Minimising Pests & Diseases in Fruit Trees

KJ Reyland | 07 May, 2022

            Minimising Pests & Diseases in Fruit Trees

Experience and science have shown that maintaining good hygiene in the garden significantly reduces incidence of disease. Cutting out and destroying diseased tissue as soon as it appears. Removing diseased leaves that have fallen as soon as possible. If fungal or bacterial diseased fruit, leaves or wood is left on the tree or the soil surface it will very quickly and easily re-infect healthy tissue. The disease spores will also overwinter and infect pruning cuts or even healthy new growth in spring. 

Apart from damaged wood or pruning cuts, another entry point for disease is leaf scars—the area where the leaves were attached following autumn leaf fall in pip and stone fruit trees. It is a good idea to commence winter clean up sprays in autumn soon after leaf fall commences. The first spray at about 30% leaf fall and the second at about 95% leaf fall. This provides protection to the leaf scars resulting in less over wintering infection. These two autumn sprays can be followed by one in late winter and another early spring just prior to bud burst.

Spray with a combination of Copper and Mineral oil for your winter clean up.

No one thing will control pests and diseases, but a combination of best practices will minimise pests & diseases. 
Each one of the following practices will contribute. Use as many of these as applicable.   

  • Add compost and raise planting areas in clay soils to improve drainage and aeration. 
  • Rotate crops in the vegetable garden to avoid build-up of soil diseases.
  • Select disease resistant varieties where possible—ican vegetables, apples, ornamentals.
  • Maintain good hygiene, by removing diseased leaves at first sign.
  • Remove alternate host plants as much as practicable. This removes infection sources.
  • If pests or diseases appear, spray at very first sign with a safe pesticide approved for the crop involved. 
    For fruit we recommendGrosafe Enspray 99 + Grosafe BioNeemfor aphids, white fly, thrips, mites, (also powdery mildew). Add Success Ultra if chewing insects appear.
  • AddGrosafe Free Flo Copper (copper hydroxide) if diseases appear. These products are all safe to bees once spray has dried, they are all certified organic, can be used on all edibles and have a nil withholding period.
  • Do not use pyrethrum as this is very toxic to beneficial insects and bees.
  • Do not useunregistered remedies on edibles —eg. unregistered brands of Neem –Native Neem, Oakdale Neem, Wally’s Super Neem.Do not useDiatomaceous Earth, DeBug, etc. 
  • Companion planting provides little or no benefit according to science.