Plant and Insect Diagnostic Clinic Update – July 15, 2019

The following are highlights and updates about sample submissions for our different services (identification or Plant problem diagnosis from fruit, vegetables, and ornamentals), 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.

Plant Problem diagnosis  (with links to articles)

Host CategoryPlantIdentification or Diagnosis
Broadleaf treesRed Maple Suspected transplant stress, trunk cracks
Broadleaf treesPoplar (Hybrids)

Marssonina leaf spot on aspen 

Marssonina Leaf Spot, caused by Marssonina spp (M. populi  and M. brunnea)
Evidence (signs) of the fungal pathogens Marssonina spp (M. populi and M. brunnea) that cause Marssonina Leaf Spot in poplar. Photo credit: Lina Rodriguez Salamanca, Iowa State University Plant & Insect Diagnostic Clinic
Broadleaf treesStar MagnoliaMagnolia Scale
Broadleaf treesServiceberrySawfly damage Pear Sawfly or Pearslug
Broadleaf treesLondon PlanetreeClick beetles
Broadleaf treesSilver MapleMaple Tar Spot, Negative for Verticillium wilt
Broadleaf treesPear (Ornamental)Pear leaf blister mite
Broadleaf treesDogwoodCercospora (Fungal) leaf spot
Broadleaf treesRed OaksOak anthracnose  Anthracnose on shade trees
Broadleaf treesWhite OakSuspected Two line chestnut borer, Tree decline
Broadleaf treesOhio BuckeyeFungal leaf spot (anthracnose), Physiological leaf scorch
Coniferous treesArborvitaePhyllosticta needle blight *** NEW ENCYCLOPEDIA ARTICLE***
Coniferous treesSpruceAbiotic disorder-Suspected environmental injury
FruitCherryCherry fruit fly Fruit, Vinegar, and Pomace Flies
FruitRaspberryDecline, virus
FruitJapanese PearFire Blight
FruitCommon AppleApple scab
FruitCommon AppleSuspected injury Preventing Herbicide Injury in the Landscape
FruitHops

Hops downy mildew  

Signs of Pseudopernospora humili
Signs of Pseudopernospora humili
Perennials and AnnualsBurning BushPotential injury Preventing Herbicide Injury in the Landscape
Perennials and AnnualsForsythiaSuspected crown and root rot
Perennials and AnnualsPinnate Prairie ConeflowerSeptoria leaf spot
Perennials and AnnualsButtonbushEriophyid mite galls Insect Galls on Trees and Shrubs
Perennials and AnnualsGoldenrodGall midge, fungal leaf spot
TurfKentucky BluegrassRed threat, Ascochyta leaf blight, Summer patch, brown patch
VegetablesTomatoTomato Spotted Wilt Virus TSWV, White mold (Sclerotinia), Alternaria blight and canker see Tomato Diseases and Disorders
PathogensCabbageAlternaria leaf spot

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on July 16, 2019. The information contained within may not be the most current and accurate depending on when it is accessed.