Integrating varietal resistance and phosphonate fungicide in management of foliar late blight in potato

Conventional potato production is not possible without fungicide and the commonly used fungicides are expensive and are considered as environmental and human hazards. The aim of the experiment was to evaluate the efficacy of Phosphonate fungicides, the potential of combination with potato cultivars and economic impact as late blight control alternative. Two Phosphonates formulations; Agrifos 400 and Fosphite were compared Ridomil alternated with Mancozeb on different potato varieties in Kabete and Koibatek. Agrifos 400 alone was compared with Ridomil alternated with Mancozeb on different varieties in Kisima, Njambini and Limuru. Planting was done in 3m×3m plots with four row and 10 tubers per row. Experimental units were replicated three times in a split-plot design. The results showed an effect of Phosphonates, which represent lower risks to human health and environment than conventional fungicides, on control of foliar late blight. In all the five sites Agrifos 400 was not significantly different with Ridomil alternated with Mancozeb in control of foliar late blight in most the varieties used and they were also comparable in yields with no significant differences in most of the sites. Preliminary economic analyses were also done and the result showed that there is more economic benefit in the use of Phosphonate formulation Agrifos 400 compared to conventional fungicides Ridomil and Mancozeb. The study suggests that the relatively inexpensive Phosphonate fungicides have significant potential to become an effective management tool for control of foliar late blight, and can be used as alternative to the hazardous conventional fungicides

Factors influencing performance of seedplot technique in seed potato quality improvement among small scale farmers.

Potato seedborne diseases majorly causes continuous low yields in potato production in East and Central Africa. A small seedplot technology (SSPT) has been developed as a step towards effective management of the seedborne diseases. This was successfully promoted and adapted to varying farming conditions, as a self-sustaining technology for on-farm seed potato production, where disease-free seed is planted at high-density in plots that are apparently free from bacterial wilt. The objectives of the study were to establish the influence of spacing and fertiliser nutrient composition on the performance of small seedplot, and to determine the influence of fertilizer levels on the performance of small seedplot. Trials with 5 potato varieties were conducted in seven locations for three seasons. Different fertiliser types (DAP and NPK) and rates (0, 45, 90 kgNha−1) were used at a spacing of 20×20 cm and 30×30 cm, to optimise management for SSPT. In most locations, tuber numbers were higher with NPK application compared with DAP. When planting in common spacing of 75×30 cm the varieties used in the trials produce about 25 tubers m−1, whereas the SSPT spacings of 20×20 cm and 30×30 cm produced 67 and 54 tubersm−2, respectively. Data was collected on tuber number, size and weight. The results indicated that the spacing of 20×20 cm produced higher tuber number per m2 (51, 71 and 80 at 0, 45 and 90 kgNha−1, respectively) than with a spacing of 30×30 cm (45, 55 and 61 at 0, 45 and 90 kgNha−1, respectively). However, double starter seed is required and handling in planting is more difficult. Moreover, the multiplication rate per tuber was about 20% higher at a spacing of 30×30 cm compared with the spacing of 20×20 cm. Hence, in general if clean land is extremely limited the spacing of 20×20 cm should be chosen to make best use of this part, whereas if clean land is relatively sufficient a spacing of 30×30 cm seems to be more practicable and economically viabl

Roadmap for investment in the seed potato value chain in Eastern Africa

This roadmap describes the five-year strategy in five african countries (Ethiopia, Kenya, Rwanda, Tanzania and Uganda) to target business investments in key areas along the seed potato value chain to increase the availability of high-quality seed potatoes and promote improved seed management. The approaches presented in the rRoadmap are consistent with those laid out in USAID’s comprehensive Feed the Future initiative and are supportive of development themes and programs of other multilateral donors

Seed potato quality improvement through positive selection by smallholder farmers in Kenya

In Kenya, seed potato quality is often a major yield constraint in potato production as smallholder farmers use farm-saved seed without proper management of seed-borne pests and diseases. Farm-saved seed is therefore often highly degenerated. We carried out on-farm research to assess whether farmer-managed positive seed selection could improve yield. Positive selection gave an average yield increase in farmer-managed trials of 34%, corresponding to a 284-€ increase in profit per hectare at an additional production cost of only 6€/ha. Positive selection can be an important alternative and complementary technology to regular seed replacement, especially in the context of imperfect rural economies characterized by high risks of production and insecure markets. It does not require cash investments and is thus accessible for all potato producers. It can also be applied where access to highquality seed is not guaranteed. The technology is also suitable for landraces and not recognized cultivars that cannot be multiplied formally. Finally, the technology fits seamlessly within the seed systems of Sub-Saharan Africa, which are dominated by self-supply and neighbour supply of seed potatoes