Effects of Two Systemic Insecticides on Damping-off Pathogens of Cotton

In vitro and greenhouse studies were conducted to investigate the possibility of an interaction between two systemic insecticides of: Thiodicarb (Larvin DF ۸۰) and Imidacloprid (Guacho SW ۷۰), and seedling disease organisms of: Rhizoctonia solani, Fusarium moniliforme and Pythium ultimum. When in vitro concentrations of Imidacloprid and Thiodicarb were applied, a fungistatic activity occurred. These insecticides inhibited mycelial growth of R. solani and F. moniliforme by ۶.۶-۱۴.۱ % and ۱۵.۲-۷۰.۸ %, respectively. F. moniliforme was more seriously affected by the insecticides while no significant effect was observed on P. ultimum. The pot experiments confirmed in vitro results so that, Thiodicarb provided excellent protection against pre- and post-emergence damping-off of the plant by ۵۴.۲% and ۹۰.۶ %, respectively.