The Dissemination of Metarhizium brunneum Conidia by Females of the Red Palm Weevil, Rhynchophorus ferrugineus, Suggests a New Mechanism for Prevention Practices

Seismic sensor-based management of the red palm weevil Rhynchophorus ferrugineus in date palm plantations

BACKGROUND

The red palm weevil (RPW), Rhynchophorus ferrugineus, is one of the gravest threats to palm trees. The challenge in monitoring RPW primarily arises from the inconspicuous presence of larvae within the stem, which is often devoid of noticeable symptoms. This study looks at the use of seismic sensors in RPW management in commercial date palm plantations. It explores whether the data garnered from the sensor domain, and its translation into the health status of date palms, can reliably inform precise decision-making.

RESULTS

Sensor and damage index values, as gauged by the Agrint IoTree seismic sensor, vividly mirrored RPW colonization activity. They also accurately portrayed the impact of three distinct insecticides: imidacloprid, phosphine, and entomopathogenic nematodes. The seismic values and damage index of healthy untreated palms strongly supported the decision to pursue tree recovery. Furthermore, this facilitated the computation of recovery pace discrepancies across the tested treatments, measured as the number of days required for tree restoration.

CONCLUSIONS

Our findings underscore the practicality of employing seismic sensors, as exemplified by the IoTree system and its network services, to both monitor and assess palm tree health. Furthermore, it validates their efficacy in evaluating the efficiency of management strategies adopted against RPW, all grounded in a wealth of sensor-derived data. © 2023 Society of Chemical Industry.

Efficacy of Entomopathogenic Fungi as Prevention against Early Life Stages of the Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae) in Laboratory and Greenhouse Trials

The red palm weevil (RPW) Rhynchophorus ferrugineus is a highly destructive invasive pest for palms whose management is mainly by application of synthetic pesticides. As a key pest of date palm plantations, it is necessary to integrate environmentally safe measures for its management. Entomopathogenic fungi (EPF) have been primarily studied as a preventative control measure due to the horizontal transfer of conidia within the RPW population. We previously demonstrated the horizontal transmission of fungal conidia from an egg-laying surface to the female weevil and then to the eggs and larvae. Based on that strategy, this study aimed to evaluate the virulence of commercial EPF products and laboratory EPF preparations to RPW females and their progeny, and their ability to protect palms against infestation. As such, it serves as a screening platform for field experiments. Mortality rates of females and eggs depended on the applied treatment formulation and fungal strain. Velifer®, a Beauveria bassiana product, and Metarhizium brunneum (Mb7) resulted in 60-88% female mortality. Mb7-as a conidial suspension or powder-resulted in 18-21% egg-hatching rates, approximately 3 times less than in the non-treated control. Treating palms with Mb7 suspension or dry formulation significantly inhibits infestation signs and results in protection. These results lay the foundation for investigating the protective rate of EPF products against RPW in date plantations.