What is shoot injection? When does it make sense? How is it done?

Many pests overwinter on fruit trees. Including aphids and scale insects, spider mites and various types of curlers. As soon as the weather gets warmer in spring, they wake up from their hibernation and get to work. Then they can hardly be stopped. Can shoot spraying kill these pests before they cause great damage? If so, when and how does it have to be done in order to be really effective?

Which pests overwinter on the wood?

Many species of insects and harmful mites overwinter on the wood. However, these are not fully grown specimens, but their eggs or Larvae. These include the following pests:

• Aphids
• Blood lice
• Scale insects
• Sitcal lice
• Spider mites
• Frost wrench
• Spider moths
• different types of wrappers

Many sprays promise effective control of these pests through early shoot spraying.

What is a shoot injection?

Many pests usually lay their eggs directly on fruit and ornamental trees, which they use as a source of food in the warm season. Sometimes also on other, neighboring trees. The eggs resp. Larvae overwinter on branches and twigs. In the following year they strike again as soon as the temperatures get warmer and budding begins. The shoot spray is spraying the trees with the aim of killing the wintering pests with a suitable spray while they are still in hibernation. Since this spraying coincides closely with the shoots of trees and bushes, it is called shoot spraying.

How does the spray work?

In the past, the spraying agents used for spraying were highly toxic. Many oil-based preparations are now available in stores. This is mostly a mineral oil or the vegetable rapeseed oil. An emulsifier is also added so that the oil dissolves in the water. The spray has the same effect on pests, regardless of the stage of development. When the pests are about to hatch, the eggs are particularly permeable. The oil from the spray forms a film over the eggs and kills them. Caterpillars that overwinter in the cocoon or that have already hatched suffocate from the oil, as it clogs their respiratory organs. This also applies to adult sitka lice that are already active in winter.

Where are the limits of effectiveness?

The spray can have a preventive effect against insects and mites. Unfortunately, however, these are not the only danger to the trees. Diseases that are caused by fungal pathogens can thus be combated or prevented. Powdery mildew, monilla and star soot remain completely unaffected by a shoot spray and can spread unhindered. Other control methods must be used here.

Is the spray also harmful?

Pesticides are used specifically against certain pests. But their destructive effect is not limited to that. Because in addition to the pests, many so-called beneficial insects overwinter on the fruit trees. Under the protective bark are the helpful predatory mites, ear peas and various parasitic wasps. They are also captured by the spray. The already hatched and early active ladybirds and lacewings also suffer from shoot spraying. Likewise, there are still some species that live on the trees that are neither harmful nor useful.
Tip: Because of these disadvantages, spraying should only be considered if a lot of pests are to be expected in the new gardening year. For example, because there was already a pest plague the previous year. Then it can be assumed that there are many eggs and larvae on the trees.

When does the expulsion injection have to take place?

The right time for the spraying is crucial so that it can develop its full effect. On the one hand, the pests must be destroyed and, on the other hand, the budding must not suffer as a result.

• The shoots are sprayed from March to April
• the time frame for this is around 14 days
• as soon as the buds swell
• depending on the weather
• no night frosts should be expected
• dry during the day, with temperatures around 14 degrees
• do not spray on and before rainy days

Note: If the first leaf tips are already visible, spraying must not be carried out any more. The oil contained in the spray damages the wax layer of the young leaves. However, this layer is important because it has a protective function.

Clearly determine the risk of pests

The spray injection is associated with costs and effort. Furthermore, it also has disadvantages, such as the destruction of beneficial insects. Therefore, before using this control method, it should be clarified whether there are any overwintering pests on the trees and bushes.

• Take a close look at the trees
• search protected hiding places
• Cracks, bud scales, wounds, etc. ä.
• Aphid eggs are oval, about 0.4 mm long and shiny black
• Spider mite eggs are brick-red, spherical, 0.1 mm in diameter
• orange-red, barrel-shaped eggs with approx. 0.7 mm length are from frost tensioners

Here, too, it should be noted that the shoot spraying only makes sense if a large infestation is likely. Used simply as a preventive measure, it can do more harm than good.
Tip: If the number of trees is small, many pests can later be "sprayed" from the trees with a hard water jet. This is a useful and environmentally friendly method for a small home garden.

Instructions for spraying

If you have found eggs of pests on your trees and bushes that can be successfully combated with shoot spraying, proceed as follows:

1. Obtain a suitable oil-based pesticide from your specialist retailer.

2. Check the trees regularly to determine the optimal time for the shoots to be sprayed.

3. First, remove any loose pieces of bark with a brush.

4. Prepare the spray mix. It is essential to observe the dosage information and the manufacturer's safety instructions.

5. Spray one after the other all trees and bushes on which you have previously discovered clear indications of relevant pests. In no case do not spray all plants indiscriminately.

6. Spray the trunk, branches, and twigs thoroughly and on all sides until they are dripping wet.

Tip: Work slowly, particularly thoroughly and do not leave out any parts of the plant. This is the only way to achieve the desired success with the spray. Spraying is particularly easy with a backpack sprayer.