Severity of angular leaf spot and rust diseases on common beans in Central Uganda

  • P Pamela
  • D Mawejje
  • M Ugen
Keywords: Common beans, disease management, Phaseolus vulgaris, Pseudocercospora griseola, Uromyces appendiculatus

Abstract

Angular leaf spot (ALS) and rust are important diseases of common beans (Phaseolus vulgaris L.) in the tropics, causing yield losses of up to 100%. ALS and rust have occurred in farmers’ fields in the tropics for years, but the significance of the two diseases in Uganda is still unknown. In 2010, the incidence and severity of ALS in five bean agro-ecologies within Uganda was between 40-99 and 21-80%, respectively; and that of rust was between 37-69 and 24-44%, respectively. To determine the impact of ALS and rust diseases on the yield of common beans, yield loss trials were established in farmers’ fields in Wakiso and Mpigi districts in central Uganda. Bush bean varieties K132 and ‘Kanyebwa’ were used. Two treatments were applied to each variety; namely: (i) where ALS and rust diseases were controlled through the application the fungicide Orius® (Tebuconazole 250 g L-1), and (ii) control treatment with no disease control. Fungicide treated ‘Kanyebwa’ plants showed the lowest ALS and rust severities in Mpigi district and this was significantly different from all the other treatments. In Wakiso, ALS and rust severities for all fungicide treated plots of both ‘Kanyebwa’ and K132 were significantly lower than that for untreated plots for both varieties. In both districts, the highest disease severities were observed for untreated K132. Marketable yield was significantly influenced by disease severity, with up to 54% yield losses observed in non-treated plots of K132 in the 2012B season where ALS and rust disease severities were 6.9 and 5.3, respectively.

Key words: Common beans, disease management, Phaseolus vulgaris, Pseudocercospora griseolaUromyces appendiculatus

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Articles

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eISSN: 2410-6909
print ISSN: 1026-0919