Hazelnut Shoot Moth (Gypsonoma dealbana): Symptoms and Spray Timing

What Is the Hazelnut Shoot Moth?

The hazelnut shoot moth (Gypsonoma dealbana) is a small brown moth 5-7 mm long. Its forewings are milky brown with white lines and a broad yellow-brown band across the middle. The damage is not done by the moth but by its cream-coloured larva, which reaches 7-8 mm when mature.

The most troublesome feature of this pest is its efficiency: a single larva can damage 4-5 shoots. Even a modest number of larvae produces visible shoot loss across the orchard.

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Directly Linked to the Big Bud Mite

Shoot moth larvae overwinter at the base of hazelnut buds, in the catkins, and inside the galls formed by the hazelnut big bud mite. In other words, if you have a big bud mite problem, you are also providing ready-made shelter for the shoot moth. Collecting galls in winter hits both pests at once.

Damage Symptoms

The damage appears in two separate periods of the year, in two different forms. To diagnose it you need to know which one you are looking at.

Spring: Dying Shoots

The larva begins feeding in March and tunnels into buds and shoots. With the conducting tissue cut, the shoot dries out. Because one larva moves through 4-5 shoots in turn, the damage multiplies quickly.

Summer: Triangular Patches on the Leaf

This is the shoot moth’s signature symptom and it is not confused with any other hazelnut pest:

Brown patches made of webbing and feeding debris, inside the triangle formed by the midrib and the side veins of the leaf.

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The Count Is Made From These Patches

At the end of summer, turn the leaves over and look at the triangles formed by the veins. Brown patches mixed with fine webbing are shoot moth feeding marks, and the threshold count is made directly from them.

Life Cycle

The shoot moth has one generation per year.

Stage	Month	What happens
Overwintering	November – February	Larvae overwinter at bud bases, in catkins and in big bud mite galls
Waking	March	The larvae start feeding
Shoot damage	March – May	Tunnels in buds and shoots; shoots dry out, one larva moving through 4-5 of them
Leaf phase	Summer	Webbing and brown feeding patches inside the vein triangle
Control window	End of harvest – end of September	Larvae are on the leaves, not yet moved to their overwintering sites
Migration	End of September	Larvae withdraw into catkins and galls — the window closes

Economic Threshold

If at least 15 feeding marks are found per 100 leaves, spraying is warranted.

Make the count after harvest, once the triangular patches on the leaves have become clearly visible.

Control Methods

1. Cultural Measures

Winter gall collection: the galls formed by the big bud mite are also the shoot moth’s overwintering shelter. Collecting and burning galls in the leafless period reduces both pests
Removing dying shoots: pruning out the shoots that die in spring lowers the larval population in the orchard

2. Chemical Control

Timing here runs opposite to every other hazelnut pest: control is carried out after harvest.

Start: at the end of harvest, once the triangular feeding marks on the leaves are clearly defined
Finish: spraying must be completed by the start of leaf fall, i.e. the end of September
Why that date matters: at the end of September the larvae migrate into the catkins and galls. Once inside, they cannot be reached and the season is lost

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Do Not Skip the Post-Harvest Spray

In hazelnut, “spraying” is associated with spring, and the orchard is usually closed up once harvest ends. The shoot moth’s only control window falls exactly in that period. This is why the Giresun Provincial Directorate announces the shoot moth together with the brown marmorated stink bug for the post-harvest period — both can be targeted in the same September application.

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Always Consult Before Choosing a Product or Dose

No trade name or dosage is given on this page, deliberately. Registered preparations and their dosages vary by region, pest and year. Do not apply any pesticide without consulting your provincial/district directorate of agriculture and forestry or an agricultural engineer. Always notify local beekeepers before spraying.

Frequently Asked Questions

When should the spray be applied? After harvest, starting once the triangular feeding marks on the leaves are clearly defined, and completed by the end of September. After that the larvae migrate into the galls and catkins and the spray has no effect.

Are the brown patches on my leaves the shoot moth or a disease? Look at where the patch sits. The shoot moth’s patch lies inside the triangle formed by the midrib and the side veins and contains fine webbing. Leaf spot diseases spread without regard to vein boundaries and contain no webbing.

My shoots have dried out — is this the shoot moth? It may be, but several hazelnut pests kill shoots. With the shoot moth the dieback happens in spring and there is a tunnel in the bud or shoot. If the tip of the shoot dries and stays hanging on the branch, consider the longhorn beetle; if there are 2 mm holes in the branch with sap seeping out, consider the shot-hole borer.

Can I combine it with the brown stink bug spray? In the September application, yes — provincial directorates announce both pests together for the post-harvest period. Make the product choice with an agricultural engineer.

This guide is based on data from the Hazelnut Research Institute of the Turkish Ministry of Agriculture and Forestry and on control announcements issued by provincial directorates of agriculture. Always make spraying decisions in consultation with an agricultural engineer.