9 homemade remedies for box caterpillar treatment
The box tree moth is a real nuisance. We have summarised the best and most effective household remedies to eliminate the box tree moth plague.
The box tree moth (Cydalima perspectalis) is a nemesis of many hobby gardeners. The invasive pest can pose a life-endangering threat to young and vulnerable box trees (Buxus). There are a number of approved chemical sprays, which work well, and therefore many garden owners assume that the application of pesticides is the only option, especially in extremely dire situations. However, it is possible to get rid of the box tree moth with ordinary household items. Before you consider choosing pesticides, take a look at our list of 9 homemade remedies and tips on how to use them.
Homemade remedies against the box tree moth
The moth and its caterpillars can be collected manually, fought with vinegar and oil, rinsed away with water or killed by heat. Pruning the boxwood can also help. The use of nets can prevent the laying of eggs and promoting wildlife (such as birds or wasps) in the garden keeps the overall population of the pest at a low level. However, we do not recommend the use of algae lime. You can find out more about the various household remedies and their effectiveness below.
1. Collecting box tree moths by hand
The simplest and the cheapest method is to pick the box tree caterpillars from the shrub by hand. However, this method is only effective if the situation is not severe. Regular inspection, recognising the moth infestation in time and removing the inner webs early can save you from the worst. You can find everything about how to recognise the box tree moth here. Since the caterpillars of the box tree moth are not poisonous, you can simply collect them by hand. If this is unpleasant, you can put on garden gloves and wash your hands thoroughly afterwards. How you can then dispose of the collected caterpillars of the box tree moth is explained in this article.
- Helps with low to moderate infestation
- Regular monitoring and early detection are very important
2. Pruning buxus to combat the box tree moth
The mainly nocturnal moths of the box tree moth lay their eggs in the outer areas of the box tree. If you observe the time of flight of the adult moths with box tree moth traps, you will therefore be able to determine the mating and egg deposition and you can remove many of the eggs and young caterpillars by cutting your shrubs before they nest in the centre of the tree. The pruning should be carried out no later than two weeks after the observation of the first moth. The waste can simply be disposed in the waste bin or biodegradable waste bin, because the early larval stages can no longer continue their development without their forage plant.
- Helps against freshly laid eggs and young larvae
- Observation of moth flight with traps is necessary
- Pruning must take place 2 weeks after the adult moths are first observed at the latest
- Dispose of the young caterpillars by putting them into biodegradable waste bin
3. Treating the box tree moth with vinegar and oil
The following application worked well for many of the affected box hedges: mix ½ litres of water, 4 tablespoons of wine vinegar and 3 tablespoons of rapeseed oil to make an emulsion. A drop of washing-up liquid can help the ingredients mix better. Spray the box tree with the mixture on the inside and on the outside of the tree until it is completely wet. You should shake the liquid in-between so that it does not segregate. After 10 to 30 minutes, the caterpillars are either dead or drop to the ground. Caterpillars in webs do not sustain any damage after just one application. If the treatment is repeated twice a week during the infestation, all caterpillars will be reached sooner or later. After one hour you should rinse the shrub again with a hard jet of water to remove dead and living caterpillars and wash the emulsion off the leaves. During application, it is recommended to cover the ground to prevent the mixture from getting into the soil.
- Helps against caterpillars outside the webbing, not against caterpillars in webs or pupae
- Mix ½ litre of water with 4 tbsp wine vinegar, 3 tbsp rapeseed oil and a drop of dish soap to create an emulsion
- Cover the ground under the box tree as much as possible
- Spray the box tree dripping wet twice a week, rinse with a hard jet of water after one hour
4. Washing the box caterpillars away with water
A proven home remedy against the box tree moth is to subject it to a nice cold shower with a strong jet of water. A high-pressure hose will wash away the pests from the tree. The plant remains almost completely undamaged. You can lay out a tarpaulin under the box before using the high pressure jet. This catches the box hedge caterpillars and makes it easier to dispose of them. This household remedy is especially helpful when a larger infestation is to be decimated. Thoroughly wash out the inner part of the shrub as well.
- Helps to reduce heavy infestations
- Rinse the box tree from inside and outside during infestation with a hard jet of water from the garden hose
- Possibly lay out a tarpaulin to catch the washed out caterpillars and then dispose of them
5. Using garbage bags to combat box tree moths
To get rid of the annoying caterpillars, you can pull black garbage bags over your box trees. This is best done early in the morning. In the course of a sunny day, the caterpillars are literally grilled under the cover of the plastic bag and thus cannot cause any further damage. Box trees usually survive the heat well. Nevertheless, this method can of course be used for a limited amount of time, as the box tree depends on sunlight. Covering the tree once a week should bring noticeable results.
- Brings results if done regularly and works only if only a couple of plants are afflicted
- Pull a garbage bag over your box tree once a week from morning to night; the heat kills the caterpillars on the box tree
- Box trees usually survive the high temperatures without any problems
6. Using fabric nets to combat box tree moths
You can use fine-meshed fabric nets to prevent the box tree moth from laying its eggs on your boxwood. These nets must completely wrap the bush whenever the box tree moths fly. Predicting the moth flight is difficult and if you have already detected some of the adult moths using pheromone traps, it is likely that many animals had already laid their eggs. For this reason, covering your box trees from April to September would be the safest – but the aesthetics of course suffer greatly.
- Can completely prevent the infestation if the timing is precise
- Not an option if you want to keep your boxwood visible
7. Treating box tree moths with algae lime
In various publications, it is stated that algae lime is a potent remedy against the infestation of the box tree moth and is also effective in treating the boxwood blight, which is a fungal disease. However, we strongly advise against treating your box trees with algae lime. In no scientific experiment has it been possible to prove the described effects. In fact, many experts warn about the negative impact of algae lime on the shrubs. The shrub can survive one or two years of the algae lime method, but a more prolonged application will impact the plant’s resilience. More information about the effects of using algae lime can be found here. If the right amount is used, algae lime is of course a wonderful fertiliser for box trees.
- There is no definite proof that algae lime helps with box tree moth infestation
- Regular use of algae lime can have negative effects that weaken the box tree
8. Eliminating box tree moths naturally with predators
This tip is not really a household remedy, but its sustainability is unbeatable. Scientists and gardeners have observed that some European native birds are slowly but surely learning to prey on the invasive and damaging caterpillars from the Far East. Some birds seem to tolerate the poison in the caterpillars and even feed them to their young. Titmice, sparrows, redstarts and starlings are reportedly among the potential helpers in the fight against the moth. Those who support the presence of beneficial organisms in their gardens can prevent any infestation from happening in the first place.
- Encouraging natural predators helps eliminate box tree moths in an environmentally friendly way
- Especially titmice, sparrows, redstarts, starlings and wasps are the natural predators of the box tree moth
9. Treating box tree moths with baking powder
Because baking powder can be used as a household remedy against both aphids and fungal diseases, its effect on box tree moths and their caterpillars was also tested. Apart from halting the feeding activity of the pests for a short time, spraying with baking powder solution did not have any effect, which is why we do not recommend this household treatment method.
- Baking powder is not an effective remedy against box moths
Summary of treating box tree moths with homemade remedies
In case of an infestation by the box tree moth, household remedies offer a gentle alternative to the chemical sprays. In order for the treatment to be successful, it is important to monitor with traps, detect the box tree moth reliably and have knowledge on how to effectively treat these pests. However, all of the household remedies mentioned above only work within narrow limits and oftentimes have considerable restrictions.
In many environmentally-conscious and professionally managed gardens, the box tree moth is successfully combated with natural spray agents. The active ingredient XenTari uses the bacterium Bacillus thuringiensis and is only toxic to the box tree moth.
If you are exhausted from the endless war against the box tree moth and are looking for alternatives for box trees, we have compiled a list of 6 perfect boxwood replacements here.