Apple sawfly – appearance and control

The apple sawfly, despite its small stature, is a huge threat to fruit trees. Its destructive impact causes leaves to fall prematurely, which weakens the plants and reduces yields. We present what the life cycle of the sawfly looks like, what its habits are, what damage it can cause and how to effectively fight it.

How to recognise the apple codling moth

Recognising this pest at different stages of its development allows for effective control measures to be taken. The larvae of the apple codling moth have a characteristic appearance – they are yellowish with small black heads and up to 20 mm long. In the adult stage, they are small butterflies with a wingspan of about 20-25 mm, with white wings covered with black dots, which is one of the most characteristic features enabling their identification. Adult specimens usually appear in the summer, when the eggs they lay attach themselves to branches and develop into new larvae.

It is also important to notice the symptoms of their presence on the trees. The larvae feed on the leaves, creating so-called ‘tents’, clusters of threads in which they live and destroy the plants by biting. As the population grows, these clusters can cover entire branches, resulting in defoliation of trees and significant crop losses. Correct identification of the tent caterpillar helps to quickly implement control measures and prevent more serious damage to orchards and protect trees from the adverse effects of this pest. By recognising the distinctive appearance of the tent caterpillar, both larvae and adults, its harmful effects can be effectively counteracted.

Life cycle and behaviour of the codling moth

The life cycle of the apple codling moth is complex and involves several stages of development that affect its habits and impact on fruit trees. The process begins when the adults, which are small butterflies with distinctive white wings covered with black dots, lay their eggs on tree branches. The eggs hatch into larvae, which quickly start feeding on leaves, forming clusters of silk called ‘tents’. They then transform into pupae, which finally metamorphose into adult butterflies. Each stage of the tent caterpillar’s life contributes to its harmful effect on plants.

For effective tree protection, it is worth keeping a few things in mind:

• Even the larvae, which feed on leaves, can damage trees.
• Keeping orchards clean helps to reduce the population of adult individuals that lay eggs in nature.
• Timely control of tent caterpillars in the larval and pupal stages will prevent them from multiplying further.

Understanding the life cycle of the tent caterpillar and its habits enables the implementation of effective preventive measures and the maintenance of healthy fruit trees.

Damage caused by the apple tree tent caterpillar

The damage caused to fruit trees by the apple sawfly is extremely serious and mainly affects the leaves. The sawfly creates characteristic ‘tents’ from its silk, which contribute to the premature falling of leaves. This process weakens the plants, which significantly affects their ability to photosynthesise, thus reducing their lifespan and yield. Chestnut trees are particularly vulnerable to tent caterpillars because the larvae feed on the leaves, leaving the trees with reduced foliage. This not only results in defoliation, but also increases the susceptibility of the trees to other pests and diseases.

The damage caused by the apple codling moth is particularly visible during an intensive attack, when entire branches can be covered with the larvae’s web. The trees then become more susceptible to environmental stresses and may have difficulty regenerating in the following growing season. Constant tentiform weevil infestation leads to weakening of trunks and branches and limits the growth of new shoots, which is why it is crucial to monitor tentiform weevil populations on trees and take quick action to control this pest.

Methods of preventing the occurrence of codling moth

Effective prevention begins with keeping orchards clean, which reduces the number of places where adults can lay eggs. Regular pruning and removal of infected branches and monitoring of plant condition allows for early detection and reduction of the codling moth population. In addition, pheromone traps help to detect the presence of adult butterflies and to control their numbers.

Horticultural biological techniques, such as the introduction of natural enemies of the tent caterpillar, greatly support the protection of fruit trees. The use of environmentally friendly plant protection products that not only combat larvae and adults but also reduce the development of pupae is an important part of an integrated protection strategy. Proper fertilisation and tree care increase the tree’s resistance to pest stress, which, in combination with other preventive methods, creates a comprehensive protection system.

Products for controlling the apple sawfly

Effective control of the apple sawfly in gardens and orchards requires the use of appropriate insecticides. There are a variety of products available on the market to help eliminate this pest. The most commonly used products include:

• insecticide sprays, which effectively eliminate tent caterpillar larvae from leaves;
• biological preparations containing Bacillus thuringiensis bacteria, which are safe for the environment;
• mineral oils, which block the pests’ respiration, helping to control them.