Root aphids

[wireme]

Got into a partial bare root today and found a serious case of root aphids. What's the current best known treatment?
The weed growers seem keen on Met52. That's one thing I want to try if I can find it. I suspected as much, this looks serious. Saw a few on other trees this week but nothing like this juniper.

 

[JoeR]

I thought they infested weak trees? Your juni looks very healthy with new white root tips in a good soil... ???

 

[Brian Van Fleet]

https://bonsaitonight.com/2014/12/30/stealthy-pests/
https://bonsaitonight.com/2015/09/01/drench-for-root-aphids-follow-up-1/
This is what I did when I suspected root aphids on this pine. It returned to good health.
@JoeR , aphids don't know if a tree is strong or weak. If they find one, it will become weak soon enough.

 

[coh]

I've been wondering if I have root aphids in a couple of my weak trees, but it's hard to tell because of the fungal stuff (myco) in the pots. So I have a question, as it's tough to really make out what is going on in the photos. Can you see the actual insects, see them moving around? I seem to recall that when Jonas talked about this on bonsaitonight, he said he really couldn't see the aphids themselves, just the "fuzz"...but he was treating essentially based on symptoms.

Chris

 

[wireme]

I've been wondering if I have root aphids in a couple of my weak trees, but it's hard to tell because of the fungal stuff (myco) in the pots. So I have a question, as it's tough to really make out what is going on in the photos. Can you see the actual insects, see them moving around? I seem to recall that when Jonas talked about this on bonsaitonight, he said he really couldn't see the aphids themselves, just the "fuzz"...but he was treating essentially based on symptoms.

Chris

I had the same problem Chris. When I saw the bonsai tonight post I thought it looked familiar.
I've been repotting all week and have seen at least a few of the little fuzzy white patches on all conifers. I've been looking closely with a good hand lens and didn't see any bugs at all. I was just about convinced that it was just myc until yesterday. They must have just hatched and now I can see aphids under magnification. They are not moving around yet but clearly are tiny white aphids, very, very small, even with a magnifier I can just barely make them out.

 

[coh]

Do they look like regular aphids? The one thing that sounds like it may be distinctive (or somewhat distinctive) is that regular myco tends to be webby and more evenly distributed, whereas root aphids are more "clumpy". At least, that's what it sounds like from my reading. In any case, I'm seeing more and more about this becoming a significant problem for nurseries, especially out west. So it makes sense that it would be affecting bonsai growers more as well.

 

[Arcto]

Ouch. I've heard of one person who had a big time problem with that. Extension service recommended soaking root balls for 10 min in a toxic insecticide. Forgot name of chemical but required hazemat suits, etc. 2-3 treatments. A lot of his trees suffered phytotoxicity. Spruce and fir particularly. It did take care of the aphid problem at a big cost. Also his infestation has being farmed by ants. He now puts out ant traps when he sees activity around the benches. Aphids aren't hard to kill. I've wondered about just submerging in water for a period of time and knocking back the population by drowning. You would have to do it several times to get the future hatch outs.

 

[wireme]

Root drenches, crap, I'll need a bathtub, hot tub maybe for the biggest boxes!
In hindsight I would say I've seen a slight decline in general vigour of the collection ever since I started using pumice, that miracle substrate. Perhaps these buggers came with it from the west coast. Increased winter protection and milder than normal winters maybe too, less winter kill of the eggs perhaps.
This guy is far less healthy than it should be following last years repot. I've been wondering why, but now I think I know.

 

[wireme]

Do they look like regular aphids? The one thing that sounds like it may be distinctive (or somewhat distinctive) is that regular myco tends to be webby and more evenly distributed, whereas root aphids are more "clumpy". At least, that's what it sounds like from my reading. In any case, I'm seeing more and more about this becoming a significant problem for nurseries, especially out west. So it makes sense that it would be affecting bonsai growers more as well.

Yep, clumpy and less connected, that's what I'm seeing.
From my readings I'm thinking that breeding and continued applications of predatory nematodes and Metarhizium fungal spores might well be the best long term solution. I don't think I have time for that now though.

 

[Arcto]

Any ant activity?

 

[wireme]

Any ant activity?

Plenty cruising around the area on the ground but no obvious activity on trees or in soils.

 

[fore]

Ryan N. had root aphids last yr and it was bad. He did drenches that did a lot of damage. Here's what I've been told:
SXs are gen loss of health/colour, yellow tips and is moisture related. Use Systemic granular Bifenthrin (fire ant killer) Brands are Granular Safari - fast uptake/fast elim lasting about 3-5 dys.

 

[wireme]

Ryan N. had root aphids last yr and it was bad. He did drenches that did a lot of damage. Here's what I've been told:
SXs are gen loss of health/colour, yellow tips and is moisture related. Use Systemic granular Bifenthrin (fire ant killer) Brands are Granular Safari - fast uptake/fast elim lasting about 3-5 dys.

Any concerns using it on newly reported trees?

 

[fore]

I can't find anything about recently repotted trees. But I'm sure it's a bit risky, but not treating is worse imo. So treat it, and then give it proper after care, shade and mist, till new growth is seen, reflecting the incr. health of the roots.

 

[coh]

Chris, just to be clear here - did Ryan use the Bifenthrin and get damage from that, or was he using something else and now recommending the bifenthrin as a better alternative? What made him think the drenches did the damage, if the trees were already infected with root aphids couldn't the damage be from them...perhaps delayed?

 

[fore]

The latter. Whatever he used...Cleary's? was way too much. And yes, delayed toxicity. Took about a yr to recover.

 

[0soyoung]

Root aphids = phylloxera, right?

 

[wireme]

Root aphids = phylloxera, right?

Beats me. You can see the white stuff in the pic. Hidden amongst that I found very small translucent white critters that looked like aphids. Could just barely make them out with a hand lens, not moving, I think they just hatched.

 

[0soyoung]

It seems to me that any sucking insect working on a tree is going to be at places where the phloem (that carries photosynthate - food for bug and tree alike) is essentially on the surface; leaf veins and petioles and the white tips of roots. The 'bark' is just too thick for their little stylets to pierce elsewhere. Phylloxera is a different bug than the common aphid and infamous for ravaging grape vines. At any rate, root aphids aren't the juicy little guys farmed by ants - a different bug.

The gist of what I've recently learned about phylloxera is that the bug is native to wild grape and pecan trees in the southeast U.S. It is believed to have imported to California from France as a result of an effort to save precious wine making strains before it was discovered that wine grapes can be grafted onto roots stocks that resist phylloxera. It is speculated to have spread from there by cuttings, so marijuana growers don't do cuttings - they grow from seed (or advised to do so).

The first I heard of 'root aphids' was a Bonsai Tonight post. Jonas is within 100 miles of the California vineyards. Problem was with JBP likely raised in the SF area. @Brian Van Fleet had a problem (weak growth, yellow needles) with a JBP that I think he got from evergreengardenworks.com which is in the same proximity. @Nybonsai12 thinks he is battling problems with root aphids too.

Now this thread reports that Ryan has had them in Portland, OR. Oregon's vineyards are in the Willamette River valley, less than 100 miles south of his nursery. For everything I have seen, Ryan's collection/stock is exclusively yamadori. So how might his have gotten infested (I ask myself)? Well, Randy Knight also grows stuff as well as collecting all those fabulous yamadori - maybe that is how/why. Michael Hagedorn is in the same area, has some stuff other than yamadori, but hasn't blogged about such problems - maybe it is because he doesn't have any stuff from Randy?

So, I wonder, how your yamadori from the Kootenays could be infested with phylloxera.

I've read that nematodes are the bane of JBP in Japan. I wonder if Jonas' root aphids and BVF's cases weren't really nematodes. Both involved JBP.

It appears to me that the publicity of 'ROOT APHIDS!!' has generated a fad panic - you're just nobody if you haven't had root aphids. Right now, it is hard for me to separate fact from fiction.

I'm not an entomologist.
I don't know what those bugs are in your tree roots.
I've just become interested enough to start educating myself and trying to solve this puzzle to some degree (well, maybe after I do the Sunday crossword).

Best of luck (just in case your trees really are infested with phylloxera).

 

[coh]

There are other types of root aphids, the phylloxera appears to be one type that attacks mostly (or only) grapes. There is a lot of discussion about root aphids on the cannabis forums. Some of those folks claim to have had success with imidacloprid (i.e. the active ingredient in many of the Bayer products). That's what I would try first if I thought I had root aphids.