The following are highlights and updates about samples and questions recently received in the Plant and Insect Diagnostic Clinic. Visit the PIDC's Facebook page for updates and more pictures. For more information on a particular disease or insect problem listed, follow the article cited.
The following are plant diseases and insect damage highlights of last month's sample submissions from fruit, vegetables, and ornamentals.
Broadleaf Trees
- Red oak, Oak wilt, suspected physiological scorch
- Bur Oak, Bur oak blight
- White oak, Two lined chestnut borer
- Hickory, Hickory scab, mites, suspected decline
- Crabapple, scab
Coniferous Trees
- Pine, Dothistroma needle blight
- Arborvitae, Suspected transplant/establishment issues, Bark beetle damage
- Spruce, Rhizosphaera needle cast, Stigmina needle cast, Sudden Needle Drop, Spruce spider mites,
- Norway Spruce, Rhizosphaera needle cast,
- Colorado Blue Spruce, Environmental Stress, Pine Needle Scale, Sudden Needle Drop
Perennials and Annuals
- Ninebark, Rhizoctonia root rot
- Dracaena, Bacterial leaf spot. To learn about management of bacterial disease
on foliage plants, see this resource form University of Minnesota - Cape Primrose, INSV (Inpatients necrotic spot virus)Vegetables
- Tomato, spider mite damage
- Swiss Chard, Pythium root rot
- Garlic, Dry bulb mite
Fruit (small and tree fruit, including hops)
- Raspberry, Crown gall
- Apple, Sooty mold due to insect activity
Plant, mushroom, and insect identifications
Mushroom Identification
- Mycena sp., Lepiota sp. Lepiota mushrooms are one of the various fungi that may be present in lawns as fairy rings.
Plant Identification
- Puncture vine (Tribulus terrestris). Puncture vine is typically found in sandy or compacted soils and disturbed sites. Common sites are along roadsides and railroad tracks, pastures, and waste areas. Puncture vine is not widespread in Iowa and is most often found in the southern half of the state.
- Broadleaf plantain
Insect Identifications
- Termites are a serious structural pest. It is important to correctly identify termites or their damage and work with a pest management company to treat them.
- Six-spotted tiger beetles are commonly submitted as suspect emerald ash borers because they are iridescent green. Luckily six-spotted tiger beetles are beneficial predators and will not harm trees.
- Bed bugs are unfortunately a very frequent sample in the clinic.
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