What broke my fruit tree?

As spring slowly comes our way, we thought it a good time of year to bring you a series of pest and disease management tips.

This week we’re focusing on identifying the damage that big pests like kangaroos, wallabies, rabbits and hares cause, because they often inflict their worst damage at this time of year, especially on newly planted trees.

Hare damage on a newly planted cherry tree
Hare damage on a newly planted cherry tree

The key to effective pest and disease management is to figure out how to protect your trees or fruit from the pest.

This may sound completely obvious, but in fact is quite opposed to the more conventional approach of trying to get rid of the pest altogether (often with chemicals).

Trying to get rid of pests doesn’t work; it’s expensive, time consuming and frustrating, and in fact every animal and insect has its place in the ecosystem – even if we don’t necessarily want them near our fruit trees!

The first step in our strategy is to figure out what’s doing the damage. It’s one of the basic principles we rely on in the Protect Fruit Trees from Pesky Pests short course (which includes identification and prevention methods for pests that damage both fruit and trees).

This photo above shows what hare damage looks like, and the one below shows a close-up view (pretty gruesome, isn’t it?)

A close-up view of fresh hare damage
A close-up view of fresh hare damage

Kangaroos will also nibble the top of young trees (they seem to find apical [tip] buds especially delicious), though kangaroo or wallaby damage often seems more incidental than purposeful, done by accident as they clumsily jump past the trees, resulting in this type of damage:

Incidental kangaroo damage on a 3 year old tree
Incidental kangaroo damage on a 3 year old tree

Another clue to identify the culprit animal that’s doing the damage is to look carefully on the ground for scats (or poo, as most of us call it).

Kangaroo poo
Kangaroo poo

To help you figure out which animal might be responsible for eating your fruit trees, here’s some photos of other types of animal scats (thanks to ABC Science and The Wildlife Trusts for these photos):

Brush-tailed possum
Fox
Rabbits and hares
Droppings are left in clusters of little, round, hard balls. They are usually yellowy-brown or green in colour, and full of grass. Hare droppings (on the right) tend to be slightly bigger and flatter than rabbit droppings (left hand side).
©Darren Tansley

5 ways to prevent large animals damaging your fruit trees

We’ve written in other blogs how to identify which animals might be causing damage to your fruit trees, but it’s also important to think about strategies for preventing the damage!

In the case of big animals, it’s usually a case of protecting the trees using either tree guards, fences or netting enclosures.

A wire netting enclosure built to keep kangaroos away from a young fruit tree
A wire netting enclosure built to keep kangaroos away from a young fruit tree

Which of these you choose will depend on:

  • the specific pest damage you’re trying to prevent;
  • the size and age of the trees; 
  • whether you need a permanent or temporary solution; and/or
  • your capacity to buy or build something in terms of ability, time, materials and money.

So, while it’s impossible for us to give solutions for every specific situation, here’s our 5 top strategies:

  1. Deterrents: Once you’ve identified the pest, do some research into what they don’t like, and consider whether you can make the environment unpleasant for them. For example, hares are herbivores and are put off by the smell of meat, so a paste made out of animal fat and strong-smelling herbs applied to the trunks, or blood and bone scattered around the trees, may be enough to put them off.
  2. Tree guards: These can range from the simple corflute guards we use on the farm, which are fantastic because they’re durable and reusable (but have the disadvantage of not being wide enough to enclose the low branches, so they only protect the trunk) to a larger and more durable type of guard, which has the disadvantage of being more expensive and time consuming to build, and limiting easy access to the tree.
  3. Fences: Installing permanent fences to keep out animals like kangaroos, deer, hares or rabbits is an engineering challenge, and can be quite costly. However, if you’re serious about food growing it’s a fantastic investment and will pay you back many times in terms of protected future crops. Once you’ve identified the problem animals, do some investigation into the type of fencing recommended to keep them out; for example, a kangaroo exclusion netting fence needs to be at least 1.5 – 2.0 m tall, and is more effective if electrified. Deer fencing works best if a double fence is installed, and rabbits and hares will dig under a fence unless the bottom is protected with buried mesh. 
  4. Netting enclosures: These are a wonderful idea, and can serve the dual purpose of keeping out both larger animals as well as birds, fruit bats, and even possums. The one in the photo below (which we saw at Kalangadoo Organics) is made from PVC pipe. The walls are reinforced over the bottom half with chicken wire, with bird netting over the hoops at the top – a brilliant solution.
  5. Other animals: One of the natural predators of kangaroos and wallabies is the dingo, so a dog in the garden or orchard may keep them away.
A netting and fence enclosure protecting cherry trees  
at Kalangadoo Organics
A netting and fence enclosure protecting cherry trees
at Kalangadoo Organics

Building appropriate protection for your trees can easily become one of those jobs that keeps falling to the bottom of the ‘to do’ list, but in nearly every case it’s worth the time and energy. To help you bump it up the list, we’ve included some resources on building hoop net systems (such as the one above) in the short course Protect Your Crop From Birds.

The reality is, if you’re trying to grow food in an environment where lots of animals are hungry, you’ll need to build protection to make sure you get some. You may like the idea of sharing, but they don’t!

How to Prevent Leaf Curl

Leaf curl is a nasty fungal disease that affects peaches and nectarines, but it’s often confused for other things (well, other things are sometimes mis-labelled as Leaf curl).

Here’s what it looks like:

A peach tree with the classic red leaves of Leaf curl disease
A peach tree with the classic red leaves of Leaf curl disease

There are other things (both pests and diseases) that can make leaves curl in other types of fruit trees, but this particular pathogen only affects your peach and nectarine trees.

If you get a bad case, it can even affect the fruit, and really bad cases will make the fruit fail and fall off while it’s very small, before it gets a chance to grow. Notice how similar it looks to the disease on the leaves, with a rough, raised texture and the red colouring.

A nectarine infected by curly le
A nectarine infected by curly leaf

Why are we showing you what Leaf curl looks like in the middle of winter? Because if you saw any signs of this disease last year, now is the time to be treating your trees to prevent it happening again this year.

It might seem too early to be thinking about spring, but if you wait until you see the disease, it’s way too late to put out the preventive sprays.

A Goldmine nectarine bud swelling
A Goldmine nectarine bud swelling

The trigger to spray is bud-swell. Different varieties reach bud-swell at different times, which is where the skill comes in. Depending on where you live and which varieties you have, your trees may already have reached (or be past) bud-swell, but if your peach and nectarine trees still look completely dormant, that’s because they are. From now on you need to be monitoring each different variety so you can spray them at the right time.

Once you’re sure your tree has reached bud-swell, it’s time to apply a preventive copper spray – Bordeaux (which is made by diluting hydrated lime in water, and copper sulphate in water, then mixing them together), or a spray containing copper hydroxide are the best options for home use. The Better Fruit With Wise Organic Spraying short course includes a video demo of how to mix Bordeaux spray if you need more detail.