Activity of extracts from three tropical plants towards fungi pathogenic to tomato (Solanum lycopersicum)

Antifungal properties were assessed of water and ethanol extracts from the pan-tropical plants Oxalis barrelieri L., Stachytarpheta cayennensis L., and Euphorbia hirta L. against Fusarium oxysporum f. sp. vasinfectum, Alternaria solani Sorauer, and Rhizoctonia solani Kuhn. The plant extracts inhibited fungal growth in vitro at 1.25-20 mg mL-1, and the degrees of inhibition increased in a dose-dependent manner. Ethanol extracts from the plants inhibited fungal growth by 80-100%, while water extracts showed less antifungal activity, with maximum growth inhibition of 62%. Growth inhibition from ethanol extracts was two- to three-fold greater than for water extracts at equivalent concentrations. Antifungal activity of the extracts varied with their content and composition of phenolics, flavonoids, tannins, and alkaloids. In greenhouse experiments, spraying tomato plants (Solanum lycopersicum L.) with ethanol extract from E. hirta at 2.5 mg mL-1 did not cause phytotoxicity, and increased plant size, when compared to untreated plants. Spraying E. hirta ethanol extract on tomato plants infected by R. solani reduced disease severity up to 80%, when compared to non-sprayed plants. These results demonstrate potential of leaf extracts from E. hirta, O. barrelieri, and S. cayennensis as biofungicides for the control of R. solani, A. solani, and F. oxysporum, which are among the most important causal agents of tomato diseases

Antifungal potential of extracts from three plants against two major pathogens of celery (apium graveolens l.) in Cameroon

With the aim of contributing to natural control of plant pathogens, the antifungal activity of 11 extracts from 3 Cameroonian plants namely, Drypetes gossweileri, Eucalyptus tereticornis and Sida acuta was evaluated against Acremonium apii and Colletotrichum dematium, respectively causal agents of brown spot and anthracnose diseases of celery (Apium graveolens L.). The supplemented media technique was used to assess the inhibition of both fungi mycelial growth by essential oils, ethanol,hot water and cold water extracts. The essential oils exhibited the highest antifungal activity at 50 ppm with essential oil from D. gossweileri; and 6000 ppm and 7000 ppm, against C. dematium and A. apii, respectively, with essential oil from E. tereticornis. Ethanol and aqueous extracts displayed a moderate inhibitory activity with the best activity obtained from D. gossweileri ethanol extracts (90.31% and 67.53%, respectively, against A. apii and C. dematium at 10000 ppm). The fungitoxic potential of essential oils was comparative to the synthetic fungicide used as positive control. Phytochemical screening of solvent extracts revealed a diverse composition in secondary metabolites and stronger inhibitory effects were recorded with extracts rich in alkaloids, phenols, anthraquinones and saponines. These findings suggest a promising potential of essential oils and ethanol extracts for botanicals control of celery fungal pathogens

The Potential of Cassava (Manihot esculenta Crantz) Peels as an Organic Fertilizer

Cassava peels are in large quantity and practically of no economic value in many developing nations such as Cameroon, where cassava is widely consumed and processed far beyond other crops. Cassava peels might be used in those countries to face declining soil fertility and soil erosion. This study aimed to evaluate the composting of cassava peels and the effect of the increasing quantity of cassava peels in the bin during the process of composting and to assess some physico-chemical qualities, biological properties and the phytotoxicity of the produced composts. After three months of composting the produced composts (C1; C2; C3 and C4)  had a dark brown color, relatively dry, uniform structure and its texture were similar to the soil's texture. The electrical conductivity of the various composts was in between 1499 and 1924 µS.cm-1. The pH (6.50-6.73), was slightly acid, favorable for the cultivation of sweet pepper. The composts were rich in minerals (Mg2+; Ca2+; K+; and Na+) and poor in heavy metals such as (Cu, Zn and Mn). The composts C/N ratios were between 13.15 to 13.42. The produced composts showed a germination index and the rate of germination higher than 80% at all amounts, indicating the absence of phytotoxicity. The increased amounts of cassava peels did not alter the process of composting and increased the fungal and bacterial populations. In conclusion, cassava peels are good substrates that can be used to produce stable and inclusive organic fertilizers, with high nutrient content, and less hazardous material which could be used in farms to remediate declining soil fertility and to promote sustainable agriculture

The Cultivation of Sweet Pepper (Capsicum Annuum) in Foumbot Agricultural Area, West Region, Cameroon

This study aimed to get information on the cultivation of sweet pepper from the North West Region of Cameroon (Foumbot).  Data for the study were obtained from 92 farmers with the aid of well-structured questionnaires. Results obtained showed that among the sweet pepper farmers, males represented 80% of the sampled population and women 12%, all of them aged between 18 to 48 years old. Their level of education varies from primary school to University with the majority found between primary school (48%) and secondary school (30%).  41% of the sampled cultivators have the greatest level of experience in between 10 to 30 years and 52% with the lowest level of experience varying from 1 to 10 years. The sweetest pepper varieties cultivated was Yolo wonder and Simba. 89 % of respondents had a sweet pepper field with a surface area between 0.5 and 1 hectare.  According to farmers, the nursery is usually attacked by fungi after one week of growth, which always cause stems rot.  Fungicides (Mancostar 80WP) and insecticides (Mocap EC, Timik, Plantineb 80WP, Jumper and Ascot) are the most chemical products used to treat stems rot. Cypermethrin and Mancozeb represent respectively 63% and 85% of active ingredients used by the sampled growers to fight against sweet pepper diseases.  46 % of the sampled farmers said that they prefer spray pesticides in all stages while 44% of sweet pepper farmers did not take note of the number of times, they applied chemicals pesticides on their crops. NPK: 20.10.10 is the most chemical fertilizer used to grow sweet pepper. The major diseases and pests encountered in that region are (1) diseases: Mildew, cercospora leaf spot, phytophthora blight, fusarium wilt, anthracnose, ripe rot, tobacco mosaic virus, cucumber mosaic virus, and gal formations; (2) pests: flee beetles, cutworms, aphids, vegetable weevil, caterpillars, grasshoppers, pepper maggots and leaf miners