Tag Archives: fungicides

The Story of Coffee Rust: Why the British Drink Tea

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In England in the early and mid-1800s, the most popular drink was coffee from plantations in Ceylon (Sri Lanka). When the coffee rust fungus destroyed Ceylon’s coffee trees in 1875, the plantations began growing tea.

“When the coffee rust fungus, Hemileia vastatrix, reached Ceylon in 1875, nearly 400,000 acres of the island were covered with coffee trees. No effective chemical fungicide was available to protect the foliage, so the fungus was able to colonize the leaves until nearly all the trees had been defoliated. … In 1870, Ceylon exported 100 million pounds of coffee. By 1889, production was down to 5 million pounds. In less than 20 years, many coffee plantations had been destroyed, and production had essentially ceased.”

“As the coffee trees were dying, however, the plantation owners noticed that the thousand or so acres of tea bushes were still healthy. …the owners replaced most of the dead coffee trees with tea bushes. By 1875, more than 1 billion tea seedlings had been planted on 300,000 acres—an amazing increase from the acreage planted only a few years earlier. … Luckily, no fungus invaded the tea crop immediately, and newly discovered fungicides were soon available to protect tea from its fungal pathogens.”

Authors: G.L. Shumann and C.J. D’Arcy
Publication: Hungry Planet: Stories of Plant Diseases. 2012. APS Press.

Without Fungicides, the Worldwide Export of Bananas Would Collapse

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About 34 billion pounds of bananas are exported around the world from tropical plantations. Black Sigatoka is the most important disease of bananas worldwide. The disease causes infected plant tissue to collapse; all leaves can be destroyed and bunches of unripe bananas can fall to the ground. Black Sigatoka is well controlled in export plantations thanks to fungicides.

“Without the frequent use of fungicides, the export trades could not control black Sigatoka and, thus, would be unable to produce profitable quantities of high quality fruit.”

“Despite recent advances in banana breeding, there are currently no resistant cultivars that could be used to replace [the most common cultivar] ‘Grand Nain’. Thus, fungicidal control of this disease will remain an absolute necessity in order for the trades to continue producing high quality fruit in the humid tropics.”

Author: R. Ploetz
Affiliation: Tropical Research & Education Center, University of Florida
Title: Black Sigatoka.
Publication: Pesticide Outlook. 2000. February:19-23.

Chile #1 Exporter of Table Grapes Thanks to Fungicides

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Chile leads the world in the export of table grapes. A major challenge for Chile is the distance from the fields to the export markets. The long distance makes necessary having grapes of extremely high quality that can endure the trip and have a long shelf life. Botrytis is a disease that severely affects stored table grapes because it can infect the grapes in the field and then continue to grow in the berries’ storage, producing nests of gray-white fungus. Botrytis is common in Chilean vineyards, so the development of mold is prevented by the use of fungicides.

“Gray mold caused by Botrytis cinerea is a common disease that causes important economical losses in grape production in Chile. Under cool and humid conditions, several fungicide treatments between bloom and harvest, in addition to cultural control measures, are essential to control gray mold of grapevines. … Gray mold requires several fungicide treatments to achieve satisfactory control in Chile.”

Authors: B.A. Latorre and R. Torres
Affiliation: Pontificia Universidad Católica de Chile, Santiago, Chile
Title: Prevalence of isolates of Botrytis cinerea resistant to multiple fungicides in Chilean vineyards.
Publication: Crop Protection. 2012. 40:49-52.

Commercial Wild Rice Production in Minnesota Depends on Fungicides

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Wild rice originated in Minnesota and the surrounding Great Lakes. It is the only cereal native to North America that has been domesticated from a wild plant. Before commercial production began, wild rice was difficult to obtain. The first commercial field of wild rice was planted in 1950 in Minnesota. After one season, fungal brown spot disease destroyed the second crop. In the next decade, fungal brown spot destroyed much of Minnesota’s wild rice crops – epidemics in 1973 and 1974 resulted in complete crop loss in many paddies. Ever since 1974 Minnesota growers have sprayed fungicides in order to produce commercial wild rice.

“Propiconazole, a systemic ergosterol biosynthesis-inhibiting fungicide, was evaluated for FBS control during 1985-1987 at the University of Minnesota North Central Experiment Station in Grand Rapids. In 1985 and 1986, propiconazole applications at both boot and heading stages of development increased yield by 68 and 40%, respectively, and in 1987 applications increased yield 113%.”

“Registration of propiconozale is crucial, because commercial wild rice production in Minnesota without fungicides may not be economically feasible.”

Author: D.R. Johnson and J.A. Percich
Affiliation: University of Minnesota, St. Paul
Title: Wild rice domestication, fungal brown spot disease, and the future of commercial production in Minnesota.
Publication: Plant Disease. 1992. December:1193-1198.

Repeat of Irish Potato Famine Unlikely Thanks to Fungicides

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The pathogen Phytophtera infestans causes a disease of potatoes called “late blight”. The pathogen grows in potato plants, breaking down cell walls so that it can use the nutrients found within them. Severely infected plants have an acrid odor which is the result of dying plant tissue. In the 1800s, Irish peasants subsisted almost entirely on potatoes. The late blight fungus arrived in 1845 and destroyed 40% of the Irish crop. In 1846, 100% of the crop was destroyed. Over 1.5 million Irish died of famine and a comparable number emigrated to America and other countries. Today, the fungus is still present in Ireland and would destroy the crop again if not for fungicides.

“Without the routine use of fungicides, large-scale commercial potato production in Ireland would be impossible. The cool, damp climate, which favours the cultivation of the potato and limits problems with virus diseases, is also ideal for the spread of blight. … In warm, wet weather when the humidity is high, P. infestans will lay waste an unprotected crop. … To prevent such devastating losses, the potato industry in Ireland has long been reliant on a substantial annual usage of fungicides.”

Author: L.R. Cooke
Affiliation: Plant Pathology Research Division, Department of Agriculture for Northern Ireland
Title: Potato blight control in Ireland: a challenging problem.
Publication: Pesticide Outlook. 1992. 13(4):28-31.

Apple Production in the UK Made Viable by Pesticides

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UK apple growers produce about 400 million pounds of apples per year. About 18 insecticide and fungicide sprays are made yearly to control pests including scab, mildew, aphids and codling moth. By applying a full spray program, good growers have restricted losses due to pests and diseases to very low levels, usually no more than 1-2%. Below, an economic cost-benefit study determined the likely effect on UK apple production if growers did not use pesticides…

“Apples are the most important fruit crop in the UK in terms of area of production and require relatively high levels of pesticide inputs. … If pesticides were not used, apple production would thus not be commercially viable, and the market shortfall would be made up by imports at a similar price. With a negative gross margin apple producers would leave the industry and find other uses for their land.”

Authors: J.P.G. Webster and R.G. Bowles
Affiliation: Farm Business Unit, Wye College, University of London, Kent, UK
Title: Estimating the economic costs and benefits of pesticide use in apples.
Publication: Proceedings of the Brighton Crop Protection Conference, Pests and Diseases. 1996. 4B-1:325-330.

The Consumer is Always Right and That’s Why Farmers Use Pesticides

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More than 90% of US fresh produce (fruits and vegetables) is sprayed with insecticides and fungicides to prevent rots and yield loss. This spraying also assures that there are no scabs or insect-feeding marks on the produce. Although some consumers would prefer no pesticide residues, many are unwilling to accept any cosmetic damage. You can’t have it both ways—picture-perfect produce requires pesticide use.

“Over 300 shoppers entering supermarkets completed a questionnaire about purchasing certified pesticide residue-free (CPRF) fresh produce. One-half expressed concern about pesticide use on fresh produce. Two-thirds were willing to pay 5 to 10% higher prices to obtain CPRF fresh produce, but were unwilling to accept any cosmetic defects or insect damage.” 

Author: S.L. Ott
Affiliation: USDA Economics Research Service
Title: Supermarket shoppers’ pesticide concerns and willingness to purchase certified pesticide residue-free fresh produce.
Publication: Agribusiness. 1990. 6(6):593-602.

Fungicides “Vital” for Potato Production in Myanmar

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Potato is a very popular vegetable crop in Myanmar and is essentially grown all year round. Phytophthora infestans, the fungus that caused the Irish Potato Famine in the 1840s, was first found in Southeast Asia in the late 1800s and has since been an annual widespread problem. Without fungicide protection, the disease spreads rapidly and can kill all the plants in a field within a few days.

“In Myanmar, late blight caused by Phytophthora infestans is the most destructive disease of potato. … High incidence and severity of potato late blight occur in this area because the crop can be found year-round at all stages of development, providing a constant source of primary inoculum.”

“At present, fungicide applications play a vital role in potato late blight control as resistant cultivars have not been widely available and adopted. … Fungicide is applied most frequently on post monsoon crops, which is when the weather conditions are ideal for late blight development.”

Author: M.M. Myint, Y.Y. Myint and H. Myint
Affiliation: Department of Plant Pathology, Yezin Agricultural University, Yezin, Myanmar
Title: Occurrence and growers’ perception of potato late blight in Kalaw Township, Myanmar.
Publication: Regional Workshop on Potato Late Blight for East and Southeast Asia and the Pacific Proceedings. 2004. 24-25 August, Yezin, Myanmar.

China Protects Their #1 Ranking in Pears with Fungicides

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Records suggest that China has cultivated pears for well over 2500 years. China ranks first in the world in pear production, growing 75% of the world’s output. Annual production has increased twenty-fold in China since the 1950s. A key to production is protecting pears from a disease known as pear scab, which is caused by a fungus that overwinters in leaves on the ground. Spores are released as a result of rain and are carried by air currents to leaves and fruit. Scab lesions form on fruit and, as they enlarge, become large black areas. Fungicides are used in China to prevent pear scab infections.

“Pear scab (Venturia nashicola) is an economically important disease in China. The pathogen is different from the European pear scab fungus (V. pirina) and causes significant annual yield loss on pears, especially on traditional Chinese varieties. … Infection by V. nashicola can occur at any time throughout the growing season from early spring until late autumn, if environmental conditions are conducive. Leaves and fruits become gradually less susceptible to infection as they age. Pear scab in China is managed by routine application of fungicides.”

Authors: Li, B.-H.¹, J.-R. Yang², B-D. Li¹ and X.-M. Xu³
Affiliation: ¹Laiyang Agricultural College, Shangdong Province, China; ² Northwest A & F University, Shaanxi, China; ³ East Malling Research, Kent, UK.
Title: Incidence-density relationship of pear scab (Venturia nashicola) on fruits and leaves.
Publication: Plant Pathology. 2007. 56:120-127.

Want Cranberries from Oregon? Growers Have to Attack Fungal Rots

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Cranberries are subject to infections by pathogens that cause rots. These pathogens are controlled with fungicide applications. Under cool, wet spring conditions the disease problem worsens, requiring additional sprays.

“Statewide, the USDA National Agricultural Statistics Service on Aug. 14 projected Oregon’s 2012 cranberry crop at 400,000 barrels, up 11 percent from las year’s 361,000 barrel crop.”

“One drawback for Oregon growers this year has been rising production costs, as growers increased fungicide treatments to avoid losses to disease. Donaldson and Anderson [two Oregon cranberry growers] said they applied between one and two additional fungicide treatments, as a cool, wet spring triggered heavy disease pressure. … ‘For years, I escaped by doing minimal fungicide treatment, but this year we had to attack (the diseases),’ Anderson said.”

Author: Mitch Lies
Headline: Cranberry growers keep an eye on spotty yields.
Publication: Capital Press. Friday, August 24, 2012.