Field evaluation of promising entomopathogenic fungal isolates against red palm weevil, Rhynchophorus ferrugineus (Coleoptera: /Dryophthoridae)

Authors: SUTANTO, K - King Abdullah University Of Science And Technology; AL-SHAHWAN, I - King Abdullah University Of Science And Technology; HUSAIN, M - King Abdullah University Of Science And Technology; RASOOL, K - King Abdullah University Of Science And Technology; Mankin, Richard; ALDAWOOD, A - King Abdullah University Of Science And Technology

Submitted to: Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2022
Publication Date: 1/2/2023
Citation: Sutanto, K.D., Al-Shahwan, I.M., Husain, M., Rasool, K.G., Mankin, R.W., Aldawood, A. 2023. Field evaluation of promising indigenous entomopathogenic fungal isolates against red palm weevil, Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae). Fungi. 9(1):68. https://doi.org/10.3390/jof9010068.
DOI: https://doi.org/10.3390/jof9010068

Interpretive Summary: Environmentally friendly management of insect pests that attack food crops is becoming increasingly important, and entomopathogenic fungi have gained increased prominence as safe and effective management tools. However, it is difficult to test the effectiveness of fungi against red palm weevil larvae that feed hidden inside date palm trunks. A new method of determining fungal effectiveness is to acoustically monitor the decline of larval sound production inside the tree after treatment. Students and scientists at King Saud University, Riyadh used methods developed by and in collaboration with a scientist at the USDA-ARS Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL, to monitor red palm weevil activity in palm trees. Together, the two groups identified two fungal isolates that decreased red palm weevil activity over a two month period and were found to have caused 95% mortality when the trees were dissected at the end of the tests. The results indicate that these two fungal isolates are effective tools for red palm weevil management.

Technical Abstract: The rate of sounds (i. e. substrate vibrations) produced by movement and feeding activity of red palm weevil (RPW) pest infestations in a date palm tree was monitored over time after trees were treated separately with injections of entomopathogenic fungal isolates, Beauveria bassiana and Metarhizium anisopliae, or water treatment as control. The activity sensing device included an ac-celerometer, amplifier, digital recorder, and signal transmitter that fed the data to a computer which excluded background noise and compared the rates of bursts of movement and feeding sound impulses among treated trees and controls. Observations were made daily for two months. The rates of bursts were representative of the feeding activity of the RPW. The unique spectral pattern of sound pulses was typical of the RPW larvae feeding activity in the date palm. The microphone confirmed that the same unique tone was produced in each burst. After two months of fungal injection, the RPW sound signal declined, while the RPW sound signal increased in the control date palms (water injection). The mean rates of bursts produced by RPW decreased to zero after the trees were injected with B. bassiana or M. anisopliae compared to increased rates over time in the control treatment.