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Box Moth Threat Teagasc Nursery Stock Advisor, Dónall Flanagan suggests vigilance and caution as the first incidence of box moth is identified in Ireland
B
ox (Buxus sempervirens) has suffered some bad press of late; already suffering from blight, now with the first reports of box moth caterpillar coming in, cultivation will need to be reviewed. In time box may well be treated like roses, requiring pest and disease control. Box contradicts the term ‘common’. It’s everywhere, but is still a desirable plant. It’s a high status plant for landscaping and topiary. Estimates of imports of close to a million plants a year show it’s an important and economically valuable plant. The vast majority of box produced in Europe is grown by specialists in Belgium and Netherlands and they are very skilled at it. However, the last few years have not been so kind to them. Demand on the Continent has declined significantly, and by 75% on some nurseries. Pest and disease have tarnished its good name. Didier Hermans, owner of Herplant (one of the biggest producers of box in Europe) says, “The markets in Belgium and Holland have crashed because of the caterpillar and the very negative news in newspapers and on TV stations”. There are widespread reports from UK and the Continent of the dramatic damage caused - defoliation of plants over a weekend. It resulted in large amounts of the plant being replaced with alternative species.
BOX BLIGHT Two relatively new box diseases have caused much damage to the plants since first reported over 15 years ago. Blackening or browning and death of foliage are caused by the fungal pathogens Calonectria pseudonaviculata (syn.Cylindrocladium buxicola) and Volutella buxi (syn. Pseudonectria buxi). Both thrive on Buxus plants in warm, humid conditions. Warm, wet summers and transport conditions give the disease a chance to take hold. Box blight can be spread by wind and by contact, e.g. pruning and on footwear. Growers have been well able to manage the disease by addressing spacing and using good hygiene. Disease control using preventative treatments has been successful but is another new job on the nursery. US research in 2015 by LaMondia et al showed systemic and protectant fungicide
Autumn/Winter 2018 / www.horticultureconnected.ie / HORTICULTURECONNECTED
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