Fight sawflies, Tenthredinidae properly

The inconspicuous sawflies bear little resemblance to the well-known wasp. The sawfly itself isn't the biggest threat, it's the small but voracious larvae that can cause major damage to shrubs and trees. When collecting, look for caterpillars that are red, yellow, or green in color. In individual cases, they also appear multicolored. They can be found on the undersides of leaves. In addition to roses, geraniums and vegetable plants are also at risk.

From generation to generation

The sawfly, also known as Tenthredinidae, usually reproduces in two generations. In regions that experience cold winters, only one generation is usually formed. During the winter the cocoon remains with a length of approx. 8 mm in the ground. The first generation hatches after the first winter, while the second generation does not hatch until the second or third year. During this time, the young remain in the ground until they finally fly off. Therefore, when digging up, watch out for larvae and caterpillars, which can be easily disposed of.

With good observation through the garden

Trees and shrubs are popular habitats. It is also often found on barberries. This is where the sawfly lays its eggs, which are later easily found on the leaf stalks. The larvae that develop here are around 10mm long and could be mistaken for slugs. The pitting they leave behind clearly indicates a sawfly infestation. If collecting the eggs and larvae is not enough, ground neem seeds, which are buried in the soil, will help be incorporated or a tincture of neem leaves, with which the leaves are also sprayed can become. This natural measure does not attack the plants.

Egg laying time

June and August are the main flight times for sawflies. Now she is laying her eggs. Each individual female animal lays approx. 100 eggs measuring only 1.3mm at the edges of serrated leaves. There is space for almost 20 eggs per leaf. The larvae take about two weeks to hatch. The now named after caterpillar eats ravenously from the edge to the middle of the leaf. Isolated larvae that do not live in the group wither and die. In the weeks that follow, four male and five female larvae develop. As soon as they feel unsafe or in danger, they assume a very typical S-shaped startle position. Each individual larva can cover an area of ​​approx. Eat 20 cm² of the leaves. If the infestation is high, this can be very damaging to the plants. Therefore, collecting and checking regularly is important to protect the plant. If parts of a tree are severely infested, a planned pruning of the affected parts of the branch can help to effectively remove the sawfly larvae.

Prevent greater damage to the larvae

Since the larvae nested in the ground during the winter, they look for suitable plants in the spring. Nevertheless, the young animals can remain in the ground for longer than two years. The annual check must therefore be carried out annually in order to find newly hatched animals. Eaten leaves always indicate a sawfly infestation. Accordingly, you must react quickly and remove the larvae. Popular flower shrubs such as roses are often attacked by sawflies. Before the damage caused by leaf damage becomes too great, regular measures are necessary. During a walk through the garden you can always examine the leaves and discarded eggs or eggs. collect larvae. On the one hand you prevent more leaves from being eaten, on the other hand you prevent the sawfly from conquering a new habitat here in your garden. Subsequent generations are also quickly prevented when collecting. Knowledge of the different types of sawflies is also important for the garden enthusiast. Here are the well over 1000 species in Europe:

• small linden sawfly,
• the swede sawfly,
• the mountain sawfly and also
• to name the figwort sawfly.

A short walk to the neighboring species of sawflies shows other habitats. The small linden sawfly prefers deciduous trees. According to their name, they can be found on linden trees, but clearly prefer the robust oaks in our regions.

Control the larvae without insecticides

The use of insecticides is usually only necessary in forestry. Depending on the number of larvae per cm², the probable infestation is calculated here. The number of remaining young animals in the soil is correspondingly high or low. In such extreme cases, insecticides are used to prevent defoliation and major damage to the tree. In a private garden without a large stock of deciduous trees, such measures are usually not necessary. Very good results can be achieved with the collection or the neem oil and water tincture.

Worth knowing about the sawfly shortly

Some sawfly species are fearsome plant pests. Female sawflies lay their eggs on leaves or the underside of leaves. From this, the larvae (after caterpillars) develop, which gnaw off the epidermis of the leaf so that only the middle layer of skin of the leaves remains. They can be recognized by a slimy secretion reminiscent of snails. In the last very voracious larval stages, caterpillars of the second generation of sawflies eat entire plants bare down to the skeleton within a few days. The fight has to be done in a timely manner.

Control of sawflies

• It is best to collect the caterpillars from indoor plants.
• Deciduous trees generally recover well from the hungry wasp caterpillars.
• Chemicals similar to those used to control caterpillars should be used in vegetables if the infestation is severe.
• When using insecticides, care must be taken to ensure that only the desired effect is achieved. Beneficial creatures should be spared.
• Sawflies are controlled by destroying the larvae. It is important to check the plant population in the spring for an infestation.
• Chemicals come in a variety of forms, spray and powder. Due to the oil content, the larvae and ice stages are also well combated.
• In order to avoid damage to people and the environment, you should always study the instructions for use carefully and follow them.

control and prevention

• Roses and geraniums are particularly popular in the garden. The plants should therefore be checked regularly so that an infestation is detected early before major damage occurs.
• Sawfly populations are monitored in forestry operations. If the insects appear in masses, entire forests are threatened with defoliation. Not too many new sawflies should swarm out in May and June.
• If you expect large swarms, something must be done about it. It is relatively difficult to predict how many juveniles can hatch from the soil where the juveniles can lie up to six years. The proportion of nymphs ready to hatch is important. To do this, larvae must be collected and examined. So you take an area of ​​0.25 square meters and collect all the larvae. The results are then extrapolated to the square meter of the forest. If the expected number of sawflies is too high, chemical agents are used.

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