Pathogenic diseases are major limitations to the cultivation of tomato in the humid rain forest agro-ecological zones (HRAZ). A study was designed to evaluate four cultivars of tomato (DT97/215A, Ajindi-kerewa, Dan-Syria and Roma VF) for tolerance to common field pathogens of the crop in the HRAZ. Analysis of soil preceded land preparation, while seeds and soil for the nursery were sterile. The land area for the field study was 200.60 m 2 , divided into 12 plots of 7.80 m 2 . Each plot had 30 tomato stands. The randomized complete block design consisting of three replicates was adopted. Data collected were subjected to statistical analysis. Four diseases, Fusarium wilt, Verticillium wilt, Bacterial wilt and Tomato mosaic were identified with significantly different incidences and severities. Fusarium wilt was the most common, followed by Verticillium wilt, while tomato mosaic was the least. DT97/215A had 61.42% (incidence) and 28.81% (severity) of fusarium wilt at 9 weeks after planting, making it the most susceptible. Ajindi-kerewa recorded 51.32% (incidence) and 16.19% (severity) in the same period. The least incidences of Fusarium and Verticillium wilt, 0.81% and 0.31% respectively, were recorded for Roma VF at 9 wap. No incidence of bacterial wilt and tomato mosaic was recorded for Dan-Syria. Roma VF and Dan-Syria gave 8.29 and 7.95 tonnes/ha yields respectively. Significantly lowest yield, 4.10 tonnes/ha was obtained from DT97/215A. Dan-Syria had the best shelf life, 77.49% intact fruits at 3 weeks after harvest. Dan-Syria and Roma VF can be recommended for cultivation in the HRAZ.
Evaluation of the relative efficacy of powdered leaf extracts of Aloe vera (Linn) and Aloe schweinfurthii (Baker) in the control of some plant pathogens was undertaken in this work. Antimicrobial activities of the extracts obtained using cold water, hot water and ethanol were tested against four fungal spp., namely, Alternaria solani, Colletotrichum lindemuthianum, Sclerotium rolfsii and Trichophyton rubrum. The phytochemical screening of the leaf extracts of the two aloe species revealed the presence of bioactive compounds such as alkaloids, tannins, saponins, flavonoids, cardiac glycosides, phytates and oxalates. The extracts were observed to exhibit varying inhibitory effects on the selected fungi. Ethanolic extract of A. vera at 50 mg/ml and 100 mg/ml had the greatest impact on A. solani and C. lindemuthianum respectively. Similarly, cold water extract of A. schweinfurthii at 100 mg/ml was the most effective against S. rolfsii and T. rubrum. However, hot water extract of A. vera was least effective against C. lindemuthianum. Also, the efficacy of cold water extract of A. schweinfurthii at 50 mg/ml was very low against T. rubrum and A. solani. The hot water extract of A. schweinfurthii at 20 mg/ml also showed the least effect against S. rolfsii. Consequently, extracts from both Aloe species can be recommended in the management of the four fungal pathogens evaluated in this study. It is hoped that in no distant future, botanical fungicides would be developed from the two Aloe species.
Fusarium wilt is one of the most devastating diseases of cowpea. The pathogen, Fusarium oxysporum f.sp. tracheiphilum is soil and seed-borne. A non-chemical approach was designed for the management of the disease in the present study. Hot water (physical) at three temperatures, 40 50 and 60°C, and Trichoderma viride (biological) at 10 6 spores/ml were evaluated singly and synergistically in the laboratory. The duration of exposure to hot water was 5 min, after which seeds were allowed to cool followed by priming in sterile water (sole hot water treatment) or T. viride (synergistic physical and bio-control) medium in Petri-dishes for 72 h. The control consisted of seed treated with water at ambient temperature, while the standard check was seeds dressed with Mancozeb fungicide. Both were primed in a sterile water medium. Nine treatments were evaluated in all. Germinated seeds were transplanted into plastic pots containing soil infested with F. oxysporum at 10 6 spores/ml in the screen house. The experimental layout was completely randomized design and data collected were subjected to statistical analysis and mean separation. Results showed that seeds treated with 50°C hot water only had the highest germination percentage, 96.66%, and seedling vigour, 460.98. Disease incidence and severity values were least in seeds treated with synergistic hot water at 50°C and priming in T. viride medium. The highest number (77.33) and weight (13.41 g) of seeds were also recorded for the same treatment, while the least, 18 and 3.60 g were obtained from control. Integrated use of hot water (50°C) and bio-priming in T. viride medium can be recommended for use in the management of fusarium wilt disease of cowpea.
The efficacy of Trichoderma harzianum and soil solarization was determined solely and in combination for the management of fusarium wilt and southern blight diseases of tomato. The treatments comprised two concentrations of T. harzianum, (104 and 107 spore/ml), two levels of solarization, (one and two months), and the interaction between solarization and T. harzianum. Formaldehyde, a soil fumigant was the standard check and the control consisted of untreated soil. The causal pathogen of the diseases was separately inoculated at 106 spore/ml into wide surfaced (410mm diameter) plastic pots of 15 liters containing 15kg of soil. Clear transparent polythene of 0.05mm thickness was used to achieve solarization. Local tomato cultivar, Hausa scissors, was the test crop and it was sown in nursery tray on a sterile nutrient-rich soil, irrigated with equal water volume and transplanted after 21 days into the treated soil. The pots were placed in the open field throughout the growing season. The experiment was arranged in a randomized complete block design with three replications for each treatment. Data collected were subjected to statistical analysis and mean separation using Minitab software. The interaction of T. harzianum at 107 spore/ml and two months solarization significantly reduced the incidence and severity index of the two diseases, increased plant growth parameters, yield quality and quantity and enhanced fruit shelf life and may be recommended for the management of fusarium wilt and southern blight diseases of tomatoes than their application as sole management agents.
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