The fungus p. infestans was first found in Europe causing the late blight rot of potatoes in the 1840s. In 1845/1846 the fungus destroyed all the potatoes in Ireland and 1.5 million people died. The fungus spread throughout Europe and caused potato crop failures until the late 1800s when the use of copper was found to be an effective fungicide for protecting potatoes from infection by p. infestans. The use of copper as a fungicide spray on potatoes became widespread throughout Europe in the early 1900s. However, in Germany during World War I, all the copper was requisitioned for making bullets. The German civilian population had become dependent on potatoes due to shortages of other foods. A late blight epidemic destroyed Germany’s potato crop in 1916 due to the lack of protection with a fungicide.
“…the last major famine caused by P. infestans occurred in 1916 during World War I. It resulted in the deaths of 700,000 German civilians, who were unable to protect their potato crop because copper was needed to produce bullets, rather than fungicides. Even today, more than 170 years after the Irish epidemic, frequent applications of fungicides are necessary to grow potatoes in moist climates, and losses occur even in dry areas, such as Israel and the western United States. Potatoes remain a fungicide-intensive crop, despite more than 150 years of study of P. infestans and the disease it causes.”
Authors: Schumann, G. L., and C. J. D’Arcy.
Affiliation: Marquette University, and University of Illinois.
Title: Hungry Planet: Stories of Plant Diseases.
Source: The American Phytopathological Society. 2012.
Greenhouse Industry, Almeria
Almeria is located in the region of Andalucia in southeastern Spain. It has an average temperature of 68° and about 3000 hours of annual sunshine. Vegetable production in greenhouses has increased dramatically in Almeria. At present, about half of the total production from this area is exported to the European Union, especially Germany, France and the Netherlands. Almeria has become very competitive because it is relying on selling via high quality and not on low prices. Spain will try to improve its export position by increasing its market share in other parts of the world. Not only are prices competitive from Spain, but also the quality of Spanish produce is excellent. Needless to say, moldy vegetables are not acceptable for export from Spain and the greenhouse crops are intensively sprayed with fungicides.
“Botrytis cinerea, is the causal agent of grey mould, one of the most important diseases of crops in Almeria, a region in south-east Spain where unheated plastic greenhouses cover an area of approximately 33.560 ha. Botrytis cinerea attacks a wide range of plant species in temperate zones and causes grey mould on many economically important crops such as vegetables, ornamentals, bulbs and fruit. Chemical control is the primary method for grey mould control, with alternative fungicides applied every 10 days, from November to March.”
Authors: Moyano, C., V. Gomez, and P. Melgarejo.
Affiliations: Department of Plant Protection, INIA, Ctra. De la Coruna, Spain.
Title: Resistance to pyrimethanil and other fungicides in Botrytis cinerea populations collected on vegetable crops in Spain.
Source: Journal of Phytopathology. 2004. 152:484-490.
The German population has access to high quality strawberries, blueberries and raspberries that are grown in the country every year. However, the climate in Germany is conducive for the growth of mold in the berry fields making fungicide use necessary.
“Small-fruit production is an important component of Northern German agriculture, covering some 4,000 ha of strawberry, 100 ha of raspberry, and 1,500 ha of highbush blueberry as well as smaller acreages of redcurrant, gooseberry, and blackberry. Under the cool and humid regional climatic conditions, several fungicide treatments at bloom are essential in order to control phytopathogenic fungi, notably the gray mold pathogen Botrytis cinerea.”
Author: R.W.S. Weber
Affiliation: Esteburg Fruit Research and Advisory Center, Jork, Germany
Title: Resistance of Botrytis cinerea to multiple fungicides in Northern German small-fruit production.
Publication: Plant Disease. 2011. 95(10):1263-1269.
In the 1950s and 1960s, as Germany industrialized, millions of workers moved from rural to urban areas and to factory jobs. When people left the farms, weed control technology was desperately needed to replace the major task of hand weeding crop fields. The introduction of herbicides saved German agriculture.
“Weeds cause drastic yield losses in food production, on average 25% in developing countries and 5% in developed countries, despite the control measures practiced. … Weed control is one of the major labour-consuming operations in traditional crop production, amounting from <30 up to about 70% of the total labour input.”
“In Germany, industry needed an increasing number of employees around 1960 and rural people left their fields. When this occurred there was no longer the question about traditional weed control with high labour input, but growing the crop with chemical weed control or no crop at all.”
Author: W. Koch
Affiliation: University of Hohenheim, Stuttgart, Germany
Title: Impact of weeds on developing countries.
Publication: Proceedings of the First International Weed Control Congress. 1992. Melbourne, Australia.
The biggest constraint to the expansion of organic crop growing is the lack of chemical controls for weeds – herbicides. Hand weeding is often required to remove weeds from organic fields. A very large number of worker hours are required for weeding, as reported in a recent article from Germany…
“In organic crop production, manual control of weeds is still laborious in a number of row crops that have poor competitive ability. It is difficult to control weeds that grow within the crop rows (intra-row weeds) by physical weed control; typical figures for hand-weeding time are in the range of 100-400 hours/hectare in carrot, direct-sown leek and onion, and it has even been reported to exceed 1000 hours/hectare.”
Authors: J Rasmussen¹, C B Henriksen¹, H W Griepentrog² and J Nielsen¹
Affiliations: ¹University of Copenhagen, Denmark; ²University of Hohenheim, Germany
Title: Punch planting, flame weeding and delayed sowing to reduce intra-row weeds in row crops.
Publication: Weed Research. 2011. 51:489-498.
Germany is a major sugar producer because of a significant number of sugar beet hectares. Historically, weeds were removed from these fields by handweeding. Today, however, herbicides are indispensable because such labor would be prohibitively costly, a point made recently by German researchers…..
“The application of herbicides in sugar beet is essential to prevent yield loss due to weed competition. … Consequently, herbicides are extensively used in sugar beet in almost 100% of the conventionally cultivated fields in Germany.”
Authors: Andreas Marwitz, Erwin Ladewig and Bernward Märländer
Affiliation: Institute of Sugar Beet Research, 37079 Göttingen, Germany
Title: Impact of herbicide application intensity in relation to environment and tillage on earthworm population in sugar beet in Germany.
Publication: European Journal of Agronomy. 2012. 39:25-34