Cassava Mosaic Disease (CMD) seriously affects cassava (Samura et al., 2013; Fargette et al., 1988). There is limited information on tuberous root yield loss and the profitability of growing improved and local varieties infected with the cassava mosaic virus for tuber and gari production in Sierra Leone. The objectives of the study were to determine yield loss associated with cassava mosaic disease and conduct cost benefit analysis (budgets and break-even analysis) on cassava production using two improved varieties (SLICASS 4 and 6) compared against the local susceptible variety Cocoa, for gari production and Cocoa as a poundable enterprises for the boil and eat market. Activity 1 involved the establishment of a yield loss trial using the paired plot technique. Activity 2 assessed productivity of cassava and gari production. Data collected were analysed using the analytical frame work that incorporates the concept of gross margin analysis as describe by Brown (1979). This included cost benefit analysis (CBA), the net social benefit (NSB) or the excess of total benefit over total cost represents the net present value (NPV) and The Internal Rate of Returns (IRR).The yield loss associated with the local variety Cocoa under this system was 4.27 t/ha which is equivalent to 38.92% yield loss resulting from the cassava mosaic disease infection. SLICASS 4 and SLICASS 6 recorded positive returns to production of tubers and gari. The local variety Cocoa enterprises for gari under the same condition recorded a negative returns even in the 6 year. However Cocoa for the boil and eat market had the highest profit level. The implication of this study is that breeding effort should be geared towards high yielding mosaic resistant varieties that are poundable more profitable and suits the cultural and domestic demand of the producers, processors and consumers.

Reports of damage by grasshopper Zonocerus variegatus (L.) to cassava and other crops has increased in recent years. The attack on cassava is particularly threatening to the livelihood of many poor subsistence farmers in Sierra Leone. As such, an evaluation was conducted to investigate the use of host plant resistance as an alternative method of managing grasshopper rather than the sole reliance on chemicals. The experiment was laid out in a randomized co mplete block design with three rep lications. Two b locks were used (protected and unprotected) with twenty cassava varieties (Slicass 1 05-21, VT 05-02, Slicass 2, SN 05-22, Slicass 1 05-14, Slicass 2 05-17, Slicass 5, VT 05-07, SN 05-41, Slicass 1 05-05, 97/ 3202-05-04, Slicass 4, Slicass 1 05-42, SN 05-17, Slicass 1, Local, 97/ 0057-05-04, Slicass 6, 97/0057-05-01 and Slicass 2 05-13) in each block. Pest assessments was done at 3, 6, 9 and 12 Months After Planting (MAP) which co incides with the various seasons; rain, dry and dry-rainy transition periods. Significant differences were recorded in percentage incidence and severity score with respect to cassava variety and time of observation. While seven cassava varieties (Slicass 5, VT05-02, Slicass 4, 97/0057-05-04, 97/0057-05-01, slicass 6 and Slicass 1 05-21) were found to be less susceptible to Z. variegatus (L.), four varieties (Slicass 2 05-17, Slicass1 05-41, Slicass 2 05-13 and 97/005-05-04) out yielded (in terms of tuber weight and nu mber) the released varieties during the two cropping seasons. Percent incidence and severity score was relatively high at 6MAP and 9MAP. Overall, tuber weight and number were higher in the protected plot compared to the unprotected plot during the two cropping seasons. Hence, protecting cassava field fro m grasshopper infestation may increase yield, number o f tubers and invariably the production of good quality planting material that is resistance to grasshopper attack.

Aims: The aim of this study was to evaluate the effect of staking and non-staking systems on disease severity, yield and quality attributes of yams. Methodology: High costs and lack of planting materials, labour, staking and inappropriate knowledge on production techniques are major constraints of yam production in Sierra Leone. A total of seven promising hybrid genotypes of yams from International Institute of Tropical Agriculture and one local cultivar, Pulli, were evaluated for yield, reaction to local pest and disease and desirable market traits during 2011 and 2012 in three agro-ecological zones of Sierra Leone. The experiment was laid out in randomized complete block replicated thrice at the experimental