A modern day threat to agriculture across the globe is the red palm weevil (Rhynchophorus ferrugineus). This creature is native to South Asia but it rather rapidly spreading its wings and crossing the globe. The red palm weevil can completely destroy palm groves, be it coconut, date or palm oil. Over the immediate past 30 years, the red palm weevil (also known as red date weevil) has penetrated over 60 countries and is now reaching the Middle East, northern Africa, southern Europe and across to the Caribbean.
Emergence in the Middle East
The weevil began to appear in Saudi Arabia and the UAE in the mid-1980s. Today, date palm farms in the south-west of Saudi Arabia have become infested. By the end of the 1990’s it was found in Jordan, Israel and the Palestinian Authority Territories.
The red palm weevil has a drastic effect on over 40 different species of palms. They are equally devastating on the local and global economy causing economic losses in the order of millions of dollars annually. Leading date farmers in this region appreciate the seriousness of the problem.
A Challenge to Detect
The red palm weevil is not easy to spot in the palm grove. The female weevil lays up to 300 eggs inside the trunk of the palm. The eggs hatch within 2-5 days. Then, when the weevil is in the larvae stage, it burrows further into the palm trunk. The weevil is eating and destroying the palm from the inside. The larval stage averages 55 days and then moves into the pupa stage. The adult weevil emerges after 2-3 weeks. So the life cycle is around 4 months.
Because the stages of the life cycle are taking place within the palm tree, it is challenging to detect. By the time the weevil is detected, it is often too late. This is when the palm is droopy and turning brown. The droopiness is due to the hollowed out interior of the trunk. The inside of the palm is now a mush with a strong odour which has been described as smelling like baby diarrhea.
How have farms detected the presence of these creatures inside their palms? An interesting question as dogs can be trained to identify the foul scent. A well seasoned farmer with experience and acute hearing can hear the weevil gnawing inside the palm trunk. Once detected, the palm can be chopped down and the area placed in quarantine while the remaining palms are aggressively treated with insecticides. It is also possible to set traps impregnated with insecticide, to capture the mature weevil.
Current trapping methods include pheromone traps. Chemical spraying especially of the crown foliage and stem injection are deployed. Biological controls such as bacteria, fungi and nematodes cannot act aggressively enough to control the weevil infestation. A weevil infestation requires an aggressive and lengthy period of pest management with toxic chemicals to defeat the hardy invader.
Ignorance is Not Bliss
As with many problematic species, people are not aware of the potential threat to the agricultural industry. In South Asia, the weevil is a delicacy to eat. Therefore, people have taken great effort to import the weevil across borders. Border crossing regulations exist but travelers will still try to bring small decorative palm trees across borders not knowing that they might well be already infested with weevil larvae. As with many introduced species, they thrive in their new environment and rapidly multiply.
Southern California has already experienced the devastating effects of the red date weevil. As the climates in regions across the globe increase and wetter, the environment becomes more suitable to the invasive species.
Time for Action
The global community and FAO are introducing strategies to limit the import of date palms across borders based on a size factor. The present proposal is to ban all imports of palms that are bigger than 6cm diameter from already known infested countries. But enforcing regulating and handling infestations requires funding and an astute agricultural and customs departments.