IITA IPM project 08: Management
of Bemisia tabaci on virus-resistant cassava plants utilizing natural enemies.
Duration: 3 years (2003 – 2005)
Purpose: To develop approaches for the management of
whiteflies as pests and virus vectors on cassava through enhancing the activity
of natural enemies.
Background/description: The whitefly, Bemisia
tabaci, causes major problems to cassava production in East Africa both as
the vector of cassava mosaic viruses and through direct physical feeding
damage. This project proposes to alleviate the whitefly-caused problems by
enhancing the natural management of the whitefly through natural enemy
conservation and augmentation. For this purpose, the natural enemy fauna of B.
tabaci on cassava will be surveyed and pest-enemy interactions followed in the
field and their relationships to season, location and available plant species
examined. The project will study the roles and shortcomings of the different
enemies in suppressing whitefly populations through observations in the field
and by particular analytical behavioural observations in the laboratory. In
addition to studying the life history and effect of climatic constraints on the
natural enemies, the project will examine their behaviour and how it relates to
different cassava varieties and the influence of different weed species on
whitefly outbreaks. The effects and possible use of additional crop plants will
be studied, such as sweetpotato, for intercropping in cassava fields and as
alternative hosts on which to rear natural enemies of whiteflies in the field.
Utilizing the results of the studies, efforts will be made to improve the
natural control of the pest through weed and crop variety manipulation,
intercropping and using banker plants. The applied part of the project will be
developed jointly with advisory personnel and implemented in growers' fields.
Agroecozone(s) and
location(s): Humid forest and savannas in East Africa
Expected outputs: a) Improved
knowledge of natural enemy fauna of B. tabaci on cassava; b) Identification of
the parasitoids and predators with greatest potential for exploitation in
biological control of B. tabaci; c) Development of approaches to augment key
natural enemies of B. tabaci including banker crop techniques; d) Validation of
B. tabaci natural enemy augmentation in farmers' fields; e) Identification of
additional exotic biocontrol agents for B. tabaci management in East Africa; f)
Training of Ugandan researchers in biology, taxonomy, conservation and
augmentation of natural enemies of B. tabaci
Potential impact and beneficiaries: Immediate beneficiaries:
Ugandan researchers benefiting from world class Israeli expertise in this
field. Ugandan research systems that will benefit from enhanced capacity. Ultimate
beneficiaries: Cassava producers in East Africa who will benefit from increased
yields of cassava that will be accrued from decreased populations of B. tabaci.
Partners: NARES in East
Africa.
Development
investor(s): USAID
IITA contact person(s)/principal investigator(s): James Legg J.Legg@cgiar.org
website http://www.iita.org