Green manures Consider growing a frost-tolerant green manure over the winter months on unused land to reduce erosion risk, improve soil structure and increase organic matter levels (after incorporation). Sow and establish before the colder months to achieve good biomass for incorporation in the spring.
Pest and disease resistance Resistance to pesticides by both pests and diseases does occur but there are a few simple rules that you can follow to delay this natural process. Use a different pesticide group in rotation in your control programmes. The UK Pesticide Guide is a valuable source of information and lists the product group under the active ingredient name. Check through your aphid, spider mite and whitefly programmes as these are the pests that seem to gain resistance more frequently. Botrytis, Septoria and downy mildew have also shown resistance to some fungicides and need care in the programme planning.
Setting red berries Achieving flower set by getting the right male/female combinations makes all the difference to the holly sales. Applying Berelex will "set" flowers now emerging and allow maximum berry retention for autumn. This also works on Viburnum and Cotoneaster.
Botrytis Check for this disease this week on crops spaced close together or those with dense foliage. Spray with Rovral WG, Scala, Scotts Octave or Serenade ASO when seen.
Asters Aster, Hebe, Penstemon and Phlox can all suffer wilt diseases at this time of year. If sections of the plant, or even a whole plant, suddenly wilt during periods of high temperature then this is the most likely cause. Spray these plants with Amistar (SOLA 2009-0443), Cercobin WG (SOLA 2008-1384), Scotts Octave or Signum (SOLA 2009-1842) to control the spread of either Fusarium or Verticillium wilt.
Leaf hopper These are a particular problem on sage and French lavenders. Consider Chess WG (SOLA 2009-1842), Gazelle, Majestik or SB Plant Invigorator on the lavenders. Majestik and SB Plant Invigorator are available on-label for edible plants like sage but other products containing deltamethrin or nicotine require a SOLA. Download and print individual SOLAs from the CRD website and observe harvest intervals.
Shot-hole Recent wet weather is encouraging bacterial shot-hole infections on laurels. Spray again this week with Cuprokylt to avoid high infection rates developing.