How to Effectively Treat Fungal Disease on Roses and Flowers Fast

Written by: Vanessa Dawson

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Time to read 2 min

If you’ve noticed brown spots, yellowing leaves, or powdery patches on your roses or flowers, you’re likely dealing with a fungal disease. And in warm, humid summer conditions, fungal infections can take over quickly—damaging your plants and ruining seasonal blooms.


The good news? Treating fungal disease doesn’t have to be complicated. With the right organic fungicide and some quick action, you can stop the spread and restore your flowering plants to full health—without risking harm to pollinators, pets, or your family.

What Are the Signs of Fungal Disease on Roses and Flowers?

Fungal diseases show up in a few telltale ways:

  • Brown or black spots on leaves

  • Yellowing or premature leaf drop

  • Powdery or fuzzy coatings on leaves and stems

  • Wilting or weakened blooms

These symptoms can signal common fungal issues like black spot, powdery mildew, rust, or blight all of which can spread quickly from leaf to leaf and plant to plant.

Why It’s Important to Act Fast

Fungal disease thrive in warm, damp conditions—like those found in summer gardens. Once the spores take hold, they can quickly weaken plant health, reduce flowering, and even kill vulnerable blooms. The longer you wait, the harder it is to control the damage.

The Best Way to Treat Fungal Disease Organically

The easiest and safest way to treat fungal disease on roses and flowers is with an organic, ready-to-spray fungicide like Arber’s Organic Fungicide for Rose & Flower.


Here’s why it works so well:
✅ Easy to Use – Just attach it to your hose and spray—no measuring, no mixing
✅ Fast-Acting – Starts working on contact to stop fungal growth
✅ Safe for Kids, Pets, and Pollinators – So you can treat with confidence
Organic & OMRI-Listed – Trusted by gardeners who care about clean growing


To apply, simply spray the infected plants—focusing on the tops and undersides of leaves—and reapply every 7–10 days or after rain for best results.

How to Prevent Fungal Disease in the Future

Once you've treated the current outbreak, prevention is key. Here’s how to keep your plants protected:

  • Avoid overhead watering to reduce moisture on leaves

  • Prune regularly to improve airflow between plants

  • Apply fungicide preventatively during warm, humid weeks

  • Clean up fallen leaves and debris around your garden beds

"After using Arber's Bio Insecticide on my tomatoes and cucumbers, I saw a major drop in aphid activity. It's now a must in my weekly garden routine!"

— Jamie R., CA

Fungal diseases are common, but with Arber’s Organic Fungicide for Rose & Flower, you can treat fungal issues quickly, safely, and easily.


Ready to treat? Shopw now and protect your roses, rhododendrons, and beyond.

FAQs

How often do I use the Organic Bio Insecticide if I already have an infestation?

We recommend first pruning or cleaning the infested areas and regularly removing debris or adult insects from the plants. Then, follow this method by treating your plant with our Organic Bio Insecticide as a foliar spray and a soil drench once every 5 days until the infestation is under control. Once the infestation is under control, we recommend continuing to treat your plant with our Organic Bio Insecticide every 2 weeks for prevention.

How does the Organic Bio Insecticide get rid of bad bugs while keeping good bugs safe?

When Organic Bio Insecticide is applied, the plant becomes inoculated with the naturally occurring bacteria. The pest then feeds on the plant and gets a dose of the bacteria, which stops feeding or molting, then dies naturally. Beneficial insects feed on the pests, but don’t get enough of a lethal dose of the bacteria for it to affect them because it does not have any effect on insects in the Hymenoptera family.

What plants can I use the Organic Bio Insecticide on?

All of our organic formulas are versatile and highly effective on all plants, indoor and outdoor. Including, but not limited to, houseplants, trees, shrubs, flowers, fruits, vegetables, lawn, seedlings, and more!