Efficiency for combinations of rimsulfuron with adhesives in maize crops

Abstract

Topicality. Adhesives are an integral part of the weed control system in the maize crops, because they increase the efficiency of herbicide application. They significantly reduce the cost of plant protection products and increase their efficiency, as well as increase the adhesive properties of the herbicide solution to prevent its runoff and prolong its action. Development of new herbicides, constant weather and climate changes require to study further the effectiveness of the combined action of herbicides and adhesives. Among the adhesives for maize, it is generated interest such products as Synergent SOC, Eco Oil Spray, Esterlip, etc. Purpose. To reveal the effectiveness for combinations of herbicides with adhesives in the maize crops, as well as their impact on plant growth and development. Materials and Methods. The experimental scheme included the following combinations of rimsulfuron with adhesives: 1. Control (Rimsulfuron without adhesive); 2. Rimsulforon (40 g/ha) + Trend 90 (0.15 % working solution); 3. Rimsulforon (40 g/ha) + Synergent (0.15 % working solution); 4. Rimsulforon (40 g/ha) + Eco Oil Spray (0.15 % working solution); 5. Rimsulforon (40 g/ha) + Esterlip (0.15 % working solution); 6. Rimsulforon (35 g/ha) + Esterlip (0.15 % working solution); 7. Rimsulforon (25 g/ha) + Esterlip (0.15 % working solution). Results. The combination of rimsulfuron with adhesive Esterlip had the highest technical efficiency compared to other adhesives, in particular, on the redroot pigweed (Amaranthus retroflexus L.) was 75–100% (complete destruction) and lamb’s quarters (Chenopodium album L.) – 85.7–92.9 %, slightly less on common ragweed (Ambrosia arte-misiifolia L.) – 83.3%. Common purslane (Portulaca oleracea L.) was highly resistant to almost all combinations of rimsulfuron with adhesives. The highest maize yield of 8.99 t/ha was in the variant with Rimsulfuron (40 g/ha) + Esterlip. Reduced application rate of Esterlip to 25–35 g/ha decreased the maize yield to 7.34–7.65 t/ha, or by 1.34–1.65 t/ha (14.9–18.3 %) due to increased weed infestation of crops. The application of adhesives Trend 90, Synergen, Eco Oil Spray also decreased maize yields to 8.48 t/ha, 8.07 t/ha and 8.62 t/ha, respectively, which was less by 0.51 t/ha (5.6 %), 0.92 t/ha (10.2 %) and 0.37 t/ha (4.1 %). The lowest yield was in the control – 5.30 t/ha due to significant weed infestation of grain crops, which decreased by 3.69 t/ha (41.0 %) compared to the best variant (Rimsulfuron (40 g/ha) + Esterlip). Conclusions. Considering the ongoing development of new adhesives and herbicides for maize, as well as climate changes, it is necessary to continue research in this area to determine the most optimal ratio of herbicide rates with adhesives. Key words: maize, weeds, herbicides, adhesives, yield, technical efficiency