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