Herbicides, preemergence cotton

Chlornidin is used as selective preemergence herbicide in cotton and soybean, for the control of Sorghum halepense, Amaranthus spp. and Digitaria spp. (Talbert,... 

Uses Butachlor is used as a preemergence herbicide for the control of annual grasses and broadleaf weeds in rice, wheat, barley, cotton, sugar beet, and peanut crops. 

Diuron was introduced by du Pont in 1954 (Fig. 3). It is one of a series of substituted urea herbicides. Diuron is applied preemergence to crops such as cotton, alfalfa, grapes, fruit and nut crops. Foliar activity is enhanced when a surfactant is added to the spray. 

Fluometuron is another substituted urea introduced by CIBA in 1964 (Fig. 4). It is a preemergence herbicide and finds its niche primarily in cotton and sugarcane. It is usually applied in combination with other herbicides to broaden the spectrum of weed species controlled. 

We first became interested in pyridazines as herbicides when a number of pyridazines synthesized in a CNS project at our Lederle division were evaluated in our primary herbicide screen. One of these compounds, AC 228,764, controlled eleven of the twelve weed species at 8 kg/ha in the preemergence test. All of the test species were bleached, emerging white from the soil. In our secondary evaluation at 4 kg/ha, AC 228,764 controlled ten out of eleven annual grass and broadleaf weed species with selectivity in cotton, soybeans and rice. This spectrum of activity and crop... 

Although the synthesis program did not result in any commercial herbicides, two types of pyridazines were discovered which produced unexpected results, both in the level and the type of activity. The first series, which includes the 3-methoxy- and the 3-dimethylaminopyridazines, resulted in a high level of postemergence activity not observed in the lead or in the other 3-sub-stituted-pyridazines. Secondly, based on a comparison with the N-oxides of other pyridazines, the N-oxide of the 3-hydropyridazine resulted in unexpectedly high preemergence activity, yet without phytotoxicity to cotton. 

Sugar herbicide RE 39571, 5,6-dideoxy-l,2-0-(l-methylethylidene)-3-0-(2-methylphenylmethyl)-a-D-xylo-hexofuranose (Figure 1), a representative of a novel series of chiral grass herbicides, has been demonstrated in our laboratories to possess a high level of preemergence herbicidal activity against grassy weeds with safety on soybeans, cotton, peanuts, and several other broadleaf crops. This herbicide has also been demonstrated to possess some broadleaf weed activity. 

Diethatyl ethyl is a selective preemergence herbicide, effective mainly for the control of grass weeds on moist soil at an application rate of 1.7-6.7 kg/ha. It is selective in sugar beet, cotton, maize, wheat, soybean and vegetable crops. Its acute oral LD,o for rats is 2318 mg/kg. 

Oxyfluorfen is applied as a preemergence herbicide in soybeans, cotton, tomatoes, tobacco and green pepper at a rate of 0.2-0.4 kg active ingredient/ha. Grassy weeds are not well controlled by oxyfluorfen, but in the case of heavy grass weed infestation it can be tank—mixed with thiocarbamates, dinitroanilines, chloroacetamides, dalapon and paraquat. Oxyfluorfen is also recommended in tree fruits, vineyards and in conifer nurseries as an early postemergence treatment. 

Trifluralin is a preemergence herbicide which must be incorporated into the soil because of its volatility (vapour pressure at 29.5°C is 1.99 10 mm Hg) and its sensitivity to ultraviolet radiation. At application rates of O.S-1.0 kg active ingredient/ha it can be used selectively against annual grass weeds and several broad-leaved weed species in cotton, potatoes, sunflower, soybean, tomato, many vegetables and orchards. Applied in a double dose in two consecutive years, it kills the rhizomes of Johnson grass (Worther, 1974). 

Methoxycarbonylamino)phenyl (N-methyl-N-phenyl)carbamate (SN 40454, 18) is a broad-spectrum pre- and postemergence herbicide effective primarily against broad-leaved weeds. Used preemergence at a rate of 2-4 kg active ingredient/ha, it is selective in peanut, cotton and soybean. In postemergence application at a rate of l.S active ingredient/ha it is effective for directed spray treatment in cotton and soybean. 

DCU is a soil herbicide used at rates of 2-50 kg active ingredient/ha for preemergence treatment in sugar beet, cotton, oil flax, potato, carrots and medicinal herb cultures. In Hungary it is used in combination with Pyramin for weed control in sugar beet (Ubrizsy and Gimesi, 1969). 

Noruron is a selective preemergence herbicide used at rates of 0.75-4 kg of active ingredient/ha on cotton, sugar cane, soybeans and potato. In combination with other herbicides, it enhances their grass weed killing effect. 

It is used as a selective herbicide for the preemergence treatment of cotton, garlic, flower bulbs and potatoes at rates of 2-6 kg active ingredient/ha. Applied... 

It is a herbicide of selective action, used preemergence at a rate of 4 kg active ingredient/ha against annual weeds in cotton and potatoes. Its herbicidal action lasts for 2-3 months. 

Of the 2-chloro-4,6-bis(dialkylamino)-i-triazines, 2-chloro-4,6-bis(diethylamino)-s-triazine (chlorazine, 13) has been investigated most extensively by the Geigy Co. This compound has the best selectivity, though its herbicidal efficiency was found to be relatively low. In oily formulation, very good weed-control results have been attained in cotton by preemergent and, particularly, postemergent treatment without any phytotoxic side effects. 

Fluridone is a selective herbicide with translocation properties, used mainly preemergence but also postemergence for the control of broad-leaved and grass weeds at a rate of 0.3-2.4 g active ingredient/ha. Of the crops cotton is tolerant. 

Amiprofos-methyl is a selective preemergence herbicide. It does not inhibit germination but suppresses the growth of roots and shoots. Its main action is the inhibition of mitosis. Its action is selective in maize, cotton, rice and several garden vegetables. 

On the basis of the limited structure-activity relationships found here, great enhancement of activity was only achieved by the introduction of a meta substituent in the phenyl ring, the imino iV-substituent, and a substituent at the thiadiazoline 5-position. From the viewpoint of the preemergence herbicidal efficacy and the selectivity on cotton, one of these compounds, 2-(A/-difluoro-acetylimino)-5-methyI-3-(3-trifluoromethyIphenyl)-1,3-diiazoline, S-3085 was finally selected as a promising candidate for preconunerciallization. 

As a methodology to search for a new lead, we focused on the chemical approach using A,S-heterocycles. This approach led to the evolution of 5-methylene-thiazolidines as the lead to bleaching herbicides. Further structural modifications based on the parent compound resulted in the creation of a new family of bleaching herbicides, 2-(W-difluoroacelylimino)-S-methyl-3-(3-trifiuoromethylphenyl)-l,3-thiazoline, (S-3085) widi potent preemergence herbicidal activity and selectivity on cotton crops. On die basis of biochemical studies, 3-phenylthiazolines have been characterized as a new inhibitor of phytoene desaturase. Facile syndieses of 1,3-thiazolines and the manufacturing process toward S-3085 will be reported in future publications. 

Uses Selective preemergence herbicide, esp. for cotton plant... 

Uses Selective preemergence herbicide used to control most atmual grasses and some broad-leaved weeds inbrassicas, com, cotton, flax, leeks, maize, milo, onions, peas, roses, ornamental trees and shrabs, soybeans, sugarcane. 

Uses Preemergence, early postemergence or soil-incorporated herbicide used to control most aimual grasses and many armual broad-leaved weeds in beans, com, cotton, milo, peanuts, peas, soybeans, sunflower and certain woody ornamentals. 

Uses Selective preemergence herbicide used to control many broad-leaved weeds and most grass weeds in okra, cotton, peanuts tomatoes, sweet potatoes, potatoes, tobacco, fruits, turf and ornamentals. 

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