DISEASE ASSESSMENT AND MODELLING FOR SUSTAINABLE PRODUCTION AS A PROSPECTIVE MEASURE OF CASHEW IN GUINEA-BISSAU

A mosaic of traditional agriculture and extensive plantations of cash crops, which alter the natural ecosystems, characterize agricultural landscapes in West Africa. Cashew (Anacardium occidentale L.) is a tropical tree native... [ view full abstract ]

A mosaic of traditional agriculture and extensive plantations of cash crops, which alter the natural ecosystems, characterize agricultural landscapes in West Africa. Cashew (Anacardium occidentale L.) is a tropical tree native to South America, currently cultivated in most tropical countries in the world. Among the main cashew production areas, West Africa accounted alone for 45% of the worldwide production of cashew nuts in 2015. Particularly, in Guinea-Bissau, cashew represents more than 90% of country exports, involving 85% of the rural population. However, little is known about the effects of the extensive implementation of cashew plantations, which dominates agricultural landscapes in Guinea-Bissau. Also, as an introduced crop and being outside of its center of diversity, emerging infectious diseases can arise and cause tremendous production losses, with devastating social and economic implications. Climate change will increase uncertainty in the production of many crops in tropical countries, including many developing countries where these crops may form an important basis of the gross domestic product. Limited information is available on climate-change impact on tropical crops, and future projections are mostly based on modeling studies.

Here, we present a multidisciplinary approach to determine: 1) phytosanitary status of cashew orchards; 2) assess incidence and severity of cashew diseases in different eco-geographic conditions; 3) identify pathogens using NGS technology from field surveys; 4) and perform a spatial-temporal modeling of potential foci of diseases outbreaks. Using a two ecogeographically dissimilar regions in GB, cashew orchards will be sampled for metagenomics approach, field work for in field incidence and severity of fungal diseases will be pursued. Also statistical and geostatistical methods based on Generalized Linear Models or MixedModels of ecological and environmental data to infer disease spread scenarios will be further pursued to design control strategies.

Our work provides an experimental approach along with a modeling perspective that will enable to assess disease occurrence in cashew plantations, and prospect their potential of dissemination as result of climate change.

The ultimate goal is to identify and discriminate the disease causal pathogens, aiming at obtaining tools to help design effective strategies for disease control and thus promote the sustainable production of cashew in West Africa Region.

Keywords: tropical agroecosystem, sustainable production, fungal diseases, policy guidelines.