The Red Palm Weevil is a serious problem of the date palm in Pakistan. The sole and combine application effects of Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes) and sub-lethal dosages of Imidacloprid against the second and fourth... more
The Red Palm Weevil is a serious problem of the date palm in Pakistan. The sole and combine application effects of Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes) and sub-lethal dosages of Imidacloprid against the second and fourth instar larvae of Rhynchophorus ferrugineus Olivier was investigated in laboratory. Additionally, the in vitro hyphal growth of B. bassiana amended with three different concentrations (50, 250, 500 μl L-1) of Confidor® 200 SL was also assessed. The results showed significantly higher mortality for the second and fourth instar larvae of RPW when B. bassiana and Imidacloprid applied together compared to their sole application. The highest mortality level (100%) for the second instar was recorded after 15 days of treatment with B. bassiana (1×106 conidia/ml) and Imidacloprid (1 μl L-1) in combination, while for the fourth instar larvae it was achieved after 20 days of application. However, the presence of Imidacloprid did not significantly affect the hyphal growth of B. bassiana on Sabouraud Dextrose Agar (SDA), and greater colony sizes compared to untreated control were recorded in all cases. The maximum number of sporulation (173, 159.83 conidia ml-1) and percentage (89.15, 79.4%) of mycosed R. ferrugineus cadavers was observed at lower dose rate (1×106 conidia/ml) of B. bassiana, exhibited the potential to be exploited for the control of RPW.
