Subproject Description ::
|
The highlands of eastern and central Africa
constitute approximately 23% of the total land mass of the region.
The area is densely populated and is currently home to more than 100
million people (approximately 51% of the total population) and is
also the major source of water for northern, eastern and central Africa.
The highlands provide 50% of the food value for the region, making
a major contribution to the countries' GDPs. They support diverse
land uses and economic opportunities; in addition to food for domestic
consumption, coffee, tea, pyrethrum and horticultural crops are largely
grown in the highland areas and are a major source of foreign exchange
for the countries in the region.
The problem of whitefly-transmitted viruses on vegetables which is
seen in Central America, Mexico and the Caribbean is beginning to
emerge in Eastern African.
Bemisia tabaci is known to infest the more common vegetable
crops in the subregion: tomatoes (Lycopersicon esculentum),
eggplant (Solanum melongena), okra (Abelmoschus esculentus)
and chillies (Capsicum annum). The legume crops which are commonly
grown in association with vegetables in the subregion include bean
(Phaseolus vulgaris), cowpea (Vigna unguiculata) and
groundnut (Arachis hypogaea). Until recently, whiteflies were
known to be minor or occasional pests on legumes. However, the trend
in Sudan indicates that whiteflies are becoming an important pest
on beans.
Tomato is one of the most widely cultivated vegetable crops in the
region. Production is predominantly by small-scale farmers for fresh
consumption, and yields are generally low. Small farmers get yields
of 20t/ha while commercial farmers get yields over 100t/ha. These
low yields are due to production constraints, particularly arthropod
pest and diseases (GTZ, 1995).
In October, 1995, 25 participants from Kenya, Mozambique, Tanzania,
Uganda, Zambia and Zimbabwe met in a tomato planning workshop for
South-eastern Africa. The workshop reviewed the past 15 years of research
on tomato plant protection for each of the countries represented.
Workshop participants defined criteria of an important disease or
pest as: 1) high yield losses, 2) widespread distribution, 3) high
incidence, and 4) frequent occurrence. Based on these criteria, Bemisia
tabaci was identified as the third most important arthropod pest,
after red spider mites and African bollworms (Table 4; Varela &
Pekke, 1995).
The participants of the tomato planning workshop for East and Southern
Africa, were unable to prioritize whitefly-transmitted viruses due
to lack of information from most countries. However, they felt that
there is a need to assess the importance of WTVs in the region (GTZ,
1995). The preliminary results of a survey of major vegetables in
southern Africa indicate that Tomato yellow leaf curl virus
(ToYLCV) is a very important tomato disease in Southern Africa (Nono-Womdim,
pers. comm.). However, there is a lack of quantitative information
on the distribution and extent of yield loss due to ToYLCV, and other
WTVs, in the region across the target crops in vegetable and legume
based cropping systems. There is a critical need for baseline information
as a prerequisite for prioritizing and planning the strategies for
sustainable pest management interventions.
Workshop participants could not prioritize the importance of viral
diseases due to lack of information from most countries, with the
exception of Tanzania where Bemisia tabaci, as a vector of
Tomato yellow leaf curl virus (TYLCV) was considered the limiting
factor for tomato production (GTZ, 1995). Subsequent survey work carried
out by the AVRDC regional office in South-eastern Africa has ascertained
that TYLCV is also a serious problem in Malawi and Zambia. And prior
work conducted by INRA (France) also found TYLCV to be a threat to
tomato production in the Sudan. All commercial varieties of tomatoes
grown in South-eastern Africa are susceptible to TYLCV (R. Nono-Womdim,
pers. comm.). Control of whiteflies is based on the use of chemicals.
Project Purpose :: To gather, generate and analyze, through
scientific and grower networks, baseline data relevant to the diagnosis
and characterization of whitefly and WTV problems in the tropics,
in order to propose a sound research agenda for improved understanding
of pest and disease dynamics, IPM development and IPM implementation.
Project Outputs ::
- International network for whiteflies and WTVs in the tropics
established
- Socio-economic and environmental impact assessed
- Epidemiological characterization initiated
- Agronomic characterization initiated
- Preliminary studies for Phase 2 conducted
Project Impact :: The immediate beneficiaries of Phase 1
of the Project will be a) IARC scientists, b) NARS scientists, c)
small holder farmers, and d) donor agencies. Additional, indirect,
beneficiaries will be the general community of whitefly and WTV
scientists and government policy makers.
|
Partner institutions
and collaborating professionals :: |
Kenya
International Center for Insect Physiology and Ecology - ICIPE
Mr. Bernhard Löhr
Dr. Mohamed Ali Bob
Ms. Rebecca Raini
Mr. Thomas Njuguna
Dr. Srinivasan Sithanantham
Kenya Agricultural Research Institute - KARI
Dr. Benjamin Odhiambo
Mr. Gilbert Kibata
Dr. Jason Ong'aro
Tanzania
Asian Vegetable Research and Development Center - AVRDC
Dr. M. L. Chadha
Dr. Remi Nono-Womdim
Sudan
University of Gezira. Plant Pathology Centre, Faculty of Agricultural
Science
Dr. Gasim Dafalla
Agricultural Research Corporation - ARC
Mr. Musa Ahmed
Malawi
Bvumbwe Agricultural Research Station - BARS
Dr. Harriet Thindwa
Mr. Patrick Khonje
|
