White Spots on Calla Lily Leaves – Causes and Solutions

If you’ve noticed unusual white spots popping up on the leaves of your calla lilies you’re not alone. These unsightly blotches can be alarming for any gardener. But don’t worry – with proper care and treatment your callas can recover.

In this article, we’ll examine what causes white spots on calla lily leaves, how to identify the problem, and most importantly – solutions to treat it effectively Read on to learn more!

What Causes White Spots on Calla Lily Leaves?

White spots appearing on calla foliage are typically caused by a fungal pathogen known as leaf blight or white blotch. The main culprit behind this disease is the fungus Stagonosporopsis curtisii. Spores of this fungus infect the leaves creating the white patches we see.

If left untreated, the spots enlarge and spread, eventually turning brown. Photosynthesis is reduced as more leaf surface area is affected. This subsequently leads to stunted plant growth, deformed flowers, and potentially death of the plant if it’s severe.

Leaf blight thrives in wet, humid conditions. Overhead irrigation and rainy weather causes it to spread rapidly. Once a few leaves show symptoms, it’s crucial to quickly treat the infection before it gets out of control.

How to Identify White Blotch on Calla Lily

Learning how to spot white blotch early is key, so you can treat your lilies right away before major damage occurs. Here’s what to look for:

• White or tan irregular spots on upper leaf surfaces, ranging in size. They may have faint darker borders.

• Spots grow larger and merge together over time, covering bigger areas of the leaves.

• Leaves with heavy spotting turn yellow, then brown and die off.

• If untreated, spots spread to more leaves and stunts growth. Flowers may be deformed.

• Fungal spores are visible under magnified examination of the discolored patches.

Thoroughly inspect all sides of the foliage at the first sign of trouble. Catching it early makes treatment much more effective!

How to Treat White Spots on Calla Lilies

If your calla lilies have fallen victim to white blotch fungus, there are several effective treatment methods to restore their health:

Improve Air Circulation

Improve air flow around the plants to prevent the moist, stagnant conditions the fungus thrives on. Space plants out, prune congested growth, and use small fans if needed.

Avoid Overhead Watering

Water at the soil level rather than wetting the leaves. This prevents fungal spore spread. Or install drip irrigation. Water early in the day so leaves dry out.

Use Fungicides

Fungicides containing chlorothalonil, mancozeb, myclobutanil or thiophanate-methyl can effectively treat leaf blotch. Always follow label directions. Repeat applications may be needed.

Remove Infected Leaves

Pick off and destroy badly infected leaves to prevent further spread. Sterilize pruners between cuts with bleach or alcohol. Remove fallen debris around plants.

Improve Soil Drainage

Stagnant moisture fosters fungus. Make sure callas have excellent drainage. Add organic material like compost to improve drainage in heavy clay soils.

Allow Soil to Dry Out

Don’t overwater. Allow the top few inches of soil to partially dry between waterings. Test moisture before adding more. Proper soil moisture discourages fungal growth.

With prompt treatment, you can get those gorgeous calla lilies looking healthy again and blooming beautifully! Be vigilant and take action at the first sign of trouble.

How to Prevent White Blotch on Calla Lilies

Once you’ve tackled an infection, it’s wise to take proactive steps to prevent white blotch problems recurring in the future:

• Select disease-resistant calla lily cultivars when possible. Look for newer bred varieties with improved resistance.

• Avoid overhead watering. Use drip irrigation or direct water at the soil level instead.

• Space plants out for good air circulation. Make sure they are not crowded.

• Water early in the day so leaves have time to dry out before nightfall.

• Clean up and remove all fallen leaves and debris around plants.

• Disinfect pruning tools after every cut by dipping in alcohol or a bleach solution.

• Scout plants frequently and treat promptly at the first sign of infection.

• Apply fungicide drenches at the start of the wet season as a preventive measure.

An ounce of prevention is truly worth a pound of cure when it comes to avoiding fungal problems on calla lilies. Be vigilant and act fast if any spots do pop up.

Common Mistakes That Make White Blotch Worse

It’s important to avoid certain mistakes that can exacerbate white blotch fungus on calla lilies:

• Continuing to use overhead watering methods after symptoms appear

• Planting callas too densely without enough spacing for air circulation

• Not removing infected leaves promptly, allowing spores to spread

• Applying too much nitrogen fertilizer, resulting in succulent growth prone to fungus

• Allowing leaves and debris to remain on the ground providing inoculum

• Poor drainage resulting in soggy soil that promotes fungal growth

• Not varying fungicides used, leading to resistance buildup

• Stopping treatment too soon before infection is fully resolved

With knowledge and vigilance, you can sidestep these missteps and effectively manage this common but treatable disease.

Calla Lily Varieties that Resist White Blotch

While no calla lily variety is 100% immune to white blotch, certain cultivars demonstrate better resistance than others. If you’ve battled leaf blotch fungas before, consider these more disease-resistant options:

• Calla Lily ‘Green Goddess’ – Deep green leaves with white flowers.

• Calla Lily ‘Black Star’ – Dramatic dark purple foliage.

• Calla Lily ‘Pink Diamond’ – Pink blooms rise above green and white variegated leaves.

• Calla Lily ‘Ben Vernooij’ – Vigorous grower with purple-red spathes.

• Calla Lily ‘Captain Ventura’ – Yellow blossoms and good resistant to leaf spotting.

There are many other resistant calla lily hybrids out there – check with your local nursery to find the best choices for your climate. A little planning goes a long way!

No calla lily is 100% immune to the ravages of white blotch fungus. But with proper cultural practices, prompt treatment at first signs of infection, and choosing resistant varieties, you can continue enjoying gorgeous, healthy calla lilies in your garden. I hope these tips help you troubleshoot and conquer any fungal problems that may arise!