Palm Borer
Palm Borer, is a type of borer beetle that infests palm trees in the Kingdom of Saudi Arabia, where there are three types of borers. They are similar in appearance but differ relatively in size, and are called "Rhinoceros Beetles". Palm borers are among the most common, with the larvae attacking the roots and trunks of the palm, while the mature insect attacks the fronds and the ribs of the fruit clusters.
Damage symptoms from Palm Borer
The adult palm borer causes varying levels of damage to palms as it drills tunnels inside the central stem of the leaf "rachis" or in the fruit cluster carrier, resulting in feeding tunnels at the base of the frond with the presence of wood shavings, breakage, and drying of the affected rachis and clusters, and the death of the fruit-bearing cluster.
The larvae also cause multiple symptoms leading to varying damage to orchards, as they feed on decaying parts and attack the roots causing damage. Their burrowing continues inside the palm trunk until it reaches the living tissues. They attack weak palm trees at the lower trunk touching the soil surface, drilling tunnels under the trunk and around the offshoots, leading to the death of the offshoot or increasing the likelihood of weevil infestation.
Palm Borer control
Certain agricultural practices help reduce the infestation of palm borer larvae, such as good fertilization, removal of weak palms, and preventing them from being in the plantation, as they are preferred breeding sites for the insect. Isolating the trunk from irrigation water prevents rot, which attracts the insect, and fermenting and sterilizing organic manure before application helps.
It is advised to remove decayed plant residues or spray them with suitable pesticides to eliminate any larvae present. Turning the organic manure piles in the plantation from time to time allows sun exposure and destroys existing larvae. Keeping manure away from the palm trunk prevents fermentation and rot that increase susceptibility to infestation.
For chemical control of palm borers, it is recommended to spray infected palms with insecticides containing active ingredients such as Deltamethrin 2.5 percent at a dose of thirty-five -fifty ml/100 liters of water, preferably used preventively before bud sprouting, and therapeutically upon infestation, using water with moderate salinity to mix the pesticide.
Sources
National Center for Palms and Dates.
Palm dates in the Kingdom of Saudi Arabia. King Abdulaziz Public Library. 2005.