Linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea) and diphenamid (N,N-dimethyl-2,2-diphenylacetamide) were applied at 5 and 25 lb/A to 13- x 3-inch columns of Wheeling sandy loam and Maury silt loam soils and leached with 1, 2, 4, and 8 inches of water. Linuron remained at or near the soil surface; diphenamid was leached more readily.

Factors influencing injury to oats from 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) residues in the soil were studied over a period of five years. Initial rate of triazine application was highly important with significant injury in about one-half of the trials on plots treated with 2 lb/A the year prior to planting oats, and on all plots treated at 4 lb/A. No material difference was found on plots treated with equivalent rates of atrazine and simazine. Granular preparations of atrazine left a residue that was more injurious than wettable powders. Disking the seedbed for oats, rather than plowing, resulted in greater injury. Cultivation of the corn between the rows after treatment did not influence the injury the following year. Soil type did not have a marked effect on injury in this study. Above-normal average mean air temperatures appeared to reduce injury the following year in some instances. Experiments initiated in years of abundant rainfall during April to October tended to have less injury the next year than experiments initiated in years when rainfall was limited.

Greenhouse evaluation of 13 herbicides indicated that several were suitable for preemergence weed control in sesame. CIPC appeared best and was field evaluated for 2 years. This herbicide provided adequate to excellent annual weed control without plant injury or reductions in yield.

Six herbicides were applied to young stands of Kentucky bluegrass at weekly intervals in treatments beginning 5, 7, 9 and 11 weeks after seeding bluegrass. In both years the arsenical containing herbicides were effective when applications were started 7, 9 or 11 weeks after seeding. Applications started five weeks after seeding were unsuccessful in 1962 but gave excellent control in 1963. Reduced stands of Kentucky bluegrass and generally poorer crabgrass control were obtained with phenyl mercuric acetate than with the arsenicals.

Dodder seedlings become attached to another plant by first twining about some part of the host. Twining is dependent on action of light. Chlorophyll also forms after exposure to light. Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] was applied to dodder seedlings to determine the nature of light action in twining. Diuron had no effect on twining but blocked photosynthesis.

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.

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.