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This study was conducted to assess the incidence of seed-borne fungi on rice seeds sourced from the major rice growing areas of SouthEastern Nigeria. The rice seeds were collected during the dry seasons between 2009 and 2010. Four hundred rice seeds randomly collected and surface sterilized by washing in 3% sodium hypochlorite and rinsed two times with sterile distilled water were placed in three circular rings inside the Petri dishes. The incubation was done one after the other for each variety from all the locations. Ten fungi species from eight genera were isolated from the rice seeds in all the rice growing areas of SouthEastern Nigeria. The fungi pathogens vary from one locality to another, as well as the frequency of occurrence. The pathogens isolated include: Fusarium moniliforme, F. solani, F. oxysporium, Aspergillus spp., Botridiploidia spp., Helminthosporium spp., Penicillium spp., Trichoconis padwickii, Curvularia oryzae and Phoma oryzae. Though, there was the presence of some seed-borne fungi in the rice seeds from the areas studied, most of the cultivars experienced up to 90% germination. But some cultivars had very low germination. IR 1416 from Arochukwu and GB90 from Arondiuzogu had less than 1% germination. This study shows that seed-borne organisms are major constraint in rice production in the SouthEastern states of Nigeria as a result of low seed germination stemmed from infestation of fungi organisms in the seeds.

Abstract:To investigate the effect of planting date, spacing and seeding methods on disease development and yield components of rice, a factorial experiment in randomized complete block design (RCBD) with four replications was conducted during 2011 planting season at Izzi Local Government Area (LGA) of Ebonyi State, Nigeria. This experiment was carried out with four levels of planting dates (early June, late June, early July and late July), three levels of spacing (15, 20 and 25 cm) and two levels of seeding method (direct seeding and seedling transplanting). The studied traits included plant height (PH), number of tillers (NT), leaf area (LA), root length (RL), panicle length (PL), 1,000 seed weight (SW), disease incidence and severity. The result showed that all the factors had significant effect on the parameters measured. Sowing in early July had the highest LA of 65.38 cm 2 , PH of 122.00 cm, RL of 29.04 cm and TN of 10.54, and the second largest PL of 25.08 cm and SW of 25.12 g. Also sowing in early July had the highest disease severity of 3.21, followed by 3.14 which occurred in late July, while the least 2.17 occurred in early June. The direct seeding method had the highest disease incidence of 70.83%, followed by plant spacing of 15 cm × 15 cm which had the disease incidence of 69.72%, while sowing in early June had the least disease incidence of 57.50%. In conclusion, planting of rice in Southeastern Nigeria should be done in early July, as the yield components were significantly better than in other dates though with the highest disease severity.

Laboratory experiment was conducted to test the effects of bio-medicinal plants (Gongronema latifolium (Utazi) leaves and Myristica fragans (Nutmeg) seeds) and synthetic fungicide (Alpron- Plus) on seed health, germination percentage and seedling vigour of sweet melon seeds. The experiment was conducted at the Crop Science and Horticulture Laboratory, Nnamdi Azikiwe University Awka, Anambra State. Bio-medicinal plants were used as crude powdery seed dressers as well as synthetic fungicide. The experiment was laid out in a simple completely randomized design (CRD) with ten replications which consisted of blotter paper germination/ seed health tests of sweet melon seeds and seedling vigour and seedling vigour index tests using soil medium. Ten petri dishes and ten polybags were used respectively for each of the plant extracts and synthetic fungicides simultaneously for both blotter paper and soil medium tests. Twenty seeds which were independently dressed with various plant extracts and synthetic fungicide were plated into one 9cm Petri dish containing three layers of blotter paper in circular form. For soil medium method, ten polybags with few small perforations underneath filled with sterilized top soil were used for each fungicide. The Petri dishes containing the plated seeds were incubated on the Laboratory benches for eight days while seedlings in polybags were kept in the screenhouse and observations were taken and recorded daily for germination count, fungal growth then germination index and seedling vigour index which were derived later with appropriate formulae and their values being expressed in percentages. The results of this investigation revealed that bio-medicinal plant crude extracts had significant effect on germination percentage and germination index of Sweet- melon seeds. Gongronema latifolium crude extract had the highest germination index. The synthetic fungicide was effective in protecting the seeds of sweet melon though had low germination percentage. Nutmeg was not effective when used in crude powdery form as dressers as it had the lowest germination percentage and the highest infestation percentage. It could therefore be recommended that the plant extracts tested in this experiment should not be used as powdery seed dressers but as essential oil using appropriate extracting solvents in order for the bioactive ingredients to act effectively in preventing micro-organisms that hinder germination of sweet melon seeds.

The use of plant products has shown great potentials as alternatives to synthetic insecticides. The present studies investigated the efficacy of Dennetia tripetala and Deltamethrin as grain protectants against adult Sitophilus zeamais in stored maize. Acetone extracts of D. tripetala and Deltamthrin 12.5EC were evaluated in the laboratory based on insect mortality, progeny production and grain damage.  Five concentration levels of each toxicant were prepared including 20mls, 15mls, 10mls, 5mls and 1ml for D. tripetala and 1ml, 0.5ml, 0.25ml, 0.1ml and 0.01ml for Deltamethrin. Controls with no toxicants were included. The design of the experiment was a CRD and each repeated 4 times. Twenty grams of insect-free maize were measured into each replicate vial and infested with ten, 1-5-days old adult insects.  Mortality was recorded at 12, 24, 48- and 72-hours post-treatment. After 35 days, progeny production and number of damaged grains were recorded. Data obtained were statistically analyzed using SPSS version 13. The results indicated that Deltamethrin was more toxic than Dennetia tripetala, however, at 10mls-20mls, D. tripetala showed moderate toxicity against S. zeamais. Comparative mortalities of the two toxicants indicated that Deltamethrin was significantly (P < 0.05) more toxic than D. tripetala at all levels. The studies however, revealed that the application of D. tripetala in controlling S. zeamais could be effective at higher concentrations. Therefore, it was suggested that D. tripetala should be applied at higher concentrations for effective control of maize weevil.