Plant Doctor Archive

 WE have several Hass avocado trees in the north. We have a problem with hares and possums — are there deterrents that we could use that will not affect the trees’ production or fruit quality? The trees are shallow rooted — other than a shelter break, are there other things we can do to help support the trees as they grow so they do not blow over in gales and such?

 THERE is a product used to deter possums. It is known under several names — Thiroprotect, Thiropel or Thiram. Some garden centres stock this product, otherwise you could try one of the large stock firms. I have heard spraying trees with liquid sheep manure as a foliar feed is an effective deterrent.

Avocados have a long tap root. Trees can become weakened if this tap root is damaged at some stage from the seed germinating to planting. This leads to trees being easily blown out of the ground. Avocados require good drainage, being very intolerant of wet feet which can lead to root rot disorders. The best thing you can do is establish a good shelter belt around your trees.

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