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There are several ways to mitigate the damage of the box tree caterpillar without harming fauna and pollinators, as more people report losing their hedging to the pest.
Express reported earlier this week that the box tree moth and caterpillar has gained a strong foothold in the Channel Islands and is munching through the popular hedge variety at an increasing rate.
Gordon Steele, Chair of the Pollinator Project, has agreed with the States and other local nature groups that the easiest way to deal with the invasive and hungry species is to replace box hedging in gardens entirely.
“There are quite a few out there, plants such as Berberis, and Choisya make good hedges and blossom in the spring to provide nectar and pollen for bees,” he said.
“Of course, native hedging with hawthorn, wild pear, and blackthorn are fantastic. If you are determined to have miniature hedging, then box leaf holly Ilex crenata or box leaf honeysuckles Lonicera ligustrina var. pileata are a suitable alternative.”
But beloved boxes could be retained with simple and early interventions, he added.
“The easiest thing is to pick them off- my chickens really enjoy them. Your best chance of doing this is when they are quite large and as a result will have caused some damage. You can also treat them using two natural methods - using a pheromone trap that contains the chemical that the female moths use to attract the males, or using a nematode drench which releases microscopic worms that kill the caterpillars.
“Both of these are readily available and are very specific to the box tree moths and caterpillars.”
Mr Steele strongly advised against using synthetic insecticides, a core mission of the Pollinator Project charity.
“Let's be clear - these are toxic chemicals that will kill the caterpillars and pretty much anything else that's around at the time. That includes bees, the ladybirds that will eat the caterpillars, butterflies, and any other insect good or bad,” he said.
“In fact, creating a garden that encourages a wide variety of natural predators is the best thing you can do. Yes, the caterpillars will cause some damage, but it's cyclical. The more there are, the better the ladybirds and lacewings will do so there will be fewer next time,and they will feast on aphids, blackfly, sawfly and any other garden pests. So why not have 10% or even 30% of your garden dedicated to nature?”
Pictured: Mr Steele recommends blackthorn as a native replacement.
Mr Steele noted that box is native to China and Korea, with selective breeding and hybrids forming the low and small hedging popular around the world today.
“There is also an English Box tree which is the basis for some topiary but grows into quite a spectacular specimen. Not surprisingly then, the box tree moth and its caterpillars originate in Asia and they have spread naturally across Asia and Europe as they are quite good fliers,” he said.
“The ones in the UK most probably arrived in imported plants from the continent.They are quite difficult to see when they are small or overwintering in the middle of the plants. Once in the UK, they established themselves and are quite common now. They often have two or three broods a year with the first one getting quite big in late spring, which is often when we see them and the damage they cause is most obvious.
“Each year we see quite a lot of moths and butterflies arriving. Only this month a huge population of Silver Y moths arrived and during the summer we will see painted ladies, clouds of white butterflies, and others flying in. Of course, we all know about other insects flying in like the Asian hornet.
So, our islands are regularly host to a lot of different arrivals - some good and some very definitely not. These invasive species that don't have natural predators can be a big problem. Plants like sour fig and Japanese Knotweed are just the tip of the iceberg.”
The States offer a free plant diagnostic service at Burnt Lane. Mr Steele said they are the best local experts for any queries.
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