Why the government drops flies on California

0:00 The Mediterranean fruit fly, or medfly, is an invasive pest in California.

0:04 Medflies lay their eggs inside fruit and breed incredibly fast.

0:07 They can devastate crops.

0:09 But today, and almost every day,

0:11 aircraft hired by the California and federal governments are

0:14 going to drop millions of them over Southern California,

0:16 and over the Los Angeles metro area specifically.

0:19 There is a really good reason for this.

0:22 California experienced recurring infestations from 1987 to 1994.

0:27 So in 1994, California began a two-year test to determine if releases of sterile

0:33 flies as a preventative measure would reduce

0:35 the size and scope of the infestations.

0:38 And during that two-year test period, California experienced zero infestations.

0:43 So in 1996, the Medfly Preventive Release Program began,

0:47 and the program currently today is 1,750 square miles.

0:52 So the plan is, breed male flies in areas where it's safe to do so,

0:56 because they're already established.

0:57 Sterilize the flies when they're in the pupal stage with radiation,

1:01 and tag them with an ultraviolet marker dye.

1:03 To be clear, irradiating something does not make that thing radioactive!

1:07 But it does make the flies sterile.

1:10 Then they're shipped here, hatched,

1:12 bundled up into planes, and dropped onto California,

1:14 where their job is to outcompete any wild

1:17 medflies that have made it to the area.

1:19 We maintain our colonies offshore in areas where medfly is already established.

1:24 'Cause we don't want to risk that any

1:26 flies escape our facility and start an infestation.

1:30 We're sourcing approximately 24 million sterile

1:32 males per day, seven days a week.

1:35 Our staff inspect the flies for sterility,

1:38 then they're poured into a hopper that sits above a volumizer.

1:42 The volumizer measures out the desired amount of pupa

1:46 and it will distribute it around the perimeter of each tray.

1:49 When the flies emerge from the pupa, they'll migrate to the center of the tray,

1:53 where there are two pieces of agar,

1:55 which will serve as their food and water source during incubation.

1:59 So then they're stacked into towers,

2:00 with our goal of placing one million pupa in each tower.

2:04 Those towers are moved to an incubation room.

2:07 After two days, most of the flies will start emerging.

2:11 On the third day, we place one milliliter of ginger root oil under each tower.

2:16 Ginger root oil contains a naturally occurring compound that increases

2:21 the chance that those sterile males will have successful matings.

2:26 If female medflies that have arrived in shipping containers or the post

2:30 or travelers' baggage mate with these, the eggs will never hatch,

2:33 which means there's nothing burrowing through the fruit to destroy it,

2:36 and no population explosion.

2:38 We'll typically load six to twelve towers into a refrigeration trailer.

2:43 The flies will enter a chill coma.

2:45 So they'll essentially be immobilized.

2:47 We have a specially engineered vacuum that will vacuum

2:50 the empty pupa casings from the perimeter of each tray,

2:53 but leave the flies in the center of the tray.

2:56 We will process those adults and load them

2:58 into the release box that's then transported to the aircraft.

3:02 Those boxes contain anywhere from 50 to 130 pounds of flies,

3:07 depending on the release area and the release rate.

3:11 It's approximately six to nine million flies.

3:15 And while hundreds of millions of flies sounds like a huge amount,

3:19 it's actually not that many over an area the size of Southern California.

3:24 The aircraft are equipped with a release machine that has a AC

3:28 unit that keeps the flies in an immobile state until release.

3:32 Drop time can vary from 30 minutes to an hour.

3:35 The aircraft are traveling at 161 miles per hour when they're releasing.

3:40 So the volume of those flies are

3:43 distributed fairly evenly throughout the target area.

3:46 If you were to see the plane flying overhead,

3:48 you would not see the flies falling from the chutes,

3:51 especially at the altitudes that we release,

3:53 which are typically around 2,000 feet above ground level.

3:57 Big numbers are scary, but I did the maths,

4:00 and they're aiming to have a density of about one sterile fruit fly every

4:04 20 to 40 square meters across thousands

4:06 of square kilometers of Californian cities and farmland.

4:10 That density is orders of magnitude less than all the insects already out there.

4:14 And that includes the quarantine areas.

4:16 We should talk about the quarantine areas.

4:19 California deploys approximately 100,000 exotic fruit

4:22 fly detection traps throughout the state.

4:24 The insect detection traps are collected from the field

4:27 and they're transported to our identification unit.

4:30 The flies are screened under a UV light,

4:33 looking for the presence of the marker dye.

4:35 So we're able to identify and differentiate a sterile fly from a wild fly.

4:40 If we detect two wild medflies within three miles of one another,

4:45 or a larva, a pupa, or a mated female, we will consider that an infestation.

4:51 And that triggers a response, so there will be increased "delimitation trapping"

4:56 to identify exactly where that infestation's occurring.

5:00 The rate of release of steriles will increase,

5:03 as well as possibly fruit removal within a particular area.

5:08 As I record this, anyone growing fruit in more than 150 square kilometers

5:12 of the LA metro area just can't legally sell it or even give it away,

5:16 to avoid the chance of spreading the infestation.

5:18 There are other larger quarantine areas out in the farmland

5:20 that makes up a lot of this region.

5:22 In theory, there is a possible video, titled,

5:24 "I Released Two Million Fruit Flies over Los Angeles." And yes,

5:27 I want to press that button.

5:29 But unfortunately, there isn't a spare seat on the plane.

5:31 And plus the quarantine area includes under and around

5:34 the approach paths to Los Angeles International Airport.

5:37 So flying it is not an easy job and they do not want the distraction.

5:40 But I can show you a shot from inside the release

5:43 tubes as millions of fruit flies are slowly dropped over LA.

5:47 We always want to have fresh, viable flies distributed into those regions.

5:51 So we're releasing every three to four days.

5:54 The goal is to release sufficient numbers of sterile males into the environment

5:58 to prevent any wild females that are

6:01 introduced from finding a wild male and reproducing.

6:05 So it's essentially biological birth control.

6:08 Does it work?

6:09 Well, in the area they're dropping flies,

6:11 there used to be seven or eight infestations a year on average.

6:14 Each one needing quarantine and pesticides and a huge amount of effort.

6:17 Since they started the program?

6:19 About one a year.

6:21 Compared to the cost if medflies got established here, it's a pretty good deal.