ABSTRACT
Cocoa beans are susceptible to fungal contamination during processing and storage. The knowledge of the use of pesticides and post-harvest handling of cocoa beans among farmers is of great importance for safe consumption. The study evaluated common cocoa production and post-harvest practices of farmers in selected study locations in South Western Nigeria. Primary data were collected through the administration of structured questionnaires, and interviews. The collected data were analyzed using inferential descriptive statistics. The results of 394 farmers showed that 52.9 % in Osun and 47.3 % in Oyo were primarily farmers by occupation, the rest had other ventures. The majority of cocoa farmers were men:83.6 % in Oyo State, 88.2 % in Osun state and 87.9 % in Ondo state. 28.6 % and 32.7 % of farmers were aged 51-60 in the Ondo and Oyo communities, respectively. Osun farming communities are dominated by young adults (51 %) of 31-50 years, followed by Ondo 40 % and36 % of farmers in Oyo State. Most cocoa farmers were married with 4-6 children as the most common household size in Osun (51 %), Ondo (60.4 %) and 49.1 % in Oyo State. The literacy level of farmers in cocoa communities was the highest in Oyo state where 47.3 % had tertiary education. Farmers in Oyo State had better knowledge of the dangers of pesticides than Ondo and Osun. However, ignorance of dangers in agrochemicals was higher among Osun farmers than in Ondo State. The highest (18 %) pesticide use during storage was recorded among Oyo farmers, while the least (11.0 %) was recorded among farmers in Ondo State. Pesticide usage was more abundant in Osun (50 %) during cocoa production than in the other study areas. The majority of farmers were positively disposed to make use of nose masks during agrochemical application, meanwhile, 69 %, 62 %, and 61 % of farmers used them already in Oyo, Ondo, and Osun states, respectively. Educational qualification (χ2 = 9.176, p = 0.027) of cocoa farmers was significantly related to knowledge of best practices. Farmers with higher education have a greater ability to receive and process information relating to global best practices in production, postharvest, and pesticide handling in cocoa. In conclusion, cocoa farmers' knowledge of processing, use of pesticides, and storage practices differed from one location to another. Intensive orientation and more enlightenment by extension workers against indiscriminate use of pesticides in cocoa plantations and stores must be consistently and continuously done.
ABSTRACT
A survey of the yam growing areas of Nigeria was conducted in January 1999 to identify the major fungal pathogens responsible for considerable tuber rot losses in storage. A total of 150 tubers of white yam showing rot symptoms were collected from 30 barns at 18 locations spanning three agroecologies (guinea savanna, forest/savanna transition, and forest) within the yam belt of Nigeria. Tuber pieces were cut at the interface between healthy and infected tissue, surface-sterilized in 10% bleach solution (0.05% sodium hypochlorite), rinsed in sterile distilled water, and plated on potato dextrose agar (PDA; Difco Laboratories, Detroit, MI) amended with lactic acid (1ml/liter) to reduce bacterial contamination. Cultures were incubated at 28°C for 4 days. Isolations from the guinea savanna agroecology showed that Nattrassia mangiferae Sutton & Dyko (synonym Hendersonula toruloidea) (3) had 42% frequency of occurence, Botryodiplodia theobromae Pat. (10%), Penicillium oxalicum Curie & Thom. (12%), and Aspergillus niger Tiegh. had 50% frequency of occurrence of the total fungi isolated from this region. In the forest/savanna transition agroecology, N. mangiferae had 28% frequency of occurrence, while B. theobromae, P. oxalicum, and A. niger had 10, 14, and 50% frequency of occurrence, respectively. In the forest agroecology, N. mangiferae and B. theobromae had 6% frequency of occurrence, while P. oxalicum and A. niger had 17 and 72% frequency of occurrence, respectively. N. mangiferae was more frequent in occurrence than the two known major fungal pathogens (B. theobromae and P. oxalicum) of yam tuber in storage. Hence, its pathogenicity was tested on healthy tubers. Fifteen healthy tubers were wounded and inoculated individually with 7-day-old mycelial plugs of each of 10 isolates of N. mangiferae from each agroecology using the cork borer technique (2), placed in polythene bags, and stored in a barn for 14 days at 27± 2°C. Control tubers were inoculated with sterile agar plugs. Tubers were sliced at the points of inoculation, and lesion development was measured. N. mangiferae was found to be pathogenic in yam tubers causing soft, wet, brown rots similar to those observed in natural infections, and it appeared as dark necrotic lesions on tuber surface. In culture however, colonies are fluffy with olivaceous gray coloration that gradually darkens as the fungus matures. The fungus grows rapidly on PDA and is able to attain a radial diameter of 90 mm by the fourth day after inoculation. Cultures reisolated from the inoculated tubers matched those used for inoculation. Isolates obtained from the forest/savanna transition agroecology caused significantly (P < 0.05) larger rot lesions (24.67mm) than those obtained from the guinea savanna (18.33mm), and the forest (21.67mm). In another experiment, tubers were inoculated with N. mangiferae without wounding the tubers (mycelial disks were firmly placed on the tuber surface to make adequate contact), and the control tubers were inoculated with sterile agar plugs. Tubers inoculated without wounding remained asymptomatic when assessed for rot development. N. mangiferae has been reported as a root and stem rot pathogen of cassava in West Africa (1). To our knowledge, this is the first report of N. mangiferae causing tuber rot of yams in storage. References: (1) W. Msikita et al. Plant Dis. 81:1332, 1997. (2) N. Okafor Exp. Agric. 2:179, 1966. (3) B. C. Sutton and B. J. Dyko. Mycol. Res. 93:466, 1989.
