Melolure - Melon Fly Pheremone

Melolure

Introduction

Although the melon fly (Dacus cucurbitae Coq.) is not known to occur on the mainland of the United States, it is found in Hawaii and in many other parts of the world. On several occassions, this economically serious pest has been intercepted at ports of entry. With increasing travel and foreign trade, the possibility of accidentally importing the melon fly from Hawaii or elsewhere is a matter of continuing concern to the agricultural community. A more effective lure is needed to detect quickly any flies that may gain entry and become established. Such a lure should be highly specific, attractive over great distances, and, if possible, long lasting. Should an infestation become established, the lure would be invaluable in guiding eradication operations by indicating where and when insecticides should be applied. In just this way, attractants aided in the rapid elimination of the Mediterranean fruit fly [Ceratitis capitata].

In 1957, Barthel and coworkers reported that anisylacetone was an effective lure for the melon fly. In the search for better lures, compounds related to anisylacetone were synthesized. Several of the them, particularly Cuelure [4-(p-acetoxyphenyl)-2-butanone], were not only much more potent than anisylacetone, but also attractive to newly emerged flies. Under optimum Hawaiian conditions, anisylacetone does not attract male melon flies until about 7 days after they emerge from pupation, and then only after they approach or attain sexual maturity. The search for an effective melon fly lure has been based on the same empirical approach that has resulted in the discovery of new insecticides, pharmaceuticals, and a host of other physiologically active substances. Briefly, many types of compounds were screened, and the structures of those exhibiting the greatest attraction were modified further to increase attractiveness. The finding of cuelure, the most effective attractant in this study, illustrated the value of volume screening as a means of discovering new insect lures.

Melon Fly
(Dacus Cucurbitae Coquille)

Today, a new, highly specific sythentic lure is now commercially produced in quantities that provides reproducible results in monitoring programs. The key benefit of an insect monitoring program is protection of crop quality by timing pesticide sprays more accurately.

Melolure™ was found to be a superior attractant for the melon fly, Bactrocera Cucurbitae (Dipteria: Tephritidae) compared to Cuelure.
Melolure™ was compared to Cuelure as an attractant for male melon flies, Batrocera Cucurbitae. Melolure™ was 1.7 times (Casma et al.) more attractive over at least one month under field conditions.
Melolure™ is available in development quantities from Interchem Technologies.

Reference: Casama Ginner, Oliver, Jang, Carvalho, Khirmian, Demiulo, Mcquate: Agricultural Research Service Bulletin, submitted to Journal of Entomological Science, March 31, 2002.

As a general rule, traps should be placed in the field one or two weeks before the earliest known emergence date (which varies each year according to temperature and rate of degree day accumulation). Other important information is the average number of flights during the season.

Traps are hung on branches of trees, plants, shrubs in the area to be monitored according to the insect emergence patterns. Pheromone lure placement in the traps varies with trap style. It is vital that pheremones be handled with extreme caution to avoid contamination since they have the affinity to penetrate many materials that come in direct contact. Also, it is important to remember when several species are involoved in monitoring the encapsulated lure for one species is not commingled with a lure from the second species as the pheromone from the first will transfer to the second via hands, contaminating the traps for the second species, or third, etc.

As a rule-of-thumb, for pheromone monitoring or baited visual traps, it is recommended:

Acres
1 or less
1-10
10-40
40-100
over 100

Number of Traps
2
4
6
8
1 every 8 acres

If monitoring more than one species of insects, pheromone traps for each species should be placed at least 30 feet apart. If possible, hang pheremone traps in the shaded area on the outside of the tree canopy at the height of 4-6 feet above the ground.

The trap program should be supplemented with a regular field scouting program, and inspecting traps twice weekly is sufficient to determine trends.

A new approach to insect pest control is that the insect pheremones can be sued as a "mating disruption" (e.g., confusing and frustrating the insect's attempts to copulate) or properly used as a mating sex disruptant. This can be accomplished by saturating an area with a female pheremone - confusing the males to location of females, thus preventing females from mating. In addition, pheremones are used to suppress insect pest populations using a variety of innovative approaches including mass trapping and various combinations of attractant baits, trap crops, and toxicants.