Sorghum diseases and their management in cultivation: seedling, seed, panicle and foliar diseases (original) (raw)

2018, Burleigh Dodds series in agricultural science

A survey was conducted in 2014 to determine the prevalence of fungal diseases on sorghum across different agroecological zones in Tanzania and Uganda. In Tanzania, 37 sorghum fields were sampled in Dodoma and Singida Provinces, representing the central drier areas, and in Simiyu, Shinyanga, Mwanza, and Mara Provinces, representing the lake-zone region. In Uganda, 134 fields were sampled across four agroecological zones of Teso, Western, Northern, and West Nile. Farmers were purposively selected, and at least 30 plants per field along two diagonal transects were visually assessed for disease. Ten and 14 diseases were identified in Tanzania and Uganda, respectively. Among the major diseases identified, those more prevalent in Tanzania than in Uganda were leaf blight caused by Setosphaeria turcica (P = 0.0031) and rust caused by Puccinia purpurea (P < 0.0001). Major diseases more prevalent in Uganda than in Tanzania were anthracnose caused by Colletotrichum sublineola (P = 0.0207) and zonate leaf spot caused by Gloeocercospora sorghi (P = 0.0312). We report for the first time the occurrence of ladder leaf spot caused by Cercospora fusimaculans in Uganda and confirm its occurrence in Tanzania. This is the first comprehensive sorghum disease survey report in over 15 years in both countries. Sorghum (Sorghum bicolor L.) is an important crop utilized for food and brewing alcohol in Tanzania and Uganda. In Tanzania, the crop is mainly grown in Dodoma, Singida, Shinyanga, Mwanza, and Mara Provinces, which fall in the central, western, and lakezone regions of the country (Monyo et al. 2004; Rowhani et al. 2011). Improved varieties such as Lulu, Pato, Macia, Serena, and Tegemeo are liked by farmers, who cite early maturity and drought tolerance as important traits (Monyo et al. 2004); however, landraces are still planted (Table 1). Interestingly, over the past few years, the net change of area under production and the annual production have both increased (by 4.6 and 1.6%, respectively); however, yield gains over the same period have reduced by 2.9% (FAO 2015), probably owing to increased biotic and abiotic stresses. Between 2010 and 2013, the total production of sorghum in Tanzania ranged from 798,000 metric tons to a high of 838,000 metric tons in 2012 (FAO 2015). In Uganda, sorghum, the third most important cereal food crop, is grown across five agroecological zones: Teso, Western, Northern, West Nile, and the South West highlands (Ebiyau et al. 2005). Both local (i.e., Akindi and Dura) and improved varieties (i.e., Seso1 and Gadam) are also grown in Uganda (Table 1). Recent crop production statistics indicate that production of sorghum in Uganda peaked in 2011 at 437,000 metric tons but dropped to 300,000 metric tons in 2013. Productivity also dropped from 1.2 metric tons/ ha in 2011 to 854 kg/ha in 2013. Importantly, unlike in Tanzania, TABLE 1 Varieties and landraces of sorghum identified in the field during the survey in Tanzania and Uganda Country, agroecological zone Varieties or landraces