Tubers of sago pondweed (Potamogeton pectinatus L.) were grown at 72 F in a 14-hr photoperiod under 400 ft-c of coolwhite fluorescent illumination. Plants were randomly harvested each day for 30 days, the organs individually weighed, and carbohydrate determinations made on selected tissues. Unsprouted tubers averaged 19.5% dry weight of which 74% was carbohydrate, predominantly in non-extractable form. During growth, the carbohydrate supply in the tubers decreased logarithmically by ½ each 4.93 days. Shoots began to grow logarithmically at 11 days, doubling in dry weight each 4.5 days. After 18 days, the carbohydrate content of the main shoot increased logarithmically, doubling each 7.35 days. Plants produced from average tubers increased 7-fold in dry weight in 30 days. Growth analysis showed that no shoots became self-sufficient before 16 days. Deduced patterns of carbohydrate flow are correlated with reports of herbicidal effectiveness.

Average monthly rooting of saltcedar (Tamarix pentandra Pall.) stem cuttings collected weekly for a year and planted on a mist-bed was 96–100% from early February through May arid decreased to 77% in November. Accompanying shoot formation reached a concurrent maximum of 96–100%, with an October low of 10%. Bud dormancy of October-November cuttings was reduced by cold treatment, but June-July cuttings were not responsive. A rooting compound reduced shoot and root formation.

Cotton and grain sorghum were treated with directed paraquat (1,1′-dimethyl-4,4′-dipyridylium cation) sprays in the field. Tall cotton was less susceptible to the herbicide than smaller plants. Some cotton varieties showed greater susceptibility to paraquat than others. In general, fiber quality was not affected by paraquat at ⅛ and ¼ lb/A, although there was some effect on the fiber coarseness of the more susceptible varieties. Increasing light intensity caused more leaf damage from cotton stem applications of paraquat. Directed paraquat applications invariably caused the outer sorghum leaf sheaths to show necrotic spots where treated. Treatments on 6-inch sorghum reduced yields, but plants treated when taller than 6 inches were not injured. Thirteen sorghum hybrid and open-pollinated varieties showed varying degrees of leaf and sheath burn due to paraquat treatments.

Aspergillus niger v. T. ATC6275, proliferation was reduced by 2,4-dichlorophenoxyacetic acid (2,4-D) at 10 and 50 ppm. Picloram (4-amino-3,5,6-trichloropicolinic acid) at rates up to 50 ppm did not reduce fungus growth. A. niger degraded both 2,4-D and picloram, 2,4-D more effectively. Both herbicides were contained in the fungus mycellium.

The relative tolerance of one-year-old peach and apricot seedlings to 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) and 2-methoxy-4,6-bis = (isopropylamino)-s-triazine prometryne was established by soil surface and soil incorporated applications. In all cases, the relative tolerance to both herbicides was greater for peach than apricot. Reciprocal grafts of peach and apricot budded seedlings indicated that the rootstock did not alter the tolerance. The greater tolerance of peach over that of apricot was attributed to physiological detoxification occurring in the scion.

Propionate, 3-chloropropionate, and 2,2-dichloropropionate (dalapon) inhibited growth of Escherichia coli 99-4, a mutant organism incapable of growth in the absence of α-ketopantoate. Growth inhibitions were circumvented by increasing the concentration of ketopantoate. Aliphatic acids (K+ salts) apparently inhibit biosynthesis of pantothenate at two metabolic sites—conversion of ketopantoate to pantoate and formation of pantothenate from pantoate. The latter inhibition has been reported previously.

A low-volume, transparent, acrylic plastic concentrate tank for herbicide spray solutions is described which includes a fast-opening filler valve, a pressure relief valve, and a compressed air intake.

A simple, inexpensive soil perfusion unit for use in studying the microbial decomposition of pesticides is described. This unit has the advantage of being equally adaptable to positive or negative pressure systems.

The pre- and postemergence herbicidal activities and specifications of 16 substituted toluidines on eight species were determined at two application rates. CF3-analogs were more active as preemergence treatments, and CH3-analogs were more active as postemergence treatments. Preemergence toxicity to crops was decreased in the CF3 and CH3 series when the N-substituents contained more than six carbons.

Mathematical relationships are developed for a general system in which the concentrate chamber and diluent vessel contain the active material to be evaluated. The use of the system for increasing the effective half-dosage distance is illustrated. A technique is described for decreasing the half-dosage distance with a conventional system.

Gross autoradiography showed that translocation of C14-labeled 3-amino-1,2,4-triazole (amitrole) from the leaf of quackgrass (Agropyron repens (L.) Beauv.) was retarded over 12 hr by ammonium thiocyanate applied as a spray or as a spot. While considerable export of C14 from the treated leaf occurred during 12, 24, and 96 hr after C14-amitrole was applied, C14-NH4SCN as a tracer was largely restricted to the treated leaf over the first 24 hr and showed only slight export over 96 hr. It was concluded that the synergistic effect of NH4SCN on amitrole is exerted in the treated areas and not at the ultimate site of amitrole action.

A knife injector was designed and tested for the application of ethyl-N,N-dipropylthiolcarbamate (EPTC). Performance was good and preliminary tests were encouraging for both preemergence and postemergence applications.

Using previously published data, a quantitative treatment of the influence of soil moisture content on herbicidal activity has been described. The treatment is based upon the use of the distribution coefficient, Kp, and is an extension of recent developments in the application of chromatographic theory to movement and sorption of chemicals in soil.

Seven insecticides were applied separately and in combination with the herbicide propanil (3,4-dichloropropionanilide) to young rice. None of the insecticides applied alone caused leaf burn. Toxaphene and endrin, in combination with propanil, did not increase leaf burn over that which occurred from propanil alone. Malathion, phosphamidon, Guthion (O,O-dimethyl S-4-OxO-1,2,3-benzotriazin-3(4-H)-ylmethyl) phosphorodithioate and Dylox, (O,O-dimethyl 2,2,2-trichloro-1-hydroxyethyl phosphonate) in combination with propanil, increased leaf burn over that which occurred from propanil alone. In general, increased leaf burn resulted in decreased yields of rough rice.