Section 2 Cassava Disease

**53**

**Chapter 3**

Leone

**Abstract**

**1. Introduction**

*and Johnny E. Norman*

Seasonal Variation on the

*Alusaine Edward Samura, Sahr N. Fomba,* 

*Augustine Mansarsy, Musa D. Saffa, Dan D. Quee* 

prevalence, incidence and severity of cassava diseases in Sierra Leone.

**Keywords:** Cassava Diseases, Incidence, severity and distribution

Incidence and Severity of Major

Foliar Diseases of Cassava in Sierra

A diagnostic survey was conducted in the rainy and dry seasons from 2014 to 2015 to determine the incidence and severity of major diseases of cassava in Sierra Leone. At least three chiefdoms and five villages per district were targeted. The survey was carried out in fourteen districts of the country with geo references using a GPS. On the spot assessment was conducted in all fields. Prevalence, severity and incidence were calculated. The most dominant diseases included the cassava mosaic disease and the cassava bacterial blight. The prevalence of cassava mosaic disease was high with 69.1% and 61.5% in the rainy season and dry season, respectively. The prevalence of cassava bacterial blight was 100% and 92% in the rainy season and dry season, respectively. Diseases of less importance included white spot and brown spot diseases as well as cassava anthracnose disease. The study provides bases for the deployment of improved varieties and provides information on the seasonal

Cassava (*Manihot esculenta* Crantz, family: Euphorbiaceae synonyms: yucca, manioc, and mandioca), a native to South America, is believed to have been introduced into Sierra Leone during the period of slave trade proliferated by Portuguese traders during the 16th century [1]. Cassava is grown over a range of climates and altitudes and on a wide variety of soils and ecologies. These includes the lowlands and uplands as commonly practised in Sierra Leone. Cassava is tolerant to drought; it is productive in poor soil where other staple crops cannot grow without intensive inputs [2]. The crop has long been recognized as an important source of carbohydrate for over 500 million people in Africa as well as feed for livestock, providing higher food energy production density (1045 kJ/hectare) than other root crops, such as maize grain (836 kJ/hectare) and fresh sweet potato root (752 kJ/hectare) [3]. The flexibility in growth conditions entertained by the cassava crop enables it

#### **Chapter 3**
