Cassava plant protection in Africa

Manihot esculenta Cassava pest problems in Africa have changed dramatically over the last century. Rapidly expanding production and waves of exotic pests have created evolving cassava agroecosystems with changing production constraints. Cassava plant protection activities in Africa began with resistance breeding against African cassava mosaic virus. Cultural manipulations and biological control interventions were implemented later as devastating new pests invaded the continent. Sustainable plant protection strategies should integrate biological control, host plant resistance and cultural practices as needed based on an understanding of the key multi-trophic and multi-disciplinary interactions in the cassava agroecosystem. Knowledge of these key interactions provide the basis for determining production losses, developing appropriate interventions and evaluating subsequent impact While little integration can be found in cassava pest management practices today, there is an increasing awareness of the value of this approach. Plant protection interventions developed and tested by teams of multi-disciplinary scientists with input from extension agents and farmers in an inter-disciplinary manner are most likely to succeed. A regional project to develop sustainable cassava plant protection in West Africa is presented as a model of appropriate cassava plant protection development; Plant protection; Pest control; Mononychellus tanajoa; Phenacoccus manihoti; Prostephanus truncatus; Zonocerus variegatus; Aleurodicus; Pathogens;AfricaManihot esculenta; Protección de las plantas; Control de plagas; Mononychellus tanajoa; Phenacoccus manihoti; Prostephanus truncatus; Zonocerus variegatus; Aleurodicus; Organismos patógenos; AfricaCassava;Yuca; Protección de plantas - Aspectos generales; Enfermedades de las plantas; Articles in proceedings; Artículos en memorias; Plagas de las PlantasProtection of plants - General aspects; Pests of plants; Plant diseases

Population dynamics of Typhlodromalus limonicus from Colombia, an introduced predator of the exotic cassava green mite in West Africa

The introduction of Typhlodromalus limonicus (Garman & McGregor) sensu lato is a major component of an on-going biological control campaign against the exotic cassava pest Mononychellus tanajoa (Bondar) in Africa. However, long-term establishment of this exotic phytoseiid predator has not yet been achieved. The Colombian biotype of 33 limonicus was evaluated as a biological control agent in Nigeria and Bénin by assessing its population response to selected abiotic and biotic factors. In field experiments, 73 limonicus temporarily survived forca. 19 generations during wet and dry seasons. 73 limonicus population densities were negatively correlated with that of M. tanajoa suggesting its prédation potential on M. tanajoa. The spider mite populations were positively while the predatory mite populations were negatively affected by the low (< 50%) relative humidity during the dry season. Competition with endemic phytoseiid species on cassava was not evident. 73 limonicus was present on top leaves with M. tanajoa, whereas indigenous predators were more frequent on bottom leaves. Alternate prey may play a role in sustaining 73 limonicus populations during times of prey scarcity. Biotypes of a potential biological control agent for M. tanajoa should be selected to improve the chances of a successful establishment in Africa