2005

A checklist of indigenous pests of cowpea, Vigna unguiculata (L.) at Mokwa, Niger state, Nigeria, and their relative abundance were reported. The impacts of two most commonly used insecticides in the locality, i.e. Dimethoate and Cypermethrin, on cowpea productivity were elucidated. Thirteen insect species were listed, three of which were prominent at the seedling and prereproductive stages. These include: - Ootheca mutabilis, Empoasca dolichi and Medythia quarterna.

The Kerri-Kerri formation Around Biri Fulani in North-eastern Nigeria is made up of reddish, modertaley well sorted, quartz arenites that are large scale cross-bedded. Field studies and laboratory analyses were conducted on these sediments to determine their depositional environments. Sieve analysis of sediments in the area of study showed that the sandstones within the Kerri-Kerri Formation are very leptokurtic and strongly fine-skewed. The sediments are texturally submature and mineralogically mature with angular to subrounded grains thus suggesting a moderate degree of reworking.

Seeds from 15 cultivars of beniseed grown in a southern guinea savanna agro-ecology were evaluated for their mineral composition as well as their physico-chemical characterization. Average percentage crude protein (15.40), crude fat (53.27), crude fibre (6.10), ash (2.33) and Nitrogen free extract (16.61) compare favourably with those of groundnut as a reference crop. However mineral composition are fairly similar in all the cultivars with calcium being the most abundant in two varieties (85-3-1 and T-4).

In-depth integrity testing of three dispersants: Corexit 9572, NalcoD4106 and Goldcrew was carried out to determine key physical characteristics of the dispersants and toxicity to the larvae of Chironomous transvaalensis Keiffer (Diptera:Chironomidae). The result revealed that Corexit 9527 and Goldcrew maintained their integrity while NalcoD4106 on the other hand deteriorated in storage. Static bioassay conducted to determine the 96hr LC50for the dispersants against the insect species showed that Corexit 9572 was the least toxic followed by Goldcrew and Nalco D4106.

Studies on the occurrence and seasonality of some harpacticoid copepods (crustacean) from a West African coastal river were carried out. An all year round sampling was made to cover the twelve months of the year, using plankton nets of 55µm and 100µm mesh sizes. Three species of harpacticoid copepods were identified, namely: Nannopus palustris, Diarthrodes cf major and Bryocampus minutes. While Nannopus palustris showed peaks in the dry season months of January and February, Diarthrodes cf major and Bryocamptus minutes showed peaks in the rainy season months of July and August.

The effect extract of Ocimum gratisimum L., Carica papaya, Azadirachta indica A. Juss, Vernonia amygdalina and Bixa orellana L. on pathogenicity and reproduction of Meloidogyne incognita race 3, the causal organism of the root-knot disease of cacao was investigated in the greenhouse. Leaf extracts were prepared by blending and filtration of 25g of chopped leaves in 100ml of distilled water. Each cocoa seedling in a naturally infested soil received 40ml water extract of the leaves. Nematode populations were reduced by the application of the extracts in a descending order of A. indica, B.

An investigation was undertaken to assess the effect of Neem-fortified Cocoa pod husks soil amendment against the root-knot disease caused by Meloidogyne ingonita on cacao seedlings, Theobroma cacao L. cv. F3 Amazon. Cocoa pod husks (CPH), combined use of Neem leaves and CPH, and Neem seeds plus CPH decreased the number of juveniles and galling due to Meloidogyne incognita. The greatest decrease was obtained with Neem seed-fortified cocoa pod husks with a corresponding increase in the plant growth.

Three cichlids, Chromidotilopia guentheri, Tilapia mariae and T. zilli were collected from the Osse River at Ikoro and examined for length frequency distribution and length weight relationships (LWR). The mean length and weight were 11.05±0.35cm and 51.75±5.63g for Chromidotilapia guentheri, 13.57±0.54cm and 124.67±17.54g for T. mariae and 17.45±0.69cm and 232.92±28.01g for T. zilli. The length frequency distributions for C. guentheri presented a slightly positively skewed distribution with modal length being 10.0 - 10.9cm size class. T.

The limnological characteristics of the aquatic habitat were studied with special emphasis on water temperature, calcium hardness and chlorine levels as they affect the abundance of Bulinus globosus and Bulinus forskali on one hand and their interfactorial effects on the other. The single regression analysis showed that calcium hardness was the only factor that showed direct significant (P<0.05) positive effect on abundance of B. globosus and B. forskali. Similarly, water temperature was significantly (P<0.05) negatively correlated with chlorine and calcium hardness levels.

The distrubution of Bulinus globosus and Bulinus forskali in relation to the water velocities in the research site was investigated. Station 6 had the highest mean velocity of 22.82 cm sec. The analysis of variance for all the stations showed a very highly significant (P<0.01) defined as negative. Station 4 with a zero velocity (stagnant) had the highest number of both snails indicating an inverse relationship between velocity of water flow and abundance. The regression analysis indicated that increase in water velocity had a non-significant negative effect on the distribution of B.