Science: Farmer’s Friend

Suburbanites battle the dogged dandelion with a chemical— 2,4-D (2,4-dichlorophenoxyacetic acid). Last week dirt farmers cheered its weed-killing feats. It had proved effective against bindweed, a wild morning-glory that is the worst weed in western grain fields. 2,4-D killed bindweed without hurting the grain.

2,4-D was only one chemical weeder. Others were on the market, with more to come. Their value as weeders depended upon their selectivity. They did not kill all plants alike, but only certain types. For instance, 2,4-D did not kill plants, such as wheat, which are related to the grasses. It did kill broad-leaved plants like bindweed.

Vulnerability of a plant to chemical killing depends on many qualities, and no two species are exactly alike. Agricultural chemists were studying crop plants and their commonest weed enemies from every possible angle. They were looking for the key difference which would make weeds vulnerable to some chemical which did not hurt the crop. Chances looked good.