Herbicide maize

The enzyme p-hydroxyphenylpyruvate dioxygenase is involved in the conversion of p-hydroxyphenylpyruvate into homogentisate, a key step in plastoquinone biosynthesis. Inhibition of this enzyme has an indirect effect on carotenoid biosynthesis as plastoquinone is a co-factor of the enzyme phytoene desaturase. The new maize herbicide isoxaflutole and the triketone herbicides such as sulcotrione (Figure 2.7), inhibit p-hydroxyphenylpyruvate dioxygenase and this leads to the onset of bleaching in susceptible weeds and ultimately plant death.4... 

A typical example of agrochemical manufacture is provided by the maize herbicide (Table 17.2b), metolachlor. 

Maize Herbicide tolerant 5.805 million pounds less herbicide active ingredients in 2001 (5.809 million acres) Comparison of glyphosate/glufosinate treatment with a theoretical alternative mix of three post-emergence herbicides, assuming a 25% reduction in preemergence applications on herbicide tolerant maize... 

A basic version of the hedonic price function for maize herbicides P z was estimated by regressing PRICE on the four characteristics RELIA, PERSI, ACTION and TOX. A standard problem in such an estimation is that all characteristics of importance for herbicides price are not likely to be included. In this study, the most obvious examples are characteristics that... 

Maize, with its shallow root system, is particularly prone to competition by other plants in its early growth stages. While older generations of maize herbicides are predominantly used as preemergent herbicides, e.g., atrazine from the triazines class, there are now modern, postemergent sulfonylurea products available to the farmer for cost-effective and time-flexible weed control. The latest compound to be introduced after 1995 is discussed below (Table 2.2.20). 

Diphenyl ethers are both systemic and contact herbicides and are used for the selective control of annual broad-leaved weeds and grasses in a variety of crops (such as soybeans, maize, rice, wheat, barley, peanuts, cotton, onions and ornamental trees) under different application scenarios. This class of herbicides contains a diphenyl ether moiety as the core substructure. Acifluorfen, bifnox, chlomethoxyfen, chlorni-trofen, fluoroglycofen-ethyl and fomesafen, etc., are representative compounds of the diphenyl ether herbicides (Figure 1). 

Metolachlor is the active ingredient of Dual, one of the most important grass herbicides for use in maize and a number of other crops. In 1996, after years of intensive research, Dual Magnum with a content of approximately 90% (S)-diaste-... 

Beynon, K.I., Stoydin, G, and Wright, A.N. A comparison of the breakdown of the triazine herbicides cyanazine, atrazine, and simazine in soil and in maize, Pestic. Biochem. Physiol, 2 153-161,1972. 

Muir, D.C.G. and Baker, B.E. Detection of triazine herbicides and their degradation products in tile-drain water from fields under corn (maize) production, J. Agric. Food Chem., 21(1) 122-125, 1976. 

Metolachlor is the active ingredient of Dual , one of the most important grass herbicides for use in maize and a number of other crops. In 1997, after years of intensive research. Dual Magnum, with a content of approximately 90% (I S)-diastereomers and with the same biological effect at about 65% of the use rate, was introduced into the market. This chiral switch was made possible by the new technical process that is briefly described below. The key step of this new synthesis is the enantioselective hydrogenation of the isolated MEA imine, as depicted in Figure 1.3. 

Mitchell G Bartlett DW, Fraser TEM, Hawkes TR, Holt DC, Townson JK, Wichert RA. (2001) Mesotrione Anew selective herbicide for use in maize. Pest Manag Sci 57 120-128. 

This was developed for Syngenta and was a landmark product for enantioselective industrial catalytic synthesis. The full story behind this remarkable piece of work has been reported by Blaser. Catalyst turnover numbers of 2000000 and turnover frequency values of around 600 000 h allow highly efficient production of this important intermediate maize crop herbicide (Dual Magnum ). ... 

In the developed world in markets such as small grain cereals, soybean, maize and rice, the value of the herbicide market is much larger than either insecticides or fungicides (Figure 1.1). This is because the econo-... 

There are a number of other herbicides that affect photosynthesis indirectly. Pyrazole herbicides such as benzofenap, pyrazolynate and pyrazoxyfen interfere with chlorophyll biosynthesis and have found commercial application for the control of annual and perennial weeds in paddy rice and maize (Figure 2.4). 

The conversion of fatty acids into very long chain fatty acids is specifically inhibited by the thiocarbamate herbicides such as EPTC and triallate (Figure 2.19). These compounds are used pre-plant incorporated for the control of grass and some small seeded broad-leaved weeds in crops such as maize and small grain cereals. 

The major crops for agrochemical use are cotton, rice, maize, vegetables and top fruit for insecticides small grain cereals, rice, vines and top fruit for fungicides, and maize, soybeans, small grain cereals, rice, industrial weed control, plantations and orchards for herbicides. Other crops that may be of interest include sugar beet, oil-seed rape, potatoes and citrus dependent upon your company s presence in these crops. 

The two most important compounds, atrazine and simazine, are used in two ways (B-78MI10700). At high concentrations they act as total herbicides, while at much lower concentrations they are used for selective pre-emergence weed control. The effectiveness of atrazine in maize has led to its being manufactured on the largest scale in the world... 

Starch production in leaves ceased after one to six days, depending on the species sucrose-14C could be substituted as a source of substrate for starch.190 Corn (maize) tolerates many of the triazine herbicides, but its isolated chloroplasts do not. Treatment did not influence catalase activity or respiration,191 but stopped oxygen output immediately.199... 

PAL activity in soybean seedlings was increased by several herbicides such as DPX-4189, glyphosate and acifluorfen [112,113]. Also, the activities of PAL and tyrosine ammonia lyase (TAL) in both maize and soybean seedlings were also increased by alachlor [110] and metolachlor [111]. 

Anthony, R. G. and Hussey, P. J. (1999). Double mutation in Eleusine indica alpha-tubulin increases the resistance of transgenic maize calli to dinitroaniline and phosphorothioamidate herbicides. Plant ]. 18, 669-674. 

Beynon, K.I., G. Stoydin, and A.N. Wright (1972b). The breakdown of the triazine herbicide cyanazine in soils and maize. Pestic. Sci., 3 293-305. 

Roth, W. (1957). Comparative study of the reaction of simazine, a herbicide, on maize and wheat. Compt. Rend, 245 942-944. 

Owen, M.D.K. (2001). World maize/soybean and herbicide resistance. In Powles, S.B. and Shaner, D.L., eds., Herbicide Resistance and World Grains, Boca Raton, FL CRC Press, pp. 101-163. 

Seibert, K., F. Fuhr, and H.H. Cheng (1995). Experiments of the degradation of atrazine in the maize-rhizosphere. European Weed Research Society Symposium Theory and Practice of the Use of Soil Applied Herbicides. 

Uses selective pre-emergence and post-emergence herbicide to effectively control a wide variety of broadleaf weeds in corn, grain, sorghum, maize, rice, and soybeans. 

Uses herbicide to control annual grass weeds in maize, by pre-plant soil incorporation also to control some broadleaf weeds. 

---