Plant Health, Climate Change and Trade - TradeMark Southern Africa

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5 Stem rust (black), stripe rust (yellow) and leaf rust (brown) are the most economically damaging diseases affecting wheat production and recently there has been an escalation in the threat posed by both stem and stripe rust. Several variants are now recognized and the emergence of the Ug99 races in East Africa transformed stem rust from a disease largely under control into a significant global threat. It was first reported in Uganda in 1999 and is now also present in Ethiopia, Kenya, South Africa, the Sudan and Zimbabwe. This disease is capable of yield losses of between 10 - 70 percent depending on inoculum pressure and environmental conditions and is spread over long distances via wind-borne spores. In South Africa, the spread of wheat stripe rust has been linked to changes in rainfall patterns. In Kenya wet and misty conditions, following successive rainfall seasons since November 2009, are making Ug99 even harder to control. The subsequent use of fungicides have been estimated to increase production costs by 40 percent with most impact on small-scale farmers that are responsible for 80 percent of wheat production in the country. In 2010 the FAO launched a website "SPORE” that aims to provide up-to-date information on the status of wheat stem rust, monitor important new strains of the disease and synthesize and provide easy access to reliable data on a global scale. Although the Ug99 pathogen is not seed-borne, there is still potential for introduction with plant debris or as seed contaminant when germ-plasm or wheat grain is imported for consumption and quarantine measures such as sampling and testing may be required. Countries will need to take pre-emptive action with sustained investment in research, surveillance, a strategies for crop diversity, and policies to encourage farmers to adopt disease-resistant crop varieties. Experts propose a framework development for regional surveillance with primary target regions being major wheat producers in Africa (Ethiopia, Kenya, Sudan, and Eritrea) with support from international scientists for training and data management. The East Africa program under the Borlaug Global Rust Initiative (BGRI) aims to minimize scale and scope of stem rust epidemics in Kenya and Ethiopia by means of monitoring (screening) and control, and to prevent that new virulent and dangerous forms originating from this region leave East Africa. Cassava is considered by experts to be a highly resistant crop that can endure high temperatures and drought and therefore has significant potential in African agriculture threatened by the effects of climate change. However, a major constraint to cassava production is the emergence of new pests and diseases that can be attributed to climate change. In Africa, whiteflies are causing direct damage to crops and indirect damage as they are vectors of Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD). CBSD has been reported to cause up to 80 percent yield losses in East Africa and occurs along the coast of East Africa, in an area extending from Kenya south to the Zambezi River in Mozambique, and along the shores of Lake Malawi in Malawi and Tanzania, but not along the shoreline in Mozambique. Angola is suggested to be a probable area to find the disease, due to cultural and economic ties to Mozambique. In 2007, a study by the International Institute of Tropical Agriculture (IITA) projected that at least 40 million people have been affected by CBSD in Tanzania with annual losses of US$50 million. CMD has been reported in all countries in Africa and affects domestic cassava and wild hosts. Studies on CMD in 1990 by Fauquet and Fragette, and in 2009 by Patil and Fauguet, estimate yield losses of up to 50% on average in Africa, with annual economic losses of US$ 1.9-2.7 billion in East and Central Africa. In Rwanda, surveillance conducted by the National Agricultural Research Institute in 2010 showed a 15.7 percent rate of infection of CBSD on local cassava varieties and 36.9 percent in improved varieties. COP 17 -‐ Trademark Climate change impact on phytosanitary risks
6 A study done in 2011 by the International Center for Tropical Agriculture (CIAT) indicates a high potential for combined outbreaks of whitefly, green mite, CMD and CBSD in Africa's Rift Valley that could lead to a collapse in production and ultimately threaten food security in the region. Scientists are working on the development of cassava varieties that are resistant to whitefly, green mite and CMD. Further studies in taxonomy and dispersal patterns of the disease vectors are required on local, landscape and regional scales to determine appropriate early warning and management strategies and policies that would control the pest and disease distribution to unaffected areas. Scientists have monitored the spread of CMD and CBSD in central and East Africa for several years but costs have been high and annual visits to the region barely kept pace with the spread. And so the Digital Early Warning Network (DEWN) was established and piloted in Tanzania. Farmer groups were involved and information received was used to generate maps and allow research teams to concentrate mitigation efforts in areas where new outbreaks occurred. In 2010 it was decided to expand the project to Rwanda. The movement of plant propagation material used in agricultural research, crop diversification, food production and commercial trade pose significant phytosanitary risks. New pests and disease may easily result in outbreaks of epidemic proportions when introduced into areas where there is no resistance or competition. In the 1970's the cassava green mite was accidentally introduced into Africa and spread to almost all cassava producing regions resulting in losses of 30-50 percent. In 1993 a biological control agent from Latin America was introduced to assist in its control. The accidental introduction of bunchy top virus affected more than 3000ha banana production in Malawi and completely destroyed production in Nkhota, Khota and Nkhatabay. Therefore national plant protection organisations have developed strict risk based phytosanitary measures that include visual inspection during active growth, virus-indexing, blotter testing and sedimentation essays for seeds, to prevent the introduction of pests and diseases by means of propagation material. True seeds and in-vitro propagation material are considered expensive but also the safest phytosanitary management options for exchange of propagating material. In 2007, the Great Lakes Cassava Initiative (GLCI) was implemented to ensure plant health of propagating material in Burundi, Democratic Republic of Congo, Kenya, Rwanda, Tanzania and Uganda, especially in the light of recent pandemics of CBSD. The prevalence and spread of fruit flies in Africa will alter considerably because of climate change and will result in corresponding changes in phytosanitary regulations, intra-regional and international trade opportunities. Fruit flies are one of the world's most devastating fruit and vegetable pests and cause millions of US$ losses in crop production each year. In Africa there are several species that attack crops and wild hosts. Since its first detection in Kenya in 2003, the fruit fly Bactrocera invadens has spread to at least 27 countries in Africa and became a major pest of economic and quarantine concern. It is known to attack at least 46 host plants, including many indigenous plant species and commercially grown crops such as mango, guava, pumpkin, melon, tomato, citrus and cashew nuts. Equatorial climates in Africa are considered most suitable for the establishment of B. invadens. The introduction and establishment of this fruit fly can severely impact on sustainable agriculture and rural livelihoods, as well as access to export markets because of its quarantine status in other countries. The detection of B. invadens in Mozambique, northern Namibia and Zambia resulted in the suspension of all host plant exports to South Africa. And for the same reason, COP 17 -‐ Trademark Climate change impact on phytosanitary risks
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