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Solve Pest Problems phase 2

​Many dozens of plants grow in Oregon gardens and landscapes. Each plant type has many common insect pests, plant diseases, and cultural (non-living) problems.

We’ve developed several example pages for this very large section of website content as shown below.

Build-A-Page Fundraising Campaign

Please consider making a donation to help make this critical pest management information available to the public as soon as possible.

Funds go directly toward the costs associated with building website pages, including general plant pests (such as slugs) and the most common pests and diseases for specific plants (such as roses).

Content development costs include the following activities:

  • Write science-based content in plain language
  • Source photos and track licenses for use
  • Enter content into website template
  • Fact-check, edit, and copyedit content

We estimate it costs about $1,000 to develop each page of website content (for example, Slugs & Snails). This estimate doesn’t include overhead costs to develop and maintain this website.

New content pages in this section will be built for priority plants and pests as funds become available.

You can Make A Difference

Donations of any amount are welcomed and appreciated

Please make a secure online donation to OSU’s Agriculture Research Foundation through PayPal 


Send a check to: Agriculture Research Foundation, ARF 8399G, IPM Website Donation, 1600 SW Western Blvd., Suite 320, Corvallis, OR 97333.


Donors will be acknowledged on our Funders and Community Partners web page.

Example of Plant Problems Content
Aphids on rose bud

Signe Danler, Oregon State University

Severe aphid infestations damage rose flowers.

Green rose aphid

© Ken Gray Insect Image Collection

Rose aphids range in color from green to deep pink or red-brown.

Aphids on the underside of a rose leaf

Aphids congregate on the underside of leaves.

Curled and distorted rose leaves

Severe aphid infestations cause distortion of leaves.

Rose Aphids

Macrosiphum rosae and other species

Rose aphid feeding causes distortion of leaves, flowers, and shoots. Aphids rarely kill plants. They produce honeydew: a sweet, sticky substance that promotes sooty mold growth.

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Mottled green and yellow leaf with black spots. The spots have diffuse edges.

 William Fountain, University of Kentucky, Bugwood.org (cropped)

Causes leaves to turn yellow and fall off. The black spots have diffuse edges.

Rose foliage with black spots before leaves yellow

Signe Danler, Oregon State University

Look for black spots forming on the leaves and stems in the spring.

Rose leaves with black spots joined along leaf veins

Signe Danler, Oregon State University

Spots may be unevenly distributed. They may follow the veins of the leaf.

Sparse leaves on rose stems

Black spot defoliates rose bushes. This bush has few leaves to create energy the bush needs to live now and in winter.

Rose Black Spot

Diplocarpon rosae

Rose black spot is a fungal disease that causes black spots on rose bush leaves and stems. It makes leaves turn yellow and fall off the rose bush. Severely infected plants often look bare with few leaves and flowers.

Action Optional
Rhododendron leaf showing pale stippling damage

Signe Danler, Oregon State University

Azalea lace bugs suck sap, which damages leaf tissue. This causes white or yellow stippling damage on the upper leaf surface.

Azalea leaf with lace bugs and fecal material

Robin Rosetta, Oregon State University

Nymphs and fecal spots are visible on the underside of a rhododendron leaf.

Rhododendron leaves showing severe bleaching

Robin Rosetta, Oregon State University

Severe damage turns rhododendron leaves yellow.

Azalea leaves showing severe damage

Severe damage turns azalea leaves white.

Close-up of nymph

Azalea lace bug nymphs and adults feed on leaves.

Azalea Lace Bugs

Stephanitis pyrioides

Azalea lace bugs suck sap, which damages leaf tissue of azalea and rhododendron plants. This causes white or yellow stippling damage on the upper leaf surface. Nymphs and fecal spots are visible on the underside of leaves.

Action Optional
Gray garden slug

Cheryl Moorehead, Bugwood.org

Brown snail

Joseph Berger, Bugwood.org

Slugs & Snails

Non-native & native species in the Pacific Northwest

Slugs and snails are mollusks. Non-native slugs and snails damage plants in gardens and landscapes in the Pacific Northwest. Native slugs (such as banana slug) and snails are not considered garden pests and may be left alone.

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Insects, Slugs & Diseases on Plants