Individual study: Small-leaved cotoneaster Cotoneaster integrifolius control by herbicide application, Isle of Portland, Dorset, England
Bond W. (2003) Controlling cotoneaster – grub, spray or burn. Conservation Land Management, 4-7
Old quarry workings on the Isle of Portland have a high conservation value for limestone grassland species but are being overwhelmed the introduced invasive, small-leaved cotoneaster Cotoneaster integrifolius. Three approaches to control (mechanical, herbicide, and flame gun) were tested in February 2002. The herbicide treatments and their consequences are outlined below.
On 14 February 2002, three herbicides were sprayed onto patches of small-leaved cotoneaster. As an assessment of the effectiveness of each was the test aim, no wetters were used. All herbicides were applied by a qualified worker using a knapsack sprayer. These, (their active ingredients), application rates and estimated costs (£ stirling/m²) were:
Roundup (glyphosate): 10 l/ha - £0.11/m²
Broadsword (24D + dicamba + triclopyr): 4 l/ha - £0.18/m²
Garlon (triclopyr): 30 l/ha - £0.12/m²
Spraying offered flexibility in terms of accessing difficult terrain and crevices with minimal disturbance of ripe Cotoneaster seed and no ground disturbance. A disadvantage was the lack of selectivity when native grassland flora was intermixed with Cotoneaster.
After four months, healthy-looking green Cotoneaster tips were growing beyond the browned off mid-level parts of the bushes. Canopy cover was still dense as there was no leaf loss. After eight months the sprayed areas appeared better as leaves were mostly dead. However, most, although dead were still in place, therefore light did not penetrate. Sporadic new green growth was restricted to ivy Hedera helix and bramble Rubus fruticosus.
All three tested herbicides achieved acceptable results. Broadsword was the most effective, closely followed by Roundup. The authors considered that performance could be improved by using wetters and refining the timing of application. Spraying, in terms of Cotoneaster kill was considered the most effective and cheapest solution of three techniques tested.
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