Leaf spots: These will appear on outdoor and protected crops, particularly if growing conditions are wet and warm. Spray with Scotts Octave, a tank mix of Cercobin WG (SOLA 2008-1384) and Bravo 500 or Amistar (SOLA 2009-0443) this month.
Volcanic ash: If this appears, to wash it off, add some wetting agent to the washing water to aid the dislodgement of particles. Foaming can be a problem in power-washing systems, but lower-pressure and brushing systems do not seem to be as affected.
Conductivity meters: This is a useful piece of equipment for measuring the level of nutrients in liquid feeds and compost. If you take weekly readings of compost now, you can soon build up a picture of the nutrient content with controlled-release fertilisers and optimum growth, using liquid feeding as a top-up. Conductivity is changed by temperature, so try to take measurements at a known water temperature.
Wetting agents: Try out "super-wetters" on large shiny-leaved subjects. They can make all the difference in getting plant protection products to their targets and improve efficacy. Headland Rhino or Slippa can give complete coverage of the leaf canopy, even on the underside of the leaf when spraying from over the crop.
Ornamental SOLAs: Do you have the latest specific off-label approvals issued from the replacement of the long-term arrangements? Go online to the Chemicals Regulation Directorate website (www.pesticides.gov.uk) to download them.
Rust: Check the stems and backs of new leaves on Campanula, Fuchsia, hollyhocks, Hypericum, Iris, Mahonia, mint roses and Vinca. Spray with Amistar (SOLA 2009-0443), Bumper 250EC (SOLA 2009-0707), Systhane 20EW or Signum (SOLA 2009-1842) on non-edible plants to reduce the damaging effects of this disease.
Aphid: Populations of aphids are building as winged females look for pastures new. Majestik, Savona and SB Plant Invigorator can be used during the despatch period because of their rapid knock down and relative handling safety for staff.
Capsids: The common green capsid will cause leaf damage to shrubs and herbaceous plants. They hatch from April and create small circular holes in newer foliage. Check outdoor crops of Choisya and roses and control with Decis (SOLA 2007-1693) or Toppel 100 EC if seen.
www.HorticultureWeek.co.uk/nurser for recent articles.