Plane anthracnose: Brown patches can start to develop underneath leaf buds so may not be easy to see.
Overwintering on leaf mould, this disease infects trees during spring with dark black patches developing. They are often worse in cooler, wet springs and destroy new bud growth as they emerge. If you recall seeing large dead patches on the leaves last summer, make sure that you spray the trees with Switch or Cercobin WG (SOLA 2008-1384).
Fireblight: Use test kits, available from Pocket Diagnostic, on vulnerable plant subjects for this notifiable disease.
Windbreaks: Installing windbreaks can achieve a 50 per cent reduction in speed for five times the height, which tapers off to 40 per cent at seven times the height and 20 per cent at 15 times the height. Solid windbreaks create more turbulence than open ones.
Cleaning beds: Clean up your container beds to remove moss and liverwort. Use a power washer to loosen and clean up ground cover material and then spray with Mogeton to kill off any remaining liverwort. A final spray two days later with Jet 5 will complete the bed-cleaning process. Starting off with clean beds reduces later seasons' growth quite dramatically. Spraying clear beds with a mixture of Harvest and Ronstar Liquid will give you the finishing touch, reducing weed seedling germination after pots have been stood down.
Pruning: What do you do with any winter prunings of trees? If left on the soil surface to rot they can become a source of coral spot and stem canker fungi ready to infect young soft material in the spring. Clean up the trimmings before the spring to reduce the canker risk. If you are pruning larger limbs from trees and shrubs, do make the effort to paint the wounds with a canker paint such as Bezel.
Fields: Make sure that you take a soil analysis of roses, trees and any other over-wintered field-grown stock before growth starts again. Avoid planting Rosaceae subjects on the same land twice. Ensure that accurate records are made of the location of Sorbus, Malus, Crataegus, Prunus, Pyrus and other Rosaceae subjects. Do not return to the same piece of land for at least 12 years. The Horticultural Development Company has looked at alternative control methods in HNS 168. I see many trees suffering from replant disease through inaccurate record keeping.
- John Adlam is managing director at Dove Associates