Tag Archives: fungicides

“Routing Pecan Scab – Protecting a Popular Nut”

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The pecan is native to North America. Serious development of orchards occurred in the early 1900s in the Southeast. Pecan scab has plagued the industry since these early days. It was not until the introduction of effective synthetic chemical fungicides in the 1960s that growers could effectively prevent losses to the fungus leading to a quadrupling in yields.

“Two of the main advances leading to the U.S. pecan industry’s success have been the introduction of fungicides and airblast spray technology for quickly and effectively dispersing pesticides throughout an orchard.”

“The approaches have quadrupled yields and boosted farmers’ profits.”

Author: T. Weaver
Affiliation: USDA ARS
Title: Routing Pecan Scab – Protecting a Popular Nut
Publication: Agricultural Research. 1998. August:8-9.

Italian Farmers Produce 700 Million Tons of Pears Thanks to Fungicides

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Italian farmers annually produce 700 million tons of pears, which require protection with fungicides from a disease known as brown spot. The fungus overwinters in leaf litter on the orchard floor and spores are released in the spring under wet conditions. Spots appear on the fruit and internal rots occur as the result of fungal invasion. Severe outbreaks can result in defoliation of the pear tree and fruit dropping off the tree.

“Stemphylium vesicarium is the causal agent of brown spot, the main fungal disease of pear in Italy since the late 1970s. … Many pear orchards in Po valley, the main pear growing area in Italy, are affected by this fungal disease that may cause heavy loss of production, up to 100%. … Besides some cultural practices, scheduled preventative applications of dithiocarbamates, dicarboximides, strobilurins and tebuconazole (DMI) from petal fall to fruit ripening are the only way to control the disease.”

Authors: G. Alberoni, M. Collina, D. Pancaldi and A. Brunelli
Affiliation: University of Bologna
Title: Resistance to dicarboximide fungicides in Stemphylium vesicarium of Italian pear orchards.
Publication: European Journal of Plant Pathology. 2005. 113:211-219.

Fungicides Essential to Carrot Production Worldwide

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Organisms that cause diseases on carrot foliage are present wherever carrots are grown. Research has demonstrated that using fungicides to control these foliar pathogens increases carrot yields by 4-8 tons/acre.

“Alternaria leaf blight (ALB) of carrot and cercospora leaf spot (CLS) contribute to significant and recurrent losses for the production of carrots worldwide. … Foliar pathogens defoliate carrots by infecting and blighting leaflets and petioles, which in turn limits photosynthesis and energy storage in roots. Several field studies have shown 20%-80% yield loss for unsprayed carrots compared with carrots subjected to a standard calendar fungicide program.”

“In addition to yield loss, deterioration of petiole and leaf health may reduce the commercial harvestability of roots since strong, healthy petioles are required to properly lift and remove carrots from the soil. When foliage is weakened by disease, additional crop losses ensue as unharvested roots are left behind in the field. … Repeated fungicide applications are expensive but necessary on susceptible carrot cultivars to maintain crop yield and value.” 

Authors: P.M. Rogers and W.R. Stevenson
Affiliation: Department of Plant Pathology, University of Wisconsin-Madison
Title: Integration of host resistance, disease monitoring, and reduced funigicide practices for the management of two foliar diseases of carrot.
Publication: Canadian Journal of Plant Pathology. 2006. 28:401-410.

Denmark Leads the World in Spinach Seed Production Thanks to Modern Crop Protection

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Denmark is a world leader in production of vegetable seeds that meet very high quality standards and are exported to growers around the world. In order to grow a high quality seed crop economically, Danish seed growers use herbicides to control weeds and fungicides to control plant diseases. Recently, an assessment was made as to whether Denmark can maintain its position as the leading spinach seed supplier, and the results show…

Can Denmark keep the position as the biggest spinach seed producer in the world?

  • Yes, if Denmark is allowed to use proper herbicides and fungicides
  • Yes, because Denmark has good climatical growing conditions for spinach – good soil, sufficient rain and long days
  • Yes, because Danish farmers are highly skilled and have top mechanization
  • Yes, because Danish seed companies have very good processing facilities
  • Yes, because Denmark has a very good infrastructure
  • and… Yes, because Denmark will fight for it!

Author: Henning van Veldhuizen
Title: Can Denmark keep the position as the biggest spinach seed producer in the world?Presented at: 2011 International Spinach Conference, October 3-4, Amsterdam, The Netherlands.

Cool Spring Weather Leads to Problems for Organic Potato Growers

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Organic growers are severely limited in the tools that they can use to fight fungal infections since they cannot use effective chemicals. One unhappy result was severe losses to diseases in the organic potato fields of Northern California last fall.

“John Crawford, part owner of Crawford Farms, Inc. for commercial farming and Cascade Farms for organic farming in Tulelake, said everyone across the county is two weeks behind on their potatoes. … The cool spring also contributed to problems with rhizoctonia disease… Rhizoctonia girdles the roots and the stem, then the plant withers and yield is reduced.”

“Rhizoctonia was a huge problem in Crawford’s conventional potatoes and crops would have a 100 percent infection rate. Now, with the new chemical compounds, he has good control. But Crawford said he continues to struggle with rhizoctonia in his organic potatoes. ‘It’s our worst enemy in organics because we really don’t have a natural compound that is very good at fighting it,’ he said, adding in one field of organic potatoes he estimates 75 percent are infected with rhizoctonia. … Crawford estimated at least a 20 percent yield loss from rhizoctonia damage.”

Author: Kathy Coatney
Title: Rhizoctonia and wilt create challenges for potato growers.
Publication: Ag Alert. September 14, 2011. p.18

China #1 Producer of Garlic Thanks to Fungicides

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China is by far the leading producer of garlic in the world, annually growing approximately 10.5 billion kilograms. Chinese garlic accounts for over 77% of world production. Following devastating outbreaks of leaf blight, research was conducted to determine the most effective means of controlling the disease.

“From autumn 2004 to spring 2008, leaf blight was found on garlic leaves in Dangyang County, Hubei, China, with the crop area affected estimated to be over 7000 ha. Garlic yield was reduced by 30% on average, with up to 70% yield losses in some fields during the winter growing season.”

“Epidemiology, cultivar resistance, and chemical controls were investigated during the 2006 to 2008 growing seasons in Dangyang County to improve disease control methods. … Relatively few of the commonly grown cultivars had high levels of resistance to leaf blight. … Fungicide applications in the field were effective in controlling leaf blight… As well, once symptoms are observed, field applications of the fungicides flusilazole (± famoxadone) or mancozeb are recommended to further combat disease.”

Authors: Lu Zheng¹, Rujing LV¹, Junbin Huang¹, Daohong Jiang¹, Xuhong Liu², Tom Hsiang³
Affiliation: ¹ Huazong Agricultural University, Wuhan, Hubei, China; ² Plant Protection Station, Dangyang County, Hubei, China; ³ University of Guelph, Guelph, Ontario, Canada
Title: Integrated control of garlic leaf blight caused by Stemphylium solani in China.
Publication: Canadian Journal of Plant Pathology. 2010. 32(2):135-145.

Fungicides Save Brazil’s Coffee Crop

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Coffee leaf rust is considered one of the most catastrophic plant diseases of all time. In the 1860s, coffee rust was largely responsible for destroying the coffee plantations of Ceylon (Sri Lanka), which had been the greatest coffee-producing country in the world. As coffee rust spread through Asia and Africa, coffee production increased significantly in Latin America where coffee rust was not present. However, coffee rust was detected in Brazil in 1970 and has since spread throughout Latin America, making fungicide use essential.

“In susceptible cultivars, chemical control has been the only option for decreasing the incidence of CLR on plants, and for reducing the harmful effects on the disease. The coffee growing regions in Brazil as well as almost all other coffee-producing regions worldwide are comprised of susceptible Coffea arabica and Coffea canephora cultivars (the latter is the second most widely cultivated coffee species). Preventive control of CLR in the main Brazilian coffee-producing regions consists from four to six applications of protective copper-based fungicides and two to three foliar applications of systemic fungicides.”

Authors: A. Fernando de Souza, L. Zambolim, V. Cintra de Jesus Jr., P.R. Cecon.
Affiliation: Federal University of Vicosa, Minas Gerais State, Brazil
Title: Chemical approaches to manage coffee leaf rust in drip irrigated trees
Publication: Australasian Plant Pathology. 2011. 40:293-300.

Fungicides are Key to Canada’s Large Chickpea Crop

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Chickpea is among the newest crops in West Canada, where it has been produced in sizeable quantity since 1997. Canada is now a competitive producer, processor and exporter of chickpeas, with exports valued at $50 million per year. Fungal diseases pose the most important constraints on chickpea production in Canada – ascochyta blight is the most problematic. Fungal infections cause initially small whitish spots that enlarge to become tan colored as the cells in the leaves die. Stem infections are considered very damaging as they often cause stem breakage, thereby destroying healthy branches.

“Ascochyta blight of chickpea has been a major biotic constraint to chickpea production in Saskatchewan where the vast majority of Canadian chickpea is grown. Under conditions conducive for disease development, yield losses of close to 100% have been encountered in the Canadian prairies. … Host plant resistance to the pathogen is partial and plants become increasingly more susceptible with the initiation of flowering. Major resistance breakdown due to genetic changes in pathogen populations has been observed in Saskatchewan.”

“The timely and efficient use of fungicides has remained a major factor in the successful management of the disease and the economic viability of the crop.”

Authors: S. Banniza¹, C.L. Armtrong-Cho¹, Y. Gan² and G. Chongo¹.
Affiliation: ¹Crop Development Centre, University of Saskatchewan; ²Agriculture and Agri-Food Canada, Saskatchewan
Title: Evaluation of fungicide efficacy and application frequency for the control of ascochyta blight in chickpea.
Publication: Canadian Journal of Plant Pathology. (2011) 33(2):135-149.

IPM Research in Turkish Tomato Fields Shows Importance of Fungicide Sprays

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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

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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.