Coconut trees in Dhofar Governorate are facing significant challenges due to pest infestations. Among these pests, the coconut mite (Aceria guerreronis) stands out for its severe impact on income, attacking the nuts and leading to substantial economic losses.
In an interview with the Observer, Dr Ahmed al Shanfari, Director of the Department of Agricultural and Livestock Research in Dhofar, said: “Traditional chemical control measures have proven inadequate and detrimental to benefit insects. There is a need for a scientific, biological approach to pest management.” “Rhinoceros beetles (Oryctes rhinoceros) and coconut hispine beetles (Brontispa longissima) attack during the early growth and mature stages, respectively, often resulting in the death of the palms. However, it is the coconut mite that poses the most critical economic threat by damaging the nuts,” he said.
Chemical control methods, according to him, offer only short-term relief and often harm beneficial insects. This leads to decline in number of beneficial insects that work as saviours against any foreign agents.
Moreover, the chemicals used against the coconut hispine beetle, become an expensive affair due to the recurrence of damage due to hispine beetle infestations.
“Consequently, biological control methods have gained prominence as a sustainable solution. These methods, though slower to show results, suppress pest populations below economic threshold levels, allowing coconut palms to thrive and maximise their yield potential,” said Dr Al Shanfari.
“The Coconut Improvement Project in Dhofar has prioritised biocontrol measures. Authorities have undertaken significant steps to introduce biocontrol agents such as Tyrophagus putresentiae, Neoseiulus baraki, Baculovirus oryctes, Asecodes hispeniarum, and Tetrastichus species into Oman. These agents were imported from reputed institutions like the Coconut Research Institute of Sri Lanka and the Department of Agriculture in Bangkok, Thailand.” Upon arrival, these biocontrol agents were established in the laboratory of the Agriculture and Livestock Research Department in Dhofar. Specific protocols were followed to rear and release these agents effectively. For instance, Baculovirus-infected rhinoceros beetles and larvae were released in Taqah and Salalah Agricultural Research Farm to disseminate the virus among the wild population. Additionally, breeding pits filled with cow dung and compost were created to attract and infect rhinoceros beetles naturally.
“The predator mites Neoseiulus baraki and Tyrophagus putresentiae faced initial challenges due to inadequate polypropylene sachets, which allowed enemies to infiltrate. This issue was resolved by importing more durable sachets from Sri Lanka and reestablishing the cultures. Despite difficulties, a total of 12,250,000 predators were successfully released into the open field last year,” said Dr Al Shanfari.
Parasitoids targeting the Brontispa beetle were released following meticulous rearing processes. However, environmental conditions hindered the development and effectiveness of these parasitoids, necessitating further research and adjustments.
Dr Ahmed put stress on training local Omani staff in these sophisticated biocontrol techniques was a crucial aspect of the initiative. Experts from the Coconut Research Institute of Sri Lanka provided extensive training, ensuring that local personnel could sustain and expand these efforts.
Looking ahead, the project aims to continue field experiments, release additional parasitoids, and refine techniques until satisfactory pest control is achieved. The scientific approach adopted in Dhofar Governorate exemplifies a sustainable, long-term strategy to safeguard the coconut industry against pest infestations, ensuring economic stability for local farmers.
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