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

SIMPLE SUMMARY: The efficacy of several treatments that could be used in integrated pest management (IPM) against infestations of red palm weevil (RPW) in date palm orchards was investigated. The effects of injections of entomopathogenic fungi and nematodes, aluminum phosphide, and emamectin, as well as fipronil sprays of trees in which naturally occurring RPW infestations had been identified were assessed using acoustic sensors to monitor mortality in naturally infested trees over a 6-month period after treatment. Reductions in insect activity levels in date palms monitored by acoustic sensors after treatments with entomopathogenic fungi and nematodes, emamectin, and aluminum phosphide indicated that each of these treatments caused significant RPW mortality. ABSTRACT: Red palm weevil (RPW) management is important to the economic success of date palm agriculture. Monitoring with acoustic sensors was conducted in naturally infested trees in date palm orchards for six months after treatments with entomopathogenic fungi (Beauveria bassiana and Metarhizium anisopliae), entomopathogenic nematodes (Steinernema carpocapsae), aluminum phosphide, emamectin benzoate, or fipronil to evaluate their efficacy in an integrated pest management treatment vs. a distilled water injection. Reductions in the mean rates of RPW sound impulse bursts over time after treatment were used as indicators of RPW mortality. Entomopathogenic fungi and nematodes, aluminum phosphide, and emamectin benzoate were the most effective treatments, reducing RPW impulse burst rates within 2–3-months to levels indicating absence of infestation. However, when applied as a spray, fipronil had only a minor effect. The results indicate that treatments utilizing entomopathogenic fungi or nematodes can beneficially manage RPW in palm orchards and can help to limit treatments that may induce insecticide resistance or cause human and environmental harm. Furthermore, the use of an acoustic sensor can be beneficial in monitoring the activities of insect borers inside the tree trunk.