Oranges in a parallel universe

The science-fiction series Fringe had a season partly set in a parallel universe. In case you have never seen the series and might want to catch it on streaming or DVD, I’ll avoid spoilers here.

For reasons I won’t get into, environmental degradation had gone further in the other universe than in ours. One of the very clever plot details the writers worked out was that certain foods that are common here were either no longer available at all or had become very scarce and expensive. For example, one of the delights visitors coming here were able to readily enjoy was coffee, something that had become an exotic luxury across the dimensional divide.

Some of you reading this may have had a glass or orange juice this morning. If you like orange juice—I do—enjoy it while you can. You may soon be living in Fringe’s alternate universe.

First a bit of botany 101.

Plants like orange trees have a circulatory system of sorts. The roots soak up water and various minerals from the soil and ship them to the branches and leaves through tissue called the xylem. The leaves return the favor by manufacturing, through photosynthesis, assorted sugars and sending them through tissue called the phloem back to feed the roots.

Enter the villain of the piece, a bacterial disease called huanglongbing that has been making a world tour through India, China, Indonesia, South Africa, and Brazil and has now arrived in Florida and California.

It infects the phloem and starves a citrus tree’s roots. The roots more or less quit shipping water and nutrients to the parts of the tree living above ground. The tree and its fruit go to hell.

HLB or “yellow dragon disease” is spread by a delightful gnat-sized insect known as the Asian citrus psyllid, also newly arrived in the Western hemisphere. It isn’t entirely clear how it got here, but there is a fair chance that somebody smuggling in a cutting of something for his garden was responsible. (You ever wonder why customs asks you all those annoying questions about whether you’ve got live plants or fruit hidden in your shorts? This is why.)

It gets better. A female psyllid can lay 800 eggs in a month. An infested orange tree can have more than 40,000 of these little guys living on it. That means that even a very good pesticide, one that’s maybe 99% effective, after a spraying will still leave plenty of survivors to be fruitful and multiply. And you have to keep doing it so often it becomes very expensive.

Okay, so spraying won’t work. How about getting rid of all the infected trees? Not really an option. In Florida and California lots of people (about 40% of houses with yards in Southern California) have fruit trees in their yards and many are already tainted.

Knock on door.

“Hi,” says a little boy.

“Hello, kid. I’m from the government. Would you mind if my trusty flamethrower and I turn your mother’s garden into charcoal?”

“Cool! Can I watch?”

Yeah, that’s gonna happen.

In California, entomologists managed to get across a diplomatic and bureaucratic minefield and import a type of Pakistani wasp that preys on psyllids. So far, this has worked as well as anything has to push back the invasion, but mass wasp releases have cut psyllid populations by only about a third. Not enough to save the oranges.

People have tried injecting sick trees with antibiotics. They’ve tried putting trees on a kind of life support by feeding nutrients the roots aren’t supplying anymore directly to the leaves and branches. This has been somewhat successful in keeping sick trees alive and producing fruit, but it’s labor intensive and expensive, and this must be passed on to the consumer. It’s also too soon to know how long these sick trees can be kept alive on life support. It doesn’t look good.

There are people working on genetically engineering a strain of orange tree that is resistant to HLB. This is probably the best long-term solution, but given that millions of people think that genetically engineered tomatoes can make their ears fall off and give their teenage sons double-D breasts, growers are worried about whether consumers will accept oranges with tweaked DNA. Even if they will, it will take many years to develop the trees and to re-stock the orchards with them.

In the meantime, there are serious people who don’t think we will have a significant orange crop in the United States within five years. Yeah, that soon. Okay, so maybe you don’t like orange juice. Why should you care? Don’t worry. We have you covered.

Climate change is coming for your morning coffee.

In the future, we will be leaving many things behind that we take for granted. Welcome to Fringe.


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