For questions about plant diseases.

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3
votes
1answer
588 views

What is this disease on my Basil?

I've planted Basil (from a pot) outside and it's been very wet in the last few weeks. The plant has now got these grey spots on it. What is wrong with it?
4
votes
1answer
276 views

What are these black spots on white splotches appearing on my tomato seedling?

Here are pictures of the infected leaves. I cut them off the plant as soon as I saw them today. Click for full size Here are close-ups of the most infected leaf: Click for full size What can ...
2
votes
1answer
1k views

How should I treat Frangipani rust?

My frangipani experiences rust. How should I best treat/protect my plant from rust (all year round)? My plant experienced severe rust during December/January (Australian Summer). It was a very wet ...
8
votes
2answers
3k 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 ...
6
votes
1answer
5k 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 ...
8
votes
2answers
706 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 ...
7
votes
1answer
230 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
10k 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 ...
3
votes
1answer
415 views

How do I get rid of tar spots appearing on my maple's leaves?

Preliminary reading suggests that the only way is to rake up the fallen leaves and get rid of them. Will this do the trick? Is there a way I could keep the leaves for compost without propagating the ...
11
votes
2answers
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 ...
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
786 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
1answer
1k 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 ...
16
votes
7answers
12k 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 ...
8
votes
1answer
751 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 ...
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 ...
9
votes
2answers
673 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 ...
10
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 ...
11
votes
3answers
876 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 ...
20
votes
6answers
380 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. ...
13
votes
1answer
577 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
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?
12
votes
3answers
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
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, ...