Glasshouse/tunnel cleaning: Wash down the inside of tunnels and glasshouses when free of crops to start clean before bringing in a new crop.
This is most important with bedding plants. Starting the season on a sound hygienic footing will help reduce the risk of pest and disease establishment. Sprays of Jet 5, Hortisept, Menno Florades or Vitafect are all suitable for this. Don't forget that Mypex and stones can be sprayed with a tank mix of Harvest and Ronstar Liquid, which will reduce germinating weeds on the beds. Oxadiazon is not root absorbed so is ideally suited to this task.
Robinia 'Frisia': Container plants that fail to come into leaf can be due to Verticillium wilt, bacterial infections (causing sunken cankers on stems) or a Phytophthora sp. Drench suspect plants with Aliette 80WG, Previcur Energy (SOLA 2008-2667), Filex/Proplant, Subdue or Prestop. Early stages of bacterial infections can be controlled with a tank mix of Cuprokylt and Serenade ASO (SOLA 2009-0246).
Scale insects: Check imported and unsold plants from last season, particularly citrus, Taxus, ivy, Euonymus and Camellia. Not much scale is actually alive at the moment but an effective winter wash to prevent eggs developing in the spring is Certis Spraying Oil. Chess WG (SOLA 2008-2834), Decis, Savona, SB Plant Invigorator and Spruzit are effective on the mobile stages.
Slug pellets: Applications should be maintained on Choisya to prevent snail damage. Consider using Ferramol Max, which is much safer where you have customers or animals present.
Downy mildew: Check Osteospermum, Digitalis, Geum and some Hebe now. Look for yellow blotches on the topside of the leaf that are followed by a grey/white fungal growth on the underside. Spray at least once this month with Aliette 80 WG, Fubol Gold WG (SOLA 2010-2567), Signum (SOLA 2009-1842) or Subdue.
IPM Essen: I saw a range of bio fibre pots at the exhibition and Lanz has now produced a fibre pot dispenser, available through Mechanical Botanical. In the past, the automatic pot dispenser has often been the limiting factor with this type of pot.
Aphids: Warmer weather will mean regular checks for early aphid activity will be required on conifer, pines, Juniperus and Picea. Products available include Hallmark WZT (SOLA 2008-2844), Decis or Aphox.
- John Adlam is managing director at Dove Associates