Prior on-station research showed that sowing dates, sowing density and applications of fungicide and phosphorus (P) increased groundnut (Arachis hypogaea) pod yield by 60-80%. Farmer-managed trials were conducted in the Wa district of the Upper West Region of Ghana from 2004 to 2007 to test the yield response to sowing density, fungicide and P and to assess economic returns of these technologies to farmers. Treatments included: an early maturing groundnut cultivar, Chinese, sown at farmers' density (5-8 plant m −2 ) without fungicide and without P application (T1, control), with fungicide sprays alone (T2), or with fungicide and P application (T3), cultivar Chinese sown at recommended (higher) density (20 plant m −2 ) with fungicide and P application (T4), and a full season cultivar, Manipinter, with fungicide and P application (T5). Soil fertility, sowing density, days from sowing to first weeding, incidence and severity of leaf-spot disease and plant population at final harvest were recorded. Relative to farmers' practice, pod yield of cultivar Chinese was significantly increased by 80% with fungicide sprays alone, 108% with fungicide and P application, and 113% with fungicide and P application at higher sowing density. Cultivar Manipinter treated with fungicide and P gave 107% increase in pod yield relative to farmers' practice. Correlation and stepwise regression analyses suggested that major determinants of groundnut pod yield in farmers' fields were plant density, leaf-spot disease and P availability. The increase in yield with fungicide and P application translated into a 4-5-fold increase in gross margin for farmers in the region. Returns to labour and labour productivity were doubled with combined use of fungicide and P fertilizer.

SU MMARYGroundnut or peanut (Arachis hypogaea L.) is a valuable food and forage crop in West Africa. It is important to determine yield-limiting factors and to develop suitable management practices to improve groundnut productivity. The objective of the present research was to determine the influence of fungicide application at different sowing densities on growth, biomass and yield of early and late maturing groundnut under rainfed conditions. Two groundnut cultivars (Chinese, 90 days duration and Manipinter, 120 days duration) were grown at low (8 plants/m 2 ), medium (12 plants/m 2 ) and high density (20 plants/m 2 ), with and without fungicide application, for two growing seasons (2004 and 2005). Data on leaf area index (LAI), light interception (LI) and total biomass were measured at different stages of crop development. Haulm (stem and leaf), pod and seed yields were measured at maturity. Fungicide application increased LAI, LI and total biomass of both cultivars from 65 days after sowing (DAS) until maturity. Fungicide application significantly increased pod and seed yields by 95 and 103 %, respectively, on average. In both years, the long duration cultivar Manipinter had significantly greater LAI, LI and total biomass at later stages of crop development when compared with the short-duration cultivar Chinese. The growth and yield of both cultivars were significantly less at the lowest population density when compared with medium or high population densities. There was no significant difference between medium and high population densities in haulm, pod and seed yield at maturity. It is concluded that sowing a long-duration cultivar at a density of 12 plants/m 2 with fungicide application significantly improved groundnut yields under rainfed conditions in Ghana.

No abstract

SUMMARYLarvae of bollworms (Helicoverpa armigera (Hubner), Earias sp., Diparopsis watersii (Rothschild) and Pectinophora gossypiella (Saunders)) feed on cotton flower buds (squares) and developing bolls causing severe yield losses. While endosulfan, an organochlorine insecticide was the most effective and widely used insecticide for bollworm control in Ghana, it has been banned due to abuse and hazard to the environment. Field experiments were conducted during the rainy seasons of 2012 and 2013 to determine the efficacy of foliar insecticides tihan (spirotetramat + flubendiamide), thunder (imidacloprid + betacyfluthrin), belt expert (flubendiamide +thiaclopride), dursban 4EC (chlorpyrifos-ethyl), lambda super 2.5EC (lambda cyhalothrin) and polytrin C (profenophos + cypermethrin) for control of bollworms and their impact on non-target beneficial organisms in Ghana. All the insecticides tested lowered bollworm densities and boll damage but applications of tihan or belt expert alternated with thunder resulted in the highest seed cotton yield. The treatments generally did not lower populations of predators such as ladybird beetles and lacewings and could be included in an integrated pest management programme for bollworms in cotton. These results suggest that alternate applications of tihan or belt expert with thunder can be recommended as a replacement for endosulfan for control of cotton bollworms and improvement of cotton yield in Ghana.

Participatory diagnostic farmer field fora (FFF) were conducted at two communities, Savelugu and Bukpomo, in northern Ghana to build the capacity of farmers on integrated pest management in cowpea production. The FFF involved a season-long comparative evaluation of farmers' practices (FP) and integrated pest management (IPM). Farmers' practices relied wholly on calendar insecticide sprays while IPM plots employed proven agronomic practices and treatment with neem (Azadirachta indica A. Juss) extract for insect pest control. Results showed that insect pest densities (Flower thrips, Megalurothrips sjostedti Trybom and pod-sucking bugs' for example, Clavigralla tomentosicollis Stal.) and percent damaged pods as well as grain yield were similar in FP and IPM plots at both Savelugu and Bukpomo. Partial budget analysis showed positive returns to investment in IPM and a near loss in FP. Post training ballot box test showed that 80% of the farmer participants across locations showed improved knowledge and skills in IPM after the training compared with about 30% before the training. An ancillary study to the FFF was conducted to expose the farmers to different cowpea genotypes in a participatory variety selection trial. Results showed that some of the genotypes selected by farmers as their most preferred genotypes at the vegetative stage were also selected at the podding stage but there were no significant correlations between these farmer preferences and yield. These findings are discussed in the context of sustainable cowpea production through farmer empowerment and involvement in technology generation and dissemination.

No abstract