Rats: If your nursery is near cereal crops, start to check your rat bait boxes. After harvest, they very often migrate to safer places. While they can do damage to container-grown plants, they are also a hazard to your staff as carriers of Weil's disease.
Botrytis: Check for this disease on crops spaced close together or those with dense foliage so that air changes around the crop foliage occur. Spray with Rovral WG, Scala (SOLA 2007-3636), Scotts Octave or Serenade ASO (SOLA 2009-0246) if seen.
Apple and pear sucker: The insects are often first spotted by black, sooty mould on the leaves. Control the sucker with Toppel 100EC, Decis or Equity according to label recommendations and including harvest intervals. The sooty mould can be controlled with chlorothalonil.
Moths: Be vigilant for species that can attack ornamentals (leopard, swift and tortrix moths, among others). Check plant species that you know are vulnerable, particularly under protection. Remember to apply Toppel 100 EC, chlorpyrifos or Decis now to pines to control pine shoot moth grubs. Check for gumming around buds and limp leader growth.
Irrigation: Keep an eye on your irrigation system and make sure it is turned off on outdoor beds if it rains. I have seen container plants outside with irrigation systems left turned on regardless. Far more plants on nurseries are killed by over-watering than under-watering.
Shot-hole: Wet weather will encourage bacterial infections on laurels. Spray again this week with a tank mix of Serenade ASO (SOLA 2009-0246) and Cuprokylt to avoid high infection rates developing. Include Codacide Oil for longer-term adherence.
Downy mildew: After the wet, humid weather of the past two weeks, check for downy mildew. Spray with products like Amistar (SOLA 2009-0443), fosetyl-aluminium, propamocarb hydrochloride, Fubol Gold WG, Previcur Energy (SOLA 2008-2667), Revus (SOLA 2008-2867), Stroby WG, Subdue or Valbon (SOLAs required).
John Adlam is managing director at Dove Associates
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