Scottish Rock Garden Club Forum
Cultivation => Cultivation Problems => Topic started by: Palustris on July 17, 2021, 12:04:35 PM
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As some folks know I used to grow Auriculas, given up on them now because of the root aphids.
However, I did sow the last lot of seed which I had as an experiment. The plants were potted up in brand new peat free compost in brand new sterile pots and put on the concrete patio in the shade of the house, well away from any of the Auriculas which I planted out in the garden.
So how come they are all now infested with root aphids? Where did they come from? No other plants get them and there were no other plants in any case anywhere near the seedlings.
The only thing we can think of is that the aphids come in with the compost or they may have been lurking on the seed trays.
Anybody got any suggestions as to how to get rid of them? At the moment all the plants are soaking in a vile mixture of Neem oil, Provado and Washing up liquid. Not bothered if it kills the plants as they are destined for the bin in any case.
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Hi Palustris,
Root aphids have a winged phase, so it's likely that even if you eradicated them, they recolonise this way.
In general I find that stressed plants (in primula this is most often too hot or dry) are more susceptible.
For more info there is a good article here:
https://www.planetnatural.com/pest-problem-solver/houseplant-pests/root-aphid-control/
Tristan
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Thanks. Still would like to know why they only seem to go on the Auriculas and nothing else. The plants were not stressed in any way that I could see though.
Bin here they come!
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When I was a Primula grower I used Methylated Spirits as drench and painted it through the root ball. Sometimes it worked, sometimes it didn’t.
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Tried that, it killed the plants!
Even odder is that I have just been looking through some P. siebodlii divisions. they were in a seed tray next to the Auriculas, not a single sign of root aphids on them.
The stuff recommended for controlling the blighters is £70 for 4 fluid ounces. Sheesh!
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I've accumulated quite a few P. sieboldii and noticed how they have been very free of the pests that afflict my auriculas/other primula. Repotting auriculas can be a depressing experience with many vine weevil larvae chomping on the roots, but only once have I found a vine weevil in the sieboldii.
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That is good to hear.
Strangely in looking for root aphids, so far I have not found any vine weevil grubs in the pots. Perhaps they do not like the taste of aphids? :P
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Just been going through the Auriculas, again. The ones which have been soaked for days in the insecticide do seem to be cleaner. It looks on some of them as if the aphids have moved up to the surface of the compost so I have been spraying the base of the plants with an insecticide which claims to kill them and their eggs.
Watch this space.
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Hi Palustris,
Root aphids have a winged phase, so it's likely that even if you eradicated them, they recolonise this way.
In general I find that stressed plants (in primula this is most often too hot or dry) are more susceptible.
For more info there is a good article here:
https://www.planetnatural.com/pest-problem-solver/houseplant-pests/root-aphid-control/
Tristan
When I used to grow a lot of Auriculas I used to use Jeyes Fluid - and leave them in a bucket drench for an hour - it cleaned the long tom clay pots as well
I presume it's illegal now, like everything else that was any good
I did move over to cat litter and Jondo Hen grit mix with oyster shells and limestone chippings - can't remember seeing any after that
The place I used to get plants from you could guarantee they came with root aphids, so I always quarantined them as soon as I got them home
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Sadly despite doing everything that has been suggested, the few remaining Auriculas all had huge numbers of root aphids so I have stopped growing them altogether. Just not worth the heartache.
The ones out in the borders can stay and survive or not as they please, but the Theatre ones are gone.
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Palustrus,
Some horticultural supply vendors sell an insectivorous specie of nematode.
I think that is probably your best control.
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Some horticultural supply vendors sell an insectivorous specie of nematode.
Not in the UK - looking at the ones available in the US, the UK climate is almost certainly too cool for them here, especially for plants such as Primulas which prefer things cool.
I have very seldom had problems (VERY seldom grown Primulas in pots though), but a change of compost could work and keeping them well-watered (which ties in with the few problems seen here - gritty, fast-drained composts).
In pots, a drench every few days with something like cypermethrin might work - very safe (approved for use on food contact surfaces) but the most persistant pyrethroid there is on the market.
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Too late. All gone. Planted out in the garden and the theatre is now empty.
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Root aphids are such a pain, and it's so annoying to get rid of because there are so many of them. I've been battling with them for three months. If the roots are rotted, I recommend flushing your medium with H202 to help with it. I would do it a couple of times, then continually add it to your nutrient mix. It would be best to flush out as many as possible for the root aphids. Physical removal is key for getting aphid populations down. But to be honest, the only thing that helped me was a pest control sydney (https://enviropcs.com.au/) company. They used an eco-solution that killed them.
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What is the danger of root aphids ?
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What is the danger of root aphids ?
Root aphids attack the roots of plants, sucking the sap there and causing considerable damage and sometimes even the death of the plants.
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And unlike their above ground relatives they are not eaten by ladybirds and their larva or indeed any other aphid eating friends. Also they are covered in a waxy layer which makes them impervious to water borne insecticides.
I think I have managed to find an insecticide which deals with them. It is a soap based one and so far there are no signs of them on the baby plants that I have tried. Fingers crossed.
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Palustris:
What was the treatment you found for the root aphids. I have a number of antique varieties of apples that are infected most of the time.
Thanks,
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Hi Arnold,
From an agricultural perspective it is much easier to control root aphids on apples by selecting resistant rootstocks for the trees. For example, dwarfing rootstock such as Malling 9 is highly susceptible to root aphids. I have had a great deal of success with MM106 as a semi-dwarfing rootstock in our Placerville orchard. I also use an intermediate stock to dwarf apples and avoid root aphid problems. Soil fertility is also an issue. Generally soil with a high carbon content creates a soil environment conducive to healthy roots and few root problems in most fruit trees. This is what works for me in California. Conditions may be very different in your area. For whatever it is worth, I speak from 50 plus years of experience as a farmer and at one time a commercial grower of bare root fruit trees. There is a solution to your root aphid problem. May all proceed well for you and your apple trees!
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Robert
Thanks, I will have to try and research the root stocks on the apple trees I have. They are all grown as a Belgian fence espalier.
I have Cox's Orange Pippin, Esopus Spitzenberg, Arkansas Black and Calville Blanc d'hiver.
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Arnold,
Cox Orange Pippin is a very uncommon apple!
The only nursery I am aware of that sells it is Trees of Antiquity, in Paso Robles, CA. [formerly Sonoma Antique Apple Nursery, in Santa Rosa].
They grow theirs on MM111.
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Arnold,
Cox Orange Pippin is a very uncommon apple!
The only nursery I am aware of that sells it is Trees of Antiquity, in Paso Robles, CA. [formerly Sonoma Antique Apple Nursery, in Santa Rosa].
They grow theirs on MM111.
Cox are uncommon outside of commercial orchards, even in the UK - they are susceptible to every disease known to man, plus other problems. They are grown because of their unique and very popular taste.
What I suspect is either a cross or selection of Cox' Orange Pippin is grown in NZ and shipped to the UK when our stocks are out of season - it looks very similar, slightly glossier, but the flavour is very poor.
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Not sure this would be any use on trees, but it did work on plants in pots.
Neudorff 250 ml Pyrol Bug and Larvae Killer
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Robert
Thanks, I will have to try and research the root stocks on the apple trees I have. They are all grown as a Belgian fence espalier.
I have Cox's Orange Pippin, Esopus Spitzenberg, Arkansas Black and Calville Blanc d'hiver.
Hi Arnold,
Cox’s Orange Pippen Apple does poorly in our Placerville orchard. This variety seems to dislike the hot, dry summers. Higher on the mountain, about 3,500 feet elevation, orchardists seem to have much more success with this variety (they have much cooler summers).
I have not grown Esopus Spitzenburg since the 1980’s. We always fall budded a few trees for retail sales and they seemed to sell on name recognition.
Arkansas Black is one of our favorite apple varieties. I have one tree in the Placerville orchard that has been producing heavy crops most years for more than 30 years. We let the apples hang on the tree until early November. A light frost on the hanging fruit seems to bring out the best favor. They store extremely well in cold storage or a cool, frost-free location. I grafted a tree for one of our Sacramento neighbors about 10 years ago. This tree is producing apples now. We still have enough winter chilling hours for this variety to set fruit in Sacramento. Based on my observations and comments for other farmers in the Central Valley of California adequate chilling hours is becoming an issue with a number of nuts and fruits, especially in the San Joaquin Valley.
Calville Blanc d’hiver is a fabulous apple variety. Currently we have one tree at our Sacramento home. It produces divinely flavorful apples consistently every year. Currently the tree is loaded with apples. I will be grafting more to plant in Placerville. The fruit seems to hold well in cold storage, however they rarely hang around long after picking.
If you feel inclined, I would love to hear about your observations and opinions on the fruit trees in our garden/orchard.
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Robert
I've had the apples in my little suburban espalier garden in New Jersey for over 30 years. Our greatest challenge is pollination. We rarely see bees these days. Our local County government decided that we needed the entire are sprayed for mosquitos so they drove a truck up and down our streets spraying a very toxic pesticide to anything that flies.
I get relative small fruit set these days. Plenty of flowers. This year the Caville Blanc set no fruit. I purchased the trees from a espalier tree dealer out at the end of Long Island. He sells whips and some already trained trees. I believe he may have Cox's Orange. https://www.henryleuthardtnurseries.com/ He apparently is responsible for the pollarded London planes at the UN in NYC.
Our summers are hot and wet which may be to liking of the Cox's Orange. I've adopted a strict organic approach to pest control.
Use Spinosad, Neem and BT for most of the issues that come along.
There is a web site run by Cornell University that lets you know the pest stage so spraying has a maximum effect. You plug in the nearest airport and it will give you degree days and stages of the pest and when to treat.
https://newa.cornell.edu/user
Second problem is that our local squirrels take fruit and runs off with it. I have solved that problem with a remay sack I put over the fruit when it gets big enough. There's even a twist tie on the top of the bag to allow easier fixation.
My real treasures are the pears. I have a number of espalier Passe Crassane, Beurre Grifard and Magness. The Magness was introduced in the 60's and does very well here.
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Hi Arnold,
Thank you for taking the time to supply so much useful information. Squirrels are a huge problem in our Sacramento garden. I have read about how the Japanese use little netted bags to protect their ripening fruit. Where do you purchase the remay sacks? It is extremely frustrating to make hand pollinated crosses and have squirrels (mostly), raccoons, or birds run off with or destroy some of the crosses. Are there larger remay sacks that might be useful for large clusters of table grapes. I use lettuce bags in my breeding work, but the material is not strong enough to keep squirrels out.
Cornell University is right in your backyard. As I remember they have conducted extensive field studies of apple rootstocks. Unfortunately they are more geared toward agri-business. U.C. Davis is 10 miles from our Sacramento home. They too are geared toward agri-business. They basically they know nothing of natural pest control. Organic has been subsumed by agri-business, so the advice is generally just as toxic and destructive as the chemical version.
A lack of chilling hours for fruit trees (some ornamental species too, such a lilac) as well as the disappearance of pollinators is becoming a huge problem in California, especially in the Central Valley and other areas of intense mega scale commercial agriculture. Almond growers are desperate for honeybees or any other pollinators they can find. Ground water over draft is so bad that in many Valley location the surface of the ground has dropped 30 feet, sometimes much more. In addition, the well water quality has declined so much that the water now contains high levels of salts. The food grown with this water, it is often cut with fresher water so the plants do not die, contain toxic levels of heavy metals such as arsenic, selenium, and other heavy metals. In the super market these foods are labeled with warnings. Crazy isn’t it! Don’t believe me? I will take a photograph of one of the labels.
I bought a Magness Pear from Arthur Wiebe, owner of Vallombrosa Gardens, Chico, California, back in the late 1970’s. Arthur died in 1983 and his amazing little nursery died with him. He grew all sorts of usual, heirloom, and rare fruits. I still have one of his ”Chinese Easter Cherries”. I have never been able to ID the plant to the species level. It is compatible with both Mazzard (Prunus avium) and Mahaleb (Prunus mahaleb) cherry rootstocks.
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The demise of bees should be of huge to all no matter where..
Remember seeing a report of the need to hand pollinate commercial fruit trees growing in parts of China where bee populations had disappeared due to the use of toxic pesticides. Mites have also contributed to a reduction in the number of live bees in hives.
DIY bee keeping has become very popular here, mainly for a cheaper source of honey. Our Kiwifruit industry sources hives for flower pollination. As long as there is an uncontaminated pollen source this practice may improve the potential for natural pollinators.
In NZ there has been a move to ban the use of systemic pesticides and fungicides by hone gardeners. The same does not apply to commercial growers of produce, the logic used to justify this is that home gardeners use garden chemicals in an indiscriminate and un controlled way. Cannot find any stats but I am sure that commercial use well out weighs DIY use. While there has been some restrictions placed on commercial users, they require their produce to be free of the possibility of disease transmission with export crops. We export huge quantities of apples to markets that place strict controls on acceptance.
I knew a small commercial grower of paeonies as a flower export crop, mainly to the US. They classed due to the requirements for their flowers to be accepted. Regular spraying was the base for acceptance.
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Hi Arnold,
Thank you for taking the time to supply so much useful information. Squirrels are a huge problem in our Sacramento garden. I have read about how the Japanese use little netted bags to protect their ripening fruit. Where do you purchase the remay sacks? It is extremely frustrating to make hand pollinated crosses and have squirrels (mostly), raccoons, or birds run off with or destroy some of the crosses. Are there larger remay sacks that might be useful for large clusters of table grapes.
Robert,
You might try planting the material you want to cross in an enclosure of chain link fence with chain link over the top, and the bottom embeded in a poured concrete footing. It could be made more attractive by planting flowering vines on it.
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Robert
The remay sacks came from a Chinese supplier. I'll see if I can find the source.
I think they may be large enough for a bunch of grapes.