For questions about plant diseases.

learn more… | top users | synonyms (1)

20
votes
6answers
297 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
5answers
9k 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 ...
13
votes
1answer
543 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 ...
11
votes
3answers
840 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 ...
11
votes
2answers
4k 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. ...
11
votes
5answers
2k 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?
11
votes
2answers
2k 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
1answer
7k 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 ...
10
votes
1answer
6k 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 ...
10
votes
1answer
1k 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 ...
9
votes
2answers
1k 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 ...
9
votes
2answers
610 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 ...
8
votes
4answers
3k 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 ...
8
votes
2answers
2k 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 ...
8
votes
2answers
601 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 ...
8
votes
2answers
2k 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
987 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
702 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 ...
8
votes
3answers
2k 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 ...
8
votes
1answer
682 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 ...
7
votes
2answers
424 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 ...
7
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 ...
7
votes
1answer
771 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
428 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
207 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
2answers
190 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
2answers
8k 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 ...
6
votes
1answer
258 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, ...
6
votes
1answer
4k 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 ...
5
votes
2answers
450 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 ...
5
votes
1answer
2k views

What is this white mold infesting my tomato plants?

Some kind of white mold is infesting several of my plants, below is one of the worst infections of a tomato seedling. It is very aggressive, if I remove the top layer of soil it will come back in a ...
5
votes
1answer
752 views

White stuff on roots

When I uproot my vegetable plants or even sometimes when I remove weeds, I see this white stuff in the soil near the roots: http://imageshack.us/photo/my-images/717/img1014be.jpg ...
5
votes
2answers
190 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 ...
5
votes
1answer
64 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 ...
5
votes
1answer
110 views

What's affecting this tomato plant? [duplicate]

Can anyone tell what's wrong with this tomato plant? Is it disease or deficiency? My areas been having issues with late blight the last few years. One spot seems to have a concentric circle around it ...
5
votes
1answer
571 views

What's causing these yellow veins on my Okra leaves?

My Okra leaves have turned as shown below Is this a deficiency or a disease? How can I remedy this? Location: India. Weather In May-June: Hot! > 95F days. Current: Overcast with light rains.
5
votes
2answers
290 views

What is this disease on the growing tips of my peppers, and how can I control it?

Please have a look at these images of my hot pepper plant. Notice the growing tips which seem withered and diseased. What disease is this and what is causing this? What are the solutions to counter ...
5
votes
1answer
3k 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 ...
5
votes
1answer
2k views

What is the cause of the dead spots in my lilac bush?

Last year, we built a home and got a Lilac as part of our landscaping package. The landscaping was planted in August, so it's almost made it a full year now. In June, we started to see dead spots ...
5
votes
1answer
145 views

How to recover a stressed hemlock?

I have a well-established hemlock tree in my yard that has started producing large quantities of cones. This is apparently a result of it being "stressed" (according to a nursery worker and a ...
4
votes
2answers
342 views

What's killing this succulent?

The death toll of plants in my apartment continues to rise, having lost both a miniature rose and a rosemary plant to powdery mildew. Now something's killing one of my succulents. It was fine when we ...
4
votes
2answers
106 views

What are these small black things appearing on my cucumber leaves, and are they harmful?

There are these little black things on my cucumber plants that have started appearing recently. They are more concentrated towards the 'top' of the plant. They don't seem to be eating away the leaves ...
4
votes
3answers
198 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 ...
4
votes
2answers
55 views

Why are my plants doing badly for the 2nd year in a row?

I live in Marin Co. California, where summers have been mostly hot and dry, winters mild with rain. All my plants are in pots, excepting the trees that were already here when we moved in 15 years ...
4
votes
1answer
158 views

White, fur like strands and spots on underside of chilli plant leaves

I am growing scotch bonnet, jalapeno and cayenne pepper plants indoors from seed. The scotch bonnet plants have what looks like white fur growing around the veins on the underside of their leaves. ...
4
votes
1answer
79 views

What are these white streaks on my tomato plant?

I've also seen similar streaks on my basil's leaves but not as pronounced.
4
votes
1answer
180 views

What is wrong with my lemon tree? [duplicate]

Below is a picture of my lemon tree, which now have some sticky web infection. See left corner on the first picture. On the second picture is a close up of something that is being spread from the ...
4
votes
1answer
56 views

What is wrong with my Philodendrons' stems and roots?

The stems of my Philodendron 'Brasil' are getting brown and soft. Is it some kind of disease? I'm growing them hydroponically. Click photo for full size
4
votes
1answer
85 views

What's causing my cucumber & melon vines to wither away?

I am in the UK and my cucumber and melon plants have started wilting. I used to water them twice a week and increased the frequency to once every two days since they started fruiting. They were ...
4
votes
1answer
303 views

Why are the lower leaves of my tropical Guava yellowing and dropping?

I had a Century Guava (世紀芭樂) shipped over from Taiwan to zone 9 California. It is nearly 6 feet tall. I planted it in the biggest container that IKEA sold, 20 inches wide, 2 feet deep. I drilled many ...