Medfly Busters

The state’s most notorious pest has surfaced again, this time in a Burbank apricot tree. A fertile but unmated female Mediterranean fruit fly was found June 17, the same day that agriculture officials lifted the state’s last remaining fruit quarantine--a two-year effort in the Los Angeles Basin that included the release of sterile male flies and limited ground spraying. In fact, a preventive program to release more sterile medflies over the next five years is scheduled to begin next month.

The day after the find, crews were quickly dispatched to Burbank to begin placing hundreds of new traps in the 81 square miles surrounding the find near Hollywood Way and Victory Boulevard. If another medfly is found, authorities could take such measures as imposing another quarantine, increasing the number of sterile medflies released and localizing ground spraying of malathion.

Even DNA analysis is being performed on the medfly, a routine measure to try to pinpoint its origin.

“This fly is the first one we’ve found in almost two years,” said Larry Hawkins, spokesman for the Cooperative Medfly Project, a federal, state and county task force working to eradicate the pest. “That’s why we’re examining this one very carefully.”


And for good cause. Since 1981, the state and federal governments have spent more than $300 million fighting the medfly, partly to prevent an international boycott of California agricultural products.

Where They’re Trapping

Traps are concentrated near the spot where the medfly was found. An 81-square-mile grid is drawn, with the location of the find in the center. Traps within a square mile of the find, called the core square mile, are checked daily, with the other traps checked every two to five days, depending on their proximity to the find to try to pinpoint its origin.

Types of Traps

Because they are most attractive to medflies, officials are using mostly the yellow panel traps in response to the medfly found in Burbank. A look at the traps and the best locations to place them:

Yellow panel trap: Male flies are attracted to the chemical Trimedlure that coats the 5 1/2-by-9-inch sticky card. This trap releases the chemical at a higher rate than the tent-style trap. Best locations: apricot, nectarine and peach trees.

Jackson trap: Shaped like a tent, this 7 1/2-by-3 3/4-inch plastic-coated cardboard trap contains a plug suspended inside that releases Trimedlure. A sticky insert on the bottom captures the flies. Best locations: apricot, nectarine and peach trees.

McPhail trap: Basically a modern Chinese fly trap, this 8-by-6 1/2-inch glass trap contains liquid torula yeast and borax pellets that attract female medflies in search of protein. Flies enter from an opening in the bottom and drown in the solution. Best locations: sapote, grapefruit, mango, guava and loquat trees.


Current Trapping

* Best location for a medfly trap: A tree with foliage and ripe fruit. The cooler interior portion of the tree is optimum. The particular type of tree depends on the season.

* Who places traps: Agricultural workers with the Cooperative Medfly Project. Workers try to get permission to place traps in front yards of homes. If no one is home, a notice is left giving homeowners information about the program and a number to call if they want the trap moved or taken away.

* Best time to catch a medfly: Spring and summer, though they can be trapped year-round. The insect is attracted to a broad range of fruit trees.


* Toll-free medfly information: (800) 491-1899

Traps placed

Core: 115 traps

Zone 1: 408 traps


Zone 2: 402 traps

Zone 3: 449 traps

Zone 4: 520 traps

Total: 1,894 traps


Note: totals approximated

Number Trapped

1986: 1

1987: 45


1988: 54

1989: 235

1990: 44

1991: 25


1992: 195

1993: 399

1994: 73

1995: 0


1996: 1


Sources: Cooperative Medfly Project, California Department of Food and Agriculture, James Carey, Professor of Entomology, UC Davis; Researched by STEPHANIE STASSEL / Los Angeles Times.