Pesticide use in coconut against leaf beetle is safe

June 24, 2009

In a recent study by pesticide toxicologists at UP Los Baños, the injection of neonicotenoid pesticides such as thiametoxam, imidachloprid and clothianidin in coconut trunks was found safe and effective in controlling the coconut leaf beetle (Brontispa longgisima).

Brontispa is a serious pest of coconut in the Philippines, having attacked more than 1.6 million coconut trees nationwide. Two years ago, 26 provinces were quarantined due to infestation to save the coconut industry- a vital component of the export economy.

Because of the emergency situation, the Philippine Coconut Authority (PCA) initially recommended the injection of pesticide into the trunks of coconut areas with severe and widespread infestation. However, the said chemicals were not yet registered for use in the country.

Thus, Dr. Leonila Varca and Mr. Lorenzo Fabro of UPLB-CA's National Crop Protection Center-Crop Science Cluster, in cooperation with the PCA in Quezon province, determined whether toxic substances were present in food products derived from coconuts given trunk injections of pesticide.

According to the group's study, the pesticides, when administered correctly, is effective against the larva and adult of the coconut leaf beetle. There is a need though to reapply the pesticides after 30 days in order to protect the coconut longer, thus raising concerns on possible toxicity of coconut products.

The researchers' results showed that the coconut water and coconut milk derived from trees 60 days after injection do not have any pesticide residue, and thus safe to consume. Processing the coconut into ordinary and virgin coconut oil, meanwhile, reduces pesticide concentration to almost zero.

The project, funded by the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development, also noted that the said pesticides have no effect on the common earwig (Chelisoches morio)-the natural enemy of the coconut leaf beetle. (By Rosario Gabatin and Florante Cruz/ http://rdenews.uplb.edu.ph)

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