The acid and amine formulations of 2,4-dichorophenoxyacetic acid (2,4-D) can be extracted from soybean seed simultaneously or separately. The method consists of partitioning first between ethyl ether and citrate-phosphate buffer and then between carbon tetrachloride and citrate-phosphate buffer. Quantitative determination of the 2,4-D can be made by means of chromatography.

Whenever moisture and temperature were favorable for germination, new seedlings of field dodder (Cuscuta campestris Yunck.) emerged each week for two years after seeding in the field or greenhouse. Many viable seeds probably remained in the soil, because 10% or less of the seeds produced seedlings.

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and 2-chloro-4,6-bis(isopropylamino)-s-triazine (propazine) affected oats and alfalfa in Nebraska planted the year following application to sorghum. No carry-over of 2-chloro-N,N-diallylacetamide (CDAA) + trichlorobenzyl (TCBC) was detected in oats and alfalfa. Intertillage of sorghum did not decrease herbicide residue.

At Lincoln 20 lb/A of 2,3,6-trichlorobenzoic acid (2,3,6-TBA) destroyed Clark soybeans five seasons after application. Soil persistence of 2,3,6-TBA in the light textured soils and low rainfall of western Nebraska was less than at Lincoln. A 10 lb/A rate of 3-(p-chlorophenyl)-1,1-dimethylurea (monuron) reduced weed and oat yields at Lincoln the third growing season after its application. Applications of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine), 2-chloro-4,6-bis-(ethylamino)-s-triazine (simazine), or monuron at 10 lb/A reduced oat yields at North Platte the third growing season after their application. Herbicide carryover is a greater problem in arid than in humid regions of the United States.

Seedlings of Siberian elm (Ulmus pumila L.) readily invade grasslands of the Southern Plains and are a serious economic problem. Siberian elm was not susceptible to foliage or basal sprays of phenoxy herbicides applied during 3 successive years. Individual trees were killed easily by 1 g (ai) per inch of trunk diameter of 3-(p-chlorophenyl)-1,1-dimethylurea (monuron) or 3-phenyl-1,1-dimethylurea (fenuron) applied in a ring around the tree. However, the dense population and rapidity of reinvasion make this treatment too expensive.

Potato fields were surveyed semi-monthly. Seedlings of barnyardgrass (Echinochloa crusgalli (L.) Beauv.) began to emerge as soon as the potatoes or shortly after. Emergence continued throughout the growing season. Barnyardgrass plants were most noticeable in the field in August and September when the potato vines started to lodge and much of the grass was headed.

Treatment of little barley (Hordeum pusillum Nutt.) at early-tillering stages with 0.25 to 0.5 lb/A of 1,1′-dimethyl-4,4′-dipyridylium cation paraquat, surfactant gave satisfactory to complete control of little barley and other annual weed species. Except under unfavorabe seasonal conditions, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) also gave good control of little barley but was ineffective against other established weed species. Coastal bermudagrass [Cynodon dactylon (L) Pers.] was not injured by atrazine and only temporarily by paraquat.

Indoleacetic acid (IAA) stimulates the incorporation of radioactivity derived from methionine-methyl-C14 into a fraction of sesbania hypocotyl that is insoluble in 80 per cent alcohol or 60 percent acetone, but is soluble in hot water. Incorporation of C14 into “hot water soluble material” was stimulated by IAA, 2,4-dichlorophenoxyacetic acid, 2,5-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, naphthaleneacetic acid, 2,3,6-trichlorophenylacetic acid, 2-methoxy-3,6-dichlorobenzoic acid, 4-amino-2,5-dichlorobenzoic acid, and 4-amino-3,5,6-trichloropicolinic acid. All compounds were stimulative at 1 × 10-5M.