Alhagi pseudalhagi (Bieb.) Desv. (camelthorn) was in troduced into California about 1915, and into the State of Washington about 1935. Here, it was declared a primary noxious weed in 1955. Seeds scarified with sulfuric acid germinated 90–98 per cent at 25 C. Some seeds were viable after burial one year in soil or submergence for 9 months in running water. Seedlings in the infested area were found only in bovine manure. Tests indicated scarification and transportation of seed in the rumen could accelerate the spread of camelthorn. Lack of favorable moisture and soil temperature at the same time prevented establishment of camelthorn planted at several locations. Eradication resulted from treatment with 2,3,6-trichlorobenzoic acid (2,3,6-TBA). Three repeated sprays with esters of 2,4-dichlorophenoxyacetic acid (2,4-D) within a growing season gave control; however, control did not appear to be directly related to depletion of reserve foods in the roots.

The morphological symptoms of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 3-(p-chlorophenyl)-1,1-dimethylurea (monuron) toxicity were expressed in the light but not in the dark. Various wavelengths of narrow band light were produced by the use of colored plastic filters. Oats, var Kanota, and red kidney beans were used. The degree of injury was a function of light intensity, the higher the light intensity the greater the injury. The action spectrum indicated that chlorophyll was the principal absorbing pigment involved in this injury.

These herbicides at rates of .01 to .25 lb/A caused moderate to severe morphological effects on soybeans and significant yield reductions. Soybeans treated in the vegetative stage were injured more than those treated in the bloom stage. The herbicide 2-(2,4,5-trichlorophenoxy)propionic acid (silvex) injured soybeans most followed by 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 2,4-dichlorophenoxyacetic acid (2,4-D), and 4-(2,4-dichlorophenoxy)-butyric acid (2,4-DB), in that order.

Listed on the basis of visual ratings in Sept. 1961, in the order of increasing toxicity to Kentucky bluegrass sown in April, 1961, and treated May 31 and June 6, the herbicides were 2,3,5,6-tetrachloroterephthalic acid (DCPA), amine methylarsonate, diphenylacetonitrile (diphenatrile), calcium propylarsonate, disodium monomethylarsonate (DMA), N,N-dipropyl-2,6-dinitro-p-toluidine (dipropalin), calcium arsenate, O-(2,4-dichlorophenyl) O-methyl isopropylphosphoramidothioate (DMPA), polychlorodicyclopentadiene isomers, and alpha, alpha, alpha-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin). All herbicides except DCPA and DMPA (liquid) persisted after two years of use until March 1963 in the top 2 inches of soil.

A plastic envelope device is described which allows separate exposure of seeds, roots, and coleoptiles of emerging grass seedlings to soil-incorporated herbicides.

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.