Tag Archives: weeds

Opium Poppies Need Pesticide Applications

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Opium

Opium Poppies

The opium poppy is cultivated in different parts of the world such as Tasmania, India, Pakistan, Slovakia, France, Spain, Yugoslavia and Italy.  The fruits of the poppy are rounded capsules. The liquid (milky latex) obtained after lancing the capsules contains opiates which are dried to produce raw opium, used for processing medicinal drugs such as codeine and morphine. The commercial production of opium poppies is adversely affected by uncontrolled weeds, insects and disease organisms. Commercial growers rely on pesticide applications as described in a recent article about poppy growing in Slovakia.

“The cropping system of poppy has seen important changes in recent years. In the past, growing this crop required a great deal of manual labor connected with singling, hoeing and particularly capsule collecting. At present, all operations of the large scale cropping system, from sowing to harvest, are fully mechanized. Registered pesticides are used to control weeds, diseases and pests.

Pre-emergent herbicides Callisto 480 SC (mesotrione), or Lentipur 500 FW + Command 36 CS (chlortoluron + clomazone) are applied within 3 days after sowing. Due to slow initial growth, the post-emergent application of herbicide in growth phase of 4-6 true leaves is usually necessary.

Protection against poppy root weevil is realized through seed treatment with Cruiser OSR preparation. …A dangerous pest of poppy is poppy weevil, against which the protection is aimed at the time of “hook stage”. Among the registered insecticides, Mospilan 20 SP (acetamiprid) and Nurelle D (chlorpyrifos + cypermethrin) are used.

Poppy downy mildew and poppy fire are considered to be the most dangerous diseases of poppy, in conditions of the Slovak Republic. Occurrence of downy mildew during the leaf rosette period is suppressed by seed treatment. …In the phase of stem elongation, application of Acrobat MZ WG (dimethomorph +mancozeb) is possible. In the “hook stage”, Discus (kresoxym-methyl) or Bumper Super (prochloraz + propiconazole) are used to suppress poppy fire on both leaves and capsules.”

Names: Fejer, J., and I. Salamon.
Affiliation: Presov University in Presov.
Title: Agro-Technology of the Poppy: Large-Scale Cultivation in Slovakia.
Source: Acta Hort. 2014. 1036:181-186.

Without Herbicides, Cranberry Beds Would Be Overwhelmed by Weeds and Growers Would Go Out of Business

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Treated vs Untreated

Herbicide Treated (L) vs Untreated (R)

71 - graph

The leaves of the cranberry plant form a dense mat over the surface. There are no paths through a cranberry bog. Weeds are particularly troublesome in cranberry bogs, since mechanical equipment (such as cultivators) cannot be used. The first synthetic chemical herbicide to receive widespread use in cranberries was registered in 1965 followed by two more in the 1970s. The use of these three herbicides is credited as the most important factor in the doubling of cranberry yields from 1960-1978. The introduction of glyphosate is credited with a steep increase in cranberry yields in the early 1980s.

“Without chemical pesticides fruit quality would be drastically reduced and it would be virtually impossible to economically produce a cranberry crop.

Without some selected herbicides or any herbicide, up to half of the growers would eventually go out of business because it would no longer be profitable to farm when their beds become overwhelmed by weeds in 5 to 10 years.

Without insecticides, fungicides, and herbicides, fruit quality would be drastically reduced. It would be virtually impossible to economically produce a cranberry crop. Ultimately, many growers would go out of business.”

Authors: Mahr, S. E. and Moffitt, L. J.
Affiliation: University of Wisconsin and University of Massachusetts.
Title: Biologic & Economic Assessment of Pesticide Usage on Cranberry.
Source: NAPIAP Report Number 2-CA-94-1994.

Herbicides Can Help in Making Tibet Food Secure

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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.

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

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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.

The Importance of Pendimethalin Herbicide in Greece

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field

Greek Cotton Field

Pendimethalin is normally used to control weeds on about 85% of the cotton and onion farms in Greece. During the last decade, the number of approved herbicides has drastically declined in Europe, leaving farmers with less choices and high weed control costs. Researchers at Aristotle University recently summarized the potential effects on Greek farmers if use of pendimethalin were to be stopped as a result of EU regulatory action.

“This work aims to determine the current state of experts’ knowledge, attitudes and beliefs regarding pendimethalin use in three crops (cotton, onion, processing tomato). The survey is focused on experts’ perceptions towards the necessity of pendimethalin in weed control, the advantages and disadvantages of pendimethalin and the probable impacts of pendimethalin withdrawal due to EU regulation or stoppage in manufacturing.

Any action of stoppage or withdrawal of pendimethalin from the market will bring about devastated effects on the farmers and crops, mainly due to lack of effective substitutes or herbicide combinations. The most significant impact, in case of pendimethalin withdrawal, would be a surge in production cost, since farmers must apply more costly and perhaps less effective weed control techniques (hoeing, covering land with plastic and using other combinations of herbicides).

…a Greek farmer hardly can harvest cotton without chemical weed control. Also, they stated that hardly can vision the possibility to cultivate onion, in the Viotia area, and cotton in Thessaly region without herbicide availability, since cost effective alternatives cannot being foreseen.

Then, considering the withdrawal effects of the use of pendimethalin in a regional level, the growers of cotton in Thessaly will lose a total of approximately €16.4 million of their gross production value and a total of approximately €7.3 million of their net revenues. …Finally, in a national level the growers of cotton in whole Greece will lose a total of approximately €42.8 million of their gross production value and a total of approximately €19.1 million of their net revenues.”

Authors: Mattas, K., et al.
Affiliations: Aristotle University of Thessaloniki.
Title: Economic assessment of Pendimethalin herbicide use in selective crops (cotton, processing tomato & onion).
Source: Aristotle University of Thessaloniki Working Papers No 166116 Available: http://EconPapers.repec.org/RePEc:ags:grauwp:166116.

Labor Shortages on Indian Tea Plantations Result in Need for Herbicides

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Scraping Weeds In Tea Fields

Scraping Weeds In Tea Fields

Historically, the most common method of weed control on tea plantations in India was to manually scrape the weeds off the surface of the soil. However, this is a labor-intensive method and needs to be repeated at regular intervals. The paucity of labor in the tea gardens of south India has made weeding a difficult exercise. Presently, tea growers rely heavily on herbicides to control weeds due to labor shortages for manual weeding.

“Grassy weeds reduce the productivity of tea by 21 per cent, while broad-leaved weeds accounts for 9-12 per cent. Weeds remove substantial amount of nutrients and moisture from the soil besides increasing the incidence of pests and diseases in crop by serving as alternate host.

Herbicides, as a tool for controlling weeds in tea plantations is very much popular and have been widely used ever since their introduction – primarily due to their cost effectiveness, efficiency in controlling diverse weed flora and less labour intensiveness, etc. Tea plantations alone use about 20 per cent of the total quantity of herbicides used in India.

Mechanical and manual control of weed are costly, time consuming, laborious and sometimes injurious to feeder roots of young tea plants in comparison to herbicidal control of weeds. Such methods are also limited by non-availability of labours in peak season.These methods require about 75 man days/ha annually for young tea and 35 man days for mature tea while, 15 man days/ha for young tea and 8 man days for mature tea in the first year are required for herbicidal control of weeds excluding the cost of herbicides.

At present, herbicides worth over Rs.7 crores are being used by tea industry of North East. India alone is expected to increase further in view of acute shortage of labours in time and escalating wages of labour.”

Authors: Rajkhowa, D. J., et al.
Affiliation: National Research Centre for Weed Science.
Title: Weed management in tea.
Source: NRC for Weed Science, Jabalpur.2005. Pgs. 3-13.

Warning: The Risks of NOT Using Herbicides

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DOODS

John Nalewaja                                                                             Homer LeBaron

For most people, weeds are usually regarded as innocuous. Controlling weeds with herbicides is practiced on a large-scale every year, largely unnoticed and unappreciated by most people. Scientists who have spent their careers studying weeds (weed scientists) know the potential risks of NOT using herbicides. Two prominent weed scientists have written eloquently about weeds and the importance of herbicides.

“Weeds are the silent, malignant, massive natural force which invades agricultural fields and paddies, spreads to deplete the soil moisture, devours the plant nutrients, and deprives crops of sunlight with severe devastation to crop yields. Weeds endanger the quantity of our food, feed, and fiber and enslave millions of men, women, and children in emerging nations to a laborious life of weeding with primitive methods and tools—machete, sickle, and hoe—just to escape starvation from day to day.”
-Nalewaja, J.D. 1972 [1]

“I maintain that never in history have so few done so much for so many in providing food and improved standard of living as weed scientists.  We have enjoyed a phenomenal success in providing the only consistent, dependable, efficient and economical means of weed control the world has ever known, even leading to surplus production on fewer acres…. We must educate the public and policy makers on the risks of not using herbicides.”
-LeBaron, H.M. 1990 [2]

Authors: [1] Nalewaja, J. D. [2] LeBaron, H. M.
Affiliations: [1] North Dakota State University [2] Syngenta.
Titles: [1] Weeds: coexistence or control. [2] Weed science in the 1990s: will it be forward or in reverse?
Sources: [1] Journal of Environmental Quality. 1972. 1(4):344-349. [2] Weed Technology. 1990. 4:671-689.

Australian Wheat Yields Have Doubled Thanks to Herbicides

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Australian Wheat Yield 1930-2010 (Trendlines)

Australian Wheat Yield 1930-2010 (Trendlines)

Australian wheat-growing areas are dry. Historically, tillage was used to remove weeds, but tillage further dried out the soil. Herbicides have made it possible for Australian wheat farmers to stop tilling entirely. As a result, soil moisture retention has increased and wheat yields have doubled.

“An analysis of the yield trends of wheat production in Australia showed that yields have increased by an average of 12-13 kg ha-1 year-1 over the past six decades, despite rainfall not changing and irrigated wheat contributing only a very small proportion to total production. A more recent analysis of wheat yield trends in Australia and the various states of Australia has shown that since the early 1980s there has been a more rapid increase in yield of over 30 kg ha-1 year-1. In Western Australia, where wheat is not irrigated and rainfall has probably declined over the last 25 years, the increases… arise solely from increases in rainfall-use efficiency.

However, the major impact of agronomic management on rainfall-use efficiency has not arisen from increasing total water use by the crop in evapotranspiration, but from increasing water use by the crop itself in transpiration at the expense of water loss by weeds or from the soil by soil evaporation, deep drainage, surface runoff, or lateral throughflow.

The use of minimum tillage or conservation tillage, whereby residues from the previous crop are left on the surface, weeds are controlled by herbicides rather than tillage, and the seed is sown with minimum disturbance of the soil surface by the use of narrow tines, has led to reduced losses of water by soil evaporation and increased yields. Further, minimum tillage systems allow earlier planting as delays resulting from using tillage to remove weeds are reduced.”

Author: Turner, N. C.
Affiliation: CSIRO Plant Industry.
Title: Agronomic options for improving rainfall-use efficiency of crops in dryland farming systems.
Source: Journal of Experimental Botany. 2004. 407[55]:2413-2425.

Restoring Nature in Hawaii with Herbicides

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Paintball gun herbicide warfare

Paintball gun herbicide application

The Nature Conservancy is the leading conservation organization working around the world to protect ecologically important lands and waters for nature and people. Invasive weeds are a major threat to natural areas and herbicides have made it possible to remove these unwanted species.

“Kaua’i is rugged and beautiful, but it is also threatened by a host of invasive plants and animals. One of those invaders is the Australian tree fern, a fast-reproducing ornamental that was brought to Kaua’i almost half a century ago to prettify resorts on the island’s North Shore. It rapidly grows frond to frond and crowds out native plants.

“I’ve been fighting weeds for 20 years and I’ve never seen anything like the Australian tree fern,” says Trae Menard, The Nature Conservancy’s director of forest conservation in Hawaii. “It’s a pretty bad weed.”

In 2001, The Nature Conservancy launched its program to fight the invaders. 

Much of the research and development has focused on the Australian tree fern—“an ecosystem dominator,” as Menard puts it—that has exploded across the island. Menard and his team have developed a wide-ranging arsenal that includes “the Stinger,” a precision herbicide dispenser slung underneath the helicopter, which Hobbs and other pilots use to spray individual Australian tree ferns. The team has also tested herbicide-packed pellets that can be fired by a crew member in the helicopter with a paintball gun. That kind of precision targeting, along with a formula tailored to the Australian tree fern, has allowed the weed fighters to kill a lot of plants with extremely small quantities of Imazapyr, a relatively short-lived herbicide that has almost no effect on animals.

“We treated over 4,000 tree ferns in a 5,000-acre area over a three-year period,” says Menard, “and we only used 11 gallons of herbicide.”

But the tide may be turning in the fight to save Kaua’i’s native forest. More than 90 percent of the mapped Australian tree ferns in  Wainiha Valley have been treated and killed, and Menard’s team is now preparing to attack ferns in neighboring Lumaha’i valley.”

Author: Jenkins, M.
Affiliation: Reporter.
Title: Pacific Invasion: on the Hawaiian island of Kaua’I, scientists are pioneering new technologies to combat a surge of superweeds that threaten native forests.
Source: Nature Conservancy. September/October 2013. Pgs. 51-59.

Herbicides Prevent Blindness in Sheep

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Sheep - NZ Pasture

Sheep – New Zealand Pasture

Eye Damage From Barley Grass

Eye Damage From Barley Grass

New Zealand is well-known for its lamb. Sheep and lambs feed in pastures. Barley grass is a common problematic weed in New Zealand pastures. The barbed spikes on barley grass seed can penetrate the eyes of sheep and can cause painful lesions, infections and blindness. Weight loss in lambs is attributed to their reluctance to feed in pastures infected with barley grass. Herbicides are used to remove the barley grass and early research in New Zealand demonstrated the benefits.

“An area of uniform barley grass (Hordeum murinum) infestation, in Waikato, was divided into twenty-four 0.2ha paddocks. Three chemicals… were used to control barley grass and the paddocks were grazed by lambs throughout the summer at two stocking rates.

All the chemicals reduced the barley grass content of the sward by over 96%, with pronamide giving 99% reduction, and significantly reduced Poa spp.

During the first month of the grazing period, the lambs on all chemical treatments at both stocking rates gained weight at approximately twice the rate of those on the untreated paddocks. …The control lambs (untreated paddocks) stopped gaining weight in mid-January and started to lose weight at the higher stocking rate.

The sudden growth check among the control lambs in mid-January coincided with maximum seed shed of the barley grass and is almost certainly attributable to the physical damage caused by the barley grass seed, especially to the eyes.

Initially the eye damage recorded was barley grass seed in the eyes but, at later stages, conjunctivitis and keratitis resulting from seed puncture and abrasion of the cornea.

During late January and throughout February, many of the control lambs were completely blind and were a pitiful sight. …this paper gives a clear indication of the benefits to stock and pasture that can arise from herbicide treatment.”

Authors: Hartley, M. J., and G. C. Atkinson.
Affiliation: Ruakura Agricultural Research Centre, Hamilton.
Title: Effect of chemical removal of barley grass on lamb growth rates.
Source: Proceedings of the New Zealand Plant Protection Society. 1972.