Pest - Gypsy Moth

Pest - Gypsy Moth

The Gypsy Moth (Latin: Lymantria dispar) - is a nightmare/moth. It is of Eurasian origin, now distributed across all regions of the world. As a moth it is harmless, however its caterpillars are a destructive force for fruit tree growers. They parasitize more than 300 species of fruit trees. They most commonly seek out: apple trees, birches, poplars, roses, oaks, beeches and lindens.

How to Identify Gypsy Moth Caterpillars?

Gypsy Moth caterpillars have a dark grey color. They are covered with long, fine but prickly hairs. They grow to a length of 5-6 cm. On the top of their backs they have five pairs of dark blue spots, followed by six pairs of dark red spots.

Symptoms of Tree and Plant Infestation:

If you find small holes in freshly opened leaves, then believe that this caterpillar has been feeding on them. Small holes in leaves are left by young caterpillars. Older ones move around the tree using fine threads and leave considerably larger chewed-out holes in the leaves. The caterpillars feed at night. During the day you often won't see them, as they hide on the ground, in the shade of grass and leaves.

TIP: Thanks to this nocturnal travel for food, they can be easily caught on sticky strips that you place around the tree trunk circumference.

The Gypsy Moth is selective. If it likes your place, or if your garden is an outbreak hotspot, plant trees that the caterpillar "doesn't find tasty". These are:

• Norway maple
• ash
• black locust
• English, black and grey walnut
• holly

Remove eggs - remove yellowish egg masses from tree trunks with a knife and destroy them. They may also appear on wooden fences.

You can set a trap for the Gypsy Moth - attach a sticky band to the trunk of their favorite tree. Check it regularly, and as soon as it becomes filled with caught caterpillars, replace it.

How the Caterpillars Come into the World

During the summer months - in July and August - the whitish-grey females mate with brownish-yellow males. The females then lay eggs in large numbers on trees and other wooden objects in the garden. Females fly mainly at night. You can see the male Gypsy Moth even during the day. These night moths survive until autumn, then die. In spring, new ones hatch from the laid eggs.

The egg masses that the Gypsy Moth lays are 2.5 cm long and 1 cm wide. They have a felt-like hairy surface.

After the caterpillars feast on tree leaves in spring, they attach themselves to trees or other solid objects in your garden and pupate. After 7 to 17 days, they hatch and fly away as moths.

Pest Control

We can fight the Gypsy Moth in several ways. Either ecologically - by collecting caterpillars, or chemically using sprays and traps. Choose the appropriate method according to the extent of infestation and the age of the pests.

Collecting caterpillars is suitable when the extent of infestation is not large. Check trees in autumn and also destroy Gypsy Moth eggs. In case of heavier infestation, it is advisable to use more invasive methods. Sprays with bacteria that kill caterpillar larvae. This spray is effective when caterpillars are larger than 1 cm and the air temperature is at least 15°C. At lower temperatures, caterpillars develop lower activity and it may happen that they eat less spray, making it less effective.

A very effective method is coating the tree trunk circumference with a sticky layer to which caterpillars crawling for food will stick.

The Gypsy Moth is a very thorough pest and is capable of eating - destroying all leaves on a tree. To help the infested tree recover quickly from the attack, provide regular and generous watering. This is to prevent the weakened tree from becoming a target for even more pests. Wait until next spring with fertilising. Tree growth will temporarily stop. Do not remove the tree unless you are 100% sure it has died. Check it regularly.

Generally, regular inspection is the best prevention. This way you can also prevent infestation by other types of pests. You can set sticky traps at any sign of infestation.

Regularly collect caterpillars from infested trees. A plastic bag is suitable, in which you can kill and dispose of the caterpillars.

When collecting Gypsy Moth caterpillars, use protective equipment - gloves. Caterpillars have dense and prickly hairs that can cause allergic reactions.

Gypsy Moth caterpillars reproduce well when winter is mild. Lower winter temperatures safely allow eggs to overwinter. A warm and dry spring is then the cherry on top. Under these conditions, a large number of caterpillars survive.

A long and cold winter, on the other hand, kills a larger proportion of Gypsy Moth caterpillars. Temperatures must drop below -15°C for an extended period.

Are you a supporter of more ecological pest control than coating the trunk with a sticky layer? Then place a strip of fabric on the tree trunk, which you fold downwards. Catch the Gypsy Moth caterpillars in this created pocket. Then deal with the trapped caterpillars according to your conscience.

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Author: Hana Michalíková