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Andrew Johnston

john3796@purdue.edu

2 articles by this author

Article List

This aphid is a double threat to the landscape

August 8, 2025 - From Issue: 25-11
By: Andrew Johnston
spiny gall
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Aphids are some of the most common insect pests of herbaceous plants and broadleaf trees and shrubs. I have to admit, I do not always enjoy identifying aphids – but I find their shapes, colors, and biology fascinating. One species of aphid, which I first met myself this year, threatens plants in our landscapes on[Read More…]

 Article Categories:
  • Entomology
  • Trees, Shrubs, Vines
 Article Tags:
  • aphid
  • gall
  • insect
  • river birch aphid
  • witch hazel
  • witch hazel gall

Is your Penstemon stem swelling? It’s probably a moth!

July 24, 2025 - From Issue: 25-10
By: Andrew Johnston
stem-galling moth
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Many Hoosier landscapes include flowering plants known as beardtongue or simply by its scientific name, Penstemon. This is the largest genus of flowering plants that is endemic to North America, with some 280 species spread throughout the continent – at least 11 of which are native to Indiana. Many of the cultivars planted in gardens[Read More…]

 Article Categories:
  • Entomology
 Article Tags:
  • beartongue
  • Caloptilia murtfeldtella
  • caterpillar
  • Gracillariidae
  • moth
  • Penstemon

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This work is supported in part by Extension Implementation Grant 2021-70006-35390 / IND90001518G-1027053 from the USDA National Institute of Food and Agriculture