Citrus needs some winter TLC

Jul 7, 2022

Keep your citrus healthy by managing pests and disease this winter. Photo by Rodney Braithwaite

Treating pests and diseases that attack citrus trees during winter helps to break the pest and disease life cycle, giving citrus trees a fresh start in spring.

Fruit fly

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As citrus fruit continues to mature during winter, maintain fruit fly prevention measures.

Visit the Goulburn Murray Valley Regional Fruit Fly Program’s website for more information on management strategies.

Citrus gall wasp

Lumpy swellings along the stems of citrus trees are an indication of citrus gall wasp.

Citrus gall wasp is native to warm coastal areas in NSW and Queensland but has also become an increasing problem in Victoria and also Western Australia.

Its original host was the native Australian finger lime but can also seriously affect other citrus including lemons, grapefruit and oranges.

There are three main stages in the citrus gall wasp life cycle:

The small black adult wasp lays eggs underneath the bark on soft new spring growth.
Larvae hatch from the eggs, eat the stem tissue and the lumpy galls form around the developing larvae.
The larvae mature into the adult wasps, which emerge from the gall the following spring, leaving small pin prick holes.

The galls not only look unattractive they can lead to poor plant health and reduced harvest.

It’s important to be vigilant and look out for these galls and winter is an ideal time to act to reduce this nasty pest, before the adult wasps emerge in spring.

There are no sprays registered for controlling citrus gall wasp in home gardens and once galls are formed the damage is permanent.

Prune off affected stems and place these sections in a sealed plastic bag and put them in the garbage (don’t put gall infested stems in the compost bin).

Disposing of affected stems before the adult wasps have emerged stops the life cycle and helps to reduce new infestations in spring.

More citrus tips

If there are shoots growing from beneath the graft, trim these back flush with the trunk.

These shoots are from the tree's hardy rootstock, but will not develop the fruit you're after. They can be viciously thorny and also eventually take over the tree if not removed.

Refresh the mulch around the rootzone of citrus trees, however keep it from contacting the trunk, as this can promote diseases.

Source: https://www.yates.com.au/