Microbial diseases of pepper (Capsicum species) are the most significant factors contributing to the loss of this economically important vegetable crop. Leaf spot disease caused by Cercospora capsici is one of the major constraints to pepper production in Nigeria. The disease is reportedly introduced through infected seeds. However, the development of Cercospora leaf spot on plants propagated from fungicide-treated seeds suggests an alternative perennial source of infection and also necessitates the development of an efficient, safe control measure. C. capsici was isolated from infected pepper plant through the direct plating method and subsequently characterised. Treated pepper seeds (with L. plantarum) were planted in C. capsici inoculated soil, while the emergence, seedling growth parameters and severity of leaf spot were observed. The severity index of Cercospora leaf spot on pepper plants (observed at the 20th day after planting) was significantly lower on L. plantarum treated plant set (0.07) than on pepper without seed treatment. Seed emergence rate index increased from 11.11 to 15.33% /day of untreated to treated pepper seeds sown in infected soil respectively, while the mean emergence time of untreated seeds (8.32 days) was significantly higher in C. capsici infected soil. It could therefore be deduced that seed priming with L. plantarum improved the seedling vigor and resistance of pepper to leaf spot disease caused by C. capsici.

The experiment was carried out to test the antifungal efficacy of some plant extracts (Ageratum conyzoides, Azadirachta indica, Morinda lucida, and Chromolaena odorata) and a chemical fungicide (mancozeb). The mycelial growth inhibition potentials of five concentrations of aqueous plant extracts were assayed at different incubation periods on the growth of Colletotrichum orbiculare and Lasiodiplodia theobromae. The experiment was carried out in a Completely Randomized Design (CRD) with five replications. A 3 mm mycelial disc of each test fungus was placed at the center of a 9 cm Petri dish containing 5, 10, 15, 20, and 25 g of the plant extracts or 0.25g/100mL of mancozeb (synthetic fungicide) in Potato Dextrose Agar. The results obtained revealed that all the plant extracts, at all concentrations, significantly inhibited the growth of these mycopathogens, with 25g C. odorata having the highest percentage inhibition of 70.78% and 73.68% at 48 and 96 hours of incubation on C. orbiculare and L. theobromae respectively. All the selected aqueous extracts inhibited more than 50% C. orbiculare mycelial growth. Antifungal extracts recovered from the selected plants could be further purified to improve and characterize their fungicidal activities in controlling plant diseases. Extracts of plant materials, which are readily available to the farmers, are better alternatives to the commonly used hazardous, synthetic fungicides. Contribution/Originality: This paper's primary contribution is finding that all the plant extracts used against cucumber pathogens had significant inhibitory properties inhibited at different concentrations and incubation periods respectively.

Due to the established toxic effects of agrochemical accumulation in humans, there is an increasing demand for organic agricultural production in Nigeria. The production of highly nutritious and daily consumed crops like tomato through organic farming (using biosupplements) would go a long way in reducing the risks associated with the consumption of inorganic pesticides and fertilizers. In order to investigate the effects of rhizobacterial biosupplement on the resistance and yield of tomato grown with organic fertilizers, the predominant rhizosphere bacteria associated with healthy tomato isolated in this study (Bacillus thuringiensis, Pseudomonas aeruginosa, Bacillus subtilis, Bacillus macerans and Bacillus cereus) were added as a consortium to improve the availability of organic nutrients to plants. Performance measures including the numbers of fruit, branches, leaves, plant height, days to first flowering and days to 50% flowering at 20.00, 17.67, 176.33, 73.33 cm, 70.43 and 78.00 were all better (higher or lower) in treated tomato plants than untreated set. A significant reduction in percentage prevalence was recorded for Fusarium wilt, as well as Early blight diseases on treated plants (seed treatment with rhizobacterial consortium) compared to plants grown from untreated seeds. However, seed treatment appeared to be less effective in the treatment of Bacterial wilt disease of tomato, with percentage prevalence of 41.70 and 42.90 recorded for treated and untreated plants at nine weeks after planting respectively. It could be concluded that the application of rhizobacterial consortium (as seed treatment) improved the yield and resistance of tomato to Fusarium wilt and Early blight diseases caused by Fusarium oxysporum and Alternaria solani respectively.