Wild oat herbicides

Most butynediol produced is consumed in the manufacture of butane-diol and butenediol. Butynediol is also used for conversion to ethers with ethylene oxide and in the manufacture of brominated derivatives that are useful as flame retardants. Butynediol was formerly used in a wild oat herbicide, Carbyne (Barban), 4-chloro-2-butynyl-A-(3-chlorophenyl)carba-mate (CnH9Cl2N02). 

Benzoylprop-ethyl is a postemergence wild oat herbicide selective in wheat, while the chemically closely related flamprop-isopropyl, isopropyl N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alaninate (WL 29762, 32) is a wild oat herbicide selective in barley. 

Anonym, (1975) Avenge. Wild Oat Herbicide, Cyanamid International Corporation, Technical Inrormation 1975, January, Zurich. 

Avenge . [Am. Cyanamid/Ag] Di-fenzoquat methyl sulfate wild oat herbicide for barley and wheat crq>s. 

Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of NOx and SOx Uses Wild oat herbicide for barley and wheat... 

Grass weed control can prove more difficult in cereals than broad-leaved weeds. The cost of grass weed herbicides, especially wild oat chemicals, is usually higher than herbicides for broad-leaved weeds. A limited range of herbicides are available, some residual and the others foliar acting. Many of the herbicides, other than the main wild oat herbicides, control some broad-leaved weeds (see Table 13.6). 

Auxin inhibitor herbicides include the so-called wild oat herbicides shown in Figure 5.22. Their classification as auxin inhibitors is based on their inhibition of auxin-induced responses in auxin bioassays and their antagonism of auxin herbicides. " This anti-auxin activity of diclofop-methyl is almost certainly secondary in importance to its inhibition of acetyl-CoA carboxylase (see Chapter 3). 

The wild oat herbicides are esters which are hydrolyzed to the free acids necessary for activity and translocation. The auxin activity of diclofop-methyl is proposed to be due to the ester however, hydrolysis to the free acid is rapid, and any physiological response by treated tissues in periods greater than 20-60 min may in fact be due to the acid. The wild oat herbicides also possess an asymmetric carbon atom, and where separate enantiomers have been available, it appears that auxin activity is restricted to the l -configuration." ... 

In conclusion, it seems likely that the wild oat herbicides bind to a membrane site(s) and that this binding alters the binding of auxin to its receptor site(s). 

Figure 5.22. The wild oat herbicides which possess anti-auxin activity.

In fields where some weeds were cleared using herbicides, other, more herbicide-resistant, species have appeared, such as common horsetail, coltsfoot, foxtail, wild oats, false wheat, etc. As a result of herbicide use, scratchweed, which cannot be destroyed by any herbicide, is making inroads into cereal crops, and chamomile has taken over rapeseed [6]. Using herbicides on rice fields caused the spread of wild, pesticide-resistant, low-yield forms of red-grain rice. 

Except direct use of allelopathic crops as cover crops, smother crops, and intercrops, applications of allelopathy for weed control include the use of allelopathic residues as an herbicide agent, e.g., pellets flours, water extracts, etc. The most common example of crop residue utilization is application of straw on the soil surface (mulching), e.g., rice straw inhibited germination of field bindweed (Convolvulus arvensis L.), winter wild oat (Avena ludoviciana Durieu), and little-seed canarygrass (Phalaris minor Retz.) (Lee et al. 1991 Tamak et al. 1994 Young et al. 1989). 

Although the compounds described above were non-selective herbicides and aromatic substitution resulted in compounds of lower activity, it was gratifying to find that the mixture, coded AC 222,293, and prepared as shown in Scheme I, had good activity against wild oats, black grass and mustards yet was well tolerated by most winter and spring wheats and barleys. 

Multiple-resistance mechanisms, defined as resistance due to more than one mode of action or class of herbicide, have been reported in several ALS-resistant weed biotypes - including false cleavers, wild oat, common waterhemp, kochia, rigid ryegrass in Australia (Powles and Matthews, 1992 Preston and Mallory-Smith, 2001), and wild radish (Walsh etal, 2004a). 

Neitschke, B.S., R.W. Medd, J.M. Matthews, T.G. Reeves, and S.B. Powles (1996a). Managing herbicide-resistant wild oats - Options and adoption. In Shepherd, R.C.H., ed., Proceedings of the 11th Australian Weeds Conference, Weed Science Society of Victoria,... 

Uses herbicide for post-emergence control of wild oats in wheat, barley, broad beans, field beans, soybeans, peas, sugar beet, flax, lucerne, lentils, mustard, oilseed rape, sunflowers, etc. 

Uses pre-emergent and selective herbicide to control wild oats and blackgrass in barley, corn, flax, lentils, peas, potatoes, soybeans, and sugar beets. 

Uses herbicide to control post-emergent wild oats, wild millets, and other annual grass weeds in wheat, barley, rye, red fescue, and broadleaf weeds in crops such as soybeans, sugar cane, fodder beet, flax, legumes, oilseed rape, sunflowers, clover, lucerne, groundnuts, brassicas, carrots, celery, beet root, parsnips, lettuce, spinach, potatoes, tomatoes, fennel, alliums, herbs, etc. 

Chemical Name 2,3,3-trichloro-2-propene-l-thiol diisopropylcarbamate S-(2,3,3-trichloro-allyl)diisopropyl-(thio-carbamate) A-(2,3,3-trichloro-2-propenyl) bis(l-methylethyl)-carbamothioate Uses herbicide to control wild oats in lentils, barley, peas, and winter wheat. 

Avadex [Solutia]. TM for a series of liquid or granular herbicides containing 2,3-dichloroallyl dii-sopropylthiocarbamate. Widely used to control growth of wild oats in agricultural crops. 

Herbicidal Activity. The 2-phenylisoxazolidinediones (3) were tested at 8 kg/ha on lima beans, wild oats and crabgrass. Although no significant kill was observed, the test species were injured as evidenced by their chlorotic condition and stunted appearance. 

---