The yellow sugarcane aphid (YSA), Sipha flava Forbes (Homoptera: Aphididae) is an invasive insect pest of many graminaceous plants which include cultivated crops, like sorghum, sugarcane, rice, maize and several species within non-cultivated genera e.g. Digitaria, Panicum, Paspalum, and Pennisetum. A survey conducted in the Kagera region indicated an infestation by YSA in nine sugarcane varieties grown. This pest causes damage to leaves leading to yellow, purple and red discoloration. This is the first report of YSA infestation in the Tanzanian sugarcane industry. Efforts to develop control measures are still in progress.

The accumulation and translocation of trace metals in soil and in sugarcane crop irrigated with treated effluents from sugar industry compared to soil and sugarcane crop irrigated with bore-well water were determined. In the present study the impact of irrigation with treated effluent from the sugar industry on the trace metal contamination of sugarcane juice was assessed. It revealed that the mean concentrations of Cd, Pb, Cu, Mn and Zn in the soil of fields irrigated with effluent and in juice from sugarcane grown on such fields were higher than those from bore-well water irrigated fields. The concentrations of trace metals in treated effluent exceeded the permissible limits of the Indian standards (Central Pollution Control Board-2000). The concentrations of Cd, Pb, Cu and Zn in juice of sugarcane grown on fields irrigated with effluent also exceeded the permissible limits of Indian standards and WHO/FAO expert committee recommendations. Their concentrations in juice of sugarcane grown in fields irrigated with bore-well water were within the limits of safety, except for Cd. The transfer factor for Zn was considerably higher than those of the other trace metals. The metal concentrations of sugarcane juice showed significant correlations with those of soil, which was not the case when bore well water was used for irrigation.

This study presents the spatial variability and dynamics of soil organic carbon (SOC), soil organic matter (SOM) and soil pH contents at the Wonji Shoa Sugar Estate (WSSE), Ethiopia. Soil samples were collected immediately after the sug-arcane was harvested and then analysed for SOC, SOM and pH content using standard procedures. The analysis resultsshowed that the pH value varied between 6.7–8.4 (neutral to moderately alkaline) and 7.3–8.5 (neutral to strongly alkaline) for the top and bottom soil profiles, respectively. The SOM content is in the range of 1.1–6.7% and 0.74–3.3% for the upper and lower soil layers, respectively. Nearly 45% of the samples demonstrated a SOM content below the desirable threshold (<2.1%) in the bottom layer and, hence, inadequate. Moreover, most of the topsoil layer (95%) has an SOM content exceed-ing the desirable limit and hence is categorized within the normal range. Interestingly, the SOC content showed a spatial variability in both the surface and sub-surface soil layers. A lower SOC and SOM content was found for the sub-soil in the south and southwestern part of the plantation. A further decline in the SOC and SOM content may face the estate if the cur-rent waterlogging condition continues in the future for a long period. Overall, the study result emphasizes the need to min-imize the pre-harvest burning of sugarcane and action is needed to change the irrigation method to green harvesting to fa-cilitate the SOC retention in the soil and minimize the greenhouse emission effect on the environment, hence improving soil quality in the long-term.