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SummaryThe response of natural and planted stands of Allium vineale L. to chlorsulfuron and metsulfuron was determined in field experiments in Illinois, U.S.A., in 1982 and 1983. In natural stands very low rates of either herbicide controlled A. vineale. Chlorsulfuron, applied in the spring at 20 g ha−1, reduced aerial bulblet production by 99% but when it was applied in the fall it reduced aerial bulblet production by only 59%. All rates of metsulfuron (5–20 g ha−1), at both times of application, effected better than 94% reduction in plant density and yield of aerial bulblets. In a glasshouse experiment, plants derived from aerial bulblets were more susceptible to chlorsulfuron than plants derived from soft offset bulbs. Soft offset bulbs were, therefore, used to establish a uniform stand of A. vineale in the field. In this experiment, non‐linear regression analysis showed that metsulfuron was two to three times more active than chlorsulfuron. GR95 values calculated from the computed regression equations show that metsulfuron and chlorsulfuron, applied in April at 5 and 15 g ha−1, respectively, reduced aerial and underground bulb production by 95%.

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Summary: Résumé: Zusammenfassung 14C‐glyphosate (N‐(phosphonomethyl)glycine) uptake by germinating maize (Zea mays L. ‘PAG SX56’) or soybean (Glycine max (L.) Merr. ‘Williams’) seeds from sterile quartz sand was minimal on a weight basis until the radicle became functional. Uptake in soybean seedlings was ten times greater (on a weight basis) than in maize. Germination of either species was not affected by glyphosate concentrations up to 10−3m, but seedling axis elongation was inhibited in soybeans at 10−4m and in maize at [0−3m When 14C‐glyphosate was applied to the fully expanded first trifoliolate soybean leaf (assimilate‐exporting), movement into root and shoot assimilate sinks occurred. About 7% of the total 14C‐glyphosate applied was absorbed and translocated into other parts of the plant by 48 h. Of the total 14C accumulated by 48 h in the roots and apical meristem, nearly 50% was present by 12 h. Minor phytotoxicity resulted from 10 nmoles of glyphosate in the plant. Absorption et migration du 14 C‐glyphosate chez le maïs (Zea mays) en germination et chez les semences et les plantes de soja (Glycine max)L'absorption du 14C‐glyphosate (N‐(phosphonométhyle) glycine)par du maïs en germination (Zea mays L.,‘PAG SX56′)ou par des semences de soja (Glycine max (L.) Merr.,‘Williams’) a partir de sable de quartz stérile a été minimale (sur la base du poids) jusquà ce que la racine devienne fonctionnelle. L'absorption par des plantules de soja a été, sur la base due poids, 10 fois plus grande que chez le maïs. La germination de ces deux espèn n'a pas été affectée par des concentrations de glyphosate allant jusquà 10−3m, maïs l'élongation des plantules a été inhibée chez le soja á 10−4m et chez le maïs à 10−3m. Lorsque le 14C‐glyphosate a été appliqué sur la première feuille trifoliée de soja pleinement dévdoppé (en état d'exporter des métabolites).une diminution du mouvemem des métabolites vers les jeunes pousses et vers les racines s'est manifestée. Eaviron 7% du 14C‐glyphosate total appliqué a été absorbé et a migré dans d'autres parties de la plume en 48 heures. Près de 50% du 14C total accumulé dans les racines et le méristème apical y était présent en 12 heures. Une faible toxicité a réulté de b présence de 10 nmoles de glyphosate dans la plante. 14 C‐glyphosat‐Aufnahme und ‐Translokation bei keimenden Samen von Mais (Zea mays) und Sojabohnen (Glycine max) und bei SojabohnenpflanzenDie Aufnahme von 14C‐Glyphosat (N‐(Phosphonomethyl)glycin) aus sterilem Quarszsand durch keimende Samen von Mais (Zea mays L.‘PAG SX56′) und Sojabohnen (glycine max (L.) Merr.‘Williams’) war, bezogen auf das Pflanzengewicht, bis zur Funktionsaufnahme der Keimwurzel, gering. Die Aufnahme war bei den Sojabohnenkeimlingen zehnmal grösser (Gewichts‐basis) als bei Mais. Die Keimung wurde bei beiden Arten durch Glyphosat bis zu 10−3m nicht beeinflusst. Das Streckungswachstum des Stengels wurde aber bei der Sojabohne bei 10−4m und beim Mais bei 10−3m gehemmt. Wenn 14C‐Glyphosat auf das erste vollstándig entwickelte dreibláttrige Sojabohnenblatt (Assimilate exportierend) appliziert wurde, konnte ein Transport in die Assimilatesinks der Wurzel und des Sprosses beobachtet werden. Nach 48 h waren etwa 7% des applizierten 14C‐Glyphosats aufgenommen und in andere Teile der Pflanze transloziert. Vom gesamten nach 48 h in den Wurzeln und im apikalen Meristem akkumulierten 14C waren fast 50% bereits nach 12 h vorhanden. 10 nmol Glyphosat in den Pflanzen waren nur geringfügig phytntoxisch.

2,4-D [(2,4-dichlorophenoxy)acetie acid] and dalapon (2,2-dichloropropionic acid) were applied to a natural stand of annual weeds at a time near flowering to determine effects on seed production and the dormancy and viability of seeds produced. At rates of 0.6 and 1.1 kg/ha, 2,4-D reduced, respectively the seed production of common lambsquarters(Chenopodium albumL.) 99 and 99%, redroot pigweed(Amaranthus retroflexusL.) 77 and 84%, and jimsonweed(Datura stramoniumL.) 64 and 100%, while giant foxtail(Setaria faberiHerrm) seed production was increased to 307 and 381% of the control, respectively. Dalapon at rates of 2.2 and 4.5 kg/ha reduced respectively seed production of giant foxtail 100 and 100%, and jimsonweed 100 and 91%. Before and after overwinter burial in the soil, common lambsquarters seeds from plants treated with 4.5 kg/ha dalapon were less dormant than control seeds. After overwintering, redroot pigweed seeds from dalapon-treated plants were less dormant than controls, and more seeds survived the winter burial. Common lambsquarters and redroot pigweed seeds from plants treated with 1.1 kg/ha 2,4-D were more dormant than control seeds before overwintering,’ while giant foxtail seeds from 2,4-D treated plants were less dormant than controls after overwintering. Viability of seeds produced by herbicide-treated plants, as determined by germination in KCN, was not greatly different from control seeds. Treatment with 2,4-D or dalapon resulted in the production of common lambsquarters seeds which produced seedlings about half as vigorous as controls. Jimsonweed seedlings grown from seeds from 2,4-D-treated plants showed phenoxy herbicide injury symptoms.

The incidence of corn injury from thiocarbamate herbicides is effectively reduced by seed treatment with 1 , 8-naphthalic anhyddride and seed or soil treatment with the dichloroacetamide R-25788. Additional selectivity provided by this dichloroacetamide expands the use areas for EPTC and butylate in weed control.

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Studies were conducted to examine over time the effects of propachlor (2-chloro-N-isopropylacetanilide) on the growth of cucumber (Cucumus sativusL. ‘Straight Eight’) roots and associated biosynthetic reactions. Complete inhibition of root elongation occurred within 16 hr after exposure to propachlor. Inhibition of growth was not found to be a result of an effect on ATP formation or respiration. Protein biosynthesis was reduced several hours before the observed inhibition of growth therefore implicating it as the causal factor. Inhibition of protein synthesis occurred prior to an observed reduction in RNA synthesis suggesting that the primary effect of propachlor is on protein biosynthesis and that its effect on nucleic acid synthesis is secondary. It is concluded that the primary mechanism of action of propachlor is its effect on nascent protein biosynthesis.

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Butylate (S-ethyl diisobutylthiocarbamate), EPTC (S-ethyl dipropylthiocarbamate), vernolate (S-propyl dipropylthiocarbamate), diallate [S-(2,3-dichloroallyl)diisopropylthiocarbamate], CDEC (2-chloroallyl diethyldithiocarbamate), and chlorpropham (isopropylm-chlorocarbanilate) at 0.1 kg/ha caused increased velvetleaf (Abutilon theophrastiMedic.) populations in field plots. Butylate caused increased populations of common lambsquarters (Chenopodium albumL.) at rates of up to 1.1 kg/ha. In the laboratory, each of the six herbicides caused increased velvetleaf seed germination, and butylate, EPTC, and CDEC caused increased common lambsquarters germination when seeds were exposed to herbicide vapors prior to germination. Germination of velvetleaf, common lambsquarters, and giant foxtail (Setaria faberiiHerrm.) was also increased by butylate solutions over a wide range of concentrations. Maximum germination stimulation generally occurred between concentrations of 10-5and 10-6M butylate. Seedling injury and death also resulted from these concentrations of butylate. Butylate stimulation of seed germination could not be correlated with light requirements of seeds, but appeared to be an additional promotive factor. Ungerminated common lambsquarters seeds after butylate treatment were viable and responded to KCN and KNO3in the same manner as control seeds which did not initially germinate in water. Butylate in combination with the antidote, R-25788 (N,N-diallyl-2,2-dichloroacetamide) stimulated germination of common lambsquarters.

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