Evaluation of Insecticides for the Management of Insect Pests of Tomato, Solanum Lycopersicon L.

Field studies were undertaken in Kumasi, Ghana in 2012 and 2013 to evaluate the efficacy of two insecticides i.e. Lambda Super 2.5 EC (a.i- lambda cyhalothrion) and Cymethoate Super EC (a. i.-cypermethrin and cymethoate) for the management of insect pests on tomato, Solanum lycopersicum L. Lambda Super was applied at 1.5 ml/0.5 L of water whilst Cymethoate Super was applied at 0.25 ml/0.5 L of water. A control plot (water application only) was also maintained. Whiteflies, Bemisia tabaci (Gennadius), thrips, Thrips tabaci Lindeman, aphids, Aphis gossypii (Glover), leaf miners, Liriomyza sp. and the tomato fruit worm, Helicoverpa armigera (Hubner) were the most important insect pests collected on tomato in the area. In 2012, there were no significant differences among the insecticide-treated plots and the control with respect to the densities of B. tabaci, A. gossypii, Liriomyza sp. and H. armigera. Cymethoate Super treated plots recorded significantly lower number of T. tabaci than the control plots. However, in 2013, the control plots recorded significantly more aggregations of B. tabaci, H. armigera and A. gossypii than the Lambda Super and Cymethoate Super treated plots. No significant differences were obtained in the numbers of Liriomyza sp. and T. tabaci among the treatments. In 2012, the insecticide-treated plots recorded significantly higher fruit yield than the control but there were no significant differences among the treatments with respect to percent damaged fruits and mean shoot dry weight in 2013. Lambda Super and Cymethoate Super can be used to manage insect pests on tomato for increased yield. Keywords: Insecticides, efficacy, tomato pests, population densities, yiel

Farmers’ Perception and Farming Practices on the Effect of Early and Late Leaf Spots on Groundnut Production in Northern Ghana

Groundnut (Arachis hypogaea L.) is an important crop both in subsistence and commercial agriculture in Ghana. Early leaf spot (Cercospora arachidicola) and late leaf spot (Phaeoisariopsis personata) are major limiting factors to groundnut productivity in Ghana. The objective of the study was to appraise farmers’ perception of the disease and effect of the cropping system on the incidence and severity of the disease. A disease-based questionnaire was administered to 100 farmers in their local language spread across 10 villages and towns selected from Tamale, Tolon-Kunbungu and Savelugu-Nanton Districts, all in the Northern Region of Ghana. The responses of the farmers showed that Cercospora leaf spot (ELS and LLS) was perceived by the farmers as one of the major constraints to groundnut production in the area to which farmers have no solution. The severity of the disease was dependent on the cropping system adopted by the farmers. The variety Chinese turned out to be the most important commercial cultivar grown by farmers but it is susceptible to both diseases. Keywords: leaf spot,  Phaeoisariopsis personata, Cercospora, groundnut, diseas

Nematode distribution in cultivated and undisturbed soils of Guinea Savannah and Semi-deciduous Forest zones of Ghana

Climate change affects air temperature, sea levels as well as the soil and its ecosystem. The Guinea Savannah and Semi-deciduous Forest zones of Ghana are characterized by different climatic conditions and vegetative cover. Annual average temperature has been steadily increasing whilst annual total rainfall has been decreasing in both zones, and this has been causing a southward shift of the Savannah into the Forest zone. Soil organisms provide crucial ecosystem services which are required for sustainable agriculture and food production yet crop cultivation disturbs the soil ecosystem. The harsh conditions associated with the Savannah further expose the soil ecosystem to disturbance and loss of biodiversity which threatens food production and security. Soil nematodes are the most abundant animals in the soil and play a central and critical role in the soil food web complex. Studying the nematode community structure gives a reflection of the status of the entire soil ecosystem. Soil samples were taken from cultivated and natural landscapes in the Guinea Savannah and Semi-deciduous Forest agroecological zones to analyse the nematode community. Results from the study showed the Guinea Savannah zone recording warmer soil temperatures, lower organic matter percentage and lower nematode diversity (Genus Richness) as compared to the Semi-deciduous Forest zone. If the Savannah continues to shift southward, the Forest zone soil ecosystem risks disturbance and loss of biodiversity due to the harsh Savannah conditions. Our findings indicate that prevailing crop cultivation practices also disturb soil ecosystem in the two ecological zones which span across West Africa. A disturbed soil ecosystem endangers the future of food production and food security. Keywords: Climate change, Guinea Savannah, Semi-deciduous Forest, Soil temperature, Soil nematode diversit

Seed transmission of BCMV-BICM threaten cowpea seed health in the Ashanti and Brong-Ahafo regions of Ghana: BCMV-BICM threaten cowpea seed health in the Ashanti and Brong-Ahafo regions of Ghana.

Antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the presence and seed transmissibility of bean common mosaic virus-blackeye cowpea mosaic (BCMV-BICM) in farm- retained cowpea seed lots obtained from 46 locations, including markets and farms in major cowpea growing areas in the Ashanti and Brong Ahafo regions of Ghana. In the growout tests, virus symptomatic plants were observed in seedlings of 19 of the 46 seed lots tested under insect-proof screen-house conditions. All the symptomatic plants tested positive to polyclonal antiserum raised against BCMV-BICM in ACP-ELISA. The seed transmission rates based on symptoms ranged from 0 to 37.8 %. RT-PCR with primer pair designed to amplify the potyvirus Cylindrical Inclusion (CI) region resulted in an expected 720 bp DNA segment in 19 seed lots as a further confirmation of virus in the seed lots. The remaining 27 lots were asymptomatic and tested negative to BCMV-BlCM in both ACP-ELISA and RTPCR. The findings of this study revealed seed as the source of primary inoculum in the farmers’ fields and may aid in the implementation of control strategies such as discouraging farmers from retaining their own seeds for subsequent sowing and encouraging them to take appropriate measures in obtaining virus-free cowpea seeds from other sources

Seed transmission of BCMV-BICM threaten cowpea seed health in the Ashanti and Brong-Ahafo regions of Ghana

Antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the presence and seed transmissibility of bean common mosaic virus-blackeye cowpea mosaic (BCMV-BICM) in farm- retained cowpea seed lots obtained from 46 locations, including markets and farms in major cowpea growing areas in the Ashanti and Brong Ahafo regions of Ghana. In the growout tests, virus symptomatic plants were observed in seedlings of 19 of the 46 seed lots tested under insect-proof screen-house conditions. All the symptomatic plants tested positive to polyclonal antiserum raised against BCMV-BICM in ACP-ELISA. The seed transmission rates based on symptoms ranged from 0 to 37.8 %. RT-PCR with primer pair designed to amplify the potyvirus Cylindrical Inclusion (CI) region resulted in an expected 720 bp DNA segment in 19 seed lots as a further confirmation of virus in the seed lots. The remaining 27 lots were asymptomatic and tested negative to BCMV-BlCM in both ACP-ELISA and RTPCR. The findings of this study revealed seed as the source of primary inoculum in the farmers’ fields and may aid in the implementation of control strategies such as discouraging farmers from retaining their own seeds for subsequent sowing and encouraging them to take appropriate measures in obtaining virus-free cowpea seeds from other sources

Nematode Community-Based Soil Food Web Analysis of Ferralsol, Lithosol and Nitosol Soil Groups in Ghana, Kenya and Malawi Reveals Distinct Soil Health Degradations

Determining if the vast soil health degradations across the seven major soil groups (orders) of Sub-Saharan Africa (SSA) can be managed on the basis of a one-size-fits-all or location-specific approach is limited by a lack of soil group-based understanding of soil health degradations. We used the relationship between changes in nematode population dynamics relative to food and reproduction (enrichment, EI) and resistance to disturbance (structure, SI) indices to characterize the soil food web (SFW) and soil health conditions of Ferralsol, Lithosol and Nitosol soil groups in Ghana, Kenya and Malawi. We applied bivariate correlations of EI, SI, soil pH, soil organic carbon (SOC), and texture (sand, silt and clay) to identify integrated indicator parameters, and principal component analysis (PCA) to determine how all measured parameters, soil groups, and countries align. A total of 512 georeferenced soil samples from disturbed (agricultural) and undisturbed (natural vegetation) landscapes were analyzed. Nematode trophic group abundance was low and varied by soil group, landscape and country. The resource-limited and degraded SFW conditions separated by soil groups and by country. EI and SI correlation with SOC varied by landscape, soil group or country. PCA alignment showed separation of soil groups within and across countries. The study developed the first biophysicochemical proof-of-concept that the soil groups need to be treated separately when formulating scalable soil health management strategies in SSA