Determination of critical period of weed control in commercial potato (Solanum tuberosum L. cultivar. Agria) in Ardebil

A field experiment was conducted to determine the critical period of weed control (CPWC) of commercial potato fields in randomized complete block design with four replications at Ardebil. Trial including twelve treatments consisted of six initial weed-free periods in which plots were kept free of weeds for 0, 10, 20, 30, 40 and 50 days after crop emergence (DAE), and then weeds were allowed to grow until harvest and six initial weed-infested periods in which, weeds were allowed to grow for 0, 10, 20, 30, 40 and 50 DAE, after which the plots were kept free of weeds until harvest. Results showed that the beginning of CPWC was 472 and 593 growth degrees days (GDD) equates 10 and 18 DAE at 5 and 10% Acceptable Yield Loss (AYL) respectively. The end of the CPWC was 1513 and 1261 GDD equates 69 and 57 DAE at 5 and 10% AYL respectively. Practical implications of this study are that post-emergence herbicides or other weed control methods should be used in Ardebil to eliminate weeds from 18 days post-crop emergence up to 57 days.