Tiny black caterpillers

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MikeHardman

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Re: Tiny black caterpillers
« Reply #15 on: June 13, 2012, 09:53:35 PM »
The plague is somewhat like a forest fire, in that it does a lot of damage but passes quickly. Some trees are better at recovering after forest fires (thicker bark, ability to shoot from below ground, etc.), and the same applies to defoliating plagues, like yours. I expect most of the trees should recover from this year's invasion. By the time new leaves appear, the caterpillars should have moved on or should be past the larval stage, so the new leaves should survive and start to rebuild the trees' reserves of starch. If the plague returns next year, however, that may be more of a problem, as the trees' reserves could get depleted.

Caterpillar plagues can also be a problem to local ecosystems (as well as to the trees themselves), in that the literally hundreds of other species that feed on oak (eg.) will be in trouble; and the birds that feed their young on those species.

But such plagues can also be self-limiting. Once the resources are used-up or disease takes hold, the exploding population crashes, and the area becomes repopulated from adjacent areas. Regaining the previous balance can take a while, however, as some pioneers can be better exploiters than others; they can dominate the race to grab the old niches. While the old order is re-establishing itself, temporary niches and opportunities occur. For instance, light reaching the forest floor in summer may permit some species of plant which normally flower at different times, to flower at the same time thereby allowing some hybrids to arise. Patient understorey trees like holly and yew get a chance to put on an extra spurt of growth (normally deciduous trees around them grow, mature and die while they slowly make headway using the lower total annual light budget arising from the deciduous canopy above them). Speckled wood butterflies will wander the sunny temporary glades and may reach newly colonizable sites. Holly blues may take advantage of the fresh holly growth. Thistles may fill what would normally have been a dim forest floor, providing a temporary feast for fritillaries (which may lay their eggs on or near burgeoning violets). And so on.

On a wider scale in time and in space, plagues are part of the normal functioning of the ecosystem. It can be hard to believe that when you're in the middle of it, I know.
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

Umbrian

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Re: Tiny black caterpillers
« Reply #16 on: June 14, 2012, 07:24:54 AM »
Mike, thank you so much for your comprehensive reply to my last posting. It is good to hear that the trees should recover and interesting to note your comments about other things taking advantage of the change in conditions - I have noticed that when areas around us are cleared of trees (wood is a "crop" here as many Italians in country areas rely on wood burning stoves in the winter) then there is a proliferation of wild flowers. Primroses spring to mind, carpeting the ground in spring between the felled trees.
It was interesting to see yesterday, when I was out in the car, that hundred of the caterpillers were "migrating" across the road in one area obviously in search of pastures new. I shall continue to try to eliminate them from my most treasured trees and shrubs - I have noticed that there are far fewer on the specimins I give a two or three daily inspection and cleanse. Off I go......
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

Umbrian

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Re: Tiny black caterpillers
« Reply #17 on: June 30, 2012, 07:05:04 AM »
I am delighted to report that some of the trees, that only a short while ago were completely stripped of their leaves, have started to reclothe themselves with beautiful fresh young foliage so that streches of countryside that had a winter look now appear quite springlike. My posting about the complete defoliation was on June 13th and so this is quite amazing especially considering that we are experiencing much higher temperatures than are normal for June (top30'sC-low 40's) I suppose the trees are benefiting from a wetter than normal spring. Such is the resilience of nature thank goodness and I am hoping that my apple trees and other specimins that were attacked show a similair response. :)
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

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MikeHardman

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Re: Tiny black caterpillers - Gypsy Moth (Lymantria dispar)
« Reply #18 on: October 28, 2012, 09:09:20 AM »
'The Garden' (Oct12, p.16) reports Gypsy Moth caterpillars stripping leaves from a willow tree for a second year. The article suggests that the moth has been introduced to the UK.

That is true, and I would just like to mention this comment from http://ukmoths.org.uk/show.php?bf=2034:
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"Since 1995 the species has been resident in small numbers in parts of London, where it has been subject to an eradication campaign led by Defra (Department for Environment, Health and Rural Affairs) due to its potential pest status. Any suspected sightings should be reported to your local Defra office."
Not that that's anything to do with Mediterranean gardening, but some of our members do garden in the UK...
Mike
Geologist by Uni training, IT consultant, Referee for Viola for Botanical Society of the British Isles, commissioned author and photographer on Viola for RHS (Enc. of Perennials, The Garden, The Plantsman).
I garden near Polis, Cyprus, 100m alt., on marl, but have gardened mainly in S.England

Umbrian

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Re: Tiny black caterpillers
« Reply #19 on: October 29, 2012, 06:01:34 AM »
As a follow up to my posting of June 17th, I am happy to report that most of the trees in my garden that were attacked this year made good recoveries. A multi stemmed ornamental Crab, name unknown as it was ordered as malus floribundia but is certainly not!, that was completely de-foliated looked as good as ever this autumn having re-leafed and retained its prolific crop of beautiful red fruits. The tree that suffered the most was my Quince, new leaves were produced but much smaller than normal and the fruit suffered too - those being smaller too and many mishaped. Obviously the de-foliating and re-foliating takes its toll on the energy of the affected trees and so I am hoping we do not get another plague next year.
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.