From the nursery

Needle cast You should have sprayed Picea, pines, Abies and Thuja for spring needle cast diseases. This week use Bravo 500, Dithane 945, Cercobin WG (SOLA 2008-1384), Signum (SOLA 2009-1842) or Switch.

Trimming If you normally trim your shrubs at potting this late in the year, consider a change of procedure. I believe that you should not allow a newly trimmed plant to be dormant for a long period afterwards. Either trim a few weeks before potting, while there is still some growth, or wait until early spring so the plant will start growing soon afterwards.

Vine weevil The lower-temperature nematodes provide good vine weevil larval control at this time of year. Make applications to protected crops, particularly those exposed to egg-laying that do not have any other protection. I find that nematodes are more effective than drench applications on large trees that have vine weevil. You can apply nematodes until we get heavy frosts that reduce the growing media temperature.

Botrytis I know I mentioned it last month but still watch out for Botrytis on a wide range of pot-thick container plants and spray where seen. Crops most at risk are those closely spaced and those with very hairy foliage. Keep the tunnel or glasshouse doors/vents open whenever the weather allows, to aid ventilation. Horticultural Development Company work showed that at between 10 degsC and 20 degsC and a humidity of 100 per cent, Botrytis growth is irreversible after three hours. If you can introduce air movement within the crop canopy and not just over the crop, the incidence of Botrytis is dramatically reduced. If you have automatic watering, alter the sequence by watering those susceptible species early in the morning rather than late at night. The foliage will dry out in the morning rather than stay wet all night. Aim to have the leaf surface dry at least once every 24 hours.

Western flower thrips It is worth continuing your Amblyseius introductions throughout the winter on crops in a frost-free structure. While they are not highly active, they do still find thrips to feed on and you will get a lower overwintering population resulting in fewer early-season infestations, especially if it is used with Nemolt (SOLA 2007-2120).

Hard water Spraying with hard water can reduce the efficacy of pesticides. Add products like the foliar feed Poliverdol, which will considerably improve the product efficiency.

 


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