Five Larvae of Medfly Raise Hopes : Infestation: Officials hope proximity of maggots in fruit of a single peach tree in a Westminster back yard means center of problem has been found and it can be controlled.

State officials on Wednesday identified five Mediterranean fruit fly larvae in the fruit of a single peach tree, raising hopes they have found the center of the infestation and can quickly bring it under control.

State workers found the maggots in the back yard of a home in the 8500 block of Lido Avenue after going door-to-door in the neighborhood near the intersection of Newland Street and McFadden Avenue on Tuesday.

That effort began after three Medflies were identified in the area Saturday and then 15 more Tuesday. But the discovery of the five larvae is a significant step toward stopping the spread of the pests, officials said Wednesday.

“The larvae finds probably pinpoint the epicenter of this infestation and if that’s correct, that’s a good sign,” said Carl DeWing, a spokesman for the state Department of Food and Agriculture. That most of the Medflies found were immature males “is also an indication that we’ve caught this at the early stage,” DeWing added.

To stem the spread of the infestation, ground spraying of about 100 acres in the area with the pesticide malathion is scheduled to begin today. DeWing said numerous studies have proven the substance will not harm humans or house pets.

Sometime next week, the state will decide where to draw quarantine boundaries, and after that, begin the release of sterile Medflies in the area to disrupt the pest’s reproductive cycle.

Fighting Flies State officials will use ground spraying of the pesticide malathion in an attempt to eradicate the latest Medflies found in Orange County. Vital Statistics Life cycle: Adult female pierces fruit skin and lays one to 10 eggs. Eggs develop into maggots, which feed on fruit. Maggots leave decayed fruit and mature. Adults emerge from ground and mate. Targets: Attacks more than 250 kinds of fruits, nuts and vegetables found in California. Origin: State officials believe Medflies arrived in Southern California about 18 years ago through illegally mailed shipments of fruit from Hawaii or Asian countries. Fly History Medflies first appeared in Orange County in 1989. 1989-1990: State conducted widespread aerial spraying of the controversial pesticide malathion. After July, 1990, ground spraying and the use of sterile fruit flies became the more environmentally friendly eradication methods. August, 1990: Single adult female trapped in a Brea peach tree. January, 1992: A male adult found in a back-yard orange tree in Los Alamitos. Sources: California Department of Agriculture, Times reports; Researched by CAROLINE LEMKE / Los Angeles Times