Dalapon, amitrole, and weed oil compared for effectiveness in control of bermudagrass in California citrus orchards

Dalapon, amitrole, and weed oil, used alone, as mixtures, or in combination, were compared for effectiveness in the control of bermudagrass. Split applications of dalapon, properly timed, were more effective than single applications with the same total amount of herbicide. Amitrole, and to a lesser extent dalapon, was more effective when applied late in the growing season. Variation in spray volume, the presence or absence of surfactant, or the inclusion of small amounts of kerosene had no effect on the toxicity of amitrole. Mixtures of dalapon and amitrole were less toxic than was dalapon applied alone at the same rate. Split applications of amitrole were less effective than single applications containing the same total amount of herbicide.

Repeat spraying with weed oil at three-week intervals was highly effective and gave control equal to the more frequent oil spraying.

In a screening program, atratone and prometone at rates of 10 pounds per acre controlled bermudagrass. Ipazine, trietazine, simetone, simazine, CIPC, EPTC, and maleic hydrazide were not highly toxic to bermudagrass. Sodium 2,3-dichloroisobutyrate was only an eighth as effective as dalapon.

This paper reports research on the evaluation of several chemicals as herbicides for the control of bermudagrass. No recommendations for or against the use of these chemicals are intended or implied. Federal and state laws regulate the use of agricultural chemicals, and persons wishing to use chemicals mentioned in this publication should consult local agricultural regulatory officials.