Effect of the pathogenic fungus Beauveria bassiana against the lesser grain borer Rhyzopertha dominica on five wheat cultivars

The aim of this research was to determine the mortality rate of the lesser grain borer Rhyzopertha dominica (Fabricius) (Col Bostrichidae) influenced by the pathogenic fungus Beauveria bassiana strain EUT116 on five wheat cultivars including the Pishtaz, Chamran, Chamran2, Sirvan and Mihan (at 25±1°C, 80 ± 5 % RH and darkness). In all experiments, 1-7-day-old individuals were used in plastic containers (8cm height, 5cm in diameter) containing seeds from each cultivar. This experiment was conducted with a different dose of the fungal spores including 0.25 and 1 g per kg of wheat from each cultivar and there were 50 replicates of each treatment. The number of conidia per gram of spores was 6.22×1010. Results showed that there was a significant difference between treatments and cultivars and the interaction between treatments and the cultivars were alsosignificant and increasing the dose of spore increased the mean mortality rate of the beetles. On the Chamran2, the highest mean mortality was observed for one g of fungal spore per kg of the wheat (20.73±0.07 adults). However, the lowest mean mortality rate was obtained on the Mihan (13.33±0.77 adults). In the treatment of one g of the sporeper kg of wheat, there was no significant difference between the mean mortality of the beetle on the Pishtaz (18.65±0.40 adults) and the Sirvan (19.23±0.43 adults) but there was a significant difference between the later cultivars and the Chamran (17.03±0.35 adults). The results showed that the beetle was relatively sensitive to the pathogenic fungus B. bassiana strain EUT116, or that the isolate had a suitable potential for controlling this store grain pest. The type of cultivar and different fungal doses could significantly be effective on the mortality rate of the beetle.

کلیدواژه ها:

Wheat cultivars ، Interaction ، Lesser grain borer ، Mortality