Evaluation of various herbicides for controlling annual ground cherry Physalis divaricata in sugar beet Beta vulgaris fields

Current study aimed to find the best herbicide for chemical management of Physalis divaricata, which is a newly emerging weed species in sugar beet fields during 2018-2019 in Kermanshah province. The herbicides evluated in the greenhouse trials included clopyralid, desmedipham, phenmedipham, chloridazon, and Betanal Progress (desmedipham + phenmedipham + ethofumesat) which are commonly used in sugar beet cultivation in Iran. Different doses of these herbicides were used at 4- and 8-leaf growth stages of P. divaricata in combination with and without ammonium sulphate (AMS) and Dash additives. Greenhouse results showed that application of clopyralid, chloridazon, and Betanal Progress herbicides resulted in acceptable control of P. divaricata. The results of field trials indicated that usage of clopyralid at the 8-leaf growth stage resulted in a higher percentage of weed control than, chloridazon, and Betanal Progress. In contrast, weeds were more susceptible to chloridazone at the 4-leaf growth stage and phytotoxicity of this herbicide was more than that of clopyralid and Betanal Progress. Addition of AMS to herbicide tank mixture was more effective than Citogate in increasing the efficiency of herbicides under greenhouse and field conditions. Application of AMS resulted in complete control of Physalis divaricata treated by chloridazon and clopyrilide used at 4- and 8-leaf stage, respectively. Based on the results of this study, application of chloridazon at 4 kg ha-1 at early growth stages of P. divaricate and clopyralid 0.75 L ha-1 at its adult growth stage in combination with AMS could be recommended for effective control of P. divaricata in sugar beet fields. Based on the results of this study, the practical recommendation for farmers is to use pyramid if annual groun cherry is in the early stages of growth, and lontrel, if it is in adult growth stages. In both herbicides, the usage of ammonium sulfate as an effective additive to the spraying solution is also recommended.