What Is Lilly Disease? How to Prevent?

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Lillies are gorgeous perennials grown from bulbs. They produce colorful flowers in late spring or summer. They are grown for bulbs, like garden flowers, or potted plants.

They add value to your garden when healthy and vigorous. Unfortunately, these flowering plants are prone to diseases and viruses that badly affect crop production.

The common Lilly diseases include Basal rot, Botrytis, stem and bulb rot, and powdery mildew. However, lilies are also susceptible to Tulip Breaking Virus or TBV, Lilly Symptomless Virus or LSV, and Cucumber Mosaic Virus or CMV. Prevention is the best method to control all of these Lilly problems.

If you notice unsightly flowers or foliage on your Lilly plants, it means your plant has fallen a victim to fungal or viral infection.

First, you need to identify the problem. For this, you’re totally in the right place 🙂 In this post, you’ll learn about the common diseases of Lilies. Besides, you’ll know how to prevent and control these diseases.

Let’s dive in to get to know more about the Lilly and the diseases it may be prone to…

Common Lilly Diseases

A healthy Lilly plant is more resistant to diseases and insects. While a stressed plant is susceptible to a lot of problems.

The common Lilly diseases include:

  • Fungal Diseases(Botrytis, Stem and Bulb rot)
  • Viruses

Mostly, the causes of Lilly’s problems are environmental conditions. Another main cause includes infected bulbs at the time of purchase from the nursery.

Lilly Diseases Caused By Fungus

Fungus is the main disease-causing agent in Lillies. Normally, fungal diseases of Lilies, if diagnosed in time, can be controlled by commercial sprays. However, a few diseases come back again and affect the nearby plants. The only solution is to destroy the plant and start with a healthy one.

Let’s have a look at the most common fungal diseases of Lilies.


Botrytis is the most serious problem of Lilies. It is caused by two fungi, B.elliptica and B cinerea. This fungal disease mostly affects the upper parts of plants like leaves, stems, flowers, and shoots. It highly affects the plants of warm, moist coastal climates as in the Pacific Northwest and west coast areas of Britain. However, the plants in cool and dry areas are not much affected.


  • White spots on the leaves.
  • Teardrop-shaped spots on the upper surface of leaves.
  • Darker spots with light margins.
  • Decaying and collapsing of leaves.


  • Use commercial fungicides spray, after every week, once the stem is 6 inches tall before flowering. The most recommended fungicide is the Bordeaux mixture with a combination of copper sulfate and slaked lime. It prevents the germination of spores. Spray the foliage as soon as you notice the spots.


  • The fungal problems are triggered after watering or rain. Therefore, maintain a google air circulation and allow the leaves to dry after watering.
  • Burn any infected leaves or stem fallen in autumn. Never add them to the compost bin as the spores can overwinter and reinfect the plant.
  • Avoid overhead watering and use a soaker hose or drip line as moisture helps to spread the problem to other plants.

Basal Rot/Fusarium

Basal rot or Fusarium is a serious disease of Asiatic Lilium. It is mainly caused by two different species of fungi, Fusarium oxysporum va lilii and Cylindrocarpon.Fusarium.

The Fusarium oxysporum affects Asiatic Lilium, while Cylindrocarpon damages Oriental Lilies.

The spores of Fusarium oxysporum can survive over winter and exist in the soil for years.

The fungus affects the roots and enters the basal plate and scales. It can be spread by infected potting soil, garden tools, or previously infected plant tissue.


  • Earlier symptoms are dark brown rot.
  • Failed root growth.
  • Premature yellowing of foliage
  • Infected basal plate


  • There is no control or solution of Basal rot or Fusarium infected plants. Remove all the infected bulbs, and plant healthy bulbs at some other place in the garden other than infected soil.
  • Destroy all the infected plant parts by burning.


  • Make sure to plant disease-resistant varieties.
  • Add well-rotted manure to keep the soil cool as Fusarium prefers warm soil.
  • Avoid using nitrogen fertilizer.
  • Lilies grow well in well-drained and moist soil. So, avoid over-watering during hot months. Transfer plants to the shade.
  • Make sure not to damage bulbs during weeding as fungus may enter the plant through these wounds.

Root Rot

Root rot is caused by poor maintenance. It is not a disease itself. The poor drainage and moisture retention in the soil result in root rot.

The main reasons for root rot are:

  • Poor drainage
  • Poor soil aeration
  • Bulbs sitting in water for long periods.

There is no solution to root rot. But it can be prevented by these steps.

  • Plant lilies in well-aerated soil to ensure oxygen supply to the roots.
  • Use lightweight and well-drained soil for planting.


Viruses affect the lilies by incorporating their own RNA and then replicating it into several RNAs that infect the other plant cells. As a result, normal plant growth is disrupted, and the virus takes control over the plant.

Mostly, viruses affect the tiger lilies and other oriental lily cultivars. The common viruses that affect lilies include;

  • TBV or Tulip Breaking Virus
  • LVS or Lily Symptomless Virus
  • CMV or Cucumber Mosaic Virus


  • Streaking or molting on the outer plant surface
  • Reduced plant size
  • Rings on the bulbs.
  • Flowers fail to bloom

Virus Transmission:

  • Aphids are the main cause of the virus transmission from one plant to another. These pests bite the infected plant and ingest the virus. Then they transmit this virus to other plants after biting.


  • Viruses are not controlled with sprays.The only control method is to take steps that can avoid further infection and transmission.


  • Control the aphid population in your garden by biological pest control.
  • Burn the whole plant infected by a virus.
  • Clean your garden tools with 100% bleach.
  • Try to purchase virus-resistant varieties of lilies.
  • The hybridization of viral-resistant cultivars is a good practice of virus control in future lily generations.
  • Regularly observe your plants for any symptoms of viruses.

Disease and Virus Be Gone

Hopefully, you are now fully ‘clued up’ on the main diseases and viruses that could spell disaster for your Lilly plants! Knowledge is power, as they say! Hopefully, you can now take preventative measures to make sure your Lillies can grow to a ripe old age 🙂