The principle and use of pencycuron and carbendazim

Pencycuron and carbendazim are the two kinds of fungicide that people often used, but because of their different action principles, the uses are also different.

There are two basic classifications of　fungicides: Contact fungicides and　Systemic fungicides.pencycuron belongs to Contact fungicides, carbendazim belongs to Systemic fungicides.

Contact fungicides: Contacts remain on the outside of the plant and form a protective barrier against diseases that penetrate the leaf blade.

Systemic fungicides: Systemics enter inside the plant and travel throughout the plant"s vascular system. They are both protective and curative before and after the disease has started.

Contacts Fungicides
After application, contact fungicides will remain on the surface of the plant. They do not penetrate enter into the plant as systemic lawn fungicides do. The primary purpose of contact fungicides is to form a protective barrier against diseases that enter through the leaf blade. In most cases, it needs to be applied before the disease begins.
Most Contacts have as short residual and are only effective for three to eight days. After that, it will need to be reapplied. The fungicide needs to remain on the surface of the blade the entire time to be effective. This means it should not be watered in. You will need to turn off your automatic sprinklers to keep from washing it off. If it rains after the application, it may need to be reapplied.
Mowing or heavy foot traffic may remove the product from the grass making it less effective.
Contacts will not have any effect on diseases that enter the grass through the root system. Anything below the surface of the ground is out of the range of contact fungicides. They will not protect any new blades that develop after the contact was applied. It can only protect the grass it touched when it was applied.

Systemic Fungicides
Systemics, on the other hand, will penetrate the grass blade or enter through the roots and work from the inside. They are longer lasting than contacts and will often last from 7 to 25 days or longer. They can be both curative (after the disease starts) and protective (before the disease begins). It often needs to be watered in after application to get the fungicide down to the root zone. Read the label carefully for specific directions on how to do that.
Systemic lawn fungicides will attack lawn fungus from the inside. Any disease that enters from any point on the plant will be subject to the fungicide. This includes any new plant growth that occurred after the fungicide was applied.
Systemics and contacts are often alternated to get the benefits of both types of fungicides.

Thus in the use process, pencycuron often used to do FS and spray for sterilization, carbendazim can be irrigated to root and absorbed by plant for sterilization.

from:Yangzhou pioneer chemical CO., LTD

The useage of herbicides just like dicamba in growing oat

Lanoie, N., Vanasse, A., Collin, J., Fregeau-Reid, J., Pageau, D., Lajeunesse, J. and Durand, J. 2010. Naked oat response to soil type and herbicides applied at two growing stages. Can. J. Plant Sci. 90: 247-255. Naked oat (Avena saliva L.) harvested in the province of Quebec, Canada, develops on average 10% covered grains and sometimes more. The objective of this study was to determine the effect of soil type, herbicides and their application stages on the proportion of covered grains in naked oat genotypes. Three genotypes were evaluated over 2 yr at two experimental sites. At each site, trials were seeded on two different soil types and each entry was treated with one of three types of herbicides: bromoxynil/MCPA, dicamba/MCPA and thifensulfuron methyl/tribenuron methyl, and compared with a weed-free check. The herbicides were applied at Zadoks 12-13 and 22-23. Results showed that dicamba/MCPA herbicide, applied at Zadoks 12-13, increased covered grains compared with the weed-free check and more covered grains were produced with the application made at Zadoks 22-23. However, differences in genotype reactions were observed. Few differences were found among the other weed control treatments. The application of dicamba/MCPA at Zadoks 22-23 decreased yield and test weight, but increased kernel weight. The other weed control treatments had no effect on agronomic characteristics.
Yangzhou pioneer chemical CO.,LTD

Dicamba resistance getting closer

Not long ago, researchers from universities and seed companies would tell growers and industry stakeholders that the road from an idea’s first concept to commercial availability was a process of 10 to 15 years. Through transgenics, dihaploid technology and nurseries in Central or South America, seed companies and researchers have reduced that time significantly.

Yet in imparting dicamba resistance to soybeans, researchers at the University of Nebraska at Lincoln (UNL) have opted for the ‘slow and steady’ approach, and for good reason. “It has been quite a complex study of biochemistry, molecular biology and microbiology,” explains Dr. Don Weeks, a biochemist and professor, who has been a lead researcher on this project for nearly a dozen years. Although news of its development came to light in May 2007, Weeks concedes word has been very slow to reach both the scientific and farming communities.
The road to developing resistance began with a simple premise: after just a few months, dicamba cannot be detected in soil. The question became, ‘Can the chemistry that works so well against broadleaf weeds in corn and wheat be used on broadleaf weeds in soybean fields without hurting them?’ The degradation that dicamba experiences comes almost entirely from the interaction of numerous bacterial strains and other life forms naturally present in soils.
“There are many different organisms that, one way or another, can inactivate dicamba,” says Weeks. Using the strain Pseudomonas maltophilia, Weeks and his team discovered a gene that marked a first step in breaking down dicamba in the soil to carbon dioxide (CO2), water and a chloride ion (Cl-). The first step itself, converting dicamba to an acid {3,6-dichlorosalicylic acid (DCSA)} was the key to furthering the research. “That first step of degradation actually inactivates the herbicidal activity. So we could take that bacterial gene, genetically engineer it so it behaved like a plant gene and then transfer it into plants and ‘ask’ those plants that express that gene to break down dicamba before it built to toxic levels.”
Durability with adaptability
From there, Weeks focussed on the bacterial conversion of dicamba to DCSA, with a chain of three enzymes including dicamba mono-oxygenase (DMO). “We were surprised with the very high levels of resistance that we attained, even in plants that are expressing relatively little of the DMO enzyme, so the plant is well protected,” says Weeks.
Once the initial genetic transformation was complete, Weeks and plant scientist Tom Clemente, head of UNL’s plant transformation core facility, placed the gene into tobacco as a model plant cell system for the purpose of transforming and regeneration. “We’ve also put it into the favourite plant model system, Arabidopsis, as well as soybeans,” says Weeks. “In tobacco, we have resistance well over 10 pounds per acre, whereas the normal rate farmers would use would be a quarter to a half a pound per acre. In soybeans, we tested them in the greenhouse, with up to five pounds per acre or 10 times the highest normal rate recommended. At this very high level, plants showed no signs of damage.”
Further study yielded the discovery that additional modifications to the DMO gene would virtually eliminate the potential for resistance to spread to other plants by targeting the DNA of a tobacco plant’s chloroplast, the site where photosynthesis takes place. Since chloroplast
genes are passed on through the maternal side of a plant, it would prevent resistance from occurring through pollination.
In 2005, the University of Nebraska licensed the technology to Monsanto and the company has been promoting it as one of the many developments in its portfolio of advancements currently in the works. Weeks acknowledges that growers can expect to see commercial availability of dicamba resistant soybeans in approximately three years.
Yangzhou pioneer chemical CO.,LTD

Metabolism of the phenylurea fungicide, pencycuron, in sensitive and tolerant strains of Rhizoctonia solani

14C-Labeled pencycuron was applied to four strains of Rhizoctonia solani different in the sensitivity to this fungicide. Of the four strains two were sensitive (S1=C-423, AG***-1, and S2=R-C, AG-4) and the other two tolerant (T1=Rh-131, AG-4 and T2=SH-1, AG-5) to pencycuron. Strain S1 metabolized 85% of the pencycuron in a 0.5 ppm liquid medium. While strains S2, T1 and T2 slowly metabolized only 10-20% of the pencycuron 24 hr after incubation. Main metabolites were cis and trans-3-hydroxycyclopentyl pencycuron (P-1 and P-2, respectively), whose fungicidal activity was weaker than pencycuron. This suggested that pencycuron itself is an ultimate active substance, and that metabolic activation or detoxification is less important to explain the difference among the strains in the sensitivity to pencycuron

Yangzhou pioneer chemical CO., LTD.

Genotoxicity analysis of the herbicide dicamba in mammalian cells in vitro

The cytogenetic effects exerted by the phenoxy herbicide dicamba and one of its commercial formulations banvel (57.71% dicamba) were studied in in vitro whole blood human lymphocyte cultures. The genotoxicity of herbicides was measured by analysis of the frequency of sister chromatid exchanges (SCEs) and cell-cycle progression assays. Both dicamba and banvel activities were tested within 10.0-500.0 microg/ml doses range. Only concentrations of 200.0 microg/ml of dicamba and 500.0 microg/ml of banvel induced a significant increase in SCE frequency over control values. The highest dose of dicamba tested (500.0 microg/ml) resulted in cell culture cytotoxicity. The cell-cycle kinetics was affected by both test compounds since a significant delay in cell-cycle progression and a significant reduction of the proliferative rate index were observed after the treatment with 100.0 and 200.0 microg/ml of .dicamba and 200.0 and 500.0 microg/ml of banvel. For both chemicals, a progressive dose-related inhibition of the mitotic activity of cultures was observed. Moreover, only the mitotic activity statistically differed from control values when doses of both chemicals higher than 100.0 microg/ml were employed. On the basis of our results, the herbicide dicamba is a DNA damage agent and should be considered as a potentially hazardous compound to humans

from:Yangzhou pioneer chemical CO.,LTD

Pioneer chemical production: Pencycuron

To be a widely used fungicide,the function of Pencycuron is very strong and it is also one of the major production of our company.

1、Name and structure
（1）Name：Pencycuron
（2）IUPAC Name：1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea
（3）Formula: C19H21ClN2O
（4）Molecular weight：328.8
2、Physical and Chemical Properties
（1）Form:　 Colourless, odourless crystals.
（2）Melting Point:　 128 °C (modification A); 132 °C (modification B)
（3）Henry"s Constant :　 5 x 10-7 Pa m3 mol-1 (20 °C)
（4）Vapour Pressure:　　5 x 10-7 mPa (20 °C, extrapolated)
（5）Specific Denisty:　　1.22 (20 °C)
（6）Solubility:　　In water 0.3 mg/l (20 °C). In dichloromethane 270, toluene 20, n-hexane 0.12 (all in g/l, 20 °C).
（7）Stability:　　Hydrolysis DT50 64-302 d (25 °C). Photodegrades in water and on soil surfaces.
3、there are three kinds of productions in pioneer chemical Pencycuron
1．95% Pencycuron TC
Description： Off-white powder

2．250G/L Pencycuron FS
Description：Red ropy liquid

3．140G/L Imidacloprid +150G/L Pencycuron FS
Description：Red ropy liquid

form:Yangzhou pioneer chemical CO., LTD

Dissipation of pencycuron in rice plant

Pencycuron is a non-systemic protective fungicide for controlling sheath blight of rice. However, information on the fate of pencycuron in rice plant is lacking. The degradation of pencycuron in waterlogged tropic rice field was investigated. Pencycuron was applied at recommended field dose (187.5 g a.i./ha) and double recommended dose to cropped plots for three consecutive years.pencycuronwas rapidly degraded in rice plant at all doses of pencycuron application with first order half-lives of 1.57 approximately 2.77 d. The study revealed that pencycuron is safe from the human and environmental contamination point of view