Investigation on the Chemical Control of the Invasive Weed, Water Hyacinth, Eichhornia crassipes, in Bandar Anzali

In order to control the invasive weed, Eichhornia crassipes (Mart.), two experiments were carried out during 2017 and 2018 in Gilan province. The first experiment was carried out in Anzali Lagoon to investigate the efficacy of Glyphosate (41%SL) at 2 and 3 Lha-1 (two applications), Glyphosate at 2 and 3 Lha-1 plus Dasher Adjuvant (0.5%) (two applications), Glyphosate at 2 and 3 Lha-1 plus Ammonium Sulfate Adjuvant (2%) (two applications) and Glufosinate-ammonium (15% SL) at 2.5 and 5 Lha-1. The second experiment was carried out in mesocosm to compare the efficacy of Glyphosate at 3 Lha-1 (two applications), Glyphosate at 3 Lha-1 plus Ammonium Sulfate (two applications), Glufosinate-ammonium at 5 Lha-1 and Bispyribac sodium (12.5% SC and 10% OF) at 200 and 300 mlha-1 (two applications). EWRC rating scale for visual control and the wet and dry weight reduction of water hyacinth were checked in comparison with the weedy check within 30 days after herbicide application. The Results of visual control in both the experiments indicated that the best treatment was Glyphosate at 3 Lha1 with 98% weed control and in the second experiment in this treatment wet and dry weight reduction was 56% and 64% compared to weedy check, within 30 days after herbicide application and complete control within three months after application respectively. Bispyribac sodium (10%OF) at 200 mlha-1 had 63% visual control, 33% and 56% wet and dry weight reduction compared with the weedy check within 30 days after herbicide application and complete control within three months after application, respectively.