Commelinaceae-A Review of the Distribution, Biology and Control of the Important Weeds Belonging to this Family

Abstract

The Commelinaceae is chiefly a tropical family, present in all the major continents and extending into the temperate zone in parts of America, E. Asia and Europe. The review includes the three major weed species in this family, Commelina benghalensis L., C. diffusa Burm. f. and Murdannia nudiflora (Linn. Brenan. The synonymy of each species is listed and the importance of the weeds discussed in relation to their biology. The results of trials in cereals, broadleaved and plantation crops are summarised. The most successful methods of herbicide application are pre-emergence or early post-emergence. Herbicides should be applied in the early stages of the growth cycle as single or sequential applications. Bentazone applied as an early post-emergence treatment, either alone or in mixtures is one of the most successful herbicides in controlling Commelina species. Metribuzin applied pre-emergence alone or in mixtures is another chemical giving satisfactory control in many parts of the world. Esters or amines of 2, 4-D applied as overall post-emergence sprays give good control of C. benghalensis when young and are also helpful as spot treatments at a later stage. The triazines and ureas give variable results when applied alone, but are more effective in mixtures. Dense mats of plant material make chemical weed control of older plants difficult and removal by hand is the only effective control at this stage.