Science to the rescue of coconut industry

Insect outbreaks occur when new strains/species are introduced into areas where they have no or very few natural enemies. However, eventually nature corrects itself; biological control agents appear and multiply in sufficient numbers to control the invaders. But this new state of equilibrium can take years, and by then farmers would have suffered heavy losses.

The new coconut scale insect (CSI) devastating coconuts in the provinces of Batangas, Laguna, Cavite and Quezon has been identified as Aspidiotus rigidus, which is different from the more common Aspidiotus destructor.

The immediate challenge is to arrest/contain the further spread of CSI from the adversely affected areas to the rest of the country. The idea is to reduce the CSI population, slow down its spread in order to give time for its natural enemies to multiply.

Scale insects are naturally preyed upon by wasps, coccinelid beetles, earwigs and lacewings, and also infected by fungi. Our key agricultural research agencies are working double-time to artificially rear these potential biocontrol agents in great numbers to release them in outbreak areas. But their efforts are relatively puny considering the gravity of the situation. Their efforts should be multiplied tenfold to make a difference.

Scale insects are ubiquitous pests. They are relatively easy to manage/control with commercially available pesticides. In fact, household detergents and oils that are inexpensive and safe to humans and the environment have proven effective against scale insects.

The problem of CSI control is the difficulty and costs of applying pesticides/detergents on tall coconut trees many of which grow on steep hillsides and in inaccessible places. Fire trucks carrying detergents and using power boom sprayers are OK for roadside coconut farms during the dry season, but their reach will be limited. Thus, the use of insecticides—whether chemical, organic or botanical in origin—whose mode of action requires physical contact with the insect pest, is constrained by the cost of application.

The solution is to deploy insecticides that are systemic—i.e., the active ingredients get into the plant parts and sap. The susceptible insects that consume the leaves, stems and sap die or fail to reproduce.

There are organic and/or botanical pesticides that local suppliers/inventors claim to be effective against CSI. But they have yet to demonstrate their efficacy, safety to humans and the environment, and cost effectiveness. Before they can be adopted on a massive scale using public funds, the suppliers/vendors must provide the Fertilizer and Pesticide Authority (FPA) proper, scientifically vetted, and reproducible proof to substantiate their claims.

The burden of proof rests with the technology suppliers/vendors, but given the urgency of need, the government should be proactive and determine which among the new products have the most potential and facilitate their testing. But testing all products will be very expensive; thus, further verification can be directed to only a few of the most promising. To eliminate bias, the government may constitute an impartial panel of scientific experts to identify the products with most potential.

Among agricultural pesticides, the most commonly used worldwide are the chemicals called neonicotinoids, which attack the nervous systems of insects and cause their death. They are toxic to insects but relatively benign to mammals, including humans. They are effective under very low concentrations and are not persistent in the environment.

And among the neonicotinoids, the newest, safest and most promising is Dinotefuran, a third-generation formulation that is Category IV in toxicity. Category I pesticides are most toxic and persistent and now banned practically worldwide. The FPA certifies only those pesticides belonging to Category II or better.

But Dinotefuran has not yet been used on coconut. The most cost-effective mode of application—as aerial spray, incorporated into the soil like fertilizer, or bored into the coconut bark or trunk—is yet to be determined. The second mode is easy but more pesticides will be needed, the effectivity delayed, and efficacy problematic. Aerial spraying with airplanes is likewise relatively easy and cost-effective.

However, resistance/objections from the rural communities will be strong despite assurances that Dinotefuran is relatively benign to humans. Thus, the preferred option for now is boring the insecticide into the coconut bark and trunk.

But neonicotinoids, including Dinotefuran, have a serious drawback: They are toxic to nontarget economic insects like honeybees and silkworms. Honeybees, of course, are very important, not so much for their honey as for their beneficial role in pollinating fruits, vegetables and other crops.

The coconut is naturally crosspollinated by wind and by other insects like flies and beetles, so the loss of honeybees will not be serious for the coconut industry. The tradeoff, therefore, is between the decimation of honeybees and the prospective death of the coconut industry on which millions of Filipino farmers depend for their livelihood, and which accounts for the lion’s share of our agriculture exports.

But the tradeoff need not be taken to the extreme because the conflict can be localized and intelligently managed.

The insecticide will be deployed on a large scale, and only in the geographical areas where the CSI outbreak is severe. As soon as the outbreak is arrested and subsides, the application will be stopped. The damage will not be permanent because the honeybee population in nearby untreated areas will recolonize the outbreak areas. And the government can hasten honeybee population buildup by bringing in new farmed beehives. By then also, the government program of mass multiplication and dispersal of natural biocontrol agents would have gotten off the ground.

The other tradeoff that needs to be managed is the loss of organic status of coconut farms that supply organic coconut water to the world.

However, this tradeoff is really between public and private goods. The few fortunate coconut farmers and cocowater processors/exporters who receive a premium for organic coconut water need not make use of chemical pesticides and conventional fertilizers deemed most cost-effective by responsible government institutions. They can always use organic pesticides and/or botanicals offered by commercial providers, but at their own cost and risk.

The CSI outbreak need not be the end of our coconut industry. As in the psyllids insect outbreak that damaged ipil-ipil trees more than a decade ago, nature will take its course and a new balance between the CSI and their natural enemies will take place.

Meanwhile, the government can take vigorous measures to arrest/contain the spread of CSI, with chemical, organic and botanical pesticides, as appropriate. The research agencies should ramp up their scientific work to identify the most effective natural enemies of CSI, facilitate their mass rearing, and determine their most cost-effective deployment.

But most importantly, the Philippine Coconut Authority, Department of Agriculture, local government units, and state colleges and universities should launch a massive coconut replanting and intercropping program to raise total farm productivity, generate additional employment, and raise the income of coconut farmers.

Emil Q. Javier chairs the Coalition for Agriculture Modernization in the Philippines and is a member of the National Academy of Science and Technology.