Borers are by far the most difficult group to manage. Weevil larvae can excavate tunnels through the trunk up to 1 meter long.
The use of insecticides varies between countries and crops; one country may allow the use of a certain chemical, while another country may prohibit it.
Palm weevils behave differently with respect to different palm varieties. Control techniques change accordingly:
Ornamental Palm Trees Suggestions:
The weevil attacks upper parts by entering pre-opened leaves (spear leaves).
Some growers use a solution of 10 to 20 litres of water per tree and add 25 cc imidacloprid (350 gr\L), 30 cc cypermethrin (100 gr \L), and 0.2% tebuconzole (250 gr\L) sprayed or poured directly into the center of the crown once every 3 months (good for prevention and eradication).
In irrigated trees, it is recommended to apply the same recipe via an irrigation system.
Other Options (all applied by pouring or spraying directly into the center of the crown):
*Dinotefuran (20%) 25 grams or 0.2% concentration in solution and 25 liters per tree in spraying application
*A 15 liter solution 0.2% concentrate combined of imidacloprid (430 gr\L) and gamma cyhalothrin (30 gr\L) – apply every 3 months
*A 20 liters solution with 0.3% Lambda-Cyhalothrin (50 gr\L) and 0.2% imidacloprid (350 gr\L)
Date Palm Suggestions:
In date palms, the weevil attacks the lower parts of stems where offshoots emerge and the connection between them and the mother occurs.
Spray the lower stem parts, especially offshoots, with the above mentioned recipes, but take into account pre-harvest interval restrictions.