Needs assessment of cowpea production practices, constraints and utilization in South Africa

Cowpea is an important grain legume. Research and production of cowpea have been neglected in South Africa in the last three decades due to lack of funding and interest of researchers to work on the improvement of the crop. The consequence of these are that cultivated varieties are unimproved and the lack of knowledge of good agronomic practices worsen the limitations to cowpea production. In order to ascertain the extent of these problems and determine the needs of farmers, a baseline survey was conducted among cowpea production provinces of South Africa (Limpopo, Kwazulu-Natal and Mpumalanga) between 2004 and 2006 cropping seasons. Questionnaires were administered among farmers in co-operative societies. Data were collected on cropping systems, cultural practices, yield levels, constraints to production and utilization. Responses obtained from farmers were analysed using non-parametric or descriptive statistics. The data was summarised into averages, percentages or ranges. Results identified major production practices, importance and constraints to cowpea production in the provinces. The results form a useful pathway for needs towards the development of well-tailored breeding objectives to improve cowpea production in South Africa

The impact of phosphate fertilizer as a pest management tactic in four cowpea varieties

Insect pests constitute serious threat to cowpea production in sub-Saharan Africa. In some severe situations, total yield loss results. Chemical control, although most effective, is very costly, hazardous and unsustainable. Investigation of other control options such as cultural practices that areenvironment friendly is critically important. This paper reports the effects of four levels of phosphorus fertilizer application (0, 15, 30 and 45 kg P2O5 ha-1) on insect population, damage and grain yield of four cowpea varieties (IT91K-180, IT95M-118, TVu 1890 and Vita 7) planted at research farm of International Institute of Tropical Agriculture (IITA), Nigeria. Data were collected on insect counts, pod evaluation index and damage by Aphis craccivora, Megalurothrips sjostedti, Maruca vitrata and pod-sucking bugs.Results indicated that damage by A. craccivora, M. sjostedti and M. vitrata were significantly (P < 0.05) lower at 30 and 45 kg P2O5 ha-1 and consequently higher grain yields were obtained

Effects of insecticide spray application on insect pest infestation and yield of cowpea [Vigna unguiculata (L.) Walp.] in the Transkei, South Africa

Field studies were conducted during the 2008 - 2009 cropping season to determine the minimal insecticide application which can reduce cowpea yield losses on the field due to insect pest infestations in the Transkei region of South Africa. Treatments consisted of five cowpea varieties andfour regimes of insecticide spray which were laid out with a split-plot experimental design with four replications. Observations were taken on the incidence of major insect pests, cowpea pod and seed damage by insects as well as growth and yield parameters of the cowpea varieties. Results showed that spray regimes had significant effects on insect population counts, pod and seed damage and consequently on cowpea yield parameters. Application of insecticide once each at flower budding andearly podding significantly reduced pod borers and pod-sucking bugs infestations by 44 and 56%, respectively, compared to the untreated control. Application of insecticide, once at flower budding, early podding and pod filling significantly reduced pod and seed damage, resulting in substantial increase in number of pods, pod weight and seed weight per plant, and also number of seeds per pod of cowpea compared to the untreated control. This study provides information on the incidence ofmajor insect pests of cowpea as well as the minimum insecticide control intervention necessary for effectively reducing cowpea yield losses on the field. Two insecticide spray regimes (once at flowering and podding) significantly reduced insect population and damage of cowpea

Annual cycle of the legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) in southwestern Burkina Faso

Maruca vitrata is an economically significant insect pest of cowpea in sub-Saharan Africa. Understanding the seasonal population patterns of M. vitrata is essential for the establishment of effective pest management strategies. M. vitrata larval populations on cultivated cowpea and adult flying activities were monitored in addition to scouting for host plants and parasitoids during 2 consecutive years in 2010 and 2011 in southwestern Burkina Faso. Our data suggest that M. vitrata populations overlapped on cultivated cowpea and alternate host plants during the rainy season. During the cowpea off-season, M. vitrata maintained a permanent population on the wild host plants Mucuna poggei and Daniella oliveri. The parasitoid fauna include three species, Phanerotoma leucobasis Kri., Braunsia kriegeri End. and Bracon sp. Implications of these finding for pest management strategies are discussed

An assessment of the risk of Bt-cowpea to non-target organisms in West Africa

Cowpea (Vigna unguiculata Walp.) is the most economically important legume crop in arid regions of sub-Saharan Africa. Cowpea is grown primarily by subsistence farmers who consume the leaves, pods and grain on farm or sell grain in local markets. Processed cowpea foods such as akara (a deep-fat fried fritter) are popular in the rapidly expanding urban areas. Demand far exceeds production due, in part, to a variety of insect pests including, in particular, the lepidopteran legume pod borer (LPB) Maruca vitrata. Genetically engineered Bt-cowpea, based on cry1Ab (Event 709) and cry2Ab transgenes, is being developed for use in sub-Saharan Africa to address losses from the LBP. Before environmental release of transgenic cowpeas, the Bt Cry proteins they express need to be assessed for potential effects on non-target organisms, particularly arthropods. Presented here is an assessment of the potential effects of those Cry proteins expressed in cowpea for control of LPB. Based on the history of safe use of Bt proteins, as well as the fauna associated with cultivated and wild cowpea in sub-Saharan Africa results indicate negligible effects on non-target organisms

Insect mediated outcrossing and geneflow in cowpea (Vigna unguiculata (L.) Walp): Implication for seed production and provision of containment structures for genetically transformed cowpea

Insect mediated out-crossing poses a lot of problems in plant breeding and seed production by creating unwanted genotypes or off-types in the field including mixtures in seed lots. Removal of off-types in thefield or seed lots increases costs of production. Information on level of out-crossing in cowpea and its insect pollinators as well as associated pollen movement would be useful in developing strategies to reduce outcrossing related problems. The objectives of this paper were to identify insect pollinators of cowpea, determine the level of outcrossing in the crop, and its implications in the deployment of genetically transformed cowpeas. Two experiments were conducted in Nigeria (IITA Ibadan and Mokwa) and Benin Republic (Cotonou) to assess geneflow frequency in cowpea under different planting arrangements. The first experiment was to quantify level of insect mediated out-crossing when three cowpea varieties (IT95K-1491, Sanzi, and IT86D-719) were respectively planted in alternate rows (onemetre apart) with IT95K-1093-5. The second was to assess the level of insect mediated outcrossing when IT95K-1491, a breeding line with morphological marker (anthocyanin pigment), was planted in 3 -4 concentric inner rows of 1 m apart while IT95K-1093-5 was planted in outer concentric rows up to 16 m from the epicenter. Incidence of insects visiting the plots was taken during the flowering stage of thecrop. During harvesting, pods of IT95K-1093-5 were harvested from every plant within 3 - 4 m length along north, south, west and east axes of each concentric circle. In the case of alternate row planting,pods from single plants were harvested from rows of IT95K-1093-5 of each pair. Seeds derived from these plants (IT95K-1093-5) were planted in the field in order to assess the level of outcrossing thatresulted from the movement of pollens from IT95K-1491, Sanzi, and IT86D-719 onto IT95K-1093-5 in the case of alternate row planting and IT95K-1491 onto IT95K-1093-5 for the concentric planting. Percentage of hybrids bearing the morphological trait of the marker parent was determined. Results obtained showed that level of out crossing was higher (0.5 to 0.85%) when cowpea was planted in alternate rows than in concentric rows (0.01 to 0.13%). Outcrossing was found to have occurred in a random fashion beyond 13 m. Among the insects observed, only honey and bumble bees were found with cowpea pollen dusts on their legs and abdomens, and were responsible for the observed level of outcrossing