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.

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.

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.

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.

The specific and general postemergence herbicidal properties of N′-4-(4-chlorophenoxy)phenyl-N,N-dimethylurea [chloroxuron] were influenced by formulation and the carrier employed.