Show new chemical weapons to combat weed pests farmers and householders wag ing war on crab grass and other troublesome weeds and grasses can look for help from two new deap ons 0 the weed killing chemicals bear the jaw breaking names ol 01 sodium isopropyl and ally mixed chloro phenyl carbonate they have been tested by federal and state agricultural experiment stations with excellent results against many weeds and grasses not eco no or satisfactorily con trolled by other chemicals or tices cices the announcement said they are being used in active exper ex penmen imen tal programs but are not yet avail able commercially the second named herbicide Is I 1 the one that combats crab grass as well as barnyard orchard and blue grass cattails and similar plants it has a hormone like action which attacks the root structure of the weed and arrests growth immediately by preventing seed develop ment even though no effect Is ap parent on the surface tor for the first week or longer it also is used effect lively in combination with 2 4 D against some broad leaved weeds not affected by 24 2 4 D used alone the sodium isopropyl Is I 1 described as a complete killer which should not be applied direct ly to crop plants it shows prom ise for pre emergence treatment in spray or dust form and has been used with success in the chemical weeding of growing crops |