Sugar Cane Whip Smut (Sporisorium scitamineum Syd) Caused Field Sucrose and Juice Quality Losses of Two Sugar Cane Varieties in Nigeria

Two sugar cane varieties were evaluated in a split plot design experiment at Badeggi (lat.9°045'N; long 6o07'E at an altitude of 70.57 m.a.s.l) with four whip smut (Sporisorium scitamineum) inoculum concentrations 0 x 106, 2 x 106, 4 x 106 and 6 x 106 teliospores/ml in four replicates between 1998 and 2000. The field sucrose production (% brix) was measured with a hand refractometer by using the stalks of five tagged healthy and smutted canes which were individually punched and a drop of the juice from each of them placed on the hand refractometer and covered. This was then held against the sun and viewed for the brix reading, which was recorded in percent. For the juice quality laboratory yield loss assessment, 2 healthy stalks were randomly cut from each plot and five smutted stalks were crushed using the Jeffco cutter to obtain at least 2 kg of crushed material for quality analysis. Six hundred grams of the crushed material were taken and pressed using the hydraulic hand press. The resulting juice was collected in 250 ml conical beakers. The first and last expressed brix of the juice were recorded. The temperature and hydrometer readings of the juice were also recorded. The weight of the wet bagasse was taken and again recorded after oven drying to a constant weight. These readings were used in the calculation of % reducing sugars, % Pol., Corrected brix, % Purity and % Fibre. Results showed that S. scitamineum reduced field sucrose (% Brix), % Pol., % Purity and % Fibre but increased % reducing sugars of the two test infected cane varieties.