Field Evaluation of Promising Indigenous Entomopathogenic Fungal Isolates against Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae)

Abstract

The rate of the sounds (i.e., substrate vibrations) produced by the movement and feeding activity of red palm weevil (RPW) pest infestations in a date palm tree was monitored over time after trees were separately treated with injection of entomopathogenic fungal isolates, Beauveria bassiana and Metarhizium anisopliae, or water treatment as the control. The activity sensing device included an accelerometer, an amplifier, a digital recorder, and a signal transmitter that fed the data to a computer that 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 RPW. The unique spectral pattern of sound pulses was typical of the RPW larval feeding activity in the date palm. The microphone confirmed that the same unique tone was produced in each burst. Two months after 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 with the increased rates over time in the control treatment plants.

Acoustic Comparisons of Red Palm Weevil (Rhynchophorus ferrugineus) Mortality in Naturally Infested Date Palms after Injection with Entomopathogenic Fungi or Nematodes, Aluminum Phosphide Fumigation, or Insecticidal Spray Treatments

“…This study is supportive of other studies that evaluated the effectiveness of microorganisms [44] and fungal treatments against RPW [26,45]. RPW can be managed by microorganisms that cause infection in insects [46].…”

“…In another study, RPW movement and feeding activities in date palm trees produced significantly lower impulse burst rates [20] after treatment with B. bassiana. It is possible that infected RPW larvae within date palm trees become weaker, lose their appetite, and move more slowly [44,47]. It should be noted that spores of fungal isolates with weak germination, low pathogenicity, and low water solubility are not recommended for use against the RPW [2].…”

Automated Vibroacoustic Monitoring of Trees for Borer Infestation

“…The effectiveness of this approach, coupled with its successful application in innovative bioacoustics tasks, has been demonstrated in prior research focused on birdsong classification [17]. Therefore, a future direction is to have our approach-which is very fast and very low in power consumption-do the heavy screening of searching for needles in the hay and direct only a small subset to heavy deep-learning models that will scrutinize these cases especially when one applies low thresholds (that produce false alarms) with the aim to detect early instars and low infestation load [18][19][20].…”

Isolation and characterization of a native strain of the entomopathogenic fungus Beauveria bassiana for the control of the palm weevil Dynamis borassi (Coleoptera: Curculionidae) in the neotropics

“…Since D. borassi and R. palmarum have been recognized as pests of economic importance for the crops of Bactris gasipaes and Cocos nucifera (Bautista-Giraldo et al 2020 ; Gaviria et al 2021 ; Gutiérrez et al 2023 ), the results obtained with the Bv065 strain show great potential for its use in the field, where different dissemination strategies can be employed such as trunk applications (Güerri-Agulló et al 2010 ), passage traps for the inoculation of adults (Dembilio et al 2018 ), release of contaminated males (León Martínez et al 2019 ); where the control objective is the adults. Additionally, exploratory studies have shown the potential use of B. bassiana in endotherapy (i.e., trunk injection) for the control of weevil larvae inside the palms (Sutanto et al 2023 ; Husain et al 2024 ).…”