Wednesday, August 13, 2014

Which Pesticides are used on our Apples? | Chem Service Pesticides| Greyhound chromatography

Which pesticides are used on our apples?


Apples are a huge commodity in the U.S. and much of the rest of the world. In 2012, the U.S. harvested about 9 billion pounds for commercial use and sale. Apples are the second most popular fruit for U.S. consumers following oranges and represent a $3.1 billion industry.

Apples are also listed as one of the foods with the most pesticide residue. Environmental Working Group, a non-profit organization, listed apples in its 2012 "dirty dozen" list. It came in first place as the top fruit or vegetable with pesticide residues found. The Wall Street Journal reported that 98 percent of the apples tested positive for at least trace amounts of pesticide residues. However, only 1 out of 744 U.S. Department of Agriculture-tested apples were above acceptable standards.

Although EWG advises consumers not to stop eating fruits and vegetables because of pesticide concern, it is interesting to many chemists, farmers and consumers to know exactly which chemicals are on U.S. apples when they are purchased in the store. Here are a few of the most common pesticides used for this major crop.

Chlorpyrifos is an organophosphate insecticide that has been used since the mid-1960s. Chemically named O,O-Diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate, chlorpyrifos is also known as Dursban, Lorsban, Whirlwind, Warhawk and Eraser. More than 10 million pounds of chlorpyrifos are used on crops each year, with more than half being applied to corn. Chlorpyrifos may lead to nervous system damage for humans, including paralysis and death in high doses, the Environmental Protection Agency explained.

Diphenylamine shows up on apples more than any other pesticide, possibly because it is used post harvest rather than in the orchard to prevent scald, which is a browning of the skin. This pesticide has been used since 1947, although since the 1990s the U.S. government has begun regulation changes. It is banned in Europe for use on apples. Written as C12H11N, diphenylamine is also known as DPA, N-phenylaniline, anilinobenzene, N-phenylbenzenamine and benzenamine.

Captan is a thiophthalimide chemical compound used on apples as a fungicide. Captan, or (3aR,7aS)-2-[(trichloromethyl)sulfanyl]-3a,4,7,7a-tetrahydro-1H-isoindole-1,3(2H)-dione, is chemically written as C9H8Cl3NO2S and used for a number of personal care and industrial products, such as cosmetics and vinyl. It is applied to apples during growth to prevent fungi that could ruin the crop. Negative effects of Captan use include conjunctivitis and dermatitis in low quantities and gastrointestinal stress in higher quantities.

There are many other herbicides, insecticides and fungicides used for apple production, some of which carry potentially damaging side effects. This highlights the importance of correct pesticide use and standards testing for anyone involved.

Author:  Christopher Boyd  August 1, 2014

Chem Service products are supplied by Greyhound Chromatography and Allied Chemicals, 6 Kelvin Park, Birkenhead, Merseyside,

CH41 1LT  Tel:  +44 (0) 151 649 4000   Email:

Wednesday, August 13, 2014

Quinmerac is an Effective Selective Herbicide | Chem Service Certified Reference Standards | Greyhound Chromatography

Quinmerac is an effective selective herbicide


Quinmerac is a synthetic herbicide from the quinoline group that has been around since the early 1990s. Used mainly on cereals and beets, it is widely applied to crops throughout Europe in pesticide mixtures.

Chemically referred to as 7-chloro-3-methylquinoline-8-carboxylic acid and written as C11H8ClNO2, quinmerac is typically mixed with metazachlor or another active ingredient to boost its herbicidal properties. Although the addition of metazachlor has raised concerns of its selectiveness in some instances, quinmerac with metazachlor is particularly effective against rapeseed, which is a growing commodity. The pesticide is commercially known as Novall or Katamaran.

Rapeseed oil - sometimes referred to as canola oil - is a steadily growing commodity. According to Soytech, rapeseed production in Europe alone has increased by more than 13 times between the 1950s and the mid-2000s. It has become one of the most popular vegetable oils and is eaten regularly as a vegetable in China.

When quinmerac is mixed with chloridazon, it has been used with sugar beets, sold as Rebell in some places. Recently, China approved the registration of a 96 percent quinmerac pesticide from the company Henan Yingtai Agrochemical, AgroNews reported.

How does quinmerac work?
Quinmerac is absorbed through the roots rather than the leaves, working to limit growth and eliminate weeds. It works best when wet and can be applied to the soil surrounding crops. Standards testing while using quinmerac can be critical to ensure a correct concentration, purity or mixture of substances.

In a European Food Safety Authority study of quinmerac, the researchers found that residues found on plants were low and that mammalian toxicity was not of significant concern. It did not impact reproduction, irritate skin or have carcinogenic effects on the animals tested. There were lower red blood cell counts in dogs however, but the herbicide was generally not rated as dangerous.

Quinmerac was also found to have no significant impact on birds, bees or other land animals when used properly. However, the EFSA did warn against its danger to water creatures.

"Based on the data available quinmerac was considered to be harmful to aquatic organisms, whereas the formulation (including metazachlor) was found to be very acutely toxic to aquatic organisms. The metabolites BH 518-2 and BH 518-5 were found to be of similar or less toxicity than the parent substance," the EFSA wrote.

The aquatic dangers underscore the importance of safe usage when applying this herbicide. If a spill of does occur, Farm Chemicals International magazine recommended that chemists or farmers dam off the area, pump it into safe containers and follow proper disposal instructions.

Author:  Christopher Boyd, Chem Service In:  August 1, 2014

Chem Service products are supplied by Greyhound Chromatography and Allied Chemicals, 6 Kelvin Park, Birkenhead, Merseyside,

CH41 1LT  Tel: +44 (0) 151 649 4000     Email:

Wednesday, August 13, 2014

Pyroxasulfone the pesticide of the future | Greyhound Chromatography Pesticides

Pyroxasulfone looks to be the pesticide of the future

Pyroxasulfone is a new herbicide that has been registered for use on major crops including corn and soy. People across the industry are excited for pyroxasulfone because this active ingredient in several new pesticide mixtures could have a big impact on the commercial agricultural community.

This herbicide is a different chemistry class – it is an isoxazoline. This means that pyroxasulfone brings more activity to a broader spectrum of small-seeded plants than other, older chemicals. Although new, pyroxasulfone has been compared to acetamide herbicides such as metolachlor and dimethenamid in the way it works. Pennsylvania State University College of Agricultural Studies examined pyroxasulfone and compared it to other products on the market. It found that farmers would not need to use as much pyroxasulfone on their crops as they did with other pesticides.

"Pyroxasulfone has annual grass activity similar to metolachlor (Dual) and acetochlor (Harness) but also provides good control of several annual broadleaves," Penn State explained. "A major difference is that pyroxasulfone has a higher specific activity which allows active ingredient (ai) rates that are about 8 times lower than Dual or Harness with comparable weed control. The maximum labeled rate for pyroxasulfone is 3 oz ai per acre where s-metolachlor (Dual Magnum) is generally used at 21 to 26 oz ai per acre in our area."

Penn State's research also found that pyroxasulfone binds with clay in the soil which can make it more effective against weeds for longer. The bonding to organic materials in the soil is one of the reasons that farmers are so excited for this product, because it can last throughout much of a season. Over the 10 years that the university conducted research, the chemicals were found to be safe and effective for weed control.

A new pesticide from a new chemistry class
​Pyroxasulfone is a VLCFAE inhibitor with the International Union of Pure and Applied Chemistry label 5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)pyrazol-4-ylmethyl 4,5-dihydro-5,5-dimethyl-1,2-oxazol-3-yl sulfone. The herbicides Anthem from FMC, Fierce from Valent, and Zidua from BASF are among the products that use pyroxasulfone as a new ingredient. All three have been approved for use on corn, while only Zidua and Fierce are registered for soy. Some products may also be approved for cotton and wheat.

This chemical compound works well against annual grass weeds, lambsquarters, waterhemp, pigweed, ragweed and black nightshade according to The Ohio State University's Crop Observation and Recommendation Network. The new herbicide is not particularly effective against marestail however, which is a major weed in many U.S. farming areas such as Ohio and Indiana.

Chemically written as C12H14F5N3O4S, pyroxasulfone carries a chemical weight of 391.3. This new herbicide has a white crystal structure and has a slight smell, according to Kumiai Chemical Industry Co., Ltd. It also has a water solubility of 3.49 milligrams per liter at 20 degrees Celsius.

​Pyroxasulfone can be toxic to aquatic life and pose risks to human organs with repeated exposure. People should wear proper safety clothing and review the safety data sheet when using the chemical compound in any capacity. Standards testing of ​pyroxasulfone is important because only such a small amount is needed for even large agricultural applications.

Author:  Christopher Boyd, Chem Service,   August 6, 2014

Chem Service products are available from Greyhound Chromatography and Allied Chemicals, 6 Kelvin Park, Birkenhead, Merseyside,

CH41 1LT  Tel: +44 (0) 151 649 4000    Email:

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