Code of Practice for Angular leaf spot (Xanthomonas fragariae)
ADVICE ON HYGIENE MEASURES FOR PHPS SOFT FRUIT PROPAGATION NURSERIES
At present this disease is not known to occur in the UK but has occurred in neighbouring countries and there is a risk of importation from abroad with symptomless infected material. The disease does not infect fruit and is mainly transmitted by movement of people, machinery, debris or movement of latently infected plants, especially contaminating leaf debris originating from infected plants. In the field, local spread is by rain splash and overhead irrigation. Overwintering is on plant debris and in symptomless plants. The following measures are advised:
- Preventative control measures are most important since there are
no curative controls.
- Supply of healthy planting material is very important, growers should
source plants from reputable sources. Preferably have imported material
tested before despatch since latent infections can occur without symptom
development.
- Visitors (e.g. advisors or grower customers) or workers (e.g. de-blossoming
staff etc.) should not have visited other strawberry growers on the
same day.
- Visitors and all staff should be restricted to necessary areas and
to wash hands with soap and water between visiting different strawberry
crops on the farm.
- Movement of machinery or visitors and staff should be from the areas
of lowest risk first (e.g. high grade propagation crops) to areas of
highest risk (e.g. lower grade crops, A-H grade and fruiting crops).
Fruiting crops should not be visited before going into propagation beds
unless very strict hygiene measures are undertaken.
- Avoid overhead watering, if possible irrigate from underneath using
drip irrigation. Bacterial ooze builds up on the leaf surface under
high humidity and facilitates spread of the pathogen.
- Remove soil and debris from footwear or use disinfectant pads or
disposable gloves/footwear.
- Machinery should preferably be cleaned of debris and washed down
with disinfectant between crops, and is strongly advised after visiting
fruiting crops.
- Try to limit spread of debris and remove from field if possible for
burning or deep burial.
- Growers should try to inspect plants whenever possible for symptoms
on the leaves and this can also be usefully done in the dormant season.
Typical angular spots can be seen on old leaves or their remains attached
to the runners. Initial symptoms are seen on the underside of the leaves
as water soaked spots, which appear yellowish and translucent, and are
more easily observed when the leaf is held up to the light.
- Comply with Defra Code of Practice regarding disposal
of agricultural and horticultural plant waste and soil on land.
- Gapping-up should be carried out only in accordance with PHPS requirements and with the prior approval of the PHSI; in particular, only eligible material of an equivalent grade must be used.
Plant Health Division
October 2004
Page last modified:
9 Nov 2006
Page published: 5 Oct 2004