A few things about citrus trees

Jul 13, 2020

It’s the time of the year when citrus trees are laden and you can barely give the fruit away.
As there are entire books devoted to caring for citrus and I have about three paragraphs, I’m just going to point out a few basics. Even so, this will be a part one and part two arrangement.

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Gall wasp. This is an important community announcement. There is no cure whatsoever for gall wasp. It ‘s a native of the Australian finger lime and it bores into a branch, lays eggs and then the hatched larvae feed on the inside of the branch which causes a lump. When mature they exit the lump, fly off and repeat. The tree gets weaker and weaker and fruits less and less with this repeated cycle. The recommended way to prevent it maturing and spreading throughout your citrus tree/s AND YOUR NEIGHBOURS (we are all connected) is to cut the gall lump out and burn it asap. There are some encouraging experiments with kaolin clay to prevent the wasp from laying in the first place. They love new sappy growth.

Scale. Citrus are prone to this pest. Check the underside of leaves, check stems and veins and the fruit for innocent looking bumps that at first seem to be part of the plant but are actually adhered pests. Scrape them off. Plant too big? The suggestion is to make a white oil – kitchen oil with detergent or soap mix which works by smothering.

Powdery mildew. A black powdery fungus that is harmlessly telling you the tree is infested with an insect pest such as scale, whitefly or aphids. It grows on their ‘honeydew’.

Bronze orange stink bug. Sap sucker that causes the tree to drop fruit. If that’s not bad enough, it shoots awful smelling citric acid when threatened which can damage your eyes and skin. The drongo bird is the major predator of stink bugs but you may have to resort to picking them off with tongs or an old vacuum (while dressed for nuclear fallout protection). Young ones and eggs can apparently be knocked over with a white oil concoction.

Orchard butterfly (Papilio aegeus). Oh so pretty! The caterpillar does prefer to feed on citrus leaves but unless there are tonnes of them it’s not a problem. As butterflies they are pollinators for a lot of flowering plants.