Integration of tall cereals and legumes through intercropping plays a pivotal role in reducing the spread of some bacterial, fungal and viral diseases. It does this by inhibiting the disease triangle pattern in groundnut (Arachis hypogaea Linn) production and reducing the landing platform for the pest vectors, ameliorating the soil by enriching it with soluble nitrates available for crops, stabilizing the soil regime, promoting better root and groundnut (Arachis hypogaea Linn) pod development, enhancing better anchorage that withstands flooding, improving water and nutrient absorption, enhancing organic matter content (organic mulches), reducing weeding labor costs and promoting clean field sanitation.
The proposed project will cover nine counties of western Kenya; Bungoma, Busia, Kakamega, Kisumu, Migori, Nandi, Siaya, Trans Nzoia and Vihiga. Six popular groundnut (Arachis hypogaea Linn) varieties of Homabay Red, Local cultivar, Red Valencia, Spanish ICGV-SM 99568, Uganda Red and Virginia CG7 will be identified, and matched to the different counties representing the Lower Midland (LM) and Upper Midland (UM) agro-ecological zones (AEZs). The specified groundnut (Arachis hypogaea Linn) varieties will also be matched to the different tall cereal crops of maize (Zea mays) and sorghum (Sorghum bicolor) grown in those areas. The local communities will be trained on the benefits of intercropping practices.
The procured certified seeds will be freely provided and distributed to the rural communities in local names as a motivation for adoption. Prior to the project, an impact assessment surveillance survey on GRD using questionnaires will be carried out to analyze the possible effects of introducing the new system of cropping against mitigation of rosette disease. This project will practically demonstrate how integrated intercropping systems will enhance the smallholder farmers’ capacity to counter the risks of food and nutritional security in western Kenya. The knowledge of intercropping system will widen the scope and knowledge base of the smallholder farmers’ efficiency, in improving the management and control of the viruliferous groundnut aphid vector Aphis craccivora Koch (Homoptera: Aphididae) which majorly transmits GRD in a polycyclic, persistent and non-propagative manner. Rosette disease is caused by two synergistic viruses; groundnut rosette assistor virus(GRAV, genus Luteovirus)andgroundnut rosette virus(GRV, genus Umbravirus) associated with a satellite-ribonucleic acid (sat-RNA). The distinct predominant symptom types of rosette disease are chlorotic rosette and green rosette which override the isolated occurrence of mosaic rosette in the different AEZs (Figure 1; Figure 2). This technology will help to increase the yield through eliminating the landing platforms of the aphid vectors, enhance soil productivity, nutrient cycling, improve microclimate and water utilization during the dry season.
Materials and Methods: Groundnut fields will be sampled during the short rain season and long rain season in all the selected AEZs; Lower Midland (LM1, LM2, LM3 and LM4) and Upper Midland (UM1 and UM2). The extensive field survey will be done by stopping at regular predetermined intervals of 3-8 KM along motorable roads that traverse each sampling area. The survey will be conducted by walking through groundnut fields, and visually inspecting groundnut crops for rosette symptomatic leaves. Depending on the farm size, quadrants of 10m2 will be estimated, disease incidence and severity will be scored, for each quadrant through random sampling. A disease diagnostic score sheet will be used to record GRD incidence and severity in each farm.
The local communities will be trained on how to integrate the cereal-groundnut project practices and how to diagnose the different symptom types of chlorotic/yellow rosette, green rosette and mosaic rosette. The cereal and groundnut seeds will be freely provided to the rural communities in local names as a motivation and facilitate the understanding on the planting patterns. The farmers will be further trained on alternative techniques for project sustainability, soil fertility improvement and pest and disease control to achieve sustainable crop protection technologies.
Expected output: This project innovation idea will bring a positive social economic impact to the rural community by imparting intercropping skills to improve groundnut crop yield, reduce the Aphis craccivora pest and GRD incidence, improve soil fertility and water retention capacity, provide animal feed hence improve household income, food security, nutritional security and general livelihood.
I am motivated to work on this innovation project because some cultural practices of intercropping to reduce pest and disease incidence have been found to work in many parts of the world, especially the developing world who harness the traditional weeds, pest and disease control/management methods based on the traditional knowledge based systems for sustainable agriculture. Intercropping is environmentally friendly and requires low capital investment and manpower. Having participated in several extensive field survey projects in farmers’ fields on the occurrence, distribution and diversity of groundnut rosette disease (GRD) in western Kenya, I am passionate that this project will succeed. I am interested in scaling up the successes stories of mitigating GRD which has become a unique and fascinating virus disease, whose origin and perpetuation in nature still remains inconclusive in spite of substantial advance in knowledge since it was first documented in 1907 in Tanzania.
Mabele Anthony Simiyu, Kenya