P<0.05).The mean percentage
seed germination , was not below 71%,at all the concentrations in the
two methods used . The relevance of this work to the production of rice
and food security in Nigeria is discussed