Fresh and stored dandelion (Taraxacum officinale Weber) seeds were studied to determine the germination response to a range of constant and alternating temperature regimes on thermogradient plates. Germination was initiated over a wide range of temperatures. Maximum germination of fresh seed occurred at an alternating temperature of 20 C for 16 hr and 10 C for 8 hr. Seed stored for 30 days germinated best at 20 C for 16 hr and 15 C for 8 hr. In addition to the shift in germination requirement, dormancy increased during the 30-day storage, especially at −15 C.

Pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide] was applied to newly sprigged centipedegrass [Eremochloa ophiuroides (Munro) Hack.] in field and greenhouse experiments at 0.56, 0.84, 1.68, and 3.36 kg/ha at various time intervals from 0 to 10 weeks after sprigging. Sequential pronamide treatments of 0.84 kg/ha applied at sprigging followed with 1.68 kg/ha at 3 weeks after sprigging did not affect plant survival and controlled large crabgrass [Digitaria sanguinalis (L.) Scop.] and goosegrass [Eleusine indica (L.) Gaertn.] sufficiently to allow optimum growth of the turfgrass. Plots treated with one pronamide application did not control weeds satisfactorily, while more than two applications either caused turf injury or generally offered no advantage in weed control when compared with sequential 0.84 and 1.68 kg/ha treatments. In field plots treated with 0.84 kg/ha at sprigging and 1.68 kg/ha at 3 weeks after sprigging, the turf ground cover was 66% after the first growing season. Plant and root growth were not adversely affected in greenhouse-grown turf receiving similar treatments.

Pesticide drift studies were conducted in which two formulations were sprayed simultaneously to eliminate meteorological differences. One formulation was traced with Brilliant Sulfo Flavine (BSF) dye and the other with Rhodamine B (RhB) dye. Combined drift from both formulations was caught downwind on Mylar sheets. A filter fluorometer was used to analyze the deposits. By proper selection of a light source, primary filters, and secondary filters, the BSF was excluded while the RhB was analyzed, and vice versa. Concentrations below 1.0 μg/L were accurately measured.

Metham (sodium methyldithiocarbamate), applied alone or in combination with dichlobenil (2,6-dichlorobenzonitrile) in foam, was effective in killing roots of eucalyptus (Eucalyptus camaldulensis Dehnhardt) or willow (Salix hindsiana Benth.). An air-aqueous (19 to 1) foam of these herbicides was at least 20 times as effective as the aqueous mixture alone. Killing of the root with metham was rapid and extended above the lower treated portion, with the extent of necrosis resulting from translocation of the herbicide varying with concentration of metham that was used. The amount of the root killed with dichlobenil was limited to the treated area regardless of concentration. Four weeks were required to control the larger roots. Root killing with metham proceeded via both the aqueous and vapor phases. Results from labeling trees with 14C-assimilates indicated that neither translocation nor accumulation were greatly affected by metham or dichlobenil except in the tissues actually killed. However, transport and accumulation into untreated roots were reduced for a few weeks by dichlobenil. Similar results were obtained with cotton (Gossypium hirsutum L. ‘Acala’) treated with dichlobenil.

Purple nutsedge (Cyperus rotundus L.) plants from tubers uniformly planted in fumigated soil were treated with 2,4-D [(2,4-dichlorophenoxy)acetic acid], paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), or dinoseb (2-sec-butyl-4-6-dinitrophenol). Repeated applications were made as required on the 1972 and 1973 plantings for one growing season. Emerged plants and their parent tubers were killed by four (1972) or five (1973) applications of paraquat. Three applications of 2,4-D were required for control in 1972. In 1973, a single treatment of 2,4-D afforded almost complete control. Three applications of dinoseb were required in 1972, but five were required in 1973.

International challenges in any field of science occur only from time to time. On occasions where the development of mankind is seriously endangered due to constraints of one kind or another, the ground for the germination of such challenges may be particularly fertile.