Tiny bug could wipe out California's citrus trees

The tiny Asian citrus psylid is killing citrus trees in California (High res image from UC Davis here).

Homegrown Evolution has an interesting story about Asian citrus psylid, and ant-sized insect that could spell doom for California citrus.

The Asian citrus psylid is not a problem in itself, but carries an incurable bacterial disease called huanglongbing (HLB). HLB, first reported in Asia in 1919, renders citrus fruit inedible and eventually kills the tree. Parts of Africa, Asia and South America are infected with HLB and in some regions of Brazil the disease is so bad that they've given up growing citrus altogether. HLB is in Florida and is adding to a nightmarish collection of other diseases afflicting citrus in the Sunshine State. Now California growers are panicking with the appearance of the psylid.
The State of California is taking all sorts of measures to stop the spread of the pest (including spraying dangerous pesticides), but Erik and Kelly of Homegrown Evolution are taking a Stoic approach to the problem.
Seneca [author of Letters from a Stoic] would say, do what is in your power to do and don't worry about what you can't fix. Taleb [author of The Black Swan] would advise always maximizing upside potential while minimizing exposure to the downside. My unsentimental conclusion: don't try to grow citrus. If I had a mature tree I'd leave it in place and rip it out at the first sign of HLB. Despite the state's offer to replace any HLB infected tree with a free citrus tree I wouldn't take them up on the offer. In our case we have three small, immature citrus trees that are already chewed up by citrus leafminers. I'm pondering pulling them up and replacing them with fruit trees unrelated to citrus. This follows our stoic, get tough policy in the garden. Planting a tree entails a considerable investment in time. It can take years to get fruit. Why not plant pomegranate instead and let other people worry about citrus diseases? If a pomegranate disease shows up, rip it up and plant something else. Following this approach will eliminate habitat for the psylid and negate the need for pesticides.
The end of California citrus?



  1. Off topic:
    Any chance the hundreds of people who know the trick of white teeth could simply tell the rest of us and move on?
    Thanks. As you were.

  2. It may be the way of things to be cyclical or to even die out, but grapefruit, oranges, lemons and limes are a non-trivial part of the human diet, not to mention responsible for a great many jobs.

    Keeping that in mind, I highly doubt that “Seneca”‘s advice (essentially crop rotation) has much value for anyone other than people who happen to have a handful of trees growing in their backyard and couldn’t give a toss if they die or not. Whereas, for people who have a few thousand or few tens of thousands trees, that sort of advice is highly impractical at best and financially ruinous at worst.

    It would be better if everyone diversified but one of the things that makes a half-gallon of orange juice so cheap is that farmers harvest oranges on a massive, gigantic scale using fairly efficient, mechanized means. It also means little room for variation which is good for psylid but bad for most everyone else.

    My guess is that if large-scale farmers followed this sort of advice, prices for fruit and juice would go up considerably. And, considering what a half-gallon of 100% organic orange juice costs right now …well, would you be willing to pay double that? Say, $6-8 for a half gallon of orange juice? If the answer is “no” or “yes, but I’d buy that sort of thing half as often as I do now” then there exactly is why they’ll just dump a bunch of pesticides on the bugs.

  3. @ DjHop – I guess. But more than that I think it is a new world / old world thing. The very thought of a gallon of OJ disturbs me and makes me feel a little unwell. Maybe if I had a dozen kids and a fridge the size of a garage….

  4. Whenever you suggest to a farmer that diversification of varieties/crops, crop rotation (where applicable), non-monoculture farming, and other proactive farming methods, they always respond “Why would I do that? How can I justify the expense?”

    These kinds of scenarios are why. Not saying that farmers should be left to suffer on their own, but a proactive approach to farming should be the norm, not the exception.

    I will say that my personal experience is limited to potato farmers on Prince Edward Island, so for all I know the citrus farmers of California may be an informed and educated bunch.

  5. A big organic farm family of 8? Chez Panisse and The Moosewood? The city block on which I live? The Royal Navy?


    When you think about it, who DOESN’T need a gallon of OJ?

  6. This is exactly the kind of thing the laws about importing/exporting plant matter (e.g. CITES) helps to prevent. I don’t know about this case, but in the UK recently an invasive moth was introduced because a housing developer didn’t get permits/permission to import some oak trees from Spain. The trees were infected with the toxic oak processionary moth, which spread around south-west London.

    It’s a shame the next article rants about the laws, without even acknowledging what they’re for.

  7. Patrick: I said a half-gallon (US). Which would be less than two litres, specifically 1.89 litres. If you and your wife/partner are drinking a glass (200ml) each every morning for breakfast then by Friday someone’s going to get shorted. So, no, I don’t think it’s too much. I live in Poland and they sell water and milk in 1.5 litre containers so, considering that it’s the US and everything is in imperial units and thus there are bound to be smallish differences in container sizes.

  8. I live in California and have always been amazed that most of the orange juice in our stores seems to be shipped cross-country from Florida. How on earth did THAT happen? We’re the state that came up with Sunkist, for crying out loud.

  9. @ Murray – sorry, I was feeling snarky and out of sorts and anyway kind of hate OJ as it reminds me of the UK in the 70s where it was served as appetiser / starter in restaurants, it was that “special”. It reminds me of grim times. I still have a bit of a mental block about it, thinking it is something rare, precious and to be doled out like gold. Or something.
    Like I said, I need to work through some of my relationship issues with OJ. Apologies all round.

  10. there’s a big difference between replacing trees in one’s backyard with pomegranates and replacing the millions of trees grown for produce in CA. besides Florida predominantly grows juice oranges and California grows table fruit (including grapefruit, lemons, tangerines, pomelos and oranges). it would be far worse ecologically in terms of carbon footprint (i.e. shipping) and unregulated pesticide use not to mention protection for workers and habitat loss through trading forests for farmland to have to import from south america.

  11. This is hilarious to me, because we called the hotline number on the mailer that was sent out and NEVER received a call back. If the state is so worried, maybe they should call back the people who are trying to report the insect.

    1. GreenEmily: try your county’s agricultural commissioner department if you spotted the psylid (collect samples for identification if possible). They are the local agricultural enforcement agency, and might respond quicker than the state’s agricultural department (the CDFA).

  12. Personally, I buy the gallon jug because the stuff takes forever to go bad. Too much eponymous acid for things to grow in it quickly, it seems.

    Orange growers in California are already calling it quits. With water prices and land values fairly high, they’ve been selling off the land for housing developments, or letting the groves die off. It’s just not profitable anymore in the area, and new and interesting pests every decade or so keep kicking it farther along that path.

    It’s an arid region, and wasn’t particularly well suited for it in the first place, as long as water isn’t irrationally cheap.

  13. I guess it’s alright if we just give up on citrus since we have can manufacture vitamin C and put it everything else you eat…

    Or you could just do without citrus and the vitamin C it gives you and die of scurvy…you know crop rotation and just plant what grows.

    And I’m not seeing how crop rotation changes any of this. This is a biological issue that’s been around almost 100 years. Once it takes hold in an area I think it would be near impossible to get rid of it.

  14. There’s Vit C in many foods. Citrus is only famous for it because citrus stores and travels better than most fruits and vegetables.

  15. screw pomegranates- why not grow something that’s actually edible and adapted to the desert, like figs?

    Speaking of which, Mark, how are those cuttings I sent you doing? If they didn’t work out, I’d be happy to ship a whole bunch of them off to you again in January…

  16. Patrick: no worries! I used to live in the US and figured you were having a go at Americans and how all the portions tend to be absurdly, ridiculously big (true).

    Ironically, the one thing that is always served small in restaurants in the US is the orange juice. It’s *never* more than 200 ml, usually more like about 150 ml. And they always charge an arm and a leg for it. Daft, but they somehow get away with it.

  17. Hi SG,

    I hate to admit it, but I let the roots go moldy before planting them. I feel bad to trouble you for more….

  18. @ 15 I work for local government and, sadly, most of the funds for pest control and eradication have been slashed. Pretty sad.

  19. #3: It sounds like the advice is pointed at people not growing them for a living.

    This is a bit of a tangent, but there are also those who, independent of this particular issue, advocate that monocultures in agriculture are something we should find an alternative to, for similar reasons to this.

    Finding a way to cultivate crops without resorting to acres upon acres of monoculture would help discourage sudden, devastating pest species booms… and would also help mitigate the environmental impact of farmland on indigenous species.

    How to do that while preserving farming efficiency seems like a very difficult problem though. That’s why it doesn’t seem that anyone has ceased monoculture on an industrial scale, yet (that I’ve heard of, anyway).

  20. Brainspore@12: Most of California’s oranges are sold whole for eating, as they tend to look better. Most of Florida’s are turned into juice as they tend to be sweeter. The humid climate in Florida causes oranges to get a greenish tinge.

  21. Nooooooo!!! Not my orange juice!! How come there’s never a plague of prostrating pestilence upon Brussels sprouts?

  22. @Dodds and Murray, OJ is out of my price range, usually. Making it from fresh oranges with a juicer makes it a slightly cheaper proposition, but not by a whole bunch. I’m in Texas, oranges are pretty pricey here.

  23. This is why Australians get all “thingy” when bilateral agreements attempt to circumvent existing quarantine legislation.

  24. I go to UF and work on purifying and obtaining the structure for an antimicrobial against Liberibacter asiaticus. So please, if you care about the oranges, go to UF, and know about Biochemistry. Let me know.

  25. Why not plant pomegranate instead and let other people worry about citrus diseases? If a pomegranate disease shows up, rip it up and plant something else.

    Why should I worry about the rain? I shall stand under this tree, and once it becomes wet, I shall simply move to another tree.

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