Cassava mosaic disease and its management in Southeast Asia

Abstract

Status of the current outbreak of cassava mosaic disease (CMD) in Southeast Asia was reviewed. Healthy cassava seed production and dissemination systems have been established in Vietnam and Cambodia, along with integrated disease and pest management systems, to combat the outbreak. Cassava (Manihot esculenta Crantz) is one of the most important edible crops in tropical and subtropical regions. Recently, invasive insect pests and diseases have resulted in serious losses to cassava in Southeast Asia. In this review we discuss the current outbreak of cassava mosaic disease (CMD) caused by the Sri Lankan cassava mosaic virus (SLCMV) in Southeast Asia, and summarize similarities between SLCMV and other cassava mosaic begomoviruses. A SATREPS (Science and Technology Research Partnership for Sustainable Development) project "Development and dissemination of sustainable production systems based on invasive pest management of cassava in Vietnam, Cambodia and Thailand", was launched in 2016, which has been funded by The Japan International Cooperation Agency (JICA) and The Japan Science and Technology Agency (JST), Japan. The objectives of SATREPS were to establish healthy seed production and dissemination systems for cassava in south Vietnam and Cambodia, and to develop management systems for plant diseases and insect pests of cassava. To achieve these goals, model systems of healthy seed production in Vietnam and Cambodia have been developed incorporating CMD-resistant planting materials through international networks with The International Center for Tropical Agriculture (CIAT) and The International Institute of Tropical Agriculture (IITA).

Keywords: Cassava mosaic begomoviruses; LAMP; Manihot esculenta; Plant diseases; Seed system.

Fig. 1

Cassava mosaic disease symptoms on cassava plants in Cambodia and Vietnam. A Mosaic symptoms on leaves. B Heavily CMD infected field. C Diseased plant. D Diseased plantlet sprouting from a seemingly healthy, yet diseased, stem

Fig. 2

SATREPS project outline

Fig. 3

Facilities in the seed system at HLARC and UBB. A–C Aeroponic culture. A Aeroponic equipment in a growth room at HLARC. B Multiplication cycle using newly obtained shoots. C Plant phenotype after cultivation for 7 days. D–H Screenhouse cultivation. D Screenhouse at UBB cassava center. E Maintenance of the initial stock of plant materials in a vector-free facility. F Harvesting of plant materials. G–H Stock seed production in the field. G Overview of the stock seed production field at the UBB cassava center. H Plant growth. I Stock seeds. J Transport to a healthy seed production field