For questions related to plant diseases.

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22
votes
7answers
22k views

What are these hard white/brown spots growing on my houseplant?

A little more then an year ago I got six palm trees (two vases). It was the Californian equivalent of an Areca palm (the guy in the nursery suggested this one after I asked for an Areca for its air ...
21
votes
6answers
473 views

Is it necessary to purchase seed potatoes?

I recently tried growing potatoes using a method I saw on TV. This is just cutting up potatoes into reasonable sized sections and placing them several inches down. The results have been fantastic. ...
15
votes
4answers
1k views

What else besides calcium deficiency could be causing tomato blossom end rot?

I've been using "Tomato Maker" (4-2-6) fertilizer, which supposedly has enough calcium to prevent blossom end rot, but I'm still getting blossom end rot on my super marzano tomatoes (no BER problems ...
13
votes
1answer
873 views

tomato plant rotting from the inside — what's going on?

I have a hydroponic garden in a greenhouse in my yard. Everything was going just great until today when I noticed that one of the 7 or so tomato plants (the biggest one in fact) was looking rather ...
13
votes
3answers
13k views

What is happening to my chilli plant? How can I help it?

Some white spots appeared recently on my Twilight chilli plant (indoors), on some leaves brown spots start appearing in the middle. First I thought - aphids, but it doesn't quite look like insects. Or ...
12
votes
3answers
5k views

Why have my tomato leaves started yellowing at the base?

One of my tomato plants (Better Boys if that matters) has a few leaves that have started yellowing on the lower branches. Not sure if they aren't getting enough water, or if they are diseased or what. ...
12
votes
5answers
5k views

What do I do about the whitish powdery mold on my peonies?

Very early this year (starting in mid-May) my peonies' foliage was covered in whitish-gray powdery mold. What is it and what if anything should I do about it?
12
votes
3answers
3k views

What's attacking one Lupin but not its neighbor?

I have two Lupin plants next to each other in my front yard: They are both Russell hybrids, both grown from seed and planted there at the same time in Spring 2009. The one on the left is healthy, ...
11
votes
4answers
13k views

Sudden Outbreak of Yellow Leaves on Tomato (and Other) Plants

My mother was in a panic this morning. She called me over to help her with her garden because many of her tomato plants had suddenly developed yellow leaves, many of which (but not all) also have ...
11
votes
1answer
795 views

What are these brown, cap-shaped mushrooms on my birch tree?

I live in Massachusetts and have several birch trees in my yard. One of them has brown, cap-shaped mushrooms growing in groups up and down the trunk. As you can see, the tree has a big crack in the ...
11
votes
2answers
15k views

Brown Spots on peppers

I have been growing peppers this summer and they have been doing great. The fruit is really starting to take off, but now I have 3 or 4 of my larger fruit getting these brown spots. This is a Red ...
11
votes
2answers
3k views

How to treat a succulent with holes in its leaves?

I have a succulent plant that got some disease and is covered with holes. The holes started to appear a month ago. At first they were green (like something was eating it), probably growing and then ...
10
votes
2answers
2k views

How dangerous are the roots of brassicas (cabbage, broccoli etc)?

I've read that putting the roots of brassicas in the compost is a bad idea because of the risk of disease. I've also read that you shouldn't even plant them in the same spot for three years! What ...
10
votes
2answers
964 views

What is this brown, shell-like thing growing on the stalk of my avocado plant?

Could you please help identifying this brown shell-like thing growing on the stalk of my avocado plant? There are several of these. It looks like a little shell (with the appearance of a woodlouse'...
9
votes
2answers
4k views

Why is my pear tree dying around the blossoms?

Shortly after the blossoms fell on my pear, areas around the blossoms started to turn black and die. This is spreading. Although the dead areas tend to be on the end of the branches, there are ...
9
votes
2answers
148 views

Why are the leaves on my houseplant turning yellow and getting black spots?

I have this shade plant in my home. The leaves are becoming dry, turning yellow and developing black dots on them. I don't know whats wrong with it. If it's a lack of food, I can give it compost, ...
9
votes
2answers
923 views

What is the problem/disease that causes bobbly peach tree leaves?

What is the likely cause of the bobbly forms on the leaves of a peach tree? Does it matter or is it just some natural anomaly that doesn't affect the tree's health? If is it a concern how can it be ...
9
votes
5answers
102 views

What is wrong with my beefsteak tomato?

My beefsteak tomato is setting lots of fruit, but the larger leaves are curling, and have fine black spots. The pot is 24x24 inches, and the soil is miracle gro. It's new in this pot this year. ...
9
votes
2answers
116 views

What is causing irregular brown sunken spots on my tomatoes?

I have been growing tomatoes in the same spot in my garden for years. This year most of my tomatoes seem to be affected by a disease which only affects the tomatoes. I prune, water & fertilize the ...
9
votes
1answer
916 views

Why do my tomato leaves look powdery?

I have a threesome of tomato plants planted in on my porch. All three have some leaves that seem to be a bit white and powdery. One of the leaves has even started to turn a bit brown. I don't think ...
9
votes
3answers
5k views

Grapevine leaking water and white mucus

Problem While I was recently helping my mother prepare her garden for the spring, I discovered that the leak on her porch was not actually coming from the overhang above the door, but rather from a ...
9
votes
1answer
1k views

Why are the leaves of my pea plant (little marvel) drying up and turning brown?

The pea plant (Pisum sativum) was grown in an ebb & flow hydroponics system until it failed; now it's in a deep water culture unit. I noticed that the leaves were turning brown/grey. I thought ...
8
votes
4answers
31k views

What causes cucumber leaves to turn yellow, brown, wilt, die, and the plants to stop producing?

Every year it seems my cukes will go gang busters then suddenly the leaves turn yellow (starting with yellow spots), then turn brown, wilt and slowly die off. This all happens from the root crown and ...
8
votes
1answer
52 views

What is this Apple disease?

Close up of lesions Close up stem side I've had this Apple tree for a couple of decades which I had always assumed it was wild since it had always produced sour small apples. For some years the ...
8
votes
1answer
6k views

What is causing the bark on my crabapple to crack and peel off?

I have a flowering crabapple in my yard whose bark has several large areas where it cracks and curls away from the wood underneath: Hover over any image for description / click for full size I ...
8
votes
2answers
1k views

What is happening to the leaves of my avocado?

I have an avocado plant in my outdoors balcony. It's been growing nicely, but there are small brown dots/holes in the leaves for some time now. I don't see anything in the underside of the leaves, and ...
8
votes
1answer
2k views

Is something wrong with my zucchini plant?

I have three large zucchini plants in my garden, and all three have been producing nice fruits for a few weeks. The last couple days, one of them has started to turn yellow and sickly: I've never ...
8
votes
2answers
3k views

How do I treat rhubarb rust?

I have a small rhubarb plant and one of the stems has gotten some rust on it. What should I do? (there are only 3 small stems on the plant)
8
votes
1answer
2k views

Is there any cure or treatment for a queen palm tree diagnosed with fusarium decline?

A "certified arborist" looked at the tree (>20ft high) and determined that this was the cause. Some of the fronds in the tree seem frozen in place, while most have actually drooped down completely (...
8
votes
1answer
91 views

Is this powdery mildew on my tomato?

Just noticed this on my store bought plant (not grown from seed). It's now fruiting, and I don't see any white spots on the leaves. Update: 25 Feb 2016 with close up of the stems and an more ...
8
votes
2answers
143 views

Is my mint plant dying or diseased?

About a week ago I decided to propagate a healthy stalk of mint that I had bought from the grocery store. The roots appear to be healthy and full, but two of the leaves appear to be abnormal. One of ...
7
votes
2answers
15k views

Why does my blueberry bush have brown/scorched leaves?

I recently purchased a dwarf Northsky blueberry bush from a mail order company. When I recieved it, roughly 15-20% of its leaves had the appearance of being burned or scorched; the bad leaves were ...
7
votes
2answers
82 views

How to treat diseases and bugs on peach tree?

I have a young peach tree (18 months old, never gave fruits) in my yard in Florida that recently lost all its leaves. The leaves are eaten but also covered with brown spots. I'm wondering if the issue ...
7
votes
1answer
1k views

What is causing diseased leaves on my French beans?

My French bean plants have diseased leaves as shown below: What can be causing this? The beans themselves are relatively plentiful. Location: India. Weather In May-June: Hot! > 95F days. The ...
7
votes
1answer
138 views

Kentia palm dying. Advice? :(

I bought a kentia palm some months ago, and during the last week one stem/group of steams is turning out yellow. Also there are some big white stains on the leaves. Some leaves also have small white ...
7
votes
1answer
429 views

Basil: cold or disease?

A few days ago I put my basil outside. In a couple of days, the temperature fell considerably, and I think it got a shock, despite moving it back inside as soon as I could. I think this is the reason, ...
7
votes
2answers
107 views

To prune or not to prune tomato's lower leaves?

I battled early blight last year, so this year I laid down a thick bed of grass clippings as mulch in my raised beds to prevent splashing of the dirt onto the plants. Last night, simply out of habit, ...
7
votes
1answer
928 views

Will peach leaf curl affect my fruit?

My peach trees have peach leaf curl. (Spring came too fast this year, I wasn't prepared, and I didn't get a chance to spray.) They're still young/small trees (10' tall), but they've got a bit of ...
7
votes
1answer
6k views

Zucchini leaves yellowing - but not powdery mildew

I have about 8 zucchini plants, about 6- 8 weeks along, which are starting to show signs of disease on the leaves. It's definitely not powdery mildew, but the end result is quite similar. Leaves are ...
7
votes
1answer
57 views

Can I use waste water from kitchen for plants? [duplicate]

Can I use the waste water mixed with dish washing liquid from kitchen for watering my garden?
7
votes
1answer
163 views

Is this fig tree disease or just malnourished?

My folks in Berkeley, CA (San Francisco Bay Area) showed me their young fig tree the other day to see if I could figure out what was wrong with it, but I wasn't certain. I searched here (during title ...
7
votes
3answers
103 views

Dying Lawn - brownish/white with moss and clumps

I am trying to figure out what is killing my lawn. The pictures below were taken a few days ago.There is only the one area of this occurring and the yard is about 1/2 acre. The dead area has been ...
7
votes
1answer
261 views

How do I get rid of box rust in December? Will fungicide work?

I have two buxus which have suffered a lack of water due to irrigation failing in the summer and no time to hand water them. There is a definite orange tinge to the first 2 or 3 inches of top growth. ...
6
votes
6answers
8k views

Why are my cucumber leaves turning yellow?

My cucumber plant's leaves are turning yellow. Could it need nutrients already? It only germinated 24 days ago, but is my biggest plant already.
6
votes
2answers
729 views

What is causing the rotting/brown spots on my plum fruit?

I inherited a plum tree in my garden. I haven't yet been able to get a healthy looking plum from it. All the plums that turn to a ripe purple colour seem to have the following problem - Can anyone ...
6
votes
3answers
884 views

Are my tomato plants damaged by a chemical or a disease?

Most of my tomato plants have started showing signs of what I think is Cucumber Mosaic Virus. I have shoestring, fernleaf, and curling leaves. They also have a leathery appearance. At first I thought ...
6
votes
3answers
282 views

What's causing the edges of my blueberry leaves to burn?

Last year, this Sunshine Blueberry plant was doing stupendously - not a burned leaf in sight. Now most of the leaves appear like they're burning. Also, the fruit never mature to full size before they ...
6
votes
2answers
233 views

How to prevent rotten end of tomatoes [duplicate]

Possible Duplicate: What else besides calcium deficiency could be causing tomato blossom end rot? Each year my tomatoes develop a brown rotten area on the bottom of the fruit. I always add ...
6
votes
1answer
42 views

Can rubber gloves spread plant diseases?

I use thin rubber gloves when gardening. It's autumn here in zone 6, and I'm in the process of pruning and pulling up spent perennials and all manner of wildflowers which have been growing since the ...
6
votes
1answer
237 views

How can I control mint rust?

Sharing knowledge here: Since I live in the San Francisco Fog Belt, I suffer from a variety of soil-borne funguses, including mint rust. In fact, mint rust is so severe that in the past I've had to ...