Biological control: Time to introduce predators for aphids, whitefly and thrips. Check aphid type and species to get good predator control. Use yellow sticky traps to monitor whitefly, sciarid, leafhoppers and blue sticky traps to monitor for thrips. If not too cold, introduce lacewings into hedges to establish early aphid control outside.
Oaks: Apply Gazelle SG or Vydate 10G (EAMU 2012-2322) in the next few weeks to young field-grown oaks to reduce the risk of midge damage to the central bud.
Spider mites: Start using predators on protected crops along with short-term products at this time of year including Majestik, Pyrethrum 5EC, Savona and SB Plant Invigorator. Where foliage is not touching, increase predator numbers to compensate. Fleece can act as a bridge on newly potted crops.
Rust: Check heuchera and fuchsia crops and apply Systhane 20EW or Topas preventively. Amistar (EAMU 2009-0443), Bumper 250EC (EAMU 2009-0707) or Signum (EAMU 2012-2141) will provide curative control.
Water discharge: Water recycling will help you in controlling any contaminated discharges from your site via drains and other methods. Include recycling in plans for new container beds.
Compost tea: Clean out all of your equipment thoroughly to start fortnightly applications onto new foliage. The beneficial bacteria, protozoa and fungi in your compost tea will help to prevent early disease attack.
Roses: Make sure that the maximum rate of Butisan S is not exceeded. As an example, if the highest application rate for ornamentals is applied (1.5 litres per hectare) then that would mean applying 750g of metazachlor. That leaves only 250g of metazachlor left to apply within the three-year period as stated on the label. Butisan S can be mixed with Flexidor or Skirmish - both contain isoxaben. An alternative to Butisan S is Springbok. Its metazachlor concentration is less than Butisan S so it can be applied more than once to a crop if using the 1.6 litres per hectare rate.
Frost: Avoid spraying if frost is predicted after a sunny, clear day. Damage is more likely to result if an emulsifiable concentrate or product containing an adjuvant is used, leaving soft foliage without adequate cuticle.
John Adlam, Managing director, Dove Associates, HorticultureWeek.co.uk/nursery