Has bacteria and fungi ever been an issue when importing plants from other countries. I know earthworms and many other insects have done a lot of damage but I don’t hear much about bacteria
Yes.
There are lots of plant diseases that are dangerous to US agriculture, so the plants that harbor them are banned from importation.
e.g. - Citrus canker - Wikipedia
(see Exclusion)
It’s not just “importing plants”, which to me has the connotation of a something commercial. For most international destinations, you can take fruit and vegetables with you.
https://www.aphis.usda.gov/aphis/resources/traveler/intl-travel/fruits-vegetables/fruits-vegetables
Almost all fresh fruits and vegetables (whole or cut) are prohibited from entering the United States because of the potential pest and disease risks to American agriculture. This includes fresh fruits or vegetables given to you on your airplane or cruise ship.
almost all frozen fruits and vegetables are prohibited
Most dried fruits and vegetables are not allowed
I believe there are restrictions to Hawaii also.
I once had an orange confiscated while trying to enter California. They were worried about some sort of fungus on untreated citrus fruit.
Ooh yeah, it’s something that doesn’t get much publicity, but yes. Happens all the damn time, but it’s not as obvious as insects. Moving plant material around is increasingly getting restricted as we’ve realised that’s where a whole bunch of ‘mysterious diseases’ came from. Fungi, plant viruses, bacteria, weirdy things that don’t quite fit in categories like slime molds and oomycetes…
Xylella fastidiosa is the current #1 check for UK imports, for example, as a bacterial disease that’s spreading through parts of Spain and Italy, with the potential to cause major damage here. Any potential host species for this disease needs to match a long list of requirements designed to mimimise the danger, before it can be imported. High risk species get tested again on arrival. The actual known infected regions have a complete ban on movement of host plants- plus a buffer zone of killing all known hosts- to try slow the spread.
When it comes to soil, it gets even tighter at least in theory: soil can contain loads of different diseases, some of which can persist for decades and are virtually impossible to get rid of once established- and except for research purposes- there’s not really a good reason to move it round, so it’s almost completely banned. We have a freezer full of soil samples in the lab upstairs from me; we’re not allowed to take them out the lab, and had to get a licence to be able to have them.
Plants imported are moved into an alternative substrate, peat, coir or something like composted bark which can be sterilised, and even stuff like agricultural machinery needs to be certified as clean before it can be imported- they’re a really effective way to move soil pathogens between sites.
Of course, then some bloke comes back from a nice overseas trek with muddy boots and tramples fungus spores around. Restricting commercial suppliers is one thing, but getting the public to take risks of importing soil seriously…? Not happening.
I have an interest in nitrogen fixing bacteria and I was curious how much of a risk it would be introducing bacterias into different areas. I guess it could be opening up the whole new can of worms
It is done, but you need to be pretty careful- there are commercial products made from live bacteria used as pesticides and I think you can buy nitrogen fixing bacteria of specific species, but there’s a lot of testing first.
First, it’s hard to know exactly what you’ve got- obviously in soil you often don’t have a clue- but even tiny genetic differences can make a huge difference to how bacteria act, and they can do fun things like swap genes with other local bacteria, so a bacterial strain that’s always been safe can randomly gain a toxic strain.
Second, bacteria can do weird stuff even without changing genetics, like only producing certain chemicals in certain conditions, so even if they’re OK in one area, that’s no guarantee. Xylella has long been known to cause a pretty mild plant disease in tropical countries, but for some reason it’s doing way more damage to trees (including killing 2000+ year old olive trees) in Europe. No-one’s really sure why the difference; temperature seems to have something to do with it, but most bacteria are less dangerous at low temperatures.
Then, of course, if something does go wrong, you can’t put the worms back in the can. You can’t scoop up all your bacteria from the soil and get rid of them.
There’s lots of potential benefits, but there are a lot of potential pitfalls too.
What about providing nourishment to native nitrogen fixing bacteria’s?