Seeds of white spruce (Picea glauca, Moench), Colorado spruce (P. pungens, Engelm.), and Scotch pine (Pinus sylvestris L.) were treated with simazine in water at rates up to 1000 ppm for 20 hours, washed 10 min., rinsed twice, and sown. There was no effect on Colorado spruce or Scotch pine, but white spruce seeds were seriously affected above 250 ppm. Simazine has been considered not to affect seeds.

A mobile, metal cabinet sprayer is described, in which an electrically-powered, chain-driven carriage with spray assembly travels back and forth over the pots or flats to be sprayed.

Carboxyl labeled 2,4–dichlorophenoxyacetic acid (2,4–D) was applied to ironweed, a perennial composite, at various stages of growth in the field and greenhouse. During phases of rapid plant development, C14 tended to concentrate in new leaves, axillary buds, petioles and stems. As plants approached full vegetative development greater quantities were detected in rhizomes and roots and less in stems and leaves. The herbicide was translocated readily into new leaves, stems and roots of ironweed seedlings. Considerable quantities of 2,4–D–C14 absorbed by ironweed were rapidly metabolized to compounds not extracted by alcohol. Non-herbicide activity was also found in alcohol extracted fractions. C14 accumulations in field-treated ironweed were detected in roots and rhizomes 3 to 6 weeks after treatment.

Comparative studies of herbicides and herbicide mixtures were conducted at Tifton, Georgia, in 1959 and 1960. Certain mixtures, which contained sodium 2,4–dichlorophenoxyethyl sulfate (sesone), tris(2,4–dichlorophenoxyethyl) phosphite (2,4–DEP), or the triethylamine salt of 3–amino–2,5–dichlorobenzoic acid (amiben) mixed with the alkanolamine salt of 4,6–dinitro–o–sec-butylphenol (DNBP), gave seasonal weed control on band-treated peanuts. Compared to herbicides applied singly, mixtures not only increased the spectrum of weeds controlled but also permitted the use of the lowest rate of each component on the weeds for which it was most effective.

Wheat, bean, and pigweed (Amaranthus retroflexus) seeds were immersed in solutions of 2,4–D (ester) and MCPA (ester) ranging from 0.001 ppm. and then germinated in petri dishes. Both products induced analogous effects but MCPA appeared to be slightly less active. Germination in pigweed was promoted by the 0.1 ppm. solutions. Growth of plumule and radicle in wheat was stimulated by lower (0.001 to 1 ppm.) concentrations and depressed by higher ones (100 and 1000 ppm.), the threshold between stimulation and depression being around 10 to 100 ppm. depending on the product and the organ affected.

Salmonberry (Rubus spectabilis Pursh.) was basally treated in Western Oregon during the dormant season and at bud bursting in April, using a 1:1 mixture of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and the same mixture of 2,4-D and 2,4,5-T monobutyl ether glycol esters, and 2,3,6-trichlorobenzoic acid (2,3,6-TBA), in two carriers and with different additives, and with diesel oil alone. January applications gave generally poorer results than those in March and April. March and April applications produced 100% defoliation and kill for all treatments, with only erratic exceptions. Diesel oil alone gave effective control only in April. Sprays containing 2½% active ingredients gave as good results as those containing 5%.

Fresh seed of Tamarix pentandra Pall. germinated at 36 to 132 F., freely at 66 to 110 F. Seed stored at the same relative humidity maintained viability best at low temperatures. Viability of seed stored at a low relative humidity continued high for 6 months over a wide range of temperature, but viability was reduced within 15 days by relative humidity of 90–95%.

In experimental work with perennial weeds it is often desirable to apply large gallonages of solution from a boom plot sprayer. Moreover, since tillage is frequently a counterpart of the control procedure the sprayer must be constructed to withstand rough usage on cloddy land. The sprayer illustrated in Figure 1 can deliver from 2 to 100 gallons of solution per acre in proper spray pattern through standard nozzles. Being light and strong, it can be pushed comparatively easily across uneven surfaces.

Overall weight of the sprayer is 150 pounds. Rate of travel is gauged by a speedometer indicating zero to 10 mph. Pressure is supplied by a quickly replaceable air pressure tank and the liquid is held in a 2-gallon pressure container. Dosage rate is determined by speed of travel and size of nozzle orifice tip. Because of the large capacity of the liquid flow system from tank to nozzle, loss of pressure is slight even when heavy gallonages of solution are applied. All parts of the system are of copper or brass except the solution tank which is of galvanized iron. However, since the outlet from tank to tubing is at the center of a dished bottom, drainage is good. Pet-cocks at each end of the boom permit thorough flushing. The boom can be set from a 6-inch to a 60-inch height and the angle of nozzle to the ground, adjusted over 20°. A supporting leg is provided at the rear of the frame to keep the sprayer upright when not in use. Air-pressure and speedometer gauges and the spray control valve are mounted directly in front of the operator. When applying 100 gallons of spray per acre, the 2-gallon solution tank permits coverage of 100 feet. Width of spray pattern is 8.5 feet.

The percentage of quackgrass (Agropyron repens (L.) Beauv.) rhizome buds producing shoots was greater with one-inch than with six-inch or longer rhizomes. The longer the rhizome cutting, the stronger the shoot and the greater the recovery from deep planting. Recovery of rhizomes covered with four or more inches of soil was poor. Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) at 1½ and 3 lb per acre did not affect the number of shoots produced. It was more effective when applied ½ inch above rhizomes than one inch or three inches above them.

A year's study of the kinds of weed seeds caught in an 18-mesh copper screen intercepting half the canal width found seeds of 20 species or genera. Bermudagrass (Cynodon dactylon) was found every month of the year; saltgrass (Distichlis spicata) only in March; others in 2 to 10 months of the year.

In trials by three methods, witchweed (Striga asiatica) did not parasitize pineapple.

Placements which did not wet the root collar and sprouting zone gave poor kills of roots.

Carbon14 carboxy labeled 2,4-D with varied amounts of Tween 20 (polyoxyethylene sorbitan monolaurate) was applied to excised Kalmia angustifolia L. (Ericaceae) leaves and, after an absorption period, the radioactivity of the dried ground leaf tissue was measured by counting. Entry rate of 2,4-D into recently formed leaves decreased with increase in Tween 20, within the range of 2,4-D/Tween 20 ratios used (roughly 5/1 to 0.5/1). Entry rate of 2,4-D into older leaves increased with increase in Tween 20.

Seeds of witchweed (Striga asiatica) were found in undisturbed Lakeland sand in all layers to 60 inches deep.