Too Great a Risk: Organic Rapeseed Growing in the EU

Rapeseed Field

Rapeseed Field

Humans have used oil pressed from the seeds of plants known as rape for thousands of years. The name rape originated from the Latin word “rapum” which means turnip. Oilseed rape has enjoyed unprecedented popularity in the EU since the 1970s due to support from the Common Agricultural Policy. European production of rapeseed plays an important role in increasing EU self sufficiency in cooking oil. Oilseed rape is harvested from about 3 million hectares in the EU. The crop is attacked by a large number of insects and insecticide use is common. There is little organic rapeseed production in the EU because the insects cannot be effectively controlled.

“The demand for organic winter oilseed rape is steadily increasing. Yet in Germany, for example, oil seed rape cultivation is negligible with a maximum cropping area of 4,000 ha. One important reason for this is the occurrence of insect pests, including the cabbage stem flea beetle, the rape stem weevil, the cabbage stem weevil, the pollen beetle, the cabbage seedpod weevil, and the brassica pod midge. Pest-related yield losses – up to total loss of the crop – make the cultivation of organic winter oilseed rape an incalculable risk.”

Authors: Ludwig, T. and S. Kuhne.
Affiliation: Federal Research Centre for Cultivated Plants.
Title: Mixed cropping with turnip rape and natural insecticides: results of field and laboratory trials on pest control in organic winter oilseed rape.
Source: Integrated Control in Oilseed Crops IOBC-WPRS Bulletin. 2013. 96:43-44.

Artichokes (California’s Official Vegetable) Would be Heavily Damaged Without Insecticides

Artichoke Plume Moth Damage

Artichoke Plume Moth Damage

Artichoke Plume Moth Larvae

Artichoke Plume Moth Larvae

In 2013, artichokes were proclaimed to be California’s official vegetable.99.99% of all commercially-grown artichokes are grown in California. The artichoke is a member of the thistle family and was introduced into California in the mid-1800s where it was met by a native insect that had been feeding on wild thistle plants. The insect quickly adapted and began feeding on artichokes and has become known as the artichoke plume moth. Losses result when they feed on artichoke buds and make them unmarketable due to tunneling in the leaves, borings inside the heads, and a blackening of the heads resulting from feeding and frass exudation. Before the introduction of chemical insecticides in the early 1950s, 50-70% of California’s artichokes were unmarketable because of the moth damage.

“Artichoke plume moth (APM), Platyptilia carduidactyla (riley) (Lepidoptera: Pterophoridae) is the most serious and persistent pest of artichokes in California. If unchecked, 70% of the artichoke buds are rendered unmarketable from worm damage. Insecticides are the most important and sole means currently used for the management of this pest.”

Author: Bari, M. A.
Affiliation: Artichoke Research Association.
Title: A potential alternative in the control of artichoke plume moth.
Source: CAPCA Advisor. 2007. October. Pgs. 58-60.

Surprise! Your Strawberries are Moldy

Grey mold on strawberries

Gray mold on strawberries

Consumers sometimes buy picture-perfect strawberries only to find them covered in mold after a few days. The cause: the gray mold fungus which infects the berries in the field but which remains symptomless until the fruit ripens. The fungus produces a velvety gray growth on the surface of the berry. Gray mold spreads in shipping containers when the fungus grows from a rotting berry to an adjacent healthy fruit. 100% of US strawberry acres are estimated to be infected with the gray mold fungus. Widespread infections are prevented with fungicide treatments.

“Gray mold is one of the most economically important diseases of cultivated strawberry (Fragaria × ananassa), and a significant threat to the United States’ $2.4 billion strawberry crop… Crop losses resulting from gray mold disease are especially severe under moist weather conditions, and occur not only during the crop growing season but also after harvest and during storage and transit.

The control of gray mold in commercial strawberry fields is largely dependent on the application of fungicides during bloom and fruit maturation.”

Authors: Grabke, A., et al.
Affiliation: Clemson University.
Title: Fenhexamid resistance in Botrytis cinerea from strawberry fields in the Carolinas is associated with four target gene mutations.
Source: Plant Disease. 2013. 97[2]:271-276.

Fungicides Enable China to Lead in Global Production of Vegetables

Greenhouses in China

Greenhouses in China

China produces nearly half of the world’s vegetables- five times the U.S. share. China’s increase in vegetable acreage between 2000 and 2004 (5.7 million acres) exceeded the entire vegetable acreage in the United States (3.7 million acres). China’s vegetable production has grown mainly to meet domestic demand from its 1.3 billion citizens. There are over 7.3 million acres of greenhouse crops in China and the growing conditions in the greenhouses are conducive to fungal outbreaks making fungicide use necessary.

“Gray mold caused by B. cinerea has become one of the most economically important diseases, since the rapid development of greenhouse cultivation in the 1990s in eastern China. B. cinerea severely reduces the yield and quality of greenhouse vegetables such as eggplant, tomato, cucumber and pepper. Jiangsu and Zhejiang provinces are the major vegetable production regions of eastern China, where unheated plastic greenhouses have been in use since 1998. Growers depend on regular fungicide treatments approximately every 7 days from November to May, besides some cultural practices such as ventilation to control the epidemic of B. cinerea.”

Authors: Zhang, C. Q., et al.
Affiliation: School of Agriculture and Food Science, Zhejiang Forest College, China.
Title: Evolution of resistance to different classes of fungicides in Botrytis cinerea from greenhouse vegetables in eastern China.
Source: Phytoparasitica. 2009. 37:351-359.

Fungicides Protect South African Grapes from Rot

Bunch Rot

Bunch Rot

South Africa ranks eleventh in the world for grape production. Wine is South Africa’s biggest agricultural export, earning R2.2 billion in foreign exchange annually. South African farmers also produce about 1.8 million tons of table and dry grapes annually. The industry is primarily export oriented with up to 90% of the total production being exported with a value of R1.5 billion per year. The majority of South African grapes are available in northern hemisphere countries during their winter and spring seasons. Fungicide spray programs are commonly applied in South African vineyards to control Botrytis bunch rot.

Botrytis cinerea Pers: Fr. is a common, destructive pathogen causing grey mould. …In South Africa, this is an economically important disease on grapevines. …In table grape production, the most serious damage is the loss of fruit quality due to pre-harvest or post-harvest berry rots. …In wine grape production, the fungus causes a serious decrease in quality of juice and wine. Wines produced from B. cinerea infected berries have off-flavours and are sensitive to oxidation and bacterial contamination, making them unsuitable for ageing.

Chemical control is the main way to reduce grey mould on crops. Producers in South Africa invest heavily in chemical products and routine spray applications each year.”

Authors: van Zyl, S. A., et al.
Affiliation: Department of Plant Pathology, University of Stellenbosch, South Africa.
Title: The use of adjuvants to improve spray deposition and Botrytis cinerea control on Chardonnay grapevine leaves.
Source: Crop Protection. 2010. 29:58-67.

Herbicides Can Help in Making Tibet Food Secure

Farmland in Tibet

Farmland in Tibet

Tibet is isolated from the outside world by physical inaccessibility. Physical remoteness is exacerbated by the lack of roads. However, even though some roads exist, the long distance contributes to remoteness. In such circumstances, to produce enough food within the region and to minimize the dependency of acquiring food through exchange are the essence of food security. Crop yields in Tibet could be much higher. It is suspected that uncontrolled weeds are a major cause of low yields in Tibet and herbicides could be an effective technology to making Tibet food secure.

“In the south of the Tibet Autonomous Region of China there is a network of valleys where intensive agriculture is practiced. Although considered highly productive by Tibetans, farm incomes in the region are low, leading to a range of government initiatives to boost grain and fodder production. … Average yields for the main grain crops are around 4.0 t/ha for spring barley and 4.5 t/ha for winter wheat, significantly lower than should be possible in the environment.

…there is a large gap between attainable yields in Tibet and those that are typically attained on farms in the cropping zone.

There is a need to identify the most important weeds on Tibetan farms and the yield penalties they impose. If weeds do prove to be a significant constraint, as is suspected, a program to improve the availability and affordability of herbicides to Tibetan farmers, and to train farmers in their effective and safe use, should lead to crop yield increases. There is also a need to promote integrated weed management practices that combine cultural and manual control methods with the use of clean seed, targeted rotations, and herbicides.

In recent decades, there has been a major shift around the world towards no-till farming systems, in which weeds are controlled using herbicides before crops are sown into undisturbed soil using no-till seed drills. Such seeding systems would likely offer several benefits in Tibet: viz. lower crop establishment costs (e.g. for fuel and labour), less disturbance to soil structure, less disturbance to levelness of fields, and the option of retaining more stubble without impeding sowing for improved soil health.”

Authors: Paltridge, N., et al.
Affiliation: The University of Adelaide, Australia.
Title: Agriculture in Central Tibet: an assessment of climate, farming systems, and strategies to boost production.
Source: Crop & Pasture Science. 2009. 60:627-639.

Desert Locust Plagues Managed with Insecticides

49-2

Spraying for locusts

49

Locust swarm

Since prehistoric times, plagues of desert locusts (a large grasshopper that swarms) have threatened food production in Africa, the Middle East and Asia. The swarms may cover several hundred square kilometers and contain 50 million locusts per square kilometer. A square kilometer of locusts can consume about 100 tons of crops per day. Regular monitoring of locust breeding areas and targeted insecticide sprays as populations increase prevent plagues most years. However, monitoring locust breeding areas can be difficult as many are located in remote areas or are in areas inaccessible due to border disputes and lack of security. When major outbreaks occur, widespread insecticide spraying is necessary.

“When locust upsurges and plagues develop, large scale control campaigns must be mounted on an emergency basis. These campaigns are expensive, use large quantities of insecticide and involve external assistance. During the last plague of 1986-89, some 40 countries were affected and more than 14 million hectares were treated. The total amount of assistance provide by the international community during the plague was about US$ 250 million. The total amount of assistance provided by the international community  during the last major upsurge from 2003-2005 was about 400 million US Dollars where about 13 million litres of pesticides were used to treat 13 million hectare in 11 countries.

Ground and aerial application of chemical pesticides is the only viable method of locust control at present.”

Authors: FAO
Title: Workshop on Spray Equipment Used in Desert Locust Control, 10-14, May. 2009.

Herbicide Technology Can Reduce Massive Crop Losses Caused by Parasitic Weeds in Africa

Treated vs. Un-treated

Treated (back) vs. Un-treated (front)

The parasitic weed Striga causes yield losses of 30-80% on 2.5 million hectares of crops in Africa. Striga seeds germinate and attach themselves to the roots of crop plants below ground. Striga sucks nutrients and water from the crop plant. The purple Striga flower appears above ground attached to the crop plant. A promising herbicide technology has been developed. The crop seed is coated with a herbicide. Striga seeds germinate, attach to the crop root and are killed by the herbicide. The herbicide technology is known as “IR-maize.”

Striga hermonthica (L.) Benth. or witchweed is a parasitic weed that attacks maize, sorghum, and pearl millet. It has become an increasing problem to small-scale subsistence farmers in sub-Saharan Africa and represents today the largest single biological barrier to food production in the region…. Striga infestations can become so severe in all major cereal producing regions of Africa that farmers will abandon their fields to cereal production and therefore large swathes of Africa will be precluded from becoming major cereal producing areas.

With this seed coating technology, Striga seeds after germination and before attachment and Striga seedlings that attach are controlled when the herbicide concentration in the soil or plant is adequate, thereby protecting the maize plant when it is most sensitive to parasitism.

New technologies being developed should be tested on-farm, under researcher- as well as under farmer-managed conditions before general dissemination…. Therefore, a set of trials, surveys, and farmer evaluations were conducted in western Kenya, parallel to the development of IR-maize.

IR-maize showed good Striga control and a dramatic yield increase of 2,400 kg ha−1 (from 1,300 to 3,700 kg ha−1).”

Authors: Ransom, J., et al.
Affiliations: North Dakota State University.
Title: Herbicide applied to imidazolinone resistant-maize seed as a Striga control option for small-scale African farmers.
Source: Weed Science. 2012. 60[2]:283-289.

700,000 Germans Died Due to Fungicide Shortage

Potato blight

Potato blight

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.

After a 20 Year “Emergency” California Walnut Growers Can Rest Easy With Full Fungicide Registration

Walnut Blight Spraying

Walnut Blight Spraying

For 20 years, California walnut growers had to convince the EPA to grant a temporary emergency registration for a fungicide to control annual outbreaks of walnut blight. At the same time, the growers assembled the data necessary to make a full registration possible. After 20 years, the EPA granted the full registration and the walnut growers can rest easy.

“Depending on variety, walnut blight can take a heavy toll on walnut production, particularly when inoculum is high and spring weather is warm and wet.

However, with the federal EPA granting Manzate (flowable or dry flowable formulations) a Section 3 registration last year, walnut growers throughout California now have a reliable option for controlling the disease. For the previous two decades, growers in the state could use this and other ethylene bis-dithio-carbamates (EBDCs) products to treat for walnut blight only in selected counties under a Section 18 (emergency exemption) registration. Applying for Section 18 registration required submitting extensive environmental, health and safety data each year.

The walnut blight bacterium (Xanthomonas arboricola pv juglandis) over-winters in dormant buds primarily under the outer bud scales or cataphylls. When buds break in the spring, cataphylls open and young shoots extend past them. Rain drops spread the disease by splashing bacteria onto any green tissue, infecting them.

The disease appears as black lesions on green tissue. As bacteria spread inside the walnut, they grow toward the center of the nut early in the season, destroying the developing kernel.

In orchards with histories of walnut blight damage, protective treatments at seven to 10-day intervals during prolonged wet springs are necessary for adequate disease control.”

Author: Northcutt, G.
Affiliation: Reporter.
Title: Tips for better control of walnut blight.
Source: Western Farm Press. 2014-04-09. Available: http://westernfarmpress.com/tree-nuts/tips-better-control-walnut-blight