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The apple is the German's favorite fruit. Whether on the meadow orchard or in the home garden, the apple tree delights with its blossom and its tasty and rich yield. But again and again it happens that pests threaten trees and harvest. Here you can find out how to get rid of the apple spider moth, one of the most common and annoying of the uninvited visitors.
Recognize the spider moth
Before looking at how to get rid of the apple spider moth, you should first be sure that the observations are actually due to the caterpillars of this widespread moth. Although many of the effects of an infestation are strikingly obvious, they should be mentioned here again to clarify any uncertainties:
moth
- white, elongated body about 20 mm long
- Wing span between 16 and 23 millimeters
- White, fringed upper wings with black dots
caterpillars
- Yellowish to greenish skin color with black dots
- Little to no hair
- Head capsule and legs dark to black in color
- Body length, depending on the stage of development, 18 to 25 millimeters
webs
- White webs that are reminiscent of cobwebs, but can be much firmer and denser
- Metamorphosis: Larvae cocoons condense into white, opaque tissues
damage
- Initial curling of the leaves, brown discoloration and drying out of the leaf tips (before web formation from around April)
- Small caterpillars can be seen in curled leaves
- As the size of the caterpillars increases, the branches become bare, and sometimes the leaves become skeletal
Get rid of the apple spider moth
If you have come to the conclusion that the visitors to the apple tree are actually the apple spider moth, you should take action quickly and fight the caterpillars. Otherwise it may be that the tree is eaten bare in a comparatively short time and at least this year no longer produces any yield. In addition, it can also be stunted in growth and even produce limited fruit in the following years. The hobby gardener has a number of different options at his disposal, from the chemical club to tried and tested or unusual household remedies.
Industrial control agents
If you look at the range of available insecticides, you will find an almost unmanageable number of different products. However, almost all agents that are suitable for controlling the caterpillars of the apple spider moth can be traced back to one of two chemical agents.
notice: Although many chemicals are advertised as "bee-friendly", the actual effects on the animals that are so important for pollination and thus the yield of the apple trees are often not conclusively clarified. Anyone who decides to use chemicals on a massive scale should therefore be aware that while this eliminates the pests, the yield of apples can also decrease.
Bacillus Thurigiensis spp.
- type of use: Spray in aqueous solution
- effect: Uptake by larvae via food, conversion into toxic substances during digestion, killing of the caterpillars by stopping food intake due to symptoms similar to blood poisoning
- operating time: can only be used during early larval stages, therefore mid-April to mid-May
- Effects on other organisms: attacks other insects also in the larval stage, no known effects on apple tree itself
Thiacloprid
- type of use: Spray in aqueous solution
- effect: Intake through food and skin contact, in the organism paralysis of the transmission of stimuli in the nervous system with subsequent death of the animals
- operating time: Before web formation, i.e. until mid-May at the latest
- Effects on other organisms: harmful to humans and mammals in high doses, deadly to numerous other insects on the apple tree in applicable doses, can have a disorienting effect on bees!
danger: Various insecticides containing the active ingredient thiacloprid have been banned in Germany for several years. Before buying, you should therefore make sure that the product is still approved and can also be used in your home orchard!
home remedies
A large number of home remedies are used to counteract the chemical substances from the specialist trade, which usually have far lesser effects on other useful insects and of course the tree itself, but are usually no less effective in terms of their effectiveness with regard to the apple spider moth.
Gathering of webs
Although collecting the pests from the tree initially sounds like a lot of effort with little effect, the spider moth in particular can be got rid of in this way. Because the caterpillars draw attention to themselves through the web and the cocoons. In addition, the spun-in animals are stationary and can thus be removed without the "risk of escaping".
- Action: Wipe webs off the branch with gloves, alternatively rinse with a strong jet of water or completely remove the infested branch
- Period: after web formation, i.e. from about mid-May
- benefits: No effects on beneficial insects on the tree, the tree itself or humans
- disadvantage: only possible after web formation and thus during possible defoliation
danger: The collected webs with the larvae should definitely be destroyed in order to prevent the animals from migrating after hatching. Flaming the webs with a gas burner after removing them from the tree is very practical.
glue rings
This method does not attempt to eliminate the caterpillars, but prevents them from migrating to their favorite food. A glue ring placed around the trunk prevents the caterpillars from reaching the ground along the trunk to the crown with its leaves and their possibility of web formation.
- Action: Place commercial glue rings well above grass height to avoid bypassing over blades of grass
- Period: after hatching, i.e. from mid-April
- benefits: No effects on other animals and humans
- disadvantage: prevents the larval stages from migrating, but does not fight animals from eggs already laid on the tree, so it is usually only effective in combination with other measures
pheromone traps
In contrast to most other methods, pheromone traps start before the eggs are laid, i.e. long before the caterpillar population emerges. The traps attract and trap female apple spider moths in a pheromone-infused sticky layer. This means that they are no longer available for reproduction and cannot lay eggs on the apple trees.
- Action: Hanging the traps in the branches of the trees
- Period: before oviposition between June and August
- benefits: if used effectively, no damage caused by feeding because young animals are prevented from the outset, no disadvantages for bees and other beneficial insects
- disadvantage: low effectiveness in strong windy locations, no effects on already existing caterpillars, due to the long storage time, usually to be replaced several times per season
Favoring Beneficiaries
The solution is to let others do the work, which is both effective and elegant. The language here is about the natural enemies of the apple spider moth. Since different animal species prefer different development stages of the spider moth, this approach can cover almost the entire development cycle of the pest. In addition, the beneficial insects enrich the fauna in the home kitchen garden and also have a positive effect on other plants and their possible pests.
- Ichneumon wasps and assassin bugs: feel particularly comfortable in a semi-natural garden, attack eggs and young larval stages
- songbirds: usually prefer hedges and densely growing solitary bushes for their nests, consume countless caterpillars of various sizes with their brood (example: an average pair of tits with brood requires around 10,000 larvae, beetles, moths, etc.)
- mice and hedgehogs: live in compost heaps, piles of leaves, dense hedges, etc. and recognize spider moth larvae as a welcome food supplement while migrating on the ground to the new host tree