The olive cultivation faces different pests and diseases. The professional farmer must learn to identify the causes of various olive tree diseases. The preventive control and the application of selective treatments against olive tree pests will help us keep our productive and healthy olive.
Although the total eradication of pests and diseases of the olive tree is technically and economically unfeasible. When olive pests are early identified and we apply the appropriate treatments, pests can be easily controlled.
Most common diseases and pests in the olive grove
Among the insects that attack the olive tree, the Prays, the fly and the black scale are the ones that usually cause the greatest damage.
Other diseases of the olive tree, are caused by fungi, is the case of olive peacock spot, Anthracnose, Verticillium…
Bacterium can also cause significant damage to the olive tree. Olive Knot disease and more recently the dreaded Xylella Fastidiosa.
If you click on the existing pictures abaut olive tree diseases, pests and problems, you can access complete information (characteristics, control measures, treatments…).
Olive Moth (Prays oleae)
Commonly known as olive moth (Prays oleae Bernard, 1788).
Prays oleae is a pest synchronized perfectly with the olive tree. It feeds on the olive tree for three annual generations (Phyllophagous, Antophagous and Carpophagous). During these phases it feeds on leaf, flower and fruit of the olive tree.
The Carpophagous generation is the one that can produce the greatest losses for the farmer, since directly affects the olives, which fall to the ground before they can be harvested.
There are insecticidal treatments for the control of the olive moth. Although the best ally of the farmer in front of the Prays are the high summer temperatures.
Olive fruit fly (Bactrocera oleae)
The olive fruit fly (Bactrocera oleae Rossi, 1790) It can wreak havoc on olive production under favorable conditions. After hardening of the olive bone, the olive fly will be on the prowl to start laying. The high temperatures and the dry summer environment prevent the correct development of the larvae.
The episodes of rains and mild temperatures favor the fly’s turn.
When applying treatments, keep in mind that some olive varieties are more sensitive to the attack of the fly. The placement of traps in olive trees is effective in controlling the first generations of fly.
Black Scale on Olive tree (Saissetia oleae)
The Black scale (Saissetia oleae Olivier, 1791), also known as caparreta is considered one of the main pests of the olive tree grove. During its activity it feeds on the sap of the olive tree and excretes sugars on the olive leaves.
These sugars are the ideal substrate for the sooty mould fungus that can cause significant damage.
Olive Peacock spot
The olive peacock spot is probably the most serious disease affecting the olive tree grove. It is caused by a fungus known by several scientific names (Fusicladium oleagineum, Spilocaega oleagina and Cycloconium oleaginum)
The rainy climates and the sensitive varieties suffer especially their incidence that reduces the productive capacity of the olive grove.
The preventive treatments with copper before the first rains of autumn and spring fungal applications. These are essential tasks, which the professional olive grower must perform, for the control of this disease problems.
The Anthracnose, is a disease of increasing importance in the Spanish olive grove. The fungi Colletotrichum acutatum and Colletotrichum gloeosporioides infect the olives and emit a toxin that dries the olive branches.
Wilt olive tree (Verticillium Dahliae)
The Verticillium, verticilosis or wilt olive tree is a disease caused by a soil fungus, its treatment being very difficult.
At present, the use of varieties or resistant rootstocks is necessary to replant infected olive tree groves.
Olive knot, is a olive tree disease of bacterial origin.
The bacterium Pseudomonas savastanoi (Janse, 1982) infects wounds in the tree. When the infection is considerable, the weakening of the tree is widespread, with dry branches and a significant reduction in production.
This dreaded bacterium, also known as olive tree ebola, has wreaked havoc on the olive groves of Apulia (Italy).
Detected in Spain at the end of 2016, the almond tree has been the most affected crop so far.
Although there is currently no possible treatment, some Italian olive varieties have been tolerant to Xylella Fastidiosa, housing a place of hope.
Other pests or olive tree diseases
Of course, not all pests and diseases of the olive tree have a high incidence, being possible to live with some of them.
In nature there are natural predators that maintain balance and help us keep harmful insects under control.
Even so, under certain conditions it will be necessary to apply specific control treatments.
The Olive Psyllid or cotton of the olive tree (Euphyllura olivina Costa, 1839), is a plague that is striking and can worry less experienced people.
Damages are usually of little consideration, so control treatments are not usually performed.
Olive tree borer (Phloeotribus Scarabaeoides)
Commonly known as olive tree borer, this olive grove is produced by the borer black (Hylesinus Oleiperda Fabricius, 1792), and Phloeotribus Scarabaeoides Bern, 1788.
The borer feeds by digging galleries in the olive bark, this cuts the sap flow and dries the olive branches.
When there are high populations of borer, the damages can be considerable. However, applying the appropriate cultural measures manages to keep this insect at bay.
Otiorhynchus of the olive tree (Cribricollis Othiorrhynchus)
The Otiorhynchus, weevil beetle or beetle of the olive tree (Cribricollis Othiorrhynchus Gyllenhal, 1834), is a pest of little impact on the traditional olive grove. On the other hand, during the development phase of the new plantations, damages may occur that require the application of control measures. Adults feed at night, taking refuge in the day.
This olive tree disease, also known as tizne or fumagina, can affect citrus species, plants… The sooty mould is a fungus that feeds on the sugary excretions that sap sucking insects produce. This black fungus, prevents or reduces the photosynthetic activity of the leaves on which it sits, weakening infected olives.
Olive bud mite
The olive bud mite is a disease caused by four different species of erythroids. These mites of the Eriophydae family are very small in size (0.1-0.35 mm), and the use of the microscope is necessary for visualization.
It is not usually necessary to carry out treatments, being the most frequent applications in the new plantations and in the olive grove.
Olive leaf moth (Palpita unionalis)
The Olive leaf moth, feeds in its larval stage the tender shoots of the olive tree. This pest affects mainly during the growth of olive seedlings. Therefore, it is usual to perform control treatments in the new olive groves.
The louse or olive violet scale (Parlatoria oleae Colvée, 1880) is a pest that produces damage mainly in olive tree groves. The spots that occur in olives depreciate their commercial value. Therefore, control treatments are usually carried out in the olive groves that were affected during the previous harvest.
Ceramida (Melolontha papposa)
Ceramida or white grub of olive tree (Melolontha papposa Illiger, 1803). It is a beetle larva that feeds on the roots of the olive tree. Large larvae feed exclusively on the roots of the olive tree and can cause significant damage when populations are out of control.
Liothrips oleae also known as olive louse, Liothrips oleae Costa. Its presence is usually small and usually does not present problems.
Euzophera pingüis Haworth, 1811. The larvae feed on the bark and wood of the olive tree, weakening the affected trees. It is parasitized by several insects, which reduce their presence to levels that do not usually require the application of control measures.
Olive leaf spots (Pseudocercospora cladosporioide)
The leaded or olive leaf spots is caused by Pseudocercospora cladosporioides, Braun 1993. However, this is less harmful than the olive peacock stain and is a secondary disease. The plumbing of the olive tree is more difficult to treat when it is located on the underside of the leaf.
Olive fruit rot
The olive fruit rot or shield is caused by the fungus Camarosporium dalmaticum (Thüm. 1979) or Dalmatian Sphaeropsis. It causes damage to the surface of the olive and the price of olives is reduced, being less profitable to green. The cupric treatments and the actions against the olive fly help keep this olive tree disease under control.
Olive Leprosy (Phlyctema vagabunda)
The olive leprosy is caused by Phlyctema vagabunda (until recently, known by Gloeosporium olivae Foschi, 1955).
It is a little known disease, but with an emerging character in the olive grove.
This is due to being less sensitive to copper treatments than other fungi that affect the olive tree.
Prolonged storage of olives after harvesting may cause fungi to appear. These mushrooms known as olive rot reduce the quality and the price of olive oil.
The gill nematode (Meloidogyne incognita), is a disease which barely affects the traditional olive grove. However, the spread of infected olive plants must be controlled in nurseries.
Olive tree root asphyxiation
Excess moisture in the soil is not beneficial for the olive tree.
Olive tree root asphyxia may cause weakening, chlorosis, yellow leaves, fall of olives, defoliation and appearance of fungi in the trunk of the olive tree.
Treatments for olive oil and table olives
The date and treatments for the olive oil are more flexible and less demanding than for the production of table olives. This is because the presence of defects is more visible in the table olives, so a more demanding control of pests and diseases that affect the olive tree is necessary..
In the case of olive cultivation for olive oil production, with two treatments with fungicides per year and if any specific treatment is necessary for pest control or correction of nutritional deficiencies, is usually enough.
On the other hand, table olives, in addition to the previous treatments, need greater monitoring and control of diseases (leprosy, shield…) and pests (violet scale, erinosis, olive fly…)
The above information is of a general nature and may vary depending on various factors. Before the application of control measures and treatments. It is advisable to receive advice from technicians and researchers based in our cultivation area. This will allow us a more adequate and precise control of pests and diseases of the olive tree.
We have translated the information on our website from Spanish to English. Note that some words may have seen their meaning altered during their translation.
4 thoughts on “Olive tree diseases and pests”
Hi I have a new mature olive tree. It has had Peacock spots and yellow leaves. I have removed affected leaves, pruned to open up the tree to light and air, also sprayed anti fungal each month during summer and autumn. But I noticed a white fungus growing at the earth line soon the main trunk.It is white with brown tinged and when removing it inside is tough pink and flesh like. I removed as much as possible and have sprayed entire area with anita fungal treatment. There were also white miscillea in the surrounding soil. I suspect I need to improve soil drainage but would appreciate and advice from the experts?
Many thanks and kind regards
I am trying to find a certified tree doctor(arborist) for a fruitless olive tree. The tree was last cut in October of 2019. I have notice the three large branches have large amounts of brown leaves. I have never seen the tree like this so I am thinking it is diseased. The tree is at least 50 years old with a 4 to 5 foot around trunk with a 14 to 18 foot height(I think). I need a certified tree person for diseased trees specifically olive trees that can consult with me to tell me what needs to be done make and keep the tree healthy and is near my area. The tree is absolutely gorgeous and want to keep it healthy. I live in Oxnard California (Ventura County)
I think you have done a good job taking care of the olive tree. Soil fungi are difficult to treat and usually affect centuries-old olive trees without apparently great consequences. Improving soil drainage and reducing the presence of moisture near the trunk can help. Also the treatment with soil fungicides, techniques such as solarization or raising the pH somewhat with slaked lime could help.
I appreciate the broad look at the diseases that affect olive trees. Im wondering if there is a “shotgun” fungicide/pesticide that gets the broadest impact on the various fungi and insects. I too have a large ornamental olive that gets dusty white on the leaves and has some kind of insect that leaves sort of a sticky residue. The tree gets stress from whatever these conditions are and Id like to know a general spray that I can use. Thanks.