Lemon tree pests and diseases

Lemon Tree Pests and Diseases; Prevention and ControlLemon Tree Pests and Diseases; Prevention and Control

Lemon tree pests and diseases infestations have crippled the citrus farming industry worldwide. If your lemon trees are plagued by lemon tree pests and diseases here are prevention, control and treatment tips for you.2

Acceptable farming practices can keep pests and diseases at bay. Citrus trees like full sun and warm tropical climates. Similarly, so do lemon trees.

When the environmental conditions change from the optimum required, the lemon tree becomes more susceptible to disease and pest attacks.

One of the challenges you will have in a lemon garden is the notorious pests and disease as a lemon farmer. In case your lemons are being attacked by any pests or disease, read on to find out how to identify them and manage them successfully.

Lemon tree pests and diseases-wilted leaves

Lemon tree pests and diseases

There are different pests and diseases that affect the lemon tree. Read on, for an in-depth analysis of lemon tree pests and diseases

Common lemon tree diseases causes and treatment

The majority of lemon diseases are fungal or bacterial. However, you may have viral infections here and there. Sometimes lemon trees will suffer from diseases caused by nematodes.

Fungal diseases are prevalent because of the climate that lemon trees like to grow in, which are ideal for fungi. Tropical warm and wet climates are the perfect incubation spots for fungi and bacteria. This makes the lemons susceptible to attacks because they’re sharing habitat with the pathogens.

Lemon tree Fungal diseases

1. Greasy spot

The greasy spot is a fungal disease that attacks the leaves of a lemon tree. The greasy spot causes swelling on the lower surface of a leaf and yellow mottle but on the swelling’s upper surface.

As the infection grows, the greasy spots collapse, and they turn brown or even black. Once the leaf has reached the stage of infection, the leaf falls off. 

Greasy spots can be controlled and prevented by spraying copper fungicide on the Lemons before spring.

2. Scab

What citrus scab looks like on lemon trees

Citrus scab is a fungal infection identified by circular swellings elevated above the lemon’s skin. The infection is wart-like with a corky covering.

Citrus scab does not affect the edibility of the lemon fruit. Still, it’s just unsightly and will lower the quality and value of the fruit. 

Similar to greasy spots, citrus scab can be controlled by spraying copper fungicide on the lemon tree.

3. Root rot and dry root rot

Root Rot is a fungal disease that can be exacerbated by moist conditions in the soil. The fungus Phytophthora spp. survives in moist soils and thrives in water-saturated soils.

Consequently, this fungus causes a severe soil-borne disease to lemon tree root. However, the trunk, and the shoot system above can also be affected by the fungus.

In moist soil, the fungus enters into the roots of the citrus lemon trees. After that, it causes an infection that can be identified by discoloration, softening of the roots tissues, and decay of the fibrous roots.

While you cannot reverse root rot, you can practice best farming practices, including adequately watering and fertilizing to encourage new root growth to save the plant. 

4. Gummosis

Gummosis is a viral disease. However, gummosis typically occurs when a tree has a perennial or bacterial canker. Gummosis infection causes the plants to ooze sap.

Gummosis is like a lemon tree’s distress call to several infections. To clarify, Gummosis occurs from infection by an opportunistic fungus that attacks wounded and distressed trees. 

Lemon tree gummosis

The most common entry mode for this fungus into the lemon tree is through wounds. For instance, pruning cuts, sunscalds, cold, and sometimes deer rubs. 

Since gummosis is challenging to control, the best way to manage this condition is to prevent it from occurring by covering any tree’s open wounds with antiseptic whitewash.

Because this fungus is optimistic and attacks weakened trees, you can prevent Gummosis by fertilizing. Fertilizer application strengthens the tree and increase its resistance to attacks.

Lemon tree Bacterial diseases

5. Citrus variegated chlorosis

Citrus variegated chlorosis is a citrus disease is a bacterial disease. The bacteria lives and multiplies in the sap of citrus plants. Sap-feeding vectors are the culprits that spread Citrus variegated chlorosis.

The bacterial population increases. As a result, it blocks the xylem vessels and blocks water uptake by the plant. 

Citrus variegated citruses chlorosis in the early stages of infection can resemble zinc deficiency by showing severe chlorosis between veins and lesions with time. However, the lesions become gummy and reddish-brown, especially on the underside of the leaf. 

The best way to keep this deadly disease at bay is to observe high hygiene levels at the farm.

You can reduce Citrus variegated chlorosis by ensuring that the propagation material seedlings you use on your farm are free of pest attacks by keeping any farm equipment disinfected. 

6. Citrus canker

What citrus canker looks like on lemon trees

Citrus canker is a bacterial infection. Xanthomonas axonopodis is the bacterium to blame for citrus canker. The disease affects leaves, twigs, and fruit of citrus plants, including lemons. One significant consequence of this disease is leaf drop and unripe fruit fall.

When bacterial citrus attacks a lemon, the canker causes lesions on the leaves, stems, and lemon fruits. The lesions are yellow to brown colored.

Citrus canker does not affect the edibility of lemon fruit. It only reduces the fruit’s marketability.

Citrus canker has no cure. However, you can control it by spraying with copper fungicide.

Lemon tree Viral diseases

7. Tristeza

Tristeza is a viral disease. Brown citrus aphid vector this disease The aphids acquire the virus after feeding on an infected plant.

Suppose the very same aphids feed on another plant within 24 hours, in that case, they will spread the virus.

Tristeza’s significant symptoms are three; a quick decline of the plant, stem pitting, and if it is at an early stage, the seedling yellows. Other symptoms include:

  • Chlorotic leaf flecking
  • Vein clearing
  • Leaf cupping
  • Corking of leaf veins.
  • Reduced fruit size

Tristeza can be majorly avoided by ensuring that the budwood used for grafting is free of Tristeza infection. You can achieve this by checking the budwood for grafted transmissible diseases.

8. Leprosis

Leprosis is a viral disease that is transmitted by false spider mites. Meanwhile, this virus is often localized in a particular plant part and is rarely transmissible.

However, in instances where there is short distance to the mid-vein and secondary veinlets, leprosis will spread.

This disease has varied symptoms, for instance, shallow foliar lesions that appear on both sides of the leaves, lesions on lemon fruit that appear as flat or depressed spots on the upper rind. On the stem, the disease causes shallow chlorotic lesions may become darker and red-brown.

Leprosis in lemons does not have a cure. However, you can control it by reducing vector mite population and pruning of diseased parts of the plant.

Common lemon tree pests and treatment

There are various pests that affect lemon trees. However, the most common ones are insects, larvae, and nematodes.

The pests range from flies to larvae of different insects through spiders and caterpillars all the way to mites.

Read on for information on common pests that affect lemon trees and how they can be treated.

1. Mite lemon tree pests

What spider mites look like on a lemon tree

Citrus mites are associated with severe symptoms. For instance, defoliation, diminished general health, and production of the plant. Many varieties and species of the mite pests, but the most common ones are the red mites, Texas mites, and dust mites. 

Small mite populations are not harmful to the plant, and a lemon tree will continue to survive. However, large populations of mites can result in leaf deformation and fall and sometimes premature fruit fall. Mites suck the plant’s nutrients. As a result, large populations can result in malnutrition of the lemon tree.

Although mites are often confused with being insects, they are not, and common insecticide may not work on them because, in actual essence, mites are arachnids. Spider mites can be controlled by the use of miticide. Ladybugs also feed on mites, so the next time you see a ladybug walking on your citrus tree, do not kill it.

2. Aphids lemon tree pests

Aphids are small soft body insects that feed by sucking up the nutrients in the sap of plants.  Different aphids species can appear white, black, brown, gray, yellow, light green, and sometimes pink.

Like other stuff, feeding pests offers them to cause the host plant to suffer symptoms of malnutrition and lack of nutrients. The most common acid infestation symptoms include stunted growth yellowing of leaves, leaf curl, and honeydew on the leaf or stem surface.

Aphids multiplying propagate so quickly that a farmer needs to cut their population before reproduction starts. A gardener can control its population by spraying cold water on the leaves and dusting the plants with flour. Flour constipates the pest. You can also use neem oil and other horticultural oils.

Some Farmers have reported success by trying companion farming, such as planting catnip near lemon trees to repel aphids.

3. Scale insects lemon tree pests

Citrus scale

Scale insects are of numerous shades and color. Over 1000 species of scale insects have been documented. The most common species are snow scale, red scale, brown scale, and black scale.

Scale insects are generally of two types; soft scales and armored scales.

Armored scale, also called hard-scale insect, secrets a hard protective covering which isn’t attached to the body. The hard scale lives under that protective shell and does not secrete honeydew.

Soft scale security waxy film that is part of the body. Soft scale insects also produce large amounts of honeydew to attract ants to protect them. 

Unlike hard scale, soft scale produces honeydew to attract ants. They have a symbiosis relationship whereby the ants protect the scale, and the ants benefit by getting honeydew.

Scale insects attach themselves to twigs, leaves, and branches of fruit host plants. They are immobile pests and almost resemble shear-like bumps growing on the plant.

Scale insects are sap feeders, and the large infestation can cause low lemon tree growth, reduced plant vigor, and chlorotic leaves. If scale insects are not controlled, the infected host may weaken and later on die.

You can get rid of scale insects by pruning and disposing of infected branches, dabbing individual pests with an alcohol-soaked cotton swab. You can also use neem seed oils, but you mustn’t use neem oil products during the day because it might burn the leaves.

Chemical controls include using Orange guard, AzaMax, and orchard spray.

4. The notorious Mealybugs

Mealybugs on a lemon tree

Mealybugs are the notorious white bugs that they see me possible to deal with. Technically, mealybugs are scale-insects, but unlike the other scale insects, adult mealybug females are motile. In contrast, other scale insect females lose their legs with age. 

Mealybugs are successful because they secret a white powder covering, which protects them from predators. Apart from causing malnutrition to a plant, mealybugs are also notorious for spreading infection from one plant to another.

Like other scale insects, Mealybugs often have a symbiosis relationship with ants where the ants protect them from predators while giving the ants honeydew. If you can prevent the ants from climbing up to the plants using a pest trap, you make the mealybugs susceptible to predators.

Because of the powdery covering with mini bags, it is difficult to kill them with pesticides. However, you can control mealybugs populations by wiping them off with a cotton swab dipped in rubbing alcohol. 

Natural pesticides for lemon trees pests and pest-vectored diseases

The organic movement has got many farmers looking for organic and natural options for synthetic and harmful pesticides. Synthetic pesticides build resistance in the past population, besides. Still, they’ve also been found to bioaccumulate in the environment and in the tissues of living organisms.

You do not need to be stuck about finding natural replacements for pesticides because listed below or home pesticide replacements.

1. Oil

The oil suffocates pests and kills them off. Oil cuts off the oxygen supply to the pest, and that is what eventually kills it.

2. Spices

Spices of and have that cake and dimension of flavor that pests dislike. 

Cinnamon kills pests.

Adding cayenne pepper to homemade pesticide sprays will repel any pests because most of them cannot stand the pepper’s spiciness and heat

3. Insecticidal soap

Soap is a natural disinfectant and kills an array of tests from microorganisms all the way to aphids scale and even larger pests. 

The antiseptic qualities of soap I would make it fit to be used as a cleaning reagent. 

To make your own insecticidal soap at home can combine three tablespoons of soap to one gallon of water.

4. Water

If you have a high power hose, you can use it to blast pests from your lemon tree.


How do I get rid of pests on my lemon tree?

You can get rid of pests on your lemon tree by practicing acceptable farming practices like the pruning of disease branches watering adequately and on time. If all else fails, spray with pesticide.

What do you spray on a lemon tree for aphids?

There very many sprays in the market that get rid of aphids. But to achieve maximum results from this product, you need to follow the application manufacturer’s instructions to the dot. 

Listed below are the most common sprays for aphids.
Neem oil
Insecticidal soaps
Horticultural oils

Diluted rubbing alcohol, which should be applied using cotton swabs.

What’s eating my lemon tree leaves?

There are very many pests that can eat up your leaves. However, the most common leaf eaters are.

Slugs and snails
Leaf miner, which is technically larvae of different insect pests, like flies.

What can I spray on citrus for bugs?

A soap spray like insecticidal soap is sufficient to control bugs for instance, mealybugs, thrips, whiteflies, and even aphids.
In addition, you can also try neem seed oil or any other horticultural spray.

Final thoughts

While pests and diseases are cumbersome problems that a lemon tree farmer is bound to experience, that shouldn’t deter you from growing your own lemons. Following the above procedures and tricks, a farmer can successfully beat any pests or diseases.

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