The Grumpy Gardener – Its Caterpillar Hair Time




The Grumpy Gardener – February

Hints & Tips With Mike Alexander

In his regular column for French News Online, professional gardener Mike Alexander explains how the pine pest Thaumetopoea pityocampa has migrated from its more traditional home in the Mediterranean region and can now be found in many areas south of Paris.

a male Pine Processionary moth (Thaumetopoea pityocampa) credit wikipedia

A male Pine Processionary moth (Thaumetopoea pityocampa) credit wikipedia

 

Got any pine trees in your garden? Keep a sharp eye out at this time of the year then, for the processionary caterpillar. More importantly beware of its hair particularly if you’ve a dogIf you have been anywhere where there are pine trees and you are south of Paris then you may have noticed gray balls clinging to the trees that look as though they are some sort of giant spiders nest. These nests are actually the home to the pine processionary caterpillar or Thaumetopoea pityocampa. They are easily noticeable at this time of year and it is also a good time to consider getting rid of them.This caterpillar was originally found only in Mediterranean regions and in North Africa but with the milder winters of recent years their range has increased dramatically, much to the consternation of the forestry industry for whom they are a major pest. Although they will feed on cedar or larch, by far their favorite delicacy is pine. They can cause defoliation of the tree if they get established in large enough numbers and this can lead to disease but that is not the primary concern for most of us gardeners. The problem is that the caterpillar hairs can cause severe allergic reactions in humans and can be fatal if inhaled by dogs.

The young caterpillars overwinter in the silky nests that you can now see in the trees. They force their way out after dark to dine on pine needles and then return to the nests just before dawn. Nests are sighted so that they can capture the suns rays and the inside of the nest will remain at several degrees above the ambient temperature. When the caterpillars are ready to go to the next phase of their life cycle in the early spring, they descend to the ground and form their long processions, marching head to tail in search of soft soil where they can bury themselves to pupate. The bland, grey brown moths will hatch in summer to start the cycle again.

They are not the only caterpillar to form these processions in France as there is also an oak processionary caterpillar which is less of a threat.

The pine processionary is orange brown in colour but what distinguishes them most readily from other caterpillars is that when in procession they actually touch the rearmost hairs of the caterpillar in front of them.

 

Caterpillar nest in French pine tree (Credit Wikipedia)

Caterpillar nest in French pine tree (Credit Wikipedia)

It is those rear hairs that stimulate the processionary march as first recorded by the famed French entomologist Jean Henri Fabre. He conducted an experiment by joining the lead caterpillar in a procession to the rear of the line to form a circle. The creatures continued to march in a circle for over a week. Those long lines of marching caterpillars are a source of great curiosity to both small children and dogs.

Foresters have been known to spray from aircraft in an attempt to get rid of this pest. For those of us a little less keen to reach for the pesticide, and with a slightly more manageable problem than thousands of hectares of pine forest, there is another solution. Note, I did not use the word easy at any stage. The nests can be cut from the tree and then gathered up and burned.

Pine Processionary Thaumetopoea pityocampa - Habitat Zonza ( Corse-du-Sud) - France credit wikipedia

Pine Processionary Thaumetopoea pityocampa – Habitat Zonza ( Corse-du-Sud) – France credit wikipedia

 

The problem is that getting to the nest is usually difficult. I normally climb into the tree and then cut the branches holding the nest with a telescopic tree pruner.

Once in the tree it is difficult to see the nest so I normally have someone on the ground to talk me onto the right target while I wobble precariously among the branches. Do not touch the nests when they are on the ground, but gather them with a garden fork into a barrow or bucket then burn them immediately.

 

 

 

 

blue31 The Grumpy Gardener – Bordeaux Eco Renewal

triangle down21 The Grumpy Gardener – Bordeaux Eco Renewal

blue31 The Grumpy Gardener – Bordeaux Eco Renewal

Previously – click an image below
wisteria alba 1501 The Grumpy Gardener – Bordeaux Eco Renewal
honey bee 1501 The Grumpy Gardener – Bordeaux Eco Renewal
Prune for Results
A World Without Bees?
apple tree fruit 1501 The Grumpy Gardener – Bordeaux Eco Renewal
prize winning rose 01 The Grumpy Gardener – Bordeaux Eco Renewal
Fruit Tree Pruning
Wars of the Roses
forsythia 1501 The Grumpy Gardener – Bordeaux Eco Renewal
cistus salvifolius 1501 The Grumpy Gardener – Bordeaux Eco Renewal
Prune When Finished
Herald of Spring…
cherries tree 01 The Grumpy Gardener – Bordeaux Eco Renewal
Lavandula angustifolia 01 The Grumpy Gardener – Bordeaux Eco Renewal
You’ve got to be quick!
Un-thirsty Lavender
nettles 01 The Grumpy Gardener – Bordeaux Eco Renewal
Star jasmine 01 The Grumpy Gardener – Bordeaux Eco Renewal
Grasp the Nettle
Star Jasmine – Madrid
Stachys byzantina 01 The Grumpy Gardener – Bordeaux Eco Renewal
Autumn arrives 01 The Grumpy Gardener – Bordeaux Eco Renewal
Jihad – on Bunnies Ears
Autumn Arrives
wellies 01 The Grumpy Gardener – Bordeaux Eco Renewal
Newton gravity 01 The Grumpy Gardener – Bordeaux Eco Renewal
Designer Chic?
Gravity – not to be ignored!
snowdrops 01 The Grumpy Gardener – Bordeaux Eco Renewal
habenero 01 The Grumpy Gardener – Bordeaux Eco Renewal
If Winter Comes….
Hottest chilli in the world
daffodils 01 The Grumpy Gardener – Bordeaux Eco Renewal
irises 01 The Grumpy Gardener – Bordeaux Eco Renewal
Dog Days…
Fleur de Lys
marqueyssac hedges 01 The Grumpy Gardener – Bordeaux Eco Renewal
To read a previous article
– click an image –
Hedge Your Bets
www.french-news-online.com

blue111 The Grumpy Gardener – Bordeaux Eco Renewal

Grumpy Gardener

Our Grumpy Gardener has been gardening professionally in France for more years than he cares to remember and before that in Africa and the UK. Today he happily shares his expertise with French News Online readers. Your gardening questions are welcome and while they may not be individually answered, they may form the basis of future monthly columns.

Writer: Mike Alexander
mike@mikealexander.fr
Follow Mike on Twitter 

Related articles

 

 



Related Posts Plugin for WordPress, Blogger...

If you enjoyed this post, make sure you subscribe to our RSS feed!