31 August 2021

Customer Question – Controlling Box Tree Caterpillars

Q. “I live in Havant Hampshire, i had 36ft of box which has been devastated by the box moth caterpillar, several box hedges have also had the same fate around the area of Havant.” From Mandy by email.

A. Thanks for the message and it doe seem to be a particularly bad year for box tree caterpillar and we are getting lots of enquiries at the moment. These caterpillars feeds on box plants causing severe defoliation and produce large amounts of webbing. As the caterpillars feed, areas of dieback may appear, which will be especially apparent on trimmed plants. Box Tree Caterpillars are greenish-yellow with black heads and once fully grown the caterpillars reach up to 4cm in length and will have a thick black and thin white stripes along its body. In the spring, the moths appear and there can be up to 3 generations of caterpillars a year. Box Tree Caterpillars over-winter as caterpillars rather than as moths, so it is essential to kill as many of the caterpillars as possible before the temperatures drop in the autumn. The caterpillars over-winter, hidden between leaves that have been spun together with silk and will then emerge next spring as moths to reproduce and produce the next generation of caterpillars.

To make sure your box plants / trees are free from Box Tree Caterpillars before the winter, we do both nematodes and Rock Dust for controlling the caterpillars and then we have a unique Moth Trap with a season long lure. :-

Box Tree Nematodes – To control Box Tree Caterpillar spray with Nemasys Fruit and Vegetable Protection Nematodes. To protect your box plants / trees from Box Tree Caterpillars, spray with Nemasys® Fruit and Vegetable Protection Nematodes when the caterpillars are spotted. We supply 3 packs, which are applied 3 times at 7 day intervals. Nemasys® F&V works at temperatures above 12°C/40°F, so apply during the growing season i.e. between March and October. Nemasys® F&V TRIPLE Pack – 3 Packs sent together for controlling caterpillars. Nemasys® F&V is a living, perishable product (it will keep for 2 weeks in the fridge), so order when you are ready to apply and the caterpillars are present. Each pack treats 60 sqm.
As featured in the European Box Tree Societies Magazine – Use V olcanic Rock Dust to control Box Tree Caterpillars. Rock dust is used commonly to improve soil fertility, but now it has been discovered that dusting you box plants with rock dust when caterpillars are discovered and then twice a year in April and July not only controls the caterpillars, but helps the plants to recover after they have been attacked. Application is simple. Shake the dust all over the plant either by hand or with a sieve (wear a mask) making sure the leaves are covered (on all sides and within the plants). This will initially give the plants a grey dusty appearance, but this will go once it rains, but the effects will stay giving long-term control. Apply a few handfuls per sqm, so a 10kg bag should treat approx 20 sqm of box plants / hedges.
Use the Box Tree Moth Trap to protect your box plants if you know there are moths in the area or position to monitor moth activity in your area. Each trap is supplied with our unique SEASON LONG pheromone lure – the Ginko Buxus lure we include will attract moths for around 240 days unlike our competitors lures, which only last for approx 6 weeks, so it works out much better value for money in the long run PLUS you do not have to remember to change lures every 6 weeks! The lure is added to the top of the trap and secured with the tie included. The trap is designed to be re-usable, so a replacement lure can be purchased the following season and the trap re-used. Each Box Tree Moth Trap comes complete with 1 seasons worth of lure.