Ameliorative Impact of Glyphosate Herbicide Treatments on Dodder (Cuscuta campestris) Control in Nerium oleander L. Shrubs

This study was conducted to evaluate the impact of Glyphosate herbicide on dodder control on Nerium oleander L. shrubs. Glyphosate herbicide was applied at several rates (50, 100, 200, 400 and 800 ppm) to control the parasitic weed Cuscuta campestris on Nerium oleander L. shrubs. Results revealed that applying glyphosate at very low rates (200 and 400 ppm) controlled (86-90%) of attached dodder, Cuscuta campestris Yunker on Nerium oleander L. after two months of treatment without any phytotoxicity and also improved growth parameters (leaf area, leaf fresh weight and percentage of leaves dry weight of N. oleander as compared to the check). Data also showed that dodder control by the use of glyphosate at the same rates reduced seed germination, length and fresh weight of dodder. The obtained results also indicate that glyphosate herbicide at the two rates were markedly increased chemical constituents of leaves (total carbohydrate, total, reducing and non-reducing sugars, chlorophylls, carotenoid, xanthophylls, prolin, total indoles, ascorbic acid and antioxidant enzymes activity). On the contrary, all dodder control treatments decreased free phenols in leaves as compared to the check.