Combination of different methods for direct control of Vicia hirsuta in winter wheat

Summary

Combinations of three different direct methods for controlling Vicia hirsuta (kainite application, flame weeding and harrowing) were investigated in field experiments. They were based on different strategies at early growth stages of V. hirsuta and standardised harrowing at late growth stages. The highest efficacy of kainite application and flame weeding was achieved at the one leaf stage of V. hirsuta. Winter wheat regeneration from damage caused by both kainite and thermal control was satisfactory when treatments were applied at early growth stages (GS 23). Vicia hirsuta plants that survived kainite application or flame weeding were successfully controlled by repeated harrowing at later crop growth stages; crop growth was not affected. Seed production of V. hirsuta declined with increasing harrowing in all treatments; however the strongest and most reliable reduction was achieved when flame weeding had been previously applied. All combinations of direct measures reduced winter wheat grain-yield losses and enhanced thousand-grain weight more efficiently than the use of a single method only. The highest wheat-grain yield was gained after repeated harrowing (3 times) both with and without kainite application.