Members from all four Weed Science Society of America (WSSA) regions in the United States ranked the research need to “develop new methods for controlling the movement of herbicides and their metabolites into ground water, surface water, and air” first of six major weed science research needs. Canadian members ranked the need to “devise more efficient and less costly weed control technology for conservation-tillage crop-production systems” first; but they also gave high ratings to “improve base knowledge of weed science, improve applicator training, and transfer of information to Extension Service personnel, farm producers, and administrators” and to “discover new ecological, biological, and non-chemical methods of weed control.” The needs to “develop improved methods of increasing the tolerance of crops to herbicides” and to “develop new technology for control of perennial weeds of crops and rangeland” were ranked low. The WSSA Research Committee, at the request of WSSA Presidents J. D. Riggleman (1985) and O. C. Burnside (1986), asked 977 members to rank weed science research needs. The members (ca 50% of the active membership in North America) were selected at random from every other state, federal, industry, and “other” member of each state or province from the up-to-date list of the WSSA business office. Within the highest ranked priority research need, the 422 U.S. and Canadian respondents consistently ranked the research areas (a) to “develop new application techniques that minimize or eliminate herbicides and their residues in air and water”, and (b) to “conduct research to regulate movement of herbicides through the soil profile to avoid contamination of ground water” high, regardless of the type of employment. They emphasized increasing research on the morningglory (Ipomoea spp. # IPOXX) complex, yellow nutsedge (Cyperus esculentus L. # CYPES), quackgrass [Agropyron repens (L.) Beauv. # AGREE], and several other weeds. More members, regardless of region or type of employment, ranked conservation tillage the most important crop or situation that needed new and improved weed control technology.

Woollyleaf bursage [Ambrosia grayi (A. Nels.) Shinners # AMBGR] and Texas blueweed (Helianthus ciliaris DC. # HELCI) increasingly are weed problems on the Texas High Plains. Field experiments were established to evaluate dimethylamine, potassium, sodium, calcium, and aluminum salts of dicamba (3,6-dichloro-2-methoxybenzoic acid) applied at 1.1, 2.2, and 4.4 kg ai/ha to infestations of each species. Initial woollyleaf bursage control was better than initial Texas blueweed control. Dimethylamine and potassium salts provided highest control levels, and increasing rates improved control. One-year control was higher for Texas blueweed than woollyleaf bursage, and 1-yr control of both species improved with increased rates.

The compatibility of rhodamine B dye {N-[9-(2-carboxyphenyl)-6-(diethylamino)-3H-xanthen-3-ylidene]-N-ethyl ethanaminium chloride} with picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) or dicamba (3,6-dichloro-2-methoxybenzoic acid) was evaluated in the laboratory and field. Rhodamine B dye formulation (with or without a surfactant) did not affect dry weight of residue precipitated when mixed with dicamba. Formulated dye precipitated 11% more residue than nonformulated dye when mixed with picloram. Common crupina (Crupina vulgaris Cass. # CJNVU) field plant density was higher after applying a picloram spray solution with nonformulated rhodamine B dye compared to picloram alone. Common crupina density and biomass were higher after application with nonformulated dye and dicamba compared to dicamba alone.

An undesirable bermudagrass [Cynodon dacytlon (L.) Pers. # CYNDA] often must be removed before converting to an improved bermudagrass turf or to a different turfgrass species. Because bermudagrass control with glyphosate [N-(phosphonomethyl)glycine] has been inconsistent, an experiment was initiated to determine the necessary application rates and frequency for glyphosate and SC-0224 (trimethylsulfonium carboxymethylaminomethylphosphonate) to control bermudagrass. Both glyphosate and SC-0224 applied in three applications (May, June, and August) had controlled three bermudagrass hybrids [Cynodon transvaalensis Burtt-Davy # CYNTR x C. dactylon (L.) Pers. Tifway’, Tifgreen’, and ‘Tifdwarf’] and ‘Ormond’ bermudagrasses when evaluated the next June. None of the cultivars were controlled effectively with either herbicide applied in one (May) or two (May and June) applications regardless of rate. Control with glyphosate and SC-0224 was similar.

In field studies conducted in 1984, 1985, and 1986, annual grass control by a microencapsulated (ME) formulation of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] generally was greater than that by the emulsifiable concentrate (EC) in no-till and was comparable to EC-alachlor in conventionally tilled corn (Zea mays L.) and soybeans [Glycine max (L.) Merr.]. In 1986, ME-metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] controlled annual grass similar to EC-metolachlor. In greenhouse studies, shoot height and fresh weight of barnyardgrass [Echinochloa crus-galli (L.) Beauv. # ECHCG] sown in pots and treated with ME-alachlor was significantly greater than that treated with EC-alachlor. Soybean straw on the soil surface did not affect the differences between alachlor formulations in the greenhouse.

Field research was conducted in 1983 and 1984 at Scottsbluff, NE, to determine the effect of cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methyl-propanenitrile} applied in corn (Zea mays L. ‘Pioneer 3732’) on fieldbeans (Phaseolus vulgaris L. ‘Valley’) planted 30 days later to replace corn. Cyanazine preplant incorporated at 1.1 kg ai/ha or higher reduced the vigor, stand, and yield of fieldbeans as a replant crop.

The butoxyethyl ester of triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} was more effective than either the triethylamine salt formulation or an equivalent combined rate of the butoxyethyl esters of triclopyr plus 2,4-D [(2,4-dichlorophenoxy)acetic acid] (1:2, w/w) for the control of Virginia creeper [Parthenocissus quinquefolia (L.) Planch. # PRTQU]. Carrier volume did not affect 14C-triclopyr absorption and distribution, but control generally was greater after high carrier-volume application (281 L/ha) because the dense Virginia creeper canopy was thoroughly penetrated. In orchards, Virginia creeper was controlled by triclopyr ester at 0.6 kg ae/ha through the second season after treatment if foliage was covered thoroughly.

Field studies were conducted to measure the response of sorghum [Sorghum bicolor (L.) Moench. ‘Conlee's Top Hand’] to foliar applications of haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} or fluazifop-P {(R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} plus either bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] at 0.84 kg ai/ha imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} at 0.21 kg ae/ha, or chlorimuron {2-[[[[(4-chloro-6-methoxy-2-pyrimidinyl) amino] carbonyl] amino] sulfonyl] benzoic acid} at 12 g ae/ha. Tank-mixing imazaquin or chlorimuron with haloxyfop or fluazifop-P reduced phytotoxicity to sorghum 12 days after treatment (DAT) by 14 to 64% compared to applications of haloxyfop or fluazifop-P alone. Much of this antagonism was reduced 24 DAT as imazaquin and chlorimuron apparently delayed the activity of haloxyfop and fluazifop-P when losses in activity ranged from 13 to 21%. Increases in haloxyfop and fluazifop-P rates tended to reduce the severity of the antagonism. Tank-mixing bentazon with haloxyfop or fluazifop-P did not reduce phytotoxicity to sorghum compared to applications of haloxyfop and fluazifop-P alone.

The response of irrigated spring barley (Hordeum vulgare L. ‘Steptoe’) to broadleaf herbicides applied at three growth stages was studied at Torrington, WY, in 1984 and 1985. Dicamba (3,6-dichloro-2-methoxybenzoic acid), dicamba plus 2,4-D [(2,4-dichlorophenoxy)acetic acid], and dicamba plus MCPA [(4-chloro-2-methylphenoxy)acetic acid] visibly injured barley when applied at all growth stages. These same treatments reduced barley height when applied at the 2- to 4-leaf and fully tillered stages. Yield differences among treatments were not significant. However, kernels/spike and kernel weight were reduced by dicamba or dicamba plus MCPA when applied at the fully tillered or boot stages, and test weight was reduced when dicamba was applied at all growth stages. Seed protein content did not differ in 1984. However, several herbicide treatments increased seed protein in 1985, especially when applied at the boot stage. Proline or lysine content did not differ among treatments.

Six postemergence herbicides were applied two consecutive years in single and split applications to compare johnsongrass [Sorghum halepense (L.) Pers. # SORHA] control in soybeans [Glycine max (L.) Merr.] planted in 25- and 76-cm inter-row spacings. Significantly less johnsongrass existed at harvest in the 25-cm spacings than in the 76-cm spacings with split applications of fenoxaprop {(±)-2-[4-[(6-chloro-2-benzoxazolyl)oxy] phenoxy] propanoic acid} at 100 g ae/ha, fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} at 100 g ae/ha, sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} at 200 g ai/ha, and SC-1084 {3-hydroxy-4-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] pentanoic acid} at 250 g ae/ha. Quizalofop {(±)-2-[4-[(6-chloro-2-quinoxalinyl)oxy] phenoxy] propanoic acid} at 70 g ae/ha and haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} at 100 g ae/ha controlled johnsongrass so well that differences between the two row spacings were not significant.

In field experiments in 1981, 36 g ai/ha of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} applied to winter wheat (Triticum aestivum L. ‘Arthur’) in early spring reduced seed yield in conventional and no-till plantings of double-cropped soybeans [Glycine max (L.) ‘Essex’]. From 1982 to 1984, three rates of chlorsulfuron (9, 18, and 36 g/ha) were applied at three different times (preemergence, early winter, and early spring) to study their residual effects on double-cropped soybeans. Chlorsulfuron at 36 g/ha applied preemergence or early spring reduced soybean seed yields when averaged over the 3-yr period. Metsulfuron {2-[[[[(4-methoxy-6-methyl-1,3,5-triazine-2-yl)amino] carbonyl] amino] sulfonyl] benzoic acid} was tested at three rates (4.5, 9, and 18 g/ha) applied at three times (same as chlorsulfuron) in field studies in 1983 and 1984. Metsulfuron did not injure subsequently planted no-till soybeans.

Vegetative growth of ‘Tifway’ African bermudagrass (Cynodon transvaalensis Burtt-Davy # CYNTR) x bermudagrass [C. dactylon (L.) Pers. # CYNDA] treated with flurprimidol {α-(1-methylethyl)-α-[4-trifluoromethoxy)phenyl]-5-pyrimidinemethanol} at 0.2 kg/ha and repeated at 3-week intervals for a total rate of 0.8 kg/ha was suppressed for 6 weeks compared to growth of nontreated grass. A single application of flurprimidol at 0.8 kg/ha in late May suppressed growth for 4 weeks. When the single 0.8 kg/ha application was delayed until mid-July, bermudagrass growth was suppressed for only 2 weeks. Applications of nitrogen (N) at 25 and 50 kg/ha did not influence flurprimidol's suppression of bermudagrass growth. Turf quality in some instances was lower when treated with 50 kg N/ha or the turfgrass required a longer recovery period than when treated with 25 kg N/ha following flurprimidol treatment. Although single or multiple applications of flurprimidol, each totaling 0.8 kg/ha, injured bermudagrass in some instances, the injury was not severe and the turfgrass fully recovered.

A simple, labor-efficient screening procedure was developed for identifying metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] tolerant southernpea [Vigna unguiculata (L.) Walp.] germplasm in the greenhouse. Of 1241 southernpea plant introduction (PI) accessions screened, two (PI 293569 and PI 427221) tolerated metribuzin. In additional greenhouse experiments, the two selected southernpea accessions were slightly more tolerant than the susceptible cultivar ‘Lady’ or the moderately tolerant cultivar ‘Big Boy’. However, several accessions from related Vigna species tolerated 1.5 ppmw metribuzin, twice the concentration that killed the southernpea selections.

Crop-herbicide systems for johnsongrass [Sorghum halepense (L.) Pers. # SORHA] control were compared in a 5-yr study at two locations in central Ohio. Monocultures of corn (Zea mays L.) and soybeans [Glycine max (L.) Merr.] were compared with a 3-yr rotation of corn, soybeans, and winter wheat (Triticum aestivum L.). Johnsongrass was controlled most effectively (over 95%) when glyphosate [N-(phosphonomethyl) glycine] was applied to emerged johnsongrass, followed by moldboard plowing, preplant incorporated (PPI) application of trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine], then soybean planting (MS-G-T). The second best control was in corn (over 90%) treated PPI with EPTC (S-ethyl dipropylcarbamothioate) in the rotation (RC-E). Johnsongrass control was least in monocultured corn treated PPI with EPTC (MC-E) and in monocultured soybeans treated PPI with trifluralin (MS-T).

‘Karla’, ‘Klages', ‘Morex’, and ‘Steptoe’ cultivars of spring barley (Hordeum vulgare L.) differed in susceptibility to postemergence recommended application rates of diclofop {(±)-2-[4-(2,4-dichlorophenoxy) phenoxy] propanoic acid}, difenzoquat [1,2-dimethyl-3,5-diphenyl-1H-pyrazolium], chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide}, and metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] in 1981 and 1982. Metribuzin injured Morex, and difenzoquat injured all cultivars within 2 weeks after herbicide application. Metribuzin reduced height and crop biomass compared to the hand-weeded control. Herbicide treatments did not affect grain yield at Moscow, ID, in either year. However, metribuzin reduced yield of Karla and Morex, and diclofop reduced yield of Karla compared to the hand-weeded control at Pullman, WA, in 1982. Barley injury and grain yield loss depended on herbicide treatment and cultivar. Early season herbicide injury to barley did not indicate grain yield response at harvest.

Thioproline (L-thiazolidine-4-carboxylic acid) partially protects sorghum [Sorghum bicolor (L.) Moench. ‘DK 42Y’] seedlings against the herbicides tridiphane [2-(3,5-dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane] and alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] in controlled environment chambers. Thioproline alone inhibits plant growth at concentrations above 10−5 M. Its phytotoxicity is intermediate between the two herbicide antidotes OTC (L-2-oxothiazolidine-4-carboxylic acid) and flurazole [phenylmethyl 2-chloro-4-(trifluoromethyl)-5-thiazolecarboxylate]. The two thiazolidine antidotes increased thiol content of excised corn (Zea mays L. ‘DK T 1100’) seedling roots whereas thiol content was decreased by the two herbicides. While thioproline or OTC partially offset tridiphane-induced decreases in thiol content, none of the antidotes effectively circumvented the reduced thiol content resulting from alachlor treatment.

A nursery of economically important weeds in Kansas field crops, representing 15 families, was designed to include 32 species from the Magnoliopsida (dicotyledons) class and 16 species from the Liliopsida (monocotyledons) class. Using hydraulically operated equipment, 48 facricated metal cylinders 60 cm in both diameter and length were inserted in 4 h. Cylinders were inserted 40 cm deep on an established turf site and were filled with Muir silt loam collected near Manhattan, KS. Thirty summer annual species, nine perennial species, and one biennial species were transplanted in the spring; and eight winter annual species either were seeded or were transplanted in the fall. All species except tall waterhemp (Amaranthus tuberculatus (Moq.) J.D. Sauer # AMATU), a dioecious species, Russian thistle (Salsola iberica Sennen & Pau # SASKR), and unicorn-plant [Proboscidea louisianica (Mill.) Thellung # PROLO] successfully propagated themselves from either seed or buds. Labor requirements for healthy plant growth and overall nursery attractiveness were estimated at 50 h/yr. Installation costs prorated over a 10-yr period plus annual labor costs totaled $300/yr.

The effect of variables that influence the retention of spray droplets impacting on leaf surfaces was studied, using a uniform-size droplet generator to produce drops ranging from 63 to 545 μm diam. To observe the impaction of spray droplets more easily and to measure their velocity before and after impaction, high-speed motion photography (6000 frames/sec) was used. Rebound of spray droplets depends on the micro-structure of the target surface. Leaf surfaces of several crops and weeds reflected 63 to 545 μm diam water drops traveling at velocities less than velocities of drops delivered by popular nozzles at commonly used spray pressures. If the concentration is high enough, some surfactants can reduce the rebound of drops. With one surfactant, its concentration had to be much greater than the critical micelle concentration to reduce reflection of spray drops.