Sounds a bit like a sci-fi challenge doesn’t it? But have you seen leaves on your plants bound together with silky threads? Then you might well be hosting the tortrix moth caterpillar!
Affecting a range of plants, and active outside from April to September and in the greenhouse all year, these caterpillars feed inside the ‘cocoons’ they make, causing damage to foliage, fruit and flowers.
What are they?
They belong to a family called tortrix moths, and the small green caterpillars you’ll see are the larval stage. Luckily there are just two species (of almost 400 found in the UK!) which feed on a wide range of plants, causing problems in the greenhouse and the garden – the carnation tortrix moth and the light brown apple moth.
What plants will they choose?
The bad news is that they’re not fussy – they love edible and ornamental plants, so you could find them almost anywhere.
What are the symptoms?
The main indications of a problem are plant leaves bound together with silky threads, in which the caterpillars feed. This causes damaged areas which dry up and turn brown, and flowers and fruit can also be affected.
Control & Prevention
There are a few non-chemical ways of controlling these pests:
- By simply squeezing the bound leaves to crush the caterpillars and pupae concealed inside, most effective for light infestations.
- By releasing a nematode biological control – Steinernema carpocapsae.
- By using a pheromone trap – using an open-sided cardboard box with a sticky sheet in the base. Simply place a pellet onto the sheet which releases a pheromone imitating the chemical produced by female moths. These are most effective in a confined space, such as a greenhouse, where the trap may catch enough males to reduce mating success.
- If the caterpillars have a real hold then chemical sprays such as Provado Ultimate Bug Killer should be applied to areas showing damage. As with all chemical sprays, you should avoid spraying plants in flower, especially fruit trees, to avoid harm to bees and other pollinators – and also be sure to read the label regarding the use of pesticides on edible plants.
If you need help with a pest, disease or plant issue then pop in-store and ask our friendly, expert staff for advice – and be the victor in your ‘pest war’!