Spindle bushes along Hertfordshire's Beane Valley are being stripped bare of leaves by a spectacular eruption of caterpillars.

HNHS member Harry Bott was astonished by the sight of a bush smothered in the silken webs protecting thousands of feeding caterpillars on his farm at Bennington, near Stevenage. As he puts it: "The most extraordinary sight that I have never seen before in 60 years of farming here." 

Harry discovered a number of other Spindle (Euonymus europaeus) bushes on the farm were under attack, But according to moth specialist Mark Sterling, Spindle along miles of the Beane Valley from Waterford to Watton at Stone is being stripped bare by caterpillars.

Larvae of Yponomeuta cagnagella, otherwise known as Spindle Ermine Moth, are responsible for the destruction, and well known for their ability to strip a whole bush of its leaves within days. Nevertheless, Mark says he has not previously seen anything  on the scale of what is happening in the Beane Valley.

Photographs © Harry Bott

According to the Royal Horticultural Society's website the defoliation caused by Yponomeuta small ermine moths can be alarming, but should not affect the long term health or vigour of host plants. It will be interesting to see whether the Beane Valley Spindle bushes recover in the way this suggests.