Cottonseed (Gossypium hirsutum L. ‘Atlas 67′) oil quality was measured by gas-liquid chromatography. Postemergent applications of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) (0.22, 0.34, or 0.45 kg/ha); 1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea (fluometuron) (0.56, 1.12, or 1.68 kg/ha); or 2,4-bis(isopropylamino)-6-(methylthio)-s-triazine (prometryne) (0.22, 0.45, or 0.90 kg/ha) in phytobland oil (4.7, 9.3, or 14.0 L/ha) did not modify the percentage myristic, palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, or arachidic acids when compared to cotton treated with phytobland oil alone or the three herbicides without oil.

The absorption of norflurazon [4-chloro-5-(methylamino)-2-(3-(trifluromethyl)phenyl)-3(2H)-pyridazinone] by 1-cm segments cut from the apical 5-cm roots of velvetleaf (Abutilon theophrasti Medik. # ABUTH) was studied. Norflurazon absorption was rapid in the first 10 min but there was very little increase thereafter up to 120 min. Norflurazon also penetrated the entire tissue volume within 30 min after the root segments were placed in absorption solution. Norflurazon did not accumulate to concentrations above the external solution over 120 min, and 90% of the absorbed herbicide diffused freely out of the tissue within 10 min. The metabolic inhibitor KCN did not affect norflurazon uptake, whereas pretreatment of root tissue with DNP increased absorption. Anoxia increased absorption by 60 and 120% above aerated treatment at 10 min and 2 h, respectively. These experiments suggest that norflurazon, which is considered to move primarily in the apoplast, moved into both the apoplast and symplast of velvetleaf root cells by simple diffusion.

The differential phytotoxicity of an unidentified amiben conjugate (hereinafter referred to as amiben-X), obtained from giant foxtail (Setaria faberii Herrm.) treated with 3-amino-2,5-dichlorobenzoic acid (amiben) was tested in several plant species. Concentrations of amiben-X up to 10 ppm had no effect on radicle elongation in seedlings of soybean (Glycine max (L.) Merr.) or ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.). Giant foxtail radicles were inhibited about 35% at 10 ppm. Amiben, amiben-X, and N-(3-carboxy-2,5-dichlorophenyl)-glucosylamine (hereinafter referred to as N-glucosyl amiben) were detected in seedling tissues of the three above species treated for 24 hr with 20 ppm amiben-X. The growth response of the plants to amiben-X probably resulted from the action of the amiben released by plant hydrolytic activity on amiben-X; amiben-X itself is considered to be relatively nonphytotoxic.

Fifteen herbicidal treatments were evaluated for weed control effectiveness in peanut (Arachis hypogaea L.) culture at three locations in the peanut production area of eastern North Carolina during 1964 and 1965. Delayed preemergence treatments of 4,6-dinitro-o-sec-butylphenol (DNBP) alone and in combination with O-(2,4-dichlorophenyl) O-methyl isopropylphosphoroamidothioate (DMPA) were superior to conventional herbicidal and non-herbicidal control methods as were single and multiple incorporated treatments of S-propyl dipropylthiocarbamate (vernolate). A single postplant vernolate treatment incorporated 1 in deep provided weed control superior to that obtained for single preplant vernolate treatments incorporated 1 in or 3 in deep. Increased weed control and increased peanut safety were obtained from 2.5 lb/A of vernolate by incorporating treatments at 0, 7, and 14 days after planting rather than by using a single application. This multiple treatment was the optimum one evaluated and provided 53 days of control and required 10 hr/A of hoeing time.

Samples of the spray pattern delivered by a tractormounted field sprayer were intercepted with 10 petri dishes divided between two heights in each of eight plots sprayed with 1.12 kg/ha of 4-amino-3,5,6-trichloropicolinic acid (picloram). The sprayer produced predictable residues on the intercept plates; no differences occurred between residues collected at ground level and 46 cm above the ground; and no differences occurred between replicate plots. Fractionation and analysis of specific plant parts, whose position relative to direction of spray and surrounding brush had been noted, revealed that the spray system delivered uniform coverage almost regardless of brush orientation.

The effect of 2,3,5-trichloro-4-pyridinol (pyriclor), as well as carbonyl cyanide m-chlorophenyl hydrazone, 2,4-dinitrophenol, and oligomycin, on oxygen uptake and oxidative phosphorylation was investigated with mitochondria isolated from hypocotyls of etiolated soybeans (Glycine max Merrill, var. Lee). Pyriclor inhibited both coupled and uncoupled reactions. This suggests that pyriclor either acts on a nonphosphorylating intermediate close to the electron carrier chain or with a component of the electron carrier chain, or both.

A new strain of the fungus Plectosporium tabacinum was isolated from naturally-infected false cleavers plants and evaluated as a bioherbicide for the control of both herbicide-resistant and herbicide-susceptible false cleavers in canola. Plectosporium tabacinum was nonpathogenic to both Argentine canola and Polish canola and to both herbicide-tolerant and conventional cultivars. Plectosporium tabacinum killed false cleavers seedlings when applied at a concentration of 1 × 107 conidia ml−1 and provided with 16 h dew. The efficacy of P. tabacinum on herbicide-resistant false cleavers was identical to that on herbicide-susceptible false cleavers. Catchweed bedstraw was also highly susceptible to P. tabacinum. Further host-range tests on 34 plant species in 26 genera and 12 families demonstrated that P. tabacinum is sufficiently host specific for false cleavers control in western Canada. This fungus may provide a novel approach for managing herbicide-resistant false cleavers.

Napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide]-binding in excised root segments of corn (Zea mays L. ‘NC + 59′) was confined to cell wall fractions (residue and 500 g pellet) remaining after homogenization and to components of the 100 000 g supernatant. Binding increased in both the cell wall and soluble fractions with continued exposure to napropamide. Microautoradiographs revealed that the napropamide bound in the cell walls was located in epidermal, cortical, and stelar tissue. Various proteins were capable of binding napropamide in vitro; however, protease treatment did not liberate the radioactivity bound in the cell wall fragments. Carbohydrate release from the cell wall material with cellulase was not correlated with the solubilization of bound radioactivity and wall carbohydrate monomers did not appear to bind to napropamide in vitro. A portion of the radioactivity found in the soluble components (at 100 000 g) was associated with a molecule of MW > 600. The continued influx of napropamide was due to binding to cell wall components and molecules within the cell.

In the pea straight growth bioassay, both benazolin and indole-3-acetic acid (auxin) solutions promoted the elongation of etiolated pea (Pisum sativum L. ‘Alaska’) epicotyls. Maximal elongation occurred at auxin concentrations ranging from 10-6 to 10-4 M; comparable elongation occurred at a benazolin concentration of 10-4 M. Results of this bioassay indicate that benazolin functions as an auxin, but is much less active than naturally occurring indole-3-acetic acid.

Twenty days after rice (Oryza sativa L. ‘IR28’) emergence, water was withheld from the stress treatment for 20 days while the control was kept well-watered by furrow irrigation. In the control plots, rice leaf water potential at 0800 hours was –5.5 bars and leaf length 30 cm on the 12th day of stress. In the stress treatment, leaf water potential decreased to –8 bars and leaf length to 20 cm, when no weeds competed with rice. With maximum weed competition, rice leaf water potential decreased to –18 bars and leaf length to 15.5 cm. on the 20th day of stress, dawn (0600 h) leaf water potential of rice in the stress treatment was reduced from –8 bars when no weeds competed with rice to –19 bars when competition was maximum. The weed species had higher water potential values than the rice in both control and water-stress treatments.

Herbicides applied to container plants in nurseries are transported in runoff water to on- and off-site ponds and retention basins. This study was conducted to determine biotic and abiotic effects on isoxaben dissipation in model flow-through retention basins to maximize aqueous isoxaben degradation. Field studies were conducted in 1999 and 2000 to evaluate the effects of gravel and pine bark amendments and water retention times on isoxaben persistence in holding basins. In 1999, total isoxaben discharge into flow-through gravel-filled basins was greater than isoxaben losses from gravel and nongravel basins in which water was retained. Photodegradation appeared to be greater in basins without gravel, indicating that gravel protected isoxaben from photolysis. Further studies determined the effect of water retention time and the presence of aged pine bark amendment on isoxaben discharge from basins. Isoxaben discharge level was reduced when water retention time was increased from 3 to 5 d. In the 3-d retention time treatment, added pine bark reduced peak isoxaben discharge by 45% and total isoxaben by 53% at 14 d after treatment. In treatments containing pine bark within the retention basins, isoxaben was released over a longer period of time. No differences were observed in 5-d water retention time treatments with and without pine bark. Analysis of gravel from isoxaben-treated retention basins indicated the presence of several genera of bacteria including Pseudomonas, Arthrobacter, and Cellulomonas. Some isolates of Pseudomonas, Rahnella, Methobacterium, and Paenibacillus from the basins grew on M9 medium with isoxaben as the sole carbon and energy source, indicating their ability to metabolize isoxaben. Results indicate that retention basins are helpful in reducing isoxaben levels before release or reuse of runoff water from a container nursery, and that retention time of runoff water in basins is the most important factor in reducing isoxaben discharge.

Biological and biochemical methods, based on glufosinate inhibitory effects on plant growth and nitrogen metabolism, were examined for their applications to detect this herbicide. Dose–response analysis of radicle growth inhibition showed that, among six vegetables tested, Chinese mustard and edible amaranth were the most sensitive to glufosinate. Field mustard and cruciferous Ching-Geeng were found to be more sensitive to this herbicide than the other four vegetables when three-leaf seedlings were tested in another bioassay. In three-leaf seedlings of Ching-Geeng, accumulation of ammonium, a biochemical marker for glufosinate toxicity because of its inhibition of glutamine synthetase, showed a linear regression to the log-transformed concentrations of glufosinate ranging from 7.5 × 10−5 to 1.5 × 10−3 M. For the detection of glufosinate lower than 7.5 × 10−6 M, a linear regression was observed between ammonium accumulation and the applied concentration, instead of the log-transformed value, of glufosinate. A similar relationship was observed between the accumulation in Ching-Geeng seedlings of glyoxylate, another biochemical marker, and glufosinate but with a narrower range than that for ammonium accumulation. The applicability of ammonium accumulation in three-leaf seedlings of Ching-Geeng to detect glufosinate residue in water and soil was confirmed by high-performance liquid chromatography (HPLC).

Rates of 0 and 5 lb/A of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) or 2-chloro-4,6-bis(ethylamino)–s-triazine (simazine) were combined with O and 200 lb/A of nitrogen fertilizer as preemergence applications on plots planted to corn (Zea mays L., var. Mo. 880) in May of 1964 and 1965. Soil samples collected in December, 1965, and again in February, 1966, were plated on Difco potato dextrose agar and nutrient agar to determine the growth of fungal and bacterial colonies. There was no difference in the total number of fungal colonies grown on media seeded with soils from the field studies, yet variation in individual species occurred. The number of bacterial colonies increased on plates seeded with soil from plots treated with 200 lb/A of nitrogen plus 5 lb/A of simazine but not from simazine-treated soil without nitrogen.

The production of red triphenyl formazan (hereinafter referred to as TPF) from colorless 2,3,5-triphenyl tetrazolium chloride (hereinafter referred to as TTC) by living cells was used as a vitality indicator for examining the effects of 6,7-dihydrodipyrido[1,2-a:2′,1′-c] pyrazidiinium salt (diquat) in elodea (Elodea canadensis Michx) shoots at varying light intensities. Diquat at 10 ppmw completely killed the elodea in 6 hr at 183 ft-c and at almost the same rate at 13,000 ft-c due to light saturation near the lower level. Over 24 hr were required for this effect in the dark. Between 29 and 183 ft-c, TPF production varied inversely with the light intensity. A comparison is made with the destruction of chlorophyll by diquat.

Field experiments were conducted to determine the interaction of grazing and herbicide treatments on cheat control and biomass, wheat biomass, wheat grain yield, and wheat yield components. Ethyl-metribuzin at 1120 g ai ha−1 and metribuzin at 420 g ai ha−1 reduced cheat biomass 91 to 99 and 97 to 98%, respectively. Grazing had no effect on herbicide efficacy. Grazing increased cheat biomass in the check by 24% at only one location but did not affect total wheat plus cheat biomass. With one exception, controlled cheat was replaced by wheat on a 1:1 biomass basis when herbicides caused no crop injury. All herbicide treatments increased grain yield, but grazing did not alter yield. At two locations, increased heads m−2 and spikelets/head accounted for most of the grain yield increases, but at one location seeds/spikelet and weight/seed were also increased. Harvest index was unaffected.

Soil incorporated into the tuber zone of purple nutsedge (Cyperus rotundus L.) at 1 to 9 kg/ha, O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl)benzenesulfonamide (bensulide) inhibited the growth of roots on plants developing from these tubers. The inhibitory effect was temporary and occurred only when bensulide was in intimate contact with the tubers and developing plants. When tubers were removed from bensulide-treated soil, washed, and replanted in untreated soil, root growth was normal. The production of shoots from tubers planted in bensulide-treated soil apparently was not affected, but shoot-growth was retarded when root growth was suppressed. When bensulide was incorporated into the upper 5-cm layer of soil, the shoots of nutsedge plants developing from tubers located below this layer grew through the treated soil with no adverse effect; the roots of these plants developed from basal bulbs below the layer of treated soil and were normal. Leaching bensulide-treated soil with 37.6 hectare-cm of water did not move enough bensulide into the soil to cause inhibitory growth effects on purple nutsedge.

The carbon banding technique was evaluated for control of volunteer Kentucky bluegrass (Poa pratensis L.) while Kentucky bluegrass was established for seed production. At Madras, Oregon, where terbacil (3-tert-butyl-5-chloro-6-methyluracil), diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] were applied at several rates each, volunteer Kentucky bluegrass control between the carbon bands ranged from 80 to 99+%. At Corvallis, Oregon, where Colonial bentgrass (Agrostis tenuis Sibth. ‘Highland’), red fescue (Festuca rubra L. ‘Pennlawn’), perennial ryegrass (Lolium perenne L. ‘NK-100’), and orchardgrass (Dactylis glomerata L. ‘S-143’) were planted to allow identification of volunteer Kentucky bluegrass both between and in the carbon bands, diuron, atrazine, and a combination of diuron and terbacil eliminated volunteer Kentucky bluegrass. Terbacil did not control all Kentucky bluegrass between the bands. None of the herbicide treatments adversely affected crop establishment or seed yield.