Plant Health, Climate Change and Trade - TradeMark Southern Africa

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3 national SPS systems to implement policies vary among countries and will affect countries' ability to deal with new SPS risks created by climate change. 3. The impact of climate change on phytosanitary risks The relationship between climate, plants and plant pests and diseases can be explained by the "disease triangle" as changes in CO2 concentration in the atmosphere, seasonality, temperature and rainfall threatens to change world patterns of comparative advantage in crop production by creating new ecological niches that will affect crop production and alter the distribution, incidence and intensity of plant pests and diseases. Temperature can affect critical stages (e.g. survival between seasons or reproduction rate) in the life cycle of plant pests and pathogens that cause plant disease. Changes in temperature and humidity may affect the susceptibility of host plants and therefore lower plant resistance to emerging pests or it may have an effect on the development of fungal and bacterial diseases. Furthermore, higher CO2 levels may increase the competition pressure between weeds and crops, the abundance of certain pathogens, such as rusts, or may increase foliar density and leaf wetness that makes infection by fungal pathogens more likely. The emergence of unexpected pests and diseases that occur because of changing climatic conditions have been observed when new vectors, selection and recombination of disease genotypes occur, when plant species and varieties mix, and when pests and vectors are introduced without their natural enemies. Climatic conditions have been drivers of the evolution of many migratory systems as migratory pests exploit seasonal changes and weather conditions that may assist or hamper their dispersal. Migratory pests such as locusts and the African armyworm are unusual because they undergo density-dependant phase changes from solitary to gregarious and are dependent on temperature, rain and vegetation. When there is sufficient rain, migrations will take the insects to patches of green vegetation for feeding and to habitats humid enough for them to lay eggs. Studies indicate that migration patterns are changing with current changes in temperature and humidity. Altered wind patterns may also contribute to the changes in the spread of wind-borne pests and diseases. Many plant species are adapted to specific habitats that occupy a narrow range along altitudinal and latitudinal climatic gradients. As temperatures increase an upward migration of plant communities and their associated pests and disease vectors occur at high-altitude locations such as the East African highlands. Any increase in the frequency or severity of extreme weather conditions such as droughts, heat waves, windstorms or floods may also disrupt the predator-prey relationships that normally keep pest populations in check. 4. The likely impact of new phytosanitary risks on trade Aflatoxins are mycotoxins that cause developmental and immune system suppression, cancer, and death and pose serious health risks for humans and animals in Africa. Changes in temperature and humidity may predispose host crops such as maize and groundnuts to aflatoxin contamination because of altered crop development and by affecting insects that COP 17 -‐ Trademark Climate change impact on phytosanitary risks
4 create wounds on which aflatoxin-producing fungi proliferate. According to the FAO, 25 percent of world food crops are affected with aflatoxin and countries situated within 40 degrees latitude of the equator are most at risk. Aflatoxin contamination is widespread and often acute in Sub-Saharan Africa where maize production is significant as livestock feed and as a staple food that accounts for 42 percent of all cereal crops in the region. Groundnuts is an important cash crop in the region that are largely controlled by women. Because of food safety regulations that aim to reduce human exposure to aflatoxins, crop contamination cause significant economic losses along the supply chain. A World Bank study estimates an annual loss of US$670 million to African food exporters from attempting to meet the EU health regulation on aflatoxin. In April 2004, rural Kenya experienced one of the world's largest documented aflatoxicosis outbreaks resulting in 317 cases and 125 deaths. The source of the outbreak was linked to home grown maize harvested in February during unseasonably early rains and stored under wet conditions conducive to fungal growth. Contaminated maize entered the market distribution system when local farmers sold a portion of their household stores to market vendors. Market maize was found to be a significant source of continued exposure to aflatoxin long after contaminated household stores were consumed or discarded. This means that the potential role of the market system in sustaining exposure must be considered when public health assessments on aflatoxin outbreaks are done. The outbreak in Kenya occurred during a time of regional and national food shortages due to prolonged drought and crop failure. Immediate response efforts mainly focused on food replacement and relief whilst the need for a comprehensive food safety programme was realised. Several research studies and projects have since been done, or are in progress, to test preharvest and post-harvest technologies and good agricultural practices that may reduce the aflatoxin risk in African agriculture. The International Food Policy Research Institute (IFPRI) is leading a project that was initiated in 2009, to analyze the impact and possible control measures of aflatoxin contamination on the livelihoods and health of people in Kenya and Mali. This project has been launched in conjunction with the International Maize and Wheat Improvement Center (CIMMYT), International Crop Research Institute for the Semi-Arid Tropics (ICRISAT), University of Pittsburgh, Uniformed Services University of the Health Sciences, Kenya Agricultural Research Institute, Institut d’Economie Rurale (Mali), ACDI/VOCA, and the East African Grains Council. Research to date shows that a variety of field management practices, chemical control, biological control, postharvest practices and timely harvesting may reduce aflatoxin development and/or contamination. However, efficient monitoring and surveillance with cost-effective sampling and analytical methods is needed in the region. COMESA is involved in the development of a Partnership for Aflatoxin Control in Africa (PACA) that will aim to support the implementation of cost-effective aflatoxin management programs and technologies, focusing on entire value chains to ensure a holistic and integrated approach for aflatoxin control. Better understanding of the potential impact of climate change will allow development of improved management procedures, better allocation of monitoring efforts, and adjustment of agronomic practices in anticipation of global climate change to reduce the risk of aflatoxin contamination. Public education and awareness is considered to play an important role to sensitize the population on aflatoxin risk and its management. COP 17 -‐ Trademark Climate change impact on phytosanitary risks
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