Pheromones for Rhynchophorus palmarum

The American palm weevil Rhynchophorus palmarum is  the main vector of the nematode Bursaphelenchus (Radinaphelenchus) cocophilus , which causes the disease known as red ring / little leaf syndrome, affecting coconut and oil palms in tropical America. The insect M. hemipterus has been associated with this disease in Colombia.

Given the importance of the red ring disease in many palm-growing regions of tropical America. ASD, in conjunction with Simon Fraser University of Canada, identified, synthesized, and tested the aggregation pheromones of both R. palmarum and M. hemipterus, which are the basis of the baits used in their capture, and which are marketed under the trademarks of RHYNKO-LURE® y META-LURE®.

The price of the pheromones produced by ASD varies according to the kind of pheromone, the region or country to which they are being exported, and the size of the order. Orders are sent out five days after a confirmed and irrevocable letter of credit has been opened at a recognized bank in the United States. Payment may also be made by bank transfer or money order.

Inquiries and orders may be directed to our representatives and distributors in various Latin American countries. 

One of the most important phitosanitary problem affecting oil and coconut palms in tropical America is caused by the nematode Bursaphelenchus ( Rhadinaphelenchus) cocophilus.

Three kinds of symptoms are most commonly associated with the presence of this nematode. One is the yellowing and drying of the lower and intermediate canopy leaves, and the presence of a brown ring which is visible when the trunk is cut crosswise. Another symptom is the appearance of dwarf leaves in the center of the canopy crown. The third is a combination of the first two symptoms mentioned. Oil and coconut palms show similar symptoms, but yellowing is the predominant symptom in coconut. Soil, vertebrates or seeds are not known to be involved in disease transmission.

Adults of R. palmarum are attracted to palms that have been physically damaged with tools lightening (i.e. during harvesting) or by rats (young palms). Spear rots or basal rot also attracts the adults.

Control of this disease is achieved through the reduction of the R. palmarum population on the plantation, along with the elimination of damaged or diseased palms in which the insect could reproduce. Plants with the red ring disease must   be eliminated, as they are source of inoculation of the nematode.

Many types of traps have been used to attract and capture R. palmarum as a source of food these traps may contain pieces of palm stem, fruits or sugar cane.

After several years of working together with scientists from Simon Fraser University, British Columbia, Canada, the "Oil Palm Research Program" (Programa de Investigaciones en Palma Aceitera, or "PIPA/ASD") identified, synthesized, and field tested " rhynchophorol, " which contain the aggregation pheromone of R. palmarum . This substance is produced by the male of the species in order to attract other insects to food sources, where mating also takes place.

" Rhynchophorol, " which has proven very useful in the fight against the weevil and red ring, has been put on the market by ASD under the commercial name RHYNKO-LURE.

In experiments using traps with RHYNKO-LURE and sugar cane (treated with an insecticide such as carbaryl 80%) as a food source, between 6 and 30 times more weevils were caught than in traps without the pheromones.

RHYNKO-LURE comes in a small, sealed transparent plastic envelope containing the pheromone " rhynchophorol ". This device allow the controlled release of the pheromone into the atmosphere. This bait attracts adult weevils of both sexes and, once placed in the field, lasts for about three months. This lifespan may vary, however, under very high or low temperatures.

RHYNKO-LURE lures come packed ten to twenty in hermetically-sealed polypropylene bags. They can be stored in a regular refrigerator for up to a year without any loss in their original attracting power. By holding the envelope up to the light, it is possible to determine if the product has been used up, as it comes in liquid form.

Of the various types of traps used for capturing the weevil, perhaps the most versatile and economical is the plastic container. These are made of buckets or some other type of plastic container, with a 5-19 liter capacity, and with openings in the upper edge for ventilation and to allow weevils to enter. The RHYNKO-LURE device is hung directly under the cup of cover of the container. It is important to ensure that the bait does not come in contact with the sides of the container. There must be enough insecticide-treated sugar cane in the bottom of the container to form two layers. The containers are hung from the petiole bases of the leaves on the palm trunk, approximate chest height, making sure that the traps will be in the shade and removing any epiphytes from the trunk. It is important to ensure that the insects, which generally found on the trunk of the palm, can eventually make their way inside the trap.

It is important to keep the trap moist, so the sugar cane has to be replaced more frequently during the dry season. During wet periods the sugar cane can be replaced every other week.

In those areas showing an initial capture rate of more than eight weevils per trap per week, a trap density of one trap per two hectares is recommended. A convenient trap placement could be in grids of 16 palms by 18 rows. The first trap could be located in the eighth palm of the ninth row beginning at the edge of the lot. This density should be maintained until fewer than eight weevils per trap per week are caught, at which time trap density could be lowered to one trap per four hectares (every 22 palms and 26 rows). When the capture rate goes down to 2 or fewer weevils per trap per week, a permanent trap density of one trap per ten hectares can be established (every 35 palms and 41 rows).

It is a good idea to follow up on the initial trapping density for at least six weeks, in order to gather all the information necessary to make appropriate decisions on the final trap density to be implemented.