Content tagged "plant diseases and disorders"

Trees and Shrubs: Problems

Trees and Shrubs | Selection | Planting | Maintenance | Problems Links to external web pages are followed by the source's name in parentheses.What's wrong...

What is wrong with a lawn that has rings of dead grass; how can it be treated? I live in Colorado.

Gardens & Landscapes Updated: February 14, 2012

Necrotic ring spot, caused by the fungus Ophiosphaerella korrae, is one of several patch diseases that affect turf in the United States. For many years a...

What do I spray my apple and pear trees with to control insects and diseases? I live in Colorado.

Gardens & Landscapes Updated: February 14, 2012

Homeowners are often surprised at the damage pests can do to apples. It is not easy to grow apples as pretty as those seen in the grocery store. There are...

Can partially decomposed wood chips from an elm that died of Dutch Elm disease be used as mulch?

Gardens & Landscapes Updated: January 12, 2012

If the wood drying and chipping process is done properly, the beetles responsible for transmitting the fungal organism {Ophiostoma ulmi (syn. Ceratocystis...

Why do leaves of phlox plants turn white and die?

Gardens & Landscapes Updated: October 19, 2011

Perennial phlox plantings are subject to powdery mildew disease, caused by the fungi Erysiphe cichoracearum and Sphaerotheca humuli. Signs of powdery mildew...

We had powdery mildew on both acorn squash and cucumbers this season. Does powdery mildew overwinter, and do we need to treat the soil for next year's garden?

Gardens & Landscapes Updated: October 18, 2011

We don't usually recommend chemical controls for powdery mildew in the home garden. Powdery mildew's prevalence is very season-dependent. It may be bad one...

What causes pepper plants to suddenly wilt and die?

Gardens & Landscapes Updated: October 17, 2011

Southern stem blight, caused by the fungus Sclerotium rolfsii, can attack the lower stem of peppers and other vegetables in the garden, causing plants to...

The leaves on my rose bush are long and skinny and occur in bunches along the stems. Plus, the buds and flowers look misshapen. If I cut off this growth, will the problem come back?

Gardens & Landscapes Updated: October 14, 2011

These symptoms could be the result of an infection by a virus. A virus is a submicroscopic disease-causing entity that can only be viewed with an electron...

What is causing the small brick-red leaf spots on my aster plants?

Gardens & Landscapes Updated: October 10, 2011

In late summer and fall, garden asters are often infected with rust disease. Severe leaf rust usually leads to death of aster leaves and reduced plant vigor....

What causes the yellow leaf spots that later develop a brown center on my apple leaves?

Gardens & Landscapes Apples Updated: August 28, 2011

This a fungal disease called cedar-apple rust. Cedar-apple rust is a common disease of apple and crabapple. The fungus that causes the disease,...

We recently planted several knockout roses and have now discovered that some of the buds had turned brown and were drooped over. The plants look very healthy otherwise. Could you give us some indication of what the problem might be?

Gardens & Landscapes Updated: April 21, 2011

Why do grape berries turn black and shrivel up in summer, even before they ripen?

Gardens & Landscapes Grapes Updated: February 28, 2011

Garden, Lawn, and Landscape Pests: Diseases

Gardens & Landscapes Updated: January 06, 2011

Garden, Lawn, and Landscape Pests | Integrated Pest Management (IPM) | Diseases | Insects | Weeds Links to external web pages are followed by the...

Vegetables: Problems

Gardens & Landscapes Updated: January 03, 2011

Vegetables | Selection | Planning and Preparing | Planting | Maintenance | Problems Links to external web pages are followed by the source's name in...

Lawns: Cool Season Lawn Care and Management

Gardens & Landscapes Updated: May 17, 2010

Lawns | Turfgrass Selection | Cool Season Lawn Care and Management | Warm Season Lawn Care and Management Links to external web pages are followed by the...

Vegetable Disease Problems by Region

Updated: May 17, 2010

Links to external web pages are followed by the source's name in parentheses. Find vegetable disease resources that most closely match conditions in your...

My Asiatic lilies look beautiful each spring, but the leaves turn yellow, then brown just as the blooms are opening. The stem of the flower appears to be fine. They get sun most of the day and are planted in soil with a layer of sand under the bed. I fertilize the lilies only in June, usually every 10 days. Any ideas on what is causing this?

Gardens & Landscapes Updated: March 22, 2010

Why are fungus “brackets” or “conks” growing on the trunks of some landscape shade trees?

Gardens & Landscapes Updated: September 05, 2008

Why did some oak leaves turn brown and drop prematurely this fall, instead of waiting until October to turn brown?

Gardens & Landscapes Updated: September 05, 2008

Lawns: Warm Season Lawn Care and Management

Gardens & Landscapes Updated: August 07, 2008

Lawns | Turfgrass Selection | Cool Season Lawn Care and Management | Warm Season Lawn Care and Management Links to external web pages are followed by the...

I have a yellow-poplar that is losing its leaves. The leaves, both green and yellow, have black spots on their undersides. The yellow leaves are falling to the ground. It looks like fall in the middle of summer. What is wrong with my tree?

Gardens & Landscapes Updated: May 16, 2008

What causes brown spots or blotches on leaves of cucumbers, cantaloupes, and watermelons?

Gardens & Landscapes Updated: May 15, 2008

i live in Colorado. What's the problem with our Autumn Blaze maple tree? Its leaves have turned yellow, and about half of the leaves have black spots and are dying.

Gardens & Landscapes Updated: May 15, 2008

Flowers: Problems

Gardens & Landscapes Updated: May 01, 2008

Flowers | Selection | General Requirements and Maintenance | Annuals | Perennials | Bulbs | Problems Links to external web pages are followed by the source's...

I have garden phlox that gets yellow and mottled leaves every year. It affects it enough to reduce the blooms. Could this be lack of water or perhaps a disease or deficiency? I live in Minnesota.

Gardens & Landscapes Updated: April 22, 2008

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.