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Banana Xanthomonas wilt was reported in Rwanda in 2005. The present study was conducted to determine the distribution and incidence of the disease and farmer knowledge of disease symptoms, modes of spread and control. A survey was conducted in Rwanda in 2009-2010 in 12 major banana-growing districts of the country. One hundred and eight banana growers were interviewed using a structured questionnaire. Farmers were asked about knowledge of disease symptoms, spread, control and use of control methods. They were also asked about their sources of information on Xanthomonas wilt. Direct field observations were made of the distribution and incidence of the disease as well. The proportion of fields with Xanthomonas wilt was highest in Rutsiro (89%) and lowest in Kayonza and Ruhango (11%). The disease was not found in Gakenke, Kicukiro or Ngoma. Within-farm incidence was highest in Rutsiro (average 36%) and lowest in Kayonza (1%). The awareness of disease symptoms ranged from 53% (discoloured fruit pulp) to 84% (wilting leaves). For modes of spread, the highest proportion of farmers (73%) was aware of the role of contaminated tools while the least known mode was spread via soil and water (24%). Some 72% of famers were aware of uprooting plants as a control measure. There were large differences between awareness and use of tool disinfection and destruction of infected plants as control measures. There is a need to develop user-friendly methods of disease control. The creation of awareness in newly affected and Xanthomonas wilt-free areas is advocated. Participatory approaches are encouraged as they may reduce the gap between knowledge and adoption of control measures.

Abs tract. Twenty-six cowpea lines were field evaluated for resistance to Xanthomonas campestris pv vignicola for two seasons in two locations of Uganda following artificial inoculation. Disease development varied significantly (P=0.001) with the cowpea lines in both locations, and higher disease incidence was observed during the first rains than in second rains. The genotype-by-environment interaction was, however, non-significant during the two seasons. During the first rains, the highest disease incidences (54.96%) and (54.53%) were recorded in the lines IT82E-12 and SLA 59, respectively. During the second rains, however, the highest disease incidence (65.85%) was recorded in the line Ife Brown. Based on AUDP C values, lines were grouped into four categories, i.e. resistant, moderately resistant, moderately susceptible and susceptible. The lines IV 1075 and Icirikukwai were consistently classified as resistant in both seasons.

Anthracnose is a serious disease affecting dry bean production especially in the cool highland areas worldwide. The objective of this research was to study the inheritance of anthracnose resistance in market-class dry beans. A complete diallel set of crosses was generated from nine diverse parents comprising six resistant and three susceptible to anthracnose. The F 1 and F 2 crosses and parents were artificially inoculated with Colletotriclum lindenumthianum Race-767 in a growth room. There was significant variation for anthracnose resistance among genotypes. General combining ability (GCA) and specific combining ability effects were significant for resistance, indicating importance of both additive and non-additive effects, respectively. Preponderance of GCA effects (66%) suggested that additive effects were more important than non-additive effects (24%), which were also reflected by high heritability estimates (70%), and suggested that simple selection or backcrossing would be useful for improving the resistance in market class varieties. The study was not conclusive on whether epistatic gene action played a major role, but if available it might have biased the dominance gene effects. Reciprocal effects (10%) were not significant (P [ 0.05), suggesting that cytoplasmic genes did not play a major role in modifying anthracnose resistance. Parental lines G2333, AB136, NAT002, and NAT003 showed highly negative GCA effects qualifying them as suitable parents for transferring resistance genes to their progenies. A few major genes, 1-3, displaying partial dominance conditioned anthracnose resistance, suggesting a possibility of using marker-assisted selection to improve anthracnose resistance in market-class dry beans.