Netting fruit trees
Whether it is a backyard fruit tree or an orchard, netting is reliable because it places a physical barrier between the pest and the crop. Growers can use a range of netting options to protect orchard crops from damage by flying foxes, birds and some insect pests.
Using the right type of netting will protect the fruit. Using the wrong type, or badly erected netting may still protect the fruit but it can also injure or kill native birds, flying-foxes and possums if they become entangled.
What is eating the fruit?
The first step in netting a fruit tree is to identify what is eating the fruit and whether netting will solve the problem.
Fruit can be damaged by a range of ‘pests’, and for netting to have any impact, it must create a barrier between the fruit and the animal trying to eat it. Netting is only an effective solution where the fruit is being eaten by larger birds or mammals like rats, possums or flying-foxes.
Bird damage is relatively easy to detect as birds are active during the day and more likely to be seen while feeding. Mammals are nocturnal but will leave clues behind in the form of damaged fruit with teeth marks, or a scatter of droppings under the tree.
The following guide will help identify what type of mammal is eating your fruit.
Indication of presence
Common ringtail and common brushtail possums
Is it worth netting?
It is important to weigh up the cost of netting against the value of the fruit being grown. If netting is too costly, it may be better to consider some alternatives (see below), or accept that a small percentage of fruit will be eaten by wildlife.
Will netting affect how the fruit develops?
No. Netting allows fruit to develop while protecting it from possums, birds and flying-foxes as well as wind and hail damage. It can even form a better microclimate for a fruit tree to grow in and fruit to develop. The size of the mesh must be large enough to allow pollinating insects to reach any flowers on the tree and fertilise them.
Shade Cloth Method. Illustration by Louise Saunders
Different animals reach the fruit in different ways. If the problem is a possum or a rat climbing up the tree, then a sheet metal collar around the trunk may stop these animals reaching the fruit. If the tree is short enough for an animal to jump into the lower branches or to climb on to the tree from a fence or a neighbouring tree, a collar will not work.
If another tree overhangs a fruit tree, the branches can be pruned back so that it becomes too far for a possum to jump between them.
A 30 per cent blackout shade cloth can be pegged or tied over a fruiting tree to protect the fruit. Shade cloth is a low risk to wildlife and still allows fruit to ripen. It should be hemmed so that there are no frayed ends for animals to get caught in. When fruiting is finished, the shade cloth can be stored away.
Covering individual fruit in paper bags can also work where the fruit can be reached easily and safely.
Teepee Method.Illustrations by Louise Saunders.
Types of netting
Netting with a knitted mesh with a maximum mesh size of 10 mm will keep out larger birds, possums and flying-foxes. A smaller mesh size may be needed to keep out rats. White netting is best as it stands out against the foliage of the fruit tree. This will make it easier for flying-foxes to see and avoid.
Thin nylon (monofilament) netting should not be used as it is easily pulled out of shape by an animal climbing on it, causing the animal to become entangled. Once entangled, birds and flying-foxes become stressed, breaking bones and tearing wing membranes as they struggle to get free. The monofilament line can cut into the animal causing deep wounds and even stop circulation. Ultimately, these injuries can lead to shock and death, particularly if the animal is trapped for a long time. Entangled flying-foxes may also be mothers nursing young that are waiting at a nursery roost. These young will starve if the parent cannot return to the roost within a day.
Suitable netting can be purchased from hardware stores, nurseries or specialist netting manufacturers’.
When netting fruit trees, ensure that the net is kept taut. If the netting is loose or easily loses its shape, it is more likely to act as a trap for wildlife.
To keep netting taut, the first step is to build a frame over the tree to support the netting. This could be a box-shaped frame of PVC pipe or timber, or a number of star pickets or stakes that are located around the tree to form a frame for the netting, e.g. crossing three or four stakes to make a tepee frame (see illustration). It is important that the frame keeps the netting off the tree and is sturdy enough for the netting to be pulled taut.
Tent pegs, or any heavy objects (e.g. bricks) wrapped in the ends of the netting, can be used to keep the netting tensioned over the frame and stop animals from getting under the net. Clothes pegs and tie wire can also be used to stop the net slipping and sagging on the frame to form traps. The more places that the netting is held in position, the more even the tension of the netting will be on the frame.
When estimating how much netting is needed, allow enough for it to be firmly attached to the ground.
It is important to have some way of getting to the tree to remove fruit. Either a flap could be cut into the netting or an overlapping section of netting built into one side of the frame to allow a person to slip in between them. Any openings in the net could be closed off with clothes pegs or by weaving a garden stake through the mesh along the edge of the flap (or overlap) and the adjoining section of netting.
The bounce test
Common brushtail possums can weigh up to 3.5 kg, common ringtails 1.1 kg, and grey-headed flying-foxes up to 1 kg, and they can weigh down loose netting. For the netting to be effective, it must be tensioned enough to stop folds of net forming around an animal when it lands on or crawls over the net. Ideally, a flying-fox should almost bounce off the netting rather than sink into it when it lands.
Check netting at least daily. Animals could still become entangled.
Entangled animals (general)
Animals entangled in netting are likely to be injured and highly stressed, meaning any attempt to remove them is potentially dangerous for the animal and the rescuer.
If you find an entangled animal, without touching the animal cover it with a towel then contact the RSPCA Qld. They will put you in contact with a licensed wildlife rescuer who is trained to handle and care for wildlife. Further information about what you can do if you come across a sick, injured or orphaned animal is available on the departmental website.
The most effective method of crop protection from flying-foxes is netting. However, orchard and backyard netting may trap flying-foxes, either underneath the netted enclosure, or by entanglement within the net itself. If not rescued, flying-foxes that are in nets may suffer injury or distress and may die. There is also a level of risk that such flying-foxes may transmit the Australian Bat Lyssavirus to humans via bites or scratches, creating a health and safety risk for fruit growers and pickers.
Under certain circumstances, trapped flying-foxes can be euthanased to prevent injury or distress to the animals or to reduce risk of people getting scratched or bitten. If a flying-fox should become trapped or entangled in nets and in consideration of the provisions of the
- Animal Care and Protection Act 2001,
- Code of Practice: Ecologically sustainable lethal take of flying-foxes for crop protection,
- Weapons Act 1990, and
- Workplace Health and Safety Act 2011
EHP would consider the taking (euthanasia) to be defensible with respect to the Nature Conservation Act 1992 providing that the following process is followed:
- where circumstances indicate that a flying-fox is likely to be injured or is suffering distress, or that the flying-fox poses a risk to human health or safety; and
- where a fruit grower has taken all reasonable and practical efforts to free the flying-fox, without handling the flying-fox or exposing themselves or other persons to the risk of bites or scratches; and
- where a fruit grower has made reasonable efforts to first obtain the services of an appropriately inoculated wildlife carer in their area to rescue the flying-fox and the wildlife carer is unable to respond on-site within 2 hours of initial contact or attempted contact by the fruit grower, the grower may proceed as follows:
- The fruit grower may humanely euthanize a flying-fox where all of the above circumstances 1 to 3 are applicable.
- Other than euthanasia undertaken by a registered veterinarian, shooting is the only allowable method to euthanize a flying-fox if the use of a firearm is lawful in the circumstances.
- In circumstances in which the use of a firearm is lawful (for example, all relevant requirements of the Weapons Act 1990 are met), the firearm may only be a shotgun with a calibre of 12 gauge or .410, and only with full choke. The shot may only be lead shot (shot size for a 12 gauge may only be from 6 to 2; shot size for a .410 may only be 7.5 to 4, with a minimum 2.5 inch cartridge).
- In circumstances in which use of a shotgun is not lawful or feasible (for example, where public safety may be compromised), a registered veterinarian may humanely euthanize the flying-fox.
- The fruit grower and persons assisting the fruit grower (other than an appropriately authorised and inoculated wildlife carer) should not handle the flying-fox due to the potential to contract from the animal the infectious disease Australian Bat Lyssavirus.
- The fruit grower must at all times ensure that risks to the health and safety of all persons involved in the activity are adequately addressed in accordance with the requirements of the Workplace Health and Safety Act 2011.
- The fruit grower must be able to demonstrate that, prior to euthanizing the flying-fox, a reasonable attempt was made to contact an appropriately authorised and inoculated wildlife carer in their area to rescue the flying-fox.
- If the fruit grower holds a Damage Mitigation Permit with respect to the relevant species of flying-fox, the grower must record details of each incident of a flying-fox being euthanised in their Return of Operations and must submit each Return to EHP as prescribed (for example, every 3 months that the permit is in effect).
- Euthanized flying-foxes are to be disposed of in a safe manner, such as by burning or burial.
Do not try to remove entangled flying-foxes. These animals can carry and transmit viruses. If the flying-fox is sick and shows signs of paralysis, or has come into contact with a dog or a cat, contact Biosecurity Queensland as they may wish to inspect the bat. If the flying-fox is dead, use a shovel and/or tongs to remove it and then burn or bury it. Do not touch the bat without wearing gloves. If burying it, ensure that the hole is deep enough so that a dog could not dig it up.