Potato Farmers in Ecuador Depend on Fungicides

Potato leaves with late blight; Fungicide treatment on right

Potato leaves with late blight (L); Fungicide treatment (R)

Carchi is the most important potato-growing zone in Ecuador. Smallholder households dominate production and they sell the vast majority of output. The biggest biological constraint to potato production in Ecuador is the disease late blight caused by the fungus p. infestans. The fungus can infect all the potato plants in a field in three days and losses can be as high as 100%. A survey of smallholder potato farmers in Carchi showed how dependent they are on fungicides.

“Even though potatoes have been one of the main crops in the Andes for thousands of years, under present production and market conditions the farmers in Carchi cannot produce potatoes without pesticides, particularly fungicides against late blight (caused by Phytophthora infestans) and insecticides to control the Andean weevil (Premnotrypes vorax). Every one of the farmers in the area covered by our project in the province of Carchi used fungicides. On average, they treated 6.7 times with 2.6 products at each treatment. They generally applied fungicides up to eight times during each production cycle, making fungicides the most frequently applied type of product.”

Authors: Sherwood, S. G., et al.
Affiliation: Integrated Pest Management Project, International Potato Center (CIP),
Title: Reduction of risks associated with fungicides: technically easy, socially complex.
Source: 2002. Reduction of Risks Associated with Fungicides: Technically Easy, Socially Complex. pp. 93–109. In: Fernández-Northcote E.N. (ed), Memorias del taller internacional Complementando la resistencia al tizón (Phytophthora infestans) en los Andes, Febrero 13–16, 2001, Cochabamba, Bolivia, GILB, Taller Latinoamérica 1. Centro Internacional de la Papa, Lima, Perú. Available online: http://www.share4dev.info/kb/output_view.asp?outputID=3480


Czech Republic: Unsprayed Potatoes Completely Destroyed

Late Blight Destroyed Field

Late Blight Destroyed Field

Spanish explorers brought the potato to Europe from the Americas in the 16th century. A fungus causes a disease of potatoes known as late blight. Infected potatoes emit a distinctive unpleasant odor due to decay of plant tissue. Late blight first appeared in Europe in 1845 and had devastating consequences, particularly in Ireland. Today potato growers in Europe spray fungicides to prevent late blight infections. In the Czech Republic, 1.6 billion pounds of potatoes are grown annually and growers typically spray fungicides seven times yearly. 2011 was an ideal year for late blight development in the Czech Republic with devastating results for unsprayed potatoes….

Czech Republic 2011. In 2011, the weather conditions were very favourable for the development of potato late blight. Rainfall in May, June and August was near the normal in the main production region; however, in July it reached 160 – 180% of the normal. The spread of foliage blight was intensive and the level of tuber infection was also severe. The first more important outbreaks in the potato production region were observed in the second decade of July; however, epidemic late blight spreading was very rapid and non-treated crops were completely destroyed in 2 – 4 weeks, based on locality and varietal susceptibility.”

Authors: Hansen, J. G., et al.
Affiliation: Aarhus University, Dept. of Agroecology, Research Centre Foulum.
Title: The Development and Control of Late Blight (Phytophthora infestans) in Europe in 2010 and 2011.
Source: Thirteenth EuroBlight workshop, St. Petersburg (Russia), 9-12 October 2011.

IPM Research in Turkish Tomato Fields Shows Importance of Fungicide Sprays

Tomatoes are a major vegetable crop grown in Turkey with an annual production of about 10 million tons. Fresh market tomatoes account for 80% of production while canned, dried and paste products from Turkey’s 55 tomato processing plants account for the remaining 20%. Late blight is a devastating disease of tomatoes for which Turkish farmers typically spray twice a season. However, IPM research has shown that 5 carefully-timed applications are much more productive.

“In 1997, Phytophthora infestans (Late Blight) caused an epidemic and great crop losses, especially in the Marmara and Trakya regions. Turkey, as a tomato paste producer, had to import tomato paste to satisfy the contracted commitments. IPM studies were conducted by Ege University, Faculty of Agriculture and Department of Plant Protection in Marmara Region (Bursa) during the years 2000-2005.”

“In all IPM programs, a total of 5 fungicide applications were made depending on which IPM program was followed. … The grower’s standard had two fungicide applications when first symptoms appeared. All of the IPM weather timed spray programs increased marketable tomato yields resulting in higher net economic returns to the farmer. The growers recognized how poorly their standard spray program yielded, resulting in lost income to their farm operation.”

Authors: H. Saygili, N. Tosun and H. Türküsay.
Affiliation: Ege University, Faculty of Agriculture, Izmir-Bornova, Turkey
Title: Integrated Disease Management in Processing Tomato in Turkey
Publication: Acta Horticulturae. 2007. 758.

Climate Change Increases Need for Fungicides in Egypt

The earlier seasonal onset of warm temperatures in parts of the world is resulting in a threat of earlier disease development. With an increase in the potential for more severe epidemics, the number of fungicide applications needed for control also increases. Researchers have determined that 1-3 more fungicide sprays will be needed in Egypt to control tomato diseases as a result of climate change…

“The ranges of several important tomato disease[s] in Egypt; including tomato late blight (the most destructive tomato disease causing fruit yield losses) have expanded since the early 1990s, possibly in response, in part, to climate trends. … Based on analysis of plant/disease/climate relations, an epidemic of late blight onset on tomatoes that is 1-2 weeks earlier means 2-3 additional sprays to achieve sufficient control of late blight. Accordingly, 1-3 more sprays will be applied at the incoming decades of the 2025-2100.”

Authors: M.A. Fahim¹, M.K. Hassanein¹, A.F. Abou Hadid² and M.S. Kadah²
Affiliation: ¹Central Laboratory for Agricultural Climate, Giza, Egypt; ²Climate Change Information Center, Giza, Egypt
Title: Impacts of climate change on the widespread and epidemics of some tomato diseases during the last decade in Egypt
Publication: Acta Horticulturae. 2011. 914.