Scientists and researchers have expressed their concern about the recent upsurge in the number of whiteflies; the tiny, sap-sucking insects that destroy important crops and vegetables such as beans, cassava and sweet potato.
The whitefly spreads diseases to important crops very swiftly, a situation which, if not urgently controlled, efforts to ensure sustainable food security and thus reduce poverty in rural areas will end up in vain.
Early this week, scientists, researchers and the private sector from across the world met in Arusha, Tanzania, to foster research and education around a broad range of whitefly-related topics of local, national and global interest.
This Second International Whitefly Symposium brought together over 130 scientists, academics and the private sector from all over the world to share the latest research and information on the whitefly.
The symposium was held in the wake of severe destruction of different crops by whiteflies that has so far paralyzed productivity and the economy of many farmers.
Crop devastation caused by whiteflies
Speaking at the symposium, the Director of Research and Development in the Northern Zone in Tanzania, Dr. January Mafuru, said the insects excrete honey dew which serves as a media for sooty mold fungi growth, which then darkens plant leaves and fruits.
He said that whiteflies and whitefly-transmitted viruses (WTVs) are also one of the biggest constraints to vegetable production with farmers often resorting to heavy use of pesticides and putting their lives and those of customers at risk.
According to him, the tropical whitefly is one of the world’s most serious agricultural pests, as its feeding damage causes severe economic losses in a wide range of food crops grown by millions of smallholder farmers.
However, it is the transmission of viruses by whiteflies that has the widest impact on global food production.
Worldwide, whiteflies cause major economic yield losses, both by directly feeding on the plants and as vectors of viruses that spread diseases to the important crops.
For example, the high populations of whiteflies are behind the two deadly viral cassava diseases spreading rapidly in East and Southern Africa, the Cassava Brown Streak (CBSD) and Cassava Mosaic Diseases (CMD).
East Africa, for instancee, has been one of the worst affected areas by whitefly, with farmers losing more than two-thirds of their cassava crops to a pandemic of whitefly-borne cassava mosaic disease.
An epidemic of severe cassava mosaic disease spread throughout much of Uganda in the 1990s, devastating the country’s cassava production.
Losses were valued at more than USD 60 million annually between 1992 and 1997. Many farmers abandoned their crop in large parts of the country. In Eastern districts, widespread food shortages were recorded.
Cassava: An important crop for both food and income
In Tanzania cassava is an important crop for both food security and income generation for low-income people.
In Coast region, cassava is one of the main food crops. Statistics released in 2013 by the Ministry of Agriculture, Food Security and Cooperatives put the annual production of fresh cassava at seven million metric tonnes.
In sub-Saharan Africa and Asia, cassava is a staple food eaten by over seven hundred million people. However, two-thirds of more than 18 million hactares of cassava cultivated worldwide are produced in Africa.
Cassava has potential for industrial use in the production of starch and biofuel. Cassava leaves are also used for food in many communities in Africa including Tanzania.
Despite all the benefits accruing from cassava, in 2005 whitefly transmitted cassava mosaic disease caused losses of up to four million metric tonnes of fresh cassava roots annually in Tanzania.
Tanzania is one of many African countries where agriculture is at the centre of life and the economy. About 80 per cent of its citizens depend on farms of less than two hectares.
Sadly, millions of them and their families are still trapped in poverty.
They cultivate on depleted soils with little or no inputs such as fertilizer and improved seeds, and often farm without reliable water sources or market access.
They have no access to finance, no crop insurance, and limited government support. Yet, despite these challenges, the food in Africa is produced by smallholder farmers whose crops are badly affected by whiteflies.
The ever rowing population on the African continent, which is estimated to be growing at 50 per cent faster than gains in food productivity, has direct impact on food security.
On the other hand, research on whitefly is also low. Apart from lack of adequate funding, there are limited number of vector entomologists with the required expertise to manage the whitefly and associated problems.
Without practical action, Africa’s food deficit is projected to increase up to 60 million tonnes by the year 2010. In similarity to other African countries, the agricultural sector in Tanzania is also the key driver of social and economic development.
For his part, the officer in charge at Mikocheni Agriculture Research Institute (MARI) Dr. Joseph Ndunguru, said it was high time governments and funders worked very closely with scientists to smoke out the diseases.
He challenged the level of commitment and determination for scientists saying they should work around the clock to put a smile on farmers’ face.
“We have more to do for the farmers who lose their crops due to whitefly director-feeding damage and the virus diseases which they transmit.
The question is, can we use our research findings to at least put a smile on them? It takes will, faith, commitment and sacrifice to achieve this,” he said.
He said that the whitefly, though looking so tiny, their devastating effects are impossible to ignore.
Citing an example of vegetables, cassava, cotton, sweet potato and flowers, he said that many countries have suffered looses caused by whitefly and Tanzania is no exception.
As societies continue to evolve and modernize agriculture, so do plant pests, potentially becoming even more devastating.
To keep up with constant threat of emerging and re-emerging plant pests, it is necessary to identify, predict and monitor sources of new pest infestations worldwide in order to minimize small infestation proportions from becoming devastating.
Plans by Mikocheni Agricultural Research Institute
Mikocheni Agricultural Research Institute (MARI), which is under the Ministry of Agriculture and Food SAecurity, has put in place different plans and strategies ranging from the village level to the national level.
According to Dr. Ndunguru, one of the plans to sustain the project is to institutionalize different projects on whiteflies. MARI is currently conducting the regional cassava virus diseases management project.
He said MARI wants to make sure that the project is coordinated and implemented by local scientists in already established research institutions.
Through the Regional Cassava Virus Diseases Management project, another plan is to train scientists and strengthen diagnostic labs in all research institutions.
Involvement of key stakeholders such as local governments, district councils, extension agents, who are also under local government, is to be increase, saying these are the people interacting with farmers on a daily basis.
Capacity building
According to Dr. Ndunguru, the project involves capacity building, especially in human capacity. Forexample, the project has trained many young scientists, and research crop inspectors.
“MARI has been conducting capacity building training on cassava disease survey and diagnostic for project research assistants and laboratory technicians,” he said.
He said the aim of training these young scientists, research crop inspectors and lab technician is to equip them with the latest techniques for tracking different viruses in plant tissues as the infections unfold.
Citing an example, Dr. Ndunguru said that so far the project has supported 14 masters degree students and six doctorate students.
“This is very significant capacity building. We have trained them on the causes of the diseases, how to recognize the disease symptoms, how the diseases spread, and their management and how to write project proposals,” he said.
Another advantage of the project is that University students for example those doing Masters and PhD’s should have gone abroad to do their research they are doing here in Tanzania using available local facilities, he added.
He explained that the “We want all cassava farmers in the country to benefit with clean planting materials like what is happening in the demonstration farms in three districts of Rorya, Mbinga and Butiama.
The Regional Cassava Virus Diseases Management project is a four-year regional project co-funded by Bill & Melinda Gates Foundation and the Department for International Development (DFID).
It is implemented in seven countries: Tanzania, Kenya, Uganda, Rwanda, Malawi, Mozambique and Zambia to improved cassava productivity.
For his part, the Director of International Institute of Tropical Agriculture (IITA), Dr Victor Manyong, explained that the threats posed by whitefly requires serious and collective intervention by scientists and other stakeholders.
“IITA has been conducting several research and projects will continue collaborating with other partners to help farmers get rid of the diseases” he said.
Diverse topics were presented in eight sessions at the symposium. They include Biology, Ecology, and invasion Biology.
Also on the list are Genomics and Genetic Diversity, Systematics and Evolution and Whitefly Endo-Symbionts, Whiteflies as Vectors of Plant Viruses.
Dr. Peter Sseruwagi, assistant project coordinator at MARI (Technical and Research), mentioned other topics as Whitefly Plant Interaction; Management Control and Integrated Pest Management (IPM), and Chemical Control, Insecticides Resistance and Chemical Ecology.
“The passionate whitefly scientist will be glad to know that so far Africa provides the widest genetic diversity of Bemisia tabaci, making it the centre of origin of the world’s most economically important but ‘beautiful’ insect pest,” said Dr. Sseruwagi, who also co-chaired the organizing committee.
The symposium was jointly organized by MARI under the Ministry of Agriculture and Food Security, and the International Institute of Tropical Agriculture (IITA).