• Contact Us
    • Send Feedback
    • Login
    View Item 
    •   Home
    • Journal and Journal Articles
    • Journal and Journal Articles
    • View Item
    •   Home
    • Journal and Journal Articles
    • Journal and Journal Articles
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    Whole Repository
    CollectionsIssue DateRegionCountryHubAffiliationAuthorsTitlesSubject
    This Sub-collection
    Issue DateRegionCountryHubAffiliationAuthorsTitlesSubject

    My Account

    Login

    Welcome to the International Institute of Tropical Agriculture Research Repository

    What would you like to view today?

    Modelling fungal (Neozygites cf. floridana) epizootics in local populations of cassava green mites (Mononychellus tanajoa)

    Thumbnail
    View/Open
    S97ArtOduorModellingInthomDev.pdf (176.6Kb)
    Date
    1997
    Author
    Oduor, G.
    Sabelis, M.
    Lingeman, R.
    Moraes, G.J. de
    Yaninek, J.S.
    Type
    Journal Article
    Metadata
    Show full item record
    Abstract/Description
    The fungus, Neozygitis cf. floridana is parasitic on the cassava green mite, Mononychellus tanajoa (Bondar) (Acari: Tetranychidae) in South America and may be considered for classical biological control of cassava green mites in Africa, where cassava is an important subsistence crop, cassava green mites are an imported pest and specific natural enemies are lacking. Spider mites generally have a viscous structure of local populations, a trait that would normally hamper the spread of a fungus that is transmitted by the contact of susceptible hosts with the halo of capilliconidia surrounding an infectious host. However, if infected mites search and settle to produce capilliconidia on sites where they are surrounded by susceptible mites before becoming infectious, then the conditions for maximal transmission in a viscous host population are met. Because the ratio between spider mites and the leaf area they occupy is constant, parasite-induced host searching behaviour leads to a constant per capita transmission rate. Hence, the transmission rate only depends on the number of infectious hosts. These assumptions on parasite-induced host search and constant host density lead to a simple, analytically tractable model that can be used to estimate the maximal capacity of the fungus to decimate local populations of the cassava green mite. By estimating the parameters of this model (host density, per capita transmission rate and duration of infected and infectious state) it was shown that the fungal pathogen can reduce the population growth of M. tanajoa, but cannot drive local mite populations to extinction. Only when the initial ratio of infectious to susceptible mites exceeds unity or the effective growth rate of the mite population is sufficiently reduced by other factors than the fungus (e.g. lower food quality of the host plant, dislodgement and death by rain and wind and predation), will the fungal pathogen be capable of decimating the cassava green mite population. Under realistic field conditions, where all of these growth-reducing factors are likely to operate, there may well be room for effective control by the parasitic fungus.
    Permanent link to this item
    https://hdl.handle.net/20.500.12478/4011
    IITA Subjects
    Pests Of Plants; Cassava; Disease Control; Plant Breeding; Plant Genetic Resources; Handling, Transport, Storage And Protection Of Agricultural Products; Plant Production; Plant Diseases; Livelihoods; Farm Management
    Agrovoc Terms
    Cassava Green Mites; Capilliconidia; Pathogen; Manihot Esculenta Crantz; Classical Biological Control
    Regions
    Acp; Africa; Europe; South America; West Africa
    Countries
    Netherlands; Brazil; Benin
    Collections
    • Journal and Journal Articles4835
    copyright © 2019  IITASpace. All rights reserved.
    IITA | Open Access Repository