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Gardening in mediterranean climates => Pests and diseases => Topic started by: Umbrian on November 08, 2011, 08:19:32 AM

Title: Pest on Lemon Tree
Post by: Umbrian on November 08, 2011, 08:19:32 AM
When staying with a friend in London last week he asked me what this "pest" is. They are on his pot grown Lemon and occur either singly or in small groups on the woody parts of the plant - mainly on the branches but some on the trunk. My guess was wooly aphids but he was not convinced so now it is up to the experts.
Also what is the best way to eradicate them?  ???
Title: Re: Pest on Lemon Tree
Post by: Umbrian on November 08, 2011, 08:22:54 AM
Sorry seem to have posted the photo twice!
Interesting to note how the pest seems to mimic the flower bud?
Title: Re: Pest on Lemon Tree
Post by: Alisdair on November 08, 2011, 08:57:34 AM
Carole, It looks like a wingless female woolly aphid, as you'd thought. In the UK they are minor pests of apples and pretty ubiquitous, but do love potted citruses and seem to find their way on to them quite quickly
When we had a small Meyer's lemon in London we kept the aphids under control by picking them off individually with an artist's paintbrush soaked in methylated spirits. On our full-size citrus trees in Greece we have sprayed them with soft soap, which does work, but may not give such lasting results as a more persistent insecticide.
Title: Re: Pest on Lemon Tree
Post by: ezeiza on November 08, 2011, 04:20:19 PM
Methylated spirits, 90%, water 10%. mixed when it is about to be used. Spray on the pests, kills instantly all insects and mites. Of course chemical insecticides can not be used on something that will produce fruit unless this is not eaten.
Title: Re: Pest on Lemon Tree
Post by: JTh on November 08, 2011, 05:06:58 PM
It is often useful to repeat this treatment around 10 days later, not all stages of these parasites are equally susceptible to the treatment, it helps to attack those that survived the first treatment before they have reached the mature stage and start producing a new generation.
Title: Re: Pest on Lemon Tree
Post by: Umbrian on November 09, 2011, 07:58:15 AM
Many thanks Alasdair, ezeiza and Jorun and good to see that you all recommend the same treatment, makes life so much simpler :) Will pass on the advice post haste.
Title: Re: Pest on Lemon Tree
Post by: Umbrian on November 20, 2011, 08:03:11 AM
Three cheers for the Forum for being so useful in gaining expert advice that can be passed on to others. The other day another friend, here in Italy this time, asked me what was attacking her Lemon tree (white,wooly infestations) I was immediately able to say, with compete confidence, Oh that's woolly aphids, you need to treat them with Methylated spirits. 8)
Title: Re: Pest on Lemon Tree
Post by: ezeiza on November 20, 2011, 01:40:33 PM
Umbrian, it works once the pest is present and provided you can spray the spirits directly on the beasts.
Title: Re: Pest on Lemon Tree
Post by: John on November 20, 2011, 06:23:36 PM
I think that these are scale insects not aphids. They occur on all sorts of woody plants around London.
Title: Re: Pest on Lemon Tree
Post by: John on November 20, 2011, 06:53:06 PM
These are the flightless females. We used to have them on our Cornus kousa var. chinensis. I suspect that they are relocated by ants which possibly are farming them. They are particularly common on Lime trees. I managed to get rid of them on this small tree with a trunk diameter of about 30cm by regularly jet washing them off with my thumb on the end of the hose.
Title: Re: Pest on Lemon Tree
Post by: ezeiza on November 20, 2011, 07:59:34 PM
They are postively farmed and distributed by ants.
Title: Re: Pest on Lemon Tree
Post by: Umbrian on November 20, 2011, 08:39:46 PM
Now I am thoroughly confused ??? Are the blighters wooly aphids or scale insects? and have I given out wrong information :-[ and am going to have to eat humble pie?  :-\
No ants were present on the tree in London that I inspected on several different days if that is any kind of clue
Title: Re: Pest on Lemon Tree
Post by: John on November 20, 2011, 08:45:16 PM
Carole I can only say that I'm pretty sure they are scale insects so we will have to wait for other opinions to come through!
Title: Re: Pest on Lemon Tree
Post by: Alisdair on November 21, 2011, 07:16:04 AM
I'd stick with the woolly aphids, Carole. The flightless females do look just like your picture, and do walk around like that if the ants haven't shifted them. Scale insects are a bit different. (But the meths would still deal with the scale insects too, anyway....)
Title: Re: Pest on Lemon Tree
Post by: David Bracey on November 21, 2011, 02:37:45 PM
I cannot tell from the photo; it is quite fuzzy when I blow it up. Do you have another pic?

Anyhow you should not go around spraying methylated spirits.  It is not green nor organic nor biologically proven.  I gives conventional pesticides a good name.  As Alisdair suggests use a soapy solution and spray as often as convenient and where practical wipe the infested branch between your fingers.

A follow up spray will control those eggs which have hatched in the meantime. 
Title: Re: Pest on Lemon Tree
Post by: JTh on November 21, 2011, 03:37:55 PM
I agree, the photo is not very clear, it does look different from other scale insects I am more familiar with, but I can see a resemblance with Icerya purchasi (cottony cushion scale), which is affecting citrus trees, I have copied a photo from Wikipedia (http://en.wikipedia.org/wiki/Scale_insect).  
Title: Re: Pest on Lemon Tree
Post by: Umbrian on November 22, 2011, 10:37:27 AM
Sorry about the quality of the photo folks but we only had a small camera with us at the time. In comparison to your photo Jorun of the cottony scale insect I would say it is a different shape altogether - the ones on the tree were really tapered toward the back end i.e. the part not attached to the tree. Of course they may have been at a different stage of development!
Anyway I passed on the advice to treat with Methylated spirits opting for the paint brush application as the tree, being in a pot, is obviously small and easily accessible.
Title: Re: Pest on Lemon Tree
Post by: ezeiza on November 22, 2011, 08:06:54 PM
Umbrian, applying it with a paint brush is a penitence. If you add 10% of water roughly you can spray it on the pests, a method a thousand times faster and easier.
Title: Re: Pest on Lemon Tree
Post by: Umbrian on November 23, 2011, 08:29:26 AM
As I said in my last posting ezeiza, the Lemon tree in question is small and so to treat the pest with a paintbrush is not too arduous! I was aware of David's concern about "spraying Methylated spirits around" but have to add that I am sure serious gardeners ,such as us who use the forum, would always proceed with care and caution especially when treating a subject with edible fruits. I, and my friend who owns the Lemon tree in question, try to be as "green" as possible but sometimes have to resort to more drastic measures. David added that the success of treatment with Methylated spirits has not been proven but the fact that three replies recommended it seems to be good proof to me that in fact it does work. 
How do other members feel about this and the whole question of what we can use to eradicate unwanted pests in our gardens? ???
Title: Re: Pest on Lemon Tree
Post by: John on November 23, 2011, 10:08:52 AM
I have to say that I have used the meths spray or brush on many subjects which has been especially effective against mealybug particularly on difficult subjects such as cacti. On a larger scale (pun here I think) I use a horticultural soap spray which theoretically can be used on edible crops.
Title: Re: Pest on Lemon Tree
Post by: ezeiza on November 23, 2011, 04:35:38 PM
Ás I understand it, David is questioning something else. The effects on insects and mites are demolishing and immediate as anyone can see. It even kills cockroaches. Instantly. Since the treatment is on the present pest and in such minute quantities, it is as organic as other products can be. So much so that if the small quantity of water is not added all of the alcohol would evaporate within seconds.

Of course the traditional method has been to paint the pests one by one but spraying the foliage, trunks, etc. affected, with a hand sprayer makes it very fast to treat several plants, etc.
Title: Re: Pest on Lemon Tree
Post by: Paul T. on November 24, 2011, 08:41:12 AM
Howdy Folks,

I've just seen this topic for the first time and my thoughts immediately on seeing the initial picture were that it was cottony cushion scale.  I get it periodically on my own lemon tree, usually cared for by ants.  The easiest treatment for it (and the one I have always used) is one of the horticultural oil or soap sprays.  These can be based on petroleum oil or the newer ones such as "Eco-Oil" are based on vegetable oils and "Natrasoap" I think.  They suffocate the scale, killing them almost instantly.  They are otherwise safe and non toxic.  I wouldn't be using methylated spirits in general, although I am fairly sure that the cell structure of citrus would hold up to it.  I have heard of people (no idea whether this is an urban myth or not) who have used metho on scale on african violets (Saintpaulia) and had the leaf material literally dissolve where it touched.  Hearing that I've tended to shy away from using any straight metho on anything plant-wise. ;D  If only it would work that way on the weeds.  ;)
Title: Re: Pest on Lemon Tree
Post by: Alisdair on November 26, 2011, 05:23:23 PM
Carole, your bold question:

As I said in my last posting ezeiza, the Lemon tree in question is small and so to treat the pest with a paintbrush is not too arduous! I was aware of David's concern about "spraying Methylated spirits around" but have to add that I am sure serious gardeners ,such as us who use the forum, would always proceed with care and caution especially when treating a subject with edible fruits. I, and my friend who owns the Lemon tree in question, try to be as "green" as possible but sometimes have to resort to more drastic measures. David added that the success of treatment with Methylated spirits has not been proven but the fact that three replies recommended it seems to be good proof to me that in fact it does work. 
How do other members feel about this and the whole question of what we can use to eradicate unwanted pests in our gardens? ???

This is such a big issue that it really deserves an entirely separate question.
So if you have views on the general question of how green we should be, to use or not to use pesticides etc, do click here (http://www.mgsforum.org/smf/index.php?topic=582.0)!