Try for Free
tab list
PictureThis
English
arrow
English
繁體中文
日本語
Español
Français
Deutsch
Pусский
Português
Italiano
한국어
Nederlands
العربية
Svenska
Polskie
ภาษาไทย
Bahasa Melayu
Bahasa Indonesia
PictureThis
Search
Search Plants
Try for Free
Global
English
English
繁體中文
日本語
Español
Français
Deutsch
Pусский
Português
Italiano
한국어
Nederlands
العربية
Svenska
Polskie
ภาษาไทย
Bahasa Melayu
Bahasa Indonesia
This page looks better in the app
picturethis icon
Instantly identify plants with a snap
Snap a photo for instant plant ID, gaining quick insights on disease prevention, treatment, toxicity, care, uses, and symbolism, etc.
Download the App for Free picturethis icon
Continue Reading
Black walnut > Dark spots
Why Does Black walnut Develop Dark Spots?
Black walnut, also known as Eastern Black Walnut, Eastern american black walnut
Dark spots is a harmful disease that affects the Black walnut by causing unsightly blemishes on its leaves, inhibiting its overall growth and health. The disease is primarily caused by fungi and can lead to significant losses if not properly managed.

Symptom Analysis

The main symptoms include the appearance of small, round, dark-brown or black spots on the leaves. As the disease progresses, these spots may coalesce, causing extensive browning and premature defoliation.
Plant disease auto-diagnose & prevention
AI-powered plant doctor helps you diagnose plant problems in seconds.
Download the App for Free

What Causes Dark spots Disease on Black walnut?

Fungi
The dark spots on Black walnut are primarily caused by a group of fungi, including Marssonina juglandis and Gnomonia leptostyla, that thrive in wet, humid environments.
Optimize plant health with ideal lighting
Find the best spots for them to optimize their health, simply using your phone.
Download the App for Free

How to Treat Dark spots Disease on Black walnut?

Non pesticide
Good sanitation: Regularly remove and properly dispose of infected leaves to reduce the source of fungal spores.

Proper spacing: Ensuring good air circulation by appropriate spacing of plants reduces humidity, limiting fungal growth.
Pesticide
Fungicide application: Application of fungicides containing mancozeb or copper hydroxide can effectively control the fungus causing dark spots.

How to Prevent Dark spots on Black walnut?

Regular Inspection
Frequent inspection can help detect early disease symptoms, allowing for timely management before the disease becomes established.
Proper Irrigation
Avoid overhead irrigation which creates a humid environment favoring disease onset.
Get tips and tricks for your plants
Keep your plants happy and healthy with our guide to watering, lighting, feeding and more!
Download the App for Free

When is Dark spots Most Active Period on Black walnut?

The disease is most active during the wet, humid seasons, particularly in spring and summer, when the fungi spores are easily spread through rainfall and wind.

Infectivity

Spores can easily spread to nearby Black walnut plants via wind or rain splash, making it highly infectious.

Lethality

While not immediately lethal, if left untreated, the disease can severely weaken the Black walnut, making it more susceptible to other diseases and pests.

FAQs on Black Walnut

How can I identify dark spots on my Black walnut?
Symptoms include small, round, dark-brown to black spots appearing on leaves. The spots may enlarge and merge over time, causing the leaves to brown and fall off prematurely.
Is dark spots disease fatal to Black walnut?
While not immediately fatal, if left untreated, it can significantly weaken the plant, leading to increased susceptibility to other diseases and pests.
Does dark spots disease spread to other Black walnut plants?
Yes, the disease is highly infectious and can easily spread to nearby plants through wind and rain splash.
How can I control dark spots on my Black walnut without using pesticides?
You can control it by practicing good sanitation such as properly disposing of infected leaves and ensuring proper plant spacing to reduce humidity.
Can fungicides eliminate dark spots on Black walnut?
Yes, fungicides, particularly those containing mancozeb or copper hydroxide, can control the fungus causing dark spots.
What preventative measures can I take to protect my Black walnut from dark spots?
Regularly inspect your plants for early signs of disease, practice proper irrigation to reduce humidity, and keep the plants properly spaced to allow good air circulation.
Discover 4 Exciting Reasons to Choose PictureThis
Instantly identify plants with a snap
Plant disease auto-diagnose & prevention
Get full care tips and tricks for your plants
Identify toxic plants around you
Download the App for Free
close
close
Your Ultimate Guide to Plants
Identify grow and nurture the better way!
product icon
17,000 local species +400,000 global species studied
product icon
Nearly 5 years of research
product icon
80+ scholars in botany and gardening
ad
ad
Botanist in your pocket
qrcode
PictureThis Ios DownloadPictureThis Android Download
Scan the QR code with your phone camera to download the app