Suitability of five plant species extracts for their compatibility with indigenous Beauveria bassiana against Aphis gossypii Glov. (Hemiptera: Aphididae)
Samy Sayed, S. A. El-Arnaouty, Esmat F. Ali
Abstract
Abstract Background The cotton aphid, Aphis gossypii Glov. (Hemiptera: Aphididae), is a major insect pest on a wide range of plants that causes high damage and transmits plant viruses. This study was carried out to evaluate an indigenous isolate, Beauveria bassiana ( Bb ), and extracts of 5 plant species: Psiadia penninervia , Pulicaria crispa , Euryops arabicus , Salvia officinalis , and Ochradenus baccatus against A. gossypii , as individual and combined treatments to estimate their compatibility under laboratory conditions. Also, the antifungal activity of these plant extracts against B. bassiana was evaluated. Results LC 50 value was 8.64 × 10 4 spores/ml of Bb against A. gossypii , while LC 50 values of the tested 5 plant extracts on A. gossypii were 103.64, 879.92, 747.90, 783.28, and 262.42 μg/ml for P. penninervia , P. crispa , E. arabicus , S. officinalis , and O. baccatus , respectively. Both P. penninervia and O. baccatus extracts had the highest antifungal activities against Bb and were significantly different from the other 3 plant extracts. After 24 h of treatment with the combination of Bb and each extract, no effect for these combinations on A. gossypii mortality was recorded. Meanwhile, 5 days after treatment, the combined treatments between Bb and each plant extract achieved a significant increase in mortality than that of the single treatment with Bb or plant extract, except for P. penninervia extract, which did not achieve a significant mortality increase when combined with B. bassiana than that of its single treatment. Conclusion P. penninervia extract was not compatible with B. bassiana , but the other tested 4 plant extracts were compatible with B. bassiana . These 4 plant extracts could be used to control aphids in combinations with B. bassiana . Further laboratory and field investigations are needed to examine the effects of these plant extracts on other insect pests or associated beneficial insects.