Recent increased incidences of potato late blight on the Jos Plateau: A case for intercropping

摘要

Potato cultivation on the Jos Plateau is a multi-Billion Naira enterprise which is on the very brink of collapse due to upsurge in the incidences and severity of late blight a disease caused by Phytophtora infestans (Mont) DeBary. This paper highlighted the scope of the spread of this scourge by assessing the magnitude of loses due to the disease in four zones of the potato growing region of the Jos Plateau- Bokkos, Ampang, Heipang and Vwang. The production parameters studied were the land area under potato, average yield, proportion of potato produced through sole/mono cropping, severity of the late blight epidemic and the level of adaptation of the new varieties imported from Europe the Americas and Australia. The results revealed that Bokkos was the most important potato growing area in terms of total land area, adoption of new planting materials, and sole/mono cropping system of production. The incidences and severity of the potato late blight was most serious in Bokkos, followed by Ampang, Heipang and Vwang in that order. The average yield of potato tubers (kg/ha) was highest in Ampang and least in Heipang. A brief view of the weather reports from these areas shows erratic patterns of rainfall and rise in temperature which may be attributed to the general climate change. A major trend observed in the weather report is the increase in early rainfall (March-April) which farmers tend to explore for early planting with severe consequences. The increasing tendency to adopt mono cropping by out growers for the multinational seed and other Agro-based companies was highlighted and the attendant risks involved while making a case for mixed/inter cropping. Other benefits suggested for inter cropping were higher resource use efficiencies, security against total crop lost, reduction in the use of pesticides to control diseases and pests as well as favorable environmental effects like shading, erosion control and suppressing weeds.