The effects of adjuvant and reduced doses of herbicides on field bindweed(convolvulus arvensis L.) control

Importance of reduced consumption of herbicides has been clear for many farmers and experts، and this is because the increased research done today in reducing consumption herbicides and optimizing their applications. To evaluate the efficiency of 2،4-D، Glyphosate and Lontrel at recommended doses (1، 4. 1 and 0. 36 kg ai ha-1، respectively)، half the above values of these herbicides and a mixture of 2،4-D+ Glyphosate (0. 67+ 3. 3 and 0. 51+ 2. 05 kg ai ha-1) each with and without adjuvant application (Cytovit or industrial oil No. 10 + detergent both at 1% v/v) for controlling field bindweed، field experiment was conducted. The results were significant differences between treatments (P=0. 01). Among between applied treatments، the tank-mixed of 2،4-D+ Glyphosate+ adjuvant (Cytovit) at 0. 67+ 3. 3 Kg ai ha-1 with 98% control and Lontrel with the average control of 2% represented the highest and lowest the percentage of control، respectively. Addition of adjuvant to 2،4-D at both rate (whole doses and half-doses) enhanced level of control، but with whole doses of Glyphosate (4. 1 kg ai ha-1) reduced level of control significantly; in other treatments no significant effects were observed. Just for Glyphosate application of reduced doses markedly decreased level of control، but with other herbicides whole doses and half-doses differed not significantly. Without the addition of adjuvant، Glyphosate alone at whole dose (4. 1 kg ai ha-1) controlled field bindweed 79% and in other cases control did not exceed 46%. Overall، the best results with average control of 91%، were achieved by applying tank-mixed of 2،4-D+ Glyphosate (regardless of applied rate and adjuvant).