Sugarcane is a strategic industrial crop and is grown commercially and extensively in more than one hundred thousand hectares in Khuzestan province. This crop is attacked heavily by a variety of annual and perennial weeds. Cogongrass, Imperata cylindrica is one of the most detrimental perennial weeds in sugarcane agro-industries in south of Khuzestan province and a large amount of Glyphosate herbicide is consumed on this grass. Control of weed complex is heavily relied upon on extensive use of chemical herbicides. This vast application of herbicides poses high cost to sugar industry, environmental pollution and increasing risk of weed resistance. One of the control methods of cogongrass is using hydroflume covering on infested area. Due to this reason, in autumn 2016, field trials were carried out in Salman Farsi Agro-industry to examine the effects of hydroflume covering time on I. cylindrica. The research trial was conducte as well as d in a randomized block design with three replications. Each trial plot consisted of four rows, 8 meter long and 1.8 meter spaces between two rows (43.2 m2). Treatments consisted of covering by hydroflumes on 1 Aban, 15 Azar, 1 Bahman, 15 Esfand and control. All treatments were applied on a third ratoon of CP57-614 field. There were three replications for each treatment and control. The number of weeds wet weight, dry weight and percentage of control of I. cylindrica was recorded in a 30 cm depth prior harvest. The results showed that there were significant differences among treatments and control. The results indicated that the best time of cogongrass covering was 1 Aban and 98% of control in comparison with control was achieved. On-time application of covering especially in the fields with high infestation rate by cogongrass can reduce the amount of consumed Glyphosate herbicide and this leads to a significant reduction of negative environmental effects.