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Sallubrious

Nexus scale infestation

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I've got few P.nexus that have just come out of winter and they look OK considering how many times they froze, but they went into a dormant state and the insects gained the upper hand.

During I autumn I noticed the scale which seems to be an armoured type of black scale which I've never struck before. I made several attempts to remove them all by hand, which I thought I did a fair job at doing but they scale has persisted over winter and flourished. I think removing the visible ones just got rid of the adult stage and the plants still had juvenile scale crawling all over them.

Now it's warming up a bit the sap is starting to rise and the plants are showing new buds and look like they are going kick in again.

I'm thinking of a rather brutal treatment method where I'll remove most of the leaves, so I'm wondering if anyone has given a nexus a really severe pruning and how did it respond.

The plants seem to be dropping a lot of last years growth so I'm hoping it won't affect them too much. After the fleecing I'll probably hit them with some white oil or a vegetable oil/detergent mix and try to keep on top of the problem.

Has anyone else had any scale issues with their Psychotrias and how did you manage it if you did?

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I have scale and rust going on with my big old nexus. It has dropped most of the previous years leaves for the last 2 cold seasons but seems to get on fine with minimal foliage. The Nexus is quite close to a big viridis which has no issues with scale and rust. Nexus must be particularly susceptible.I generally just scrape off the scale - doesn't seem to be a huge problem because it has grown to be close to 2mx2m in size and absolutely booms during the warmer months... But I am a fair bit up the coast from you and in a fairly warm humid coastal microclimate where tropical species do well.

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I have scale and rust going on with my big old nexus. It has dropped most of the previous years leaves for the last 2 cold seasons but seems to get on fine with minimal foliage. The Nexus is quite close to a big viridis which has no issues with scale and rust. Nexus must be particularly susceptible.I generally just scrape off the scale - doesn't seem to be a huge problem because it has grown to be close to 2mx2m in size and absolutely booms during the warmer months... But I am a fair bit up the coast from you and in a fairly warm humid coastal microclimate where tropical species do well.

Thanks for that, so it looks like they might handle a good fleecing, they are over a foot tall and have a good rootball.

Are yours in the soil or in pots?

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Hi SallyD,, I don't have any psychotria, but some of my plants get scale frequently. I noticed that ants are farming them! Lil buggers.. when I can alleviate the ant problem, the scale is easier to deal with. I use Yates scale gun only when I have to. Its not that toxic and does a good job. A day or two after, I soak/spray my plants with a lot plain water to wash off any residue. And of course give it a month til any leaves are used. i also just squeeze the scale to kill them when its not an infestation.

Edited by upside

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So is the Yates scale gun an oil based spray or a pyrethrin type of thing ?

EDIT: just google it, seems like a pyrethrin based product

Edited by SallyD

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Thanks for that, so it looks like they might handle a good fleecing, they are over a foot tall and have a good rootball.

Are yours in the soil or in pots?

Mine is in the ground - planted approx 10mths ago into clay-loam soil with lotsa good compost. It has grown close to over 50cm high and wide in this time. It stopped growing about June but has held a lot more leaves than when it was in a pot.

I would be a bit cautious about taking all the foliage off plants as small as yours.

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Yeah I was thinking I'll leave about 20% of the leaf on them, I just want eliminate a good percentage of the hiding spots for the critters and help me to ensure they get a good spray all over.

Full moon today so I don't know if that will affect the alkaloid content, it will be a real shame to compost all that leaf.

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I fleeced them out to get rid of the worst affected leaves. Then I sprayed them with the hose and gave them a good coating of diatomaceous earth to try and stop the bastards coming back.

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if I were you I would try to find the ants, which put the scale onto the plants.

any treatment, is useless unless, you cut off the ants going to this plant.

cut off the ants, and than treat with white oil, than rinse off, oil with water.

repeat after a few day's, than use pyrethrum, and rinse after five minutes.

many pests, display life forms, which can't be killed (by above measures), like in egg form, that's why you have to respray after a few day's.

organic approach, you still have to get rid of the ants, and I am 85 % sure they hide, to a large degree, in the potting mix of the plant effected.

so take the plant out of the pot, and look for ant nests.

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Thanks PH

Yeah I did find ants coming from the potting mix, I get that a lot around this place. The little bastards make the soil repellent and even a 2 day soak in a bucket won't fix it or get rid of the ants. So the ants cause havoc at the rootzone which makes the foliage more likely to get attacked by insects - which the ants also transport.

I might plant them in the garden and let the green ants bully the little black ants out of the area. At least the green ants don't transport aphids and scale etc.

Edited by SallyD

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but was the pot totally submerged in the bucket of water?

if one, submerges the pot, over the rim with water the ants will die after even one day or less.

sometimes they crawl up the stem of the plant to survive, so inspect this process closely, to make sure there are no survivors.

good thing is, a psychotria doesn't mind, some very wet feet, for some day's.

drowning the ants works, but finding big buckets/containers, could be an issue.

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Yeah I've fully submerged pots for 2 days and added wetting agent but the water just hasn't soaked in. The ants form a waxy residue and it creates air pockets that just won't allow water in. I've tried poking sticks and screwdrivers and all sorts things in to break up the air pockets but nothing seems to work. Most plants that get infested like that I end up having to remove all the soil and then soak the bare roots.

I haven't tried it with these plants though & it doesn't always form that repellent zone, it's mainly the brown ants that cause that problem. These ones have black ants so it could be the way to go.

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hmm, a rare case, and somehow you might have used not the right potting mix.

every hydrophobic soil will soak up water eventual, some stuff might take 14 day's to re wet...

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hi, i've been trying to get a handle on growing psychotoria just incase i manage to get some. one thing i've read is below, it's only from crapapedia but perhaps it is a shelter for nymphs that the ants can use. Foveolae[edit source | editbeta]

These are small pockets found on the lower leaf surface near the junction of the secondary (i.e., side) veins with the central vein. They function as shelter for tiny invertebrates such as mites that live on the plant leaf. These mites apparently often are symbiotic with the plant, taking shelter in these structures and eating fungi and herbivorous invertebrates that can damage the leaf. The foveolae (also called domatia) are distinctive for Psychotria viridis and a few related species: They are generally 1.5-5 mm long and 0.5-1 mm wide at the top, conical and tapered to a closed base, open and truncate or variously ornamented at the top, and situated along the sides of the central vein with the opening usually near a secondary vein (Figure 4C). These foveolae vary in shape among different plants (Figure 4C, 4D, 4E, 4F), and in number on individual leaves, and may not even be present on some leaves. Most often each leaf bears at least one pair of foveolae, which may be close to the apex; the foveolae are often more numerous on leaves from vegetative stems than on those from reproductive stems

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hmm, a rare case, and somehow you might have used not the right potting mix.

every hydrophobic soil will soak up water eventual, some stuff might take 14 day's to re wet...

Yeah I'd never struck it before I moved here. I thought it was the potting mix I used when I got here but all brands do it if the ants get in there.

The brown ants lay their eggs in the pot and then seal it off so it's waterproof. It doesn't just happen to 1 pot at a time either so they must have multiple queen ants all over the place.

I've lost a few plants from soaking them for too long too, so I'm a bit hesitant to do it sometimes.

I've tried all sorts of things to stop the ants but not much seems to work. Ant sand,borax, cinnamon all seem to do nothing. I covered the top of the potting mix on a few plants one time with cinnamon and the fucking things started collecting it and taking it back to their nest.

I haven't forgotten about that trade either PH, I'll get something sorted out soon - sorry mate

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hi, i've been trying to get a handle on growing psychotoria just incase i manage to get some.

Someone over there should be able to hook you up with a few leaves to get started from. Maybe post a thread in seed&plant exchange forum

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Someone over there should be able to hook you up with a few leaves to get started from. Maybe post a thread in seed&plant exchange forum

Thanx I shall, still feel like a lurker though. Trepidation makes for awkward posts :-)

I guess the foveolae arent an issue then.

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Thanx I shall, still feel like a lurker though. Trepidation makes for awkward posts :-)

I guess the foveolae arent an issue then.

52 posts is way past lurking, if the plant is legal where you live then there shouldn't be any problems. Go for it man.

There was evidence of mite recent damage on some of the newer leaves so there could be some hiding out in the foveolae. I've never had a close look at the underside of a nexus leaf to see how big the domatia are - now you've got me interested.

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Maybe some Vaseline around the trunk? http://www.abc.net.au/gardening/stories/s3301063.htm

I have never tried it though and it would only work on big plants, so it maybe not.

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Def going to try it on my lime.

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You can get a wrap for trees to stop the ants. It's like a woven tape that's impregnated with a really thick sticky grease. Greenharvest has them in their catologue they call them a fruit tree grease band. They also sell a few glues that do the same thing, one comes in mini caulking gun and the other one comes in a tube.

http://greenharvest.com.au/PestControlOrganic/HorticulturalGlueProducts.html

That was my first thought when I read what PH said about the ants on the nexus. Maybe the vaseline would be better for a small diameter stem though.

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