Privet leaf miner damage

Following the winter’s damage, I’ve been keeping an eye out to make sure the privet bushes recover OK. By and large, they are doing just that. However, I’d say some are a little weaker than would be usual, but it’s hard to tell. One thing I have noticed though is a surge in the amount of leaf miner damage.

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Damage on a privet leaf caused by leaf mining caterpillars (Gracillaria syringella)

The damage first shows as brownish marks on the leaves. They quickly expand to become a large brown blister. By this stage the blisters are easy to pull open and inside there are little tribes of larvae living a sheltered life between the upper and lower leaf surfaces.

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Inside the blister there are little tiny caterpillars – they’re quite hard to see and to photograph because as soon as their blister is burst they try and wriggle away to hide

These larvae will grow up to become tiny little micro moths – Gracillaria syringella. As the name suggests, they also mine lilac (Syringa) leaves and are known as lilac leaf miners as well as privet leaf miners. There are plenty of them on the lilac bushes this year too.

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Leaf miner damage on a lilac leaf
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…and here are the larvae inside the lilac leaf’s blister

 

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Winter damage: privet

The first two weeks of March were very mild here, spurring some plants on to make early growth. Fresh growth on privet (Ligustrum ovalifolium) was particularly noticeable. But then, the third week of March brought a week of frosts and freezing winds.

It was at the beginning of April that I started to notice wilt and blackening on privets. My first thought was that it must be cold damage.

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Wilt and discolouration of new growth on privet, April 2017

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But then I wondered whether it might be something worse. It seemed the more I looked, the more I found wilting shoots of privet. I found them on all ages of bushes – from last year’s cuttings to gnarly old hedge plants – and on plain and variegated plants. I found them at the bottom of bushes and at the top; on plants that were pot grown, and plants in the ground. You can see in the pictures that one shoot would be wilted whilst its neighbour seems to continue in rude health.

In the end, it is the fact that the problem is so widely spread, especially that it is in pot grown cuttings as well as plants in the ground, that makes me think it must be cold damage.

For now, until I am sure that winter has finally gone away, I am leaving the dead shoots on the plants and will trim them over when better weather finally arrives.