Chemical characterization of an aqueous extract and the essential oil of Tithonia diversifolia and their biocontrol activity against seed-borne pathogens of rice.

The high cost of chemical pesticides and their negative impact on the environment prompted the search for natural pesticides from plants. The objective of our study was to control rice seed pathogenic fungi and bacteria using aqueous extract and essential oil from Tithonia diversifolia leaves. We obtained aqueous extract and essential oil, respectively, by maceration and hydrodistillation; the antimicrobial activities were determined in vitro on a solid medium by the food poisoning method. The secondary metabolites were determined by qualitative and quantitative assays; the chemical composition of the essential oil obtained from Titonia diversifolia was studied using gas-chromatography coupled with mass spectrometry. The results showed that phenols, tannins, flavonoids, alkaloids, terpenoids, sugars and saponins were present in the aqueous extract. The essential oil contained mainly hydrocarbonated, oxygenated monoterpenes, terpenoids and sesquiterpenes. α-terpineol (20.3%), eucalyptol (14.6%), camphor (14.3%) and α-pinene (13.5%) as the main compounds. Regarding the antimicrobial activity, all tested bacteria were sensitive to aqueous extract and essential oil. The activity of the aqueous extract on the tested fungi showed an inhibitory concentration 50 (IC50) of 50 mg/mL against Bipolaris oryzae and Fusarium moniliforme. The activity of the essential oil on bacteria and fungi showed MIC of 125 μg/mL (Xanthomonas oryzae pv. oryzae and Pseudomonas fuscovaginae) and MFC of 5000 μg/mL (Bipolaris oryzae and Fusarium moniliforme). These results allow us to consider Tithonia diversifolia as a potential source of natural biopesticides against rice seed-borne pathogens

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