Treating fruit tree moth: Zeuzera pyrina

How to identify fruit tree moth?

The fruit tree moth ( Zeuzera pyrina ), also called the "pear moth", is a pest that attacks several fruit and deciduous trees. Native to Europe, it is widespread in temperate regions, including France.

It is recognizable by:

• Size : The adult is a white butterfly with black spots on the wings, measuring about 35 to 50 mm in wingspan.
• Appearance of larvae : The larvae, which cause the main damage, are large pale yellow or pink caterpillars with black spots and can measure up to 6 cm long.
• Life cycle : Females lay their eggs on bark or in cracks in trunks and branches. The larvae then tunnel into the wood and remain inside for several months to two years.

The zeuzera attacks the branches and trunks of fruit trees, causing a general weakening of the tree and risks of branch breakage.

Presence of the zeuzère in France

The zeuzera is present in several regions of France, particularly in the orchards of the South and Center of the country. It is active mainly in spring and summer, when the adults emerge and the larvae begin to dig galleries in the trees.

Plants affected by fruit tree moth

Fruit trees

Stone fruit and pome trees are most affected, including:

• Pear trees ( Pyrus communis )
• Apple tree ( Malus domestica )
• Apricot tree ( Prunus armeniaca )
• Cherry trees ( Prunus avium )
• Plum trees ( Prunus domestica )

Other trees

• Oaks ( Quercus spp. )
• Poplars ( Populus spp. )
• Willow ( Salix spp. )

Damage caused by the fruit tree moth

Zeuzera larvae cause internal damage to the branches and trunks of trees:

Galleries in the woods

The larvae bore deep into branches and trunks, disrupting sap transport and weakening the tree. These tunnels make the branches brittle and vulnerable to breakage.

Branch dieback

Branches infested with larvae may wilt, lose their leaves and die, leading to partial decline of the tree . Internal damage may be invisible until the branch breaks.

General weakening of the tree

Severe infestations can seriously weaken the tree, reducing its fruit production and increasing the risk of secondary infections such as fungal diseases.

Treatment with Steinernema Carpocapsae nematodes against fruit tree zeuzera

Nematodes are naturally present in the soil in small quantities, they are microscopic worms invisible to the naked eye, respectful of useful insects, crops and vertebrates (human beings and domestic animals). They are safe for dogs and cats.
Steinernema Carpocapsae nematodes are microscopic worms used as a biological treatment against larvae. Their mode of action is simple but effective: once applied, the nematodes penetrate the larvae through natural channels and release symbiotic bacteria that destroy the inside of the larva, causing its death within a few days.
Nematodes do not have "legs", they move using water.

Delivery and storage of nematodes

Nemtodes can be delivered by non-refrigerated tracked letter directly to letter boxes up to 25 million.
Nematodes can survive more than 8 days at room temperature without any problem. Storing them in the fridge is just to be able to keep them longer by slowing down their development.
Nematodes should be kept cool after receipt in order to slow down their metabolism ("hibernation") so that they can be stored until the DLU date.
At room temperature, nematodes do not die but continue their development. Without food (larvae), they would eventually die naturally after about ten days.
Nematodes are supplied in the form of a more or less moist granular powder. The entire pot (or sachet) must be used in a single treatment to ensure uniform distribution and optimum effectiveness.

Available packaging of nematodes against fruit tree moth SOLU'NÉMA

Steinernema Carpocapsae nematodes against fruit tree leaf beetle are available in different packaging adapted to the surface to be treated:

Pot of 5 million nematodes for approximately 40 holes - Supplied with a 20ml syringe
Pot of 10 million nematodes for approximately 100 holes - Supplied with a 20ml syringe
Pot of 25 million nematodes for approximately 200 holes - Supplied with a 20ml syringe
Pot of 50 million nematodes for approximately 400 holes - Supplied with a 20ml syringe
PS: Pot containing a moist granular powder.

Dosage and application of nematodes

Instructions for use of nematodes against fruit tree moth

1. Identify the Problem
The zeuzera is identifiable by its long antennae and white wings with black spots. However, it is the symptoms caused by its larvae that usually alert arborists. The larvae tunnel into the trunks and branches, weakening and sometimes killing the host tree. Signs of infestation include the presence of sawdust at entry points and reduced tree growth. Weakened branches can break, especially during adverse weather conditions. Early detection is crucial to protect trees. Regular inspections can identify the warning signs of an attack and take action before the damage becomes irreversible.
Processing period: April – May and August – September
The treatment is done directly into the holes of the zeuzeras using a syringe or a sprayer.

2. Preparation of Nematode Solution
Before use, leave the nematodes at room temperature for 30 minutes. Dilute the entire sachet in a small container of clean water at room temperature, pre-diluting the nematodes before mixing them. Stir well and let the contents dilute for 5 minutes. Then pour this preparation into your sprayer and add the rest of the water (between 15°C and 25°C). Mix again.

3. Application of Nematodes
Use a sprayer or syringe (provided) to apply the nematode solution directly into the galleries dug by the zeuzera larvae. It is important to inject the nematodes as deep into the galleries as possible so that they reach the larvae.
Also water the area around the galleries before treatment to ensure that the nematodes move and enter the holes undetected.
Spray while continuing to agitate the mixture to prevent nematodes from ending up at the bottom of the sprayer.

4. Continue Humidification
Nematodes require a moist environment to move to their prey. Water your crop regularly to maintain their effectiveness.

5. Monitor Results
Nematodes work quickly to control larvae. You should see a decrease in the larvae population after a few days. If larvae persist, repeat the treatment.
It is important to follow the application instructions to achieve the best results.

Other biological treatments against fruit tree moth

Several biological methods can be used to combat the fruit tree moth :

Bacillus thuringiensis

Bacillus thuringiensis (Bt) is a naturally occurring soil bacterium that is used as a biological insecticide. It specifically targets caterpillars, causing their death after ingestion.

Pheromone traps

Pheromone traps can be used to capture adult male moths, reducing the chances of reproduction.

Chemical treatment

In case of severe infestation, chemical treatments may be necessary. Pyrethrin-based insecticides or other products registered for fruit trees can be applied to control larval populations. However, it is important to limit the use of chemicals in orchards to preserve the ecosystem.

Prevention and advice against fruit tree moth

• Regular monitoring : Inspect your trees regularly, especially during the laying period, to detect the first signs of galleries or weakened branches.
• Removal of infected branches : If a branch is infested, it is recommended to prune it and burn it to prevent the spread of larvae.
• Preventative treatment : Applying nematodes or setting pheromone traps before adults emerge can prevent infestation.