Minimising Pests & Diseases

KJ Reyland | 05 October, 2021

            Snail Garden Pests NZ

No one thing will control pests and diseases, but a combination of practices will.  

Each one of the following practices will contribute. For a pest and disease-free garden use as many of the following that are applicable to the crop/plants being grown.   

  • Add compost and raise planting areas in clay soils to improve drainage and aeration, minimising root rots.
  • Rotate crops in the vegetable garden to avoid build-up of soil diseases.
  • Select disease resistant varieties where possible—hybrid vegetables, resistant apples, ornamentals.
  • Maintain good hygiene, by removing diseased leaves at first sign.
  • Remove alternate host plants as much as practicable. This removes infection sources. (The plant equivalent of ‘social distancing’)
  • If pests or diseases appear, spray at the very first sign with a safe pesticide approved for the crop involved.  
  • For vegetables we recommendGrosafe Enspray 99 + Grosafe BioNeem  for aphids, white fly, thrips, mites. Add Yates Mavrik if caterpillars appear (or Grosafe Spinosad for organic gardeners).  
  • For spots and blights of vegetables use Grosafe Free Flo Copper  (copper hydroxide). For powdery mildew use Grosafe Enspray 99.
  • Fruits require a spray programme  for pip and stone fruits, with protection/clean up winter sprays followed by different sprays just prior to and immediately after flowering for control of fruit rot diseases and codling moth. See full illustrated details for timing, and the best products to use in our ‘Pro advice’ section.   
  • The products above are all safe to bees once spray has dried. They are all certified organic except Yates Mavrik. They can be used on all fruits and have a nil withholding period, except Grosafe Spinosad .
  • Avoid using  Pyrethrum as this is very toxic to beneficial insects.
  • Do not use  unregistered remedies on edibles —eg. unregistered brands of Neem – Native Neem, Oakdale Neem, Wally’s Super Neem.  Do not use  Diatomaceous Earth, DeBug etc. on edibles. 
  • Companion planting provides little or no benefit according to science.