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Can anybody suggest a good website or book that illustrates a comprehensive catalogue of plant pests and diseases?

I've done a lot of web surfing, and looked through a few books, but I'm struggling to identify some cotton wool buds that are on the branches of a young willow tree. They are fluffy white blobs about 5 mm across, with a protective 'scale' that they were probably hidden under until they got too big for it. There are several dozen of them; I've opened one up and there is a mass of tiny red dots inside, presumably developing into something. But is it a good thing or bad thing?

The tree is currently awash with aphid, but I think I am getting this under control with a spray of washing up liquid, and there is an interesting colony of maybe a hundred little yellow spiders on one branch, but I don't think the aphids or spiders are related to the cotton buds.

Anybody got any ideas?

Wow there is life in that tree! I wondered at first if it was something that my dad had years ago on his apple trees, but that was not housing living things.

Found this book http://www.eco-logicbooks.com/index.cfm ... iate_id=18

It is called Pests and how to control them and is for organic gardeners. I am afraid I have not read it myself so cannot really tell yopu if it was you are look for. but it does seem to focus mainly on Fruit and vegetables so might not be much use for a willow.

Not much on the web you are right just found this http://www1.br.cc.va.us/murray/Arboricu ... ructor.htm - might help but the pics seem a bit too small and out of focus.

There is an insect called woolly something! Is it woolly aphid? Then again there is scale insect but I've seen pictures of some scale insect on the TV which is quite woolly and the scale insect I have on my oleanders is smooth.

I remember Stephan B??????? (you know who I mean - sounds like Buchatski!) talking on his plant roadshow about willows harbouring loads of insect pests; a lady had brought some branches in and he identified about 6 different things. He told her it was normal and not to worry, there was nothing really she could do and that it wouldn't kill the tree.

If it is a big tree then it's probably just not worth it, but if it is small or in a pot you could just pick them off. They are most likely sucking the sap which would be possibly harmful to a little tree.

Yep, Stew,

Sounds like wooly Aphids to me. I get 'em on the apple tree. I'm in melbourne at the moment, when I get home I can look up what to do with 'em.

Nev

Sounds like scale insects. They are sucking sap. They can be removed manually with alcohol (use a man-made cotton bud to rub it on them) or a horticultural oil like neem oil. Time consuming, but better than blasting the plant with chemicals IMHO!

Alcina

Well thanks all for your suggestions. I've Googled both woolly aphid and scale insect, and what I've got doesn't match any description or picture that I've found. I may have mislead you by saying there is a 'scale' involved - it's like the fluffy blobs are wearing a cap. I think the fluffy blobs are some sort of egg case, and are quite discrete, a bit like a Q-Tip, rather than an amorphous mass. Certainly the current aphid infestation is not of the woolly variety. I think a book from Eco-Logic may be on the shopping list.

However, all that aside, what is really interesting is the colony of spiders. Yesterday they were a tight group of maybe a hundred tiny, mustard-yellow spiders, each with a single black triangular spot on their backs, huddled together, but spinning a dense web of very fine filaments. Any disturbance would see them disperse along these threads, eventually to settle back down again in one mass of spideriness. Today, most of them have moved to a different home on another branch, but a few remain in the old nest - along with a bigger spider (10 mm) that is flourescent green. I've never seen any spiders quite like these (not that that means much), but maybe they will like to eat aphid.

The tree, incidently, is one that self seeded iteslf in my garden, probably brought in from the woods on my boots. It was in an awkward place, so I dug it up and put it in a tub. It struggled a bit for a year or two, with some of it dying back, but it seems OK now. I always think it is a shame to destroy a growing tree.

I still think they're a variety of scale insect - I used to get exactly what you describe on my apple tree. And they're still sucking your plants! :) I'd try the alcohol or oil...

The spiders you talk about are the young of I think the Common Garden Spider (the adult can be really big! - well...for British spiders!...fantastic markings they have). They would have started out as a small web of eggs, which then hatch (often you can find dried up clutches of eggs in the corner of a shed or somewhere, not sure why some hatch and some don't - probably temperature, humidity and the like). The baby spiders stay close to each other in a little ball, unless disturbed (like by dripping water on them [hehehehehe]) in which case they scatter! After a couple of weeks they clearly feel they no longer need each other's support and they go their separate ways. You'll find them, gradually getting bigger, in your garden all year :)

Alcina

It's just as well that I'm not still Margo - she wouldn't want anything that was common in her garden.

It might all be academic now, for this tree. Either the aphids, or my attempts to remedy them, has done for it; all the leaves have curled up and died and are dropping. There are about five leaves left alive on the plant.