What are the diseases and pests of mandarin?

The mandarin is one of the citrus fruits that is most resistant to pests and diseases, but unfortunately that does not mean that it cannot have some other problem throughout its life. In fact, if we are careless with the crop, that is, if we do not fertilize it and water it every time it needs it, it is more than likely that some microorganism or insect will harm our tree.

To prevent this from happening, it is important to know what the mandarin diseases and pests are , and also how to treat them. 


  • 1 Mandarin diseases
    • 1.1 Phytophthora
    • 1.2 Viruses and viroids
  • 2 mandarin pests

mandarin diseases



It is a fungus that is favored by excess humidity and warm but mild temperatures, between 15 and 30ºC. Depending on the species, it can affect the roots first or the leaves directly. The symptoms are: brown spots on the upper part of the leaves and with a grayish-white powder on the underside; rotting of the root system, weakening and, in severe cases, death .

To treat it, use copper-based fungicides, and avoid excessive watering.

Viruses and viroids

orange tree with virus

Orange tree affected by the citrus sadness virus (Closterovirus or CTV).
Image – Agenciasinc.es

Like the virus of sadness , exocortis and psoriasis. They are microorganisms that cause mosaics of different colors in the leaves and fruits. The symptoms are: leaf drop for no apparent reason, excessive fruit production, general weakening , and in severe cases, can also cause the death of the tree .

Unfortunately there is no cure. The best thing to do is to make sure you are buying a healthy specimen.

mandarin pests

Red spider

Red spider, a pest that can affect your Chamaedorea

It is a red mite measuring about 0.5cm that loves a warm and dry environment. It perches on the leaves to feed on their cells. The damage and symptoms it causes are: discolored spots on the affected parts, cobwebs, slow growth .

It can be easily combated with acaricides, or with neem oil whose dose is about 3ml per liter of water.


Cottony mealybug on a leaf

They are insects that can be of various types: cottony or limpet type. In any case, they perch on tender stems and on the undersides of leaves to feed on them. The symptoms are: discolored spots on the affected parts, slowing of growth, and general weakening of the tree .

The best natural remedy is diatomaceous earth , which is a very fine white powder made up of microscopic fossilized algae that contains silica, the stuff from which glass is made. When they come into contact with the parasites, they break their protective shield, causing them to die of dehydration. The dose is 35g per liter of water , which should be poured into a watering can (do not use a sprayer since it clogs immediately).

White fly

Whitefly, a plague that affects the poplar

They are very small insects, about 0.5cm long and white in color that adhere to the leaves and more tender shoots to feed. The symptoms are: yellowing of the leaves, sticky substance on the leaves as a result of the appearance of the fungus, and weakening .

To control it, the ideal is to place yellow sticky traps, which is a color that attracts these flies and other parasites, such as aphids. This is how the population of this pest is kept at bay. 

citrus miner

citrus miner

Image – Flickr/Scot Nelson

It is a micro-lepidoptera that feeds on the most tender shoots of the tree, such as the youngest leaves. The symptoms and damage it causes are: discolored galleries in the leaves, yellowing, leaf drop, growth slowdown, and general weakening .

To combat it, it is best to apply neem oil, whose dose is 3 to 5ml per liter depending on the severity of the damage it has caused, or with Bacillus thuringiensis , which is a bacterium that can help us a lot to control pests

Now you know what diseases or pests mandarins can have. I hope that the remedies to treat them are useful to you. 

What are the diseases and pests of mandarin?

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