How to tell if plant leaves have blight or pest damage
Visual symptoms like spots or discoloration often look identical across different diseases and pests, making it impossible to diagnose plants accurately from standard photos. This uncertainty leaves gardeners guessing whether to treat the issue or risk losing the plant altogether.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 212.3× more often in r/gardening than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Checking the inner foliage for webbing or spottingDid this help you?
- 2Cutting off blighted pieces to keep it from spreadingDid this help you?
- 3Checking for spider mites or bag wormsDid this help you?
- 4Considering heat stress and lack of waterDid this help you?
- 5Applying horticultural oil, sevin, or other pest treatments suggested by community membersDid this help you?
- 6Refusing to plant arborvitaes again in the futureDid this help you?
- 7Avoiding specifying conifers for landscaping projectsDid this help you?
- 8Digging up the plant to inspect whether the roots are mushyDid this help you?
- 9Amending the soil to improve drainageDid this help you?
- 10Reducing watering frequencyDid this help you?
- 11Replacing the plant with a different species suited to the locationDid this help you?
- 12cutting off the soft and mushy parts of the stemDid this help you?
- 13moving the plant to a bigger potDid this help you?
- 14asking for diagnostic help on gardening forumsDid this help you?
- 15evaluating recent weather patterns like heat and droughtDid this help you?
- 16pruning overgrown areas to see if health improvesDid this help you?
- 17Searching Google for symptoms like iron deficiencyDid this help you?
- 18Applying seaweed fertilizer and NPK 19-19-19Did this help you?
- 19Adding coffee grounds to the soil to boost nitrogenDid this help you?
- 20Posting photos on gardening forums for diagnosisDid this help you?
- 21Letting the soil dry out completely.Did this help you?
- 22Drilling extra drainage holes in the bottom of the pot.Did this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Hi, I'm new to gardening and first time growing saffron. Does saffron normally bloom like this or did it flower too soon?”source ↗
“The rest of the plant looks great and even the leaves on these limp branches are vibrant and rigid”source ↗
“Now that im home and its gotten rain its got a lot of yellowing and dropping leaves. It doesn't look as happy as it used to and I am unsure of what to do.”source ↗
“Definitely not overwatering but could be the small pot for sure”source ↗
“The leaves on my plants are either turning yellow and falling off like the hibiscus or growing in much lighter green than normal.”source ↗
“Some of these plants have shown some overwatering symptoms like edges browning. It will be blazing hot the whole week so they are watered daily but then it will for 2 days and the soil will stay moist. Not sure how to fix that.”source ↗
“However when I noticed my vincas turning yellow I added coffee grounds.”source ↗
“Any idea what's going on with the peach tree? Growing near Houston, TX USA. Looks diseased.”source ↗
“you're right i have never given it fertilizer cause im a newbie and didnt know. Ugh! Do I need to wait to do that until it dries out and do that with the watering?”source ↗
“Moving into a new house in North Carolina. What is killing my bushes and how should I treat it?”source ↗
“Is there something I should be doing to these to help them?”source ↗
“Probably blight, but I can't tell from the pictures.”source ↗
“One dog! He likes to run behind them”source ↗
“Why are my arborvitaes turning yellow? I planted them about a month and a half ago and after 3 days of rain i noticed yellowing on inner leaves.”source ↗
“I had 7 of these and down to 3. Such annoying drama queen trees to care of.”source ↗
“Can anyone tell me what’s going on with this boxwood ?”source ↗
“I have 12 arborvitae that look great but it's been a hard summer and I just noticed this!”source ↗
“Is it diseased?”source ↗
“These are beautiful but very unpredictable. I’m pretty sure it’s a weird kinda fungus that causes dieback in conifers.”source ↗