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Bosah O.,Delta State University, Abraka | Igeleke C.A.,Benson Idahosa University | Omorusi V.I.,Rubber Research Institute of Nigeria
International Journal of Agriculture and Biology | Year: 2010

In this study, pure cultures of three antagonistic fungi, Trichoderma, Penicillium and Aspergillus species and a fungal pathogen, Sclerotium sp. were obtained after inoculation on potato dextrose agar (PDA) fortified with antibiotics to prevent bacterial contamination. Pathogenicity test was carried out when the antagonistic isolates were inoculated on PDA 24 h before and after Sclerotium inoculation. Of the three fungal antagonists evaluated for inhibitory efficacy, Trichoderma sp. proved to be the most effective as it exhibited the greatest inhibition to Sclerotium sp. (P<0.01) both at the initial and final tests. This was closely followed by Aspergillus sp. with inhibitory effect on the pathogen at both trials (P<0.01). However Penicillium sp. was slightly inhibitory against Sclerotium. Percentage inhibitions of the antagonists on Sclerotium by Trichoderma, Aspergillus, and Penicillium, were up to 81.36-80.29%, 88.35-73.12% and 56.98-46.24%, at the 6th day of inhibition at both trials, respectively. The result implied that the extent of inhibition by the fungi provides the use of potential antagonists capable of controlling the pathogenicity of Sclerotium sp. in crops for sustainable agriculture. © 2010 Friends Science Publishers. Source

Ebewele R.O.,University of Benin | Iyayi A.F.,Rubber Research Institute of Nigeria | Hymore F.K.,Covenant University
International Journal of Physical Sciences | Year: 2010

Rubber seeds from the rubber tree (hevea brasiliensis) are in abundance in Nigeria from which nonedible oil could be obtained. However, the seeds are wasted in the rubber plantations annually even though the extractable oil has potential technical applications. If the full potentials of the oil are to be realized, there is need to have a data base information on the oil extraction process and its properties. Rubber seeds were collected from different rubber clones and extracted first by n-hexane to determine the yield characteristics. Second, the seeds were extracted by a hydraulic press at varied operating conditions: pressure range (5-8MPa), temperatures, 40-90°C; and moisture content, 7-16%. The effect of particle size and other operating variables on oil yield were studied. The physico-chemical properties of the extracted oil were evaluated. It was found that the percentage oil yield from the seeds of the rubber clone NIG800 at 45.03% was higher than the yield from other clones; GTI (40.21%) and RRIM 707 (38.42%) when the particle size of 1.16 mm was used. Oil yield increased with increase in temperature and pressure. Maximum oil yield was obtained during mechanical pressing at a moisture content of 10% (wt), temperature of 70°C and pressure of 8MPa. The physicochemical characteristics of the oil showed high incidence of free fatty acid (FFA) of 37.96% (wt) and the high iodine value (IV) of 142.45 is indicative of the presence of high unsaturation. Rubber seed oil could therefore serve as semi-drying oil used in ingredients for surface coating and in the formulation of products where the presence of unsaturation is important. © 2010 Academic Journals. Source

Ebewele R.O.,University of Benin | Iyayi A.F.,Rubber Research Institute of Nigeria | Hymore F.K.,Covenant University
International Journal of Physical Sciences | Year: 2010

Some studies have shown that rubber seed oil (RSO) from the seed of rubber tree (hevea brasiliensis) has potential technical applications. However, the high free fatty acid (FFA) associated with the oil may be a limiting factor in its applications. In this study, crude rubber seed oil (RSO) containing 37.69% FFA was deacidified using 4.3-5.6% of glycerol. The reactions were carried out at a pressure of 20mmHg in the presence of zinc dust and zinc chloride catalysts added separately at high temperature (150 - 2500C). The progress of the reaction was monitored by determining the FFA at various time intervals. The FFA content in the RSO was reduced to 1.5% in six hours when 4.3% glycerol was used with zinc dust at a temperature of 2000C while the triglycerides content of the oil increased from 40.32% in the crude oil to 80.62% in the deacidified RSO. The study showed that this process is effective in the deacidification of RSO without loss of neutral glycerides as in alkali neutralization. ©2010 Academic Journals. Source

Omorusi V.I.,Rubber Research Institute of Nigeria | Ayanru D.K.G.,University of Benin
International Journal of Agriculture and Biology | Year: 2011

A screen house study was conducted to evaluate the effects of a compound fertilizer (NPK) on the response of cassava (Manihot esculenta Crantz) to diseases, pests and mycorrhizal symbiosis. Soil drenches of NPK (15 - 15 - 15, N - P 2O 5- K 2O) were applied at the rates of 0.083 g (10 kg ha -1) and 0.832 g (100 kg ha -1) per 4.2 kg soil. Mycorrhizal spores in rhizosphere soil and root colonization of cassava by arbuscular mycorrhizal (AM) fungi were estimated at 5.5 months. Shoot heights and girths (cm) were assessed at 5.5 months. Incidence of pests-cassava green spider mites (Mononychellus tanajoa Bondar) (CGM), cassava mealybug (Phenaccocus manihoti Matt-Ferr.) (CM), African cassava mosaic disease (ACMD) and cercospora leaf spot disease (CLSD) were rated on varying scales. Mycorrhizal spores and root colonization were significantly higher in the control experiments (P< 0.01) with percentage decreases of 67 and 83% per g/soil of spores and root colonization of 61 and 83%, in the 10 and 100 kg ha -1, respectively. NPK fertilizer significantly increased plant vigour (stem & girth) (P<0.01), with increases by 16.82 to 36.45% for height and 15.20 to 25.45% for girth. Mycorrhizal symbiosis was lowest in plants amended with the highest fertilizer dosage. NPK concentrations diminished CGM, CM (P< 0.01) and ACMD (P< 0.05). However, no significant effects on CLSD infection were obtained. © 2011 Friends Science Publishers. Source

Ogbebor N.O.,Rubber Research Institute of Nigeria | Adekunle A.T.,University of Benin | Eghafona O.N.,University of Benin | Ogboghodo A.I.,University of Benin
Fungal Biology | Year: 2015

The study was conducted to evaluate invitro and invivo control of fungal antagonists on Rigidoporus lignosus (klotzsch) Imaz in Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg. in the rain forest zone of Nigeria. Invitro assessments of biological agents were carried out in dixenic cultures in Petri plates. Invivo tests were carried out in the nursery using Hypocrea virens and Hypocrea jecorina. Significant differences were observed with the dual inoculations of fungal antagonists and R. lignosus inoculated the same day, and the antagonists inoculated 24h before inoculation of R. lignosus. Hypocrea jecorina was most effective in the control of R. lignosus with percentage inhibition of 86.83%. Hypocrea virens, H. jecorina, Trichoderma spirale, Trichoderma sp., Trichoderma sp. Pers, and Hypocrea lixii were effective on R. lignosus. Fungal antagonists inoculated 24h before inoculation of R. lignosus exhibited higher inhibitory efficacies than antagonists and R. lignosus inoculated the same day. In the invivo evaluation of fungi antagonists on R. lignosus, seedlings in H. jecorina treatment at 60dand H. virens treatment at 150dafter inoculations respectively had the highest plant heaths (highest length of stem and length of tap rot, lowest plant death, and least foliar symptom) compared to the control. Mortality rate was higher at 60dafter inoculation and decline from the third months onward. Significant differences were observed between the control and R. lignosus treatment in all the parameters evaluated. © 2014 The British Mycological Society. Source

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