Paraquat applied as a directed inter-row spray gave economical control of weeds in cassava for a period of three months or more. Applications were made at rates of 0.2-0.4 kglha post-emergence in young cassava of 3 months or more with 15-20 cm of brown bark at the base of the stems; a repeat application was made after an interval of 10-14 days. Usually, one further spray was required to obtain acceptable weed control until harvesting, weed control being facilitated by the increased shade given by the developing crop canopy. PANS 20: 185 -189, 1974.

Three rates of the postemergent herbicide paraquat, 0.7, 0.35 and 0.175 kga.i./ha in 560 //ha were applied t o weed5 between rows of rubber seedlings. At each rate of paraquat, spray drift caused some defoliation of the seedlings but this was considerably higher at 0.7 k g a.i./ha than at the t w o lower rates. Death o f individual seedlings was negligible at 0.175 kg a.i./ha. Weed control increased with dosage, but 0.175 kg a.i./ha gave acceptable control, which was also completely safe t o budgrafts. A t this rate, bud development was not affected and growth was comparable t o the hand-weeded control. PANS 21: 401-405.1975.

A l i s t of common weeds and their distribution in South Thailand is given. The methods used for weed control under mature and immature rubber trees, in nurseries, and the control of encroachment by leguminous cover crops are discussed.