2022 Invasive Species Scavenger Hunt

Pictured above: Large-flower primrose-willow (Ludwigia grandiflora ssp. hexapetala)

The  Pennsylvania iMapInvasives Program  is pleased to be hosting the 3rd annual Invasive Species Scavenger Hunt in 2022. Our program is a partnership of the  Western Pennsylvania Conservancy , the  Pennsylvania Natural Heritage Program , and  NatureServe . Funding for Pennsylvania iMapInvasives comes from the  Great Lakes Restoration Initiative .

For the following two questions, type your answers into the Chat box.

1. Have you participated in the Invasive Species Scavenger Hunt before?
2. What was your motivation for signing up?
3. What do you hope to learn by participating as an on-the-ground surveyor and reporter to iMapInvasives?

Learn to identify each plant and animal on this year's Scavenger Hunt checklist, find out their preferred habitat(s), and be aware of their native and exotic look-alikes.

Pace yourself - there's a lot to learn from the information provided below!

Scientific name: Polygonum perfoliatum

• Status in Pennsylvania: Class B noxious weed ( view full list )
• Identification Tips & Harm Caused:  DCNR ,  Penn State Extension 
• Video: " Invasive Species Spotlight - Mile-A-Minute " by DCNR and " Mile-a-Minute: Accurate Identification " by Penn State Extension
• Look-Alike Species:
  •  Halbard-leaved tearthumb  (Polygonum arifolium)
  •  Climbing false buckwheat  (Polygonum scandens)
  •  Wild morning glory  (Ipomoea purpurea)
  •  Hedge bindweed  (Calystegia sepium)
• Preferred Habitat(s): Disturbed areas along forest edges, wetlands, stream banks, and roadsides.

Notes: To tell the difference between mile-a-minute vine and plants with a similar appearance, look for the presence of spines and  ocreae ; if both are present, you are looking at mile-a-minute vine.

Scientific name(s): Berberis thunbergii & Berberis vulgaris

• Status in Pennsylvania: Japanese barberry is a Class B noxious weed ( view full list )
• Identification Tips & Harm Caused:  DCNR ,  Penn State Extension ,  Go Botany 
• Video: " Japanese Barberry: Accurate Identification " by Penn State Extension
• News Media: " Pennsylvania Banning Sale of Japanese Barberry by 2023 " by WPXI
• Look-Alike Species:  American barberry  (Berberis canadensis)
• Preferred Habitats: Woodlands, wetlands, and disturbed areas

Notes: Japanese barberry is a more pressing problem than its European relative.

Use the following tips to tell apart Japanese and European barberry from one another:

• Japanese barberry has single spines. European barbery produces three-pronged spines.
• The leaf edges of Japanese barberry are smooth. European barberry leaf edges have coarse serrations.

Scientific name(s): Fallopia japonica var. japonica, Fallopia sachalinensis, & Fallopia x bohemica

• Status in Pennsylvania: All 3 species are Class B noxious weeds ( view full list )
• Identification Tips & Harm Caused:  DCNR ,  Penn State Extension ,  Minnesota Dept of Ag 
• Video: " Japanese Knotweed: Accurate Identification " by Penn State Extension
• Look-Alike Species:  Bamboo spp.  (Phyllostacys spp.), such as  Golden bamboo 
• Preferred Habitat(s): Along streams and rivers, railroads and utility rights-of-way, and in ditches, vacant lots, and waste places

Notes: If you find knotweed but are unsure what species it is, report your observation to iMapInvasives as "Knotweed (species unknown)".

Scientific names: Rhamnus cathartica & Frangula alnus

• Status in Pennsylvania: Both species are Class B noxious weeds ( view full list )
• Identification Tips & Harm Caused:  DCNR  (CB),  DCNR  (GB),  Penn State Extension ,
• Videos: " Buckthorn: Accurate Identification " by Penn State Extension and " Buckthorn Invasive Species " by Iowa State University
• Look-Alike Species: Native species of  dogwoods  (Cornus spp.),  Smooth alder  (Alnus serrulata)
• Preferred Habitat(s): Common buckthorn prefers open fields, prairies, and upland sites. Glossy buckthorn prefers swamps, bogs, fens, and wet meadows. Both species can be found in full sun or dense shade.

Notes: Use the following tips to tell the difference between common and glossy buckthorn:

• Common buckthorn leaf edges are finely toothed. Glossy buckthorn leaf edges are smooth and toothless.
• Common buckthorn leaves are suboppositely arranged. Glossy buckthorn leaves are alternately arranged. Glossy buckthorn leaves are also tough, leathery, and shiny.
• Common buckthorn leaf viens have distinct arcing veins. The leaf veins of Glossy buckthorn have curved, parallel veins.

Scientific name: Ludwigia grandiflora & Ludwigia grandiflora ssp. hexapetala

• Status in Pennsylvania: Ludwigia grandiflora ssp. hexapetala is a Class B noxious weed ( view full list )
• Identification Tips & Harm Caused:  University of Florida ,  Western PA Conservancy 
• Look-Alike Species:
  •  Creeping water primrose  (Ludwigia peploides)
  •  Seedbox  (Ludwigia alternifolia)
  •  Wingleaf primrose-willow  (Ludwigia decurrens)
• Preferred Habitat(s): Ponds, lake margins, wetlands, and ditches

Notes: Both Ludwigia grandiflora and L. grandiflora ssp. hexapetala are rare in Pennsylvania.

Important! The differences between these two species are subtle. If reporting presence data for these species to iMapInvasives, do your best to determine the proper ID. Keep in mind that all reports submitted to iMapInvasives are expert-vetted to ensure species ID accuracy.

Scientific name: Cabomba caroliniana

• Status in Pennsylvania: High priority species (found in less than 1/3 of PA counties)
• Identification Tips & Harm Caused:  PA Sea Grant ,  Western New York PRISM 
• Video: " Aquatic Invasive Species Spotlight: Fanwort " by NY's Lower Hudson PRISM
• Look-Alike Species: See list below. More details are provided on page 21 of the " PA Field Guide to Aquatic Invasive Species 
  • Other leafy  milfoils 
  •  Beck's water-marigold  (Megalodonta beckii)
  • Some  bladderworts 
  •  Hornworts 
  •  Mermaid weeds 
  •  Water-crowfoots 
• Preferred Habitats: Lakes and ponds; occasionally found in rivers

Notes: Important! Because Carolina fanwort is a submerged aquatic species, you'll need a weed rake to properly survey for it. Instructions on how to build and use a homemade weed rake are provided in the  following video  created by the Finger Lakes PRISM in New York State.

Scientific name: Nelumbo nucifera

• Status in Pennsylvania: Not confirmed from PA, but known from surrounding states
• Identification Tips & Harm Caused:  Mid-Atlantic Field Guide to AIS,   Wisconsin DNR 
• Look-Alike Species:  American lotus  (Nelumbo lutea),  Waterlily spp.  (Family Nymphaeaceae)
• Preferred Habitat(s): Small ponds, lagoons, marshes, and shallow areas of lakes and rivers

Notes: Use the following tips to tell the difference between Pink lotus and some of its look-alikes:

• Pink lotus flowers are pink. American lotus flowers are yellow.
  • Note: Cultivars of these two species tend to have whitish-pink flowers.
• The leaves of the pink lotus lack the characteristic slits found on water lily leaves.

Scientific Name: Trapa natans

• Status in Pennsylvania: Class A noxious weed ( view full list )
• Identification Tips & Harm Caused:  PA Sea Grant ,  Chesapeake Bay Program 
• Videos: " Water Chestnut: An Aquatic Invasive Plant " by Bucks County Conservation District, and " Aquatic Invasive Species Spotlight: Water Chestnut " by the Lower Hudson PRISM
• Look-Alike Species: No known look-alikes from Pennsylvania
• Preferred Habitat(s): Ponds, lakes, slow-moving streams, and rivers

Notes:  Two-horned water chestnut  (Trapa bispinosa) looks very similar in appearance to water chestnut (Trapa natans); however, T. bispinosa has not yet been discovered in Pennsylvania to date ( only in Virginia and Maryland ). Trapa bispinosa is distinguished from T. natans by the reddish undersides of the leaves, reddish sepals, pink petals, and two horizontally opposed pseudo-horns.

Scientific name: Amynthas-Metaphire spp.

• Status in Pennsylvania: High priority species (found in less than 1/3 of PA counties)
• Identification Tips & Harm Caused:  NY Invasive Species Research Institute ,  Cornell University ,  Wisconsin DNR 
• Videos: " Jumping Worm Identification " by Yale University, and " If You See This Jumping Worm, Kill It " by Inside Edition
• News Media: " 'Crazy Worms' Threaten America's Trees - And (Gasp!) Our Maple Syrup " by NPR, and " Invasive Earthworms are Taking Over Forests in Parts of the U.S. and Canada " by NPR
• Look-Alike Species:  Nightcrawlers  (Lumbricus spp.)
• Preferred Habitat(s): On the soil surface and in leaf litter of forests, yards, and gardens. Also found in compost piles and along roadsides.

Notes: Jumping worms are easily distinguished by their snake-like movements and a white ring (called a clitellum) that completely encircles their body, located close to the head.

Scientific name: Lymantria dispar

• Status in Pennsylvania: Common in the state; Both  PA DCNR  and  PA Game Commission  have active spray programs to manage spongy moth across the Commonwealth
• Identification Tips & Harm Caused:  DCNR ,  NY DEC ,  Maryland Extension 
• Videos: " Spongy Moth Outbreak Worse Than Last Year " by WNEP, and " Spongy Moth Spraying " by PA Game Commission
• News Media: " 'Spongy Moth' Proposed as New Common Name for Lymantria Dispar " by the Entomological Society of America
• Look-Alike Species:
  • Egg masses of some  tussock moths  and the  spotted lanternfly  may look similar to spongy moth's egg masses.
  • Common look-alikes for caterpillars include the  forest tent caterpillar  and the  Eastern tent caterpillar .
  • Female adult spongy moths are very unmistakable - very white and flightless. The male adult moths flit around, kind of like some  geometrids  that are also brown, but often they will land somewhere and you can see they have scalloped wings and don't have the feathery antenna.
• Preferred Habitat(s): Anywhere where host trees/shrubs occur such as forests and other wooded areas. Spongy moth can be found in urban, surburan, and rural settings. Note: Spongy moths prefer to feed on oaks and aspens, but do not eat conifer needles unless they are starving.

Notes: The common name for the moth species Lymantria dispar was recently updated to "spongy moth" by the Entomological Society of America (ESA) in January 2022. It replaces "gypsy moth", a name removed in July 2021 from ESA's  Common Names of Insects and Related Organisms List  for its use of a derogatory term for the Romani people. The new is derived from the common name used in France and French-speaking Canada, " spongieuse ", which refers to the moth's sponge-like egg masses. ( View news article .)

"This event was a fun and interesting way to explore the natural areas around us while developing better plant identification skills. I participated in this event while working as a seasonal Park Ranger in the local parks system. Documenting the presence of certain invasive species was helpful for identifying priority locations for natural resource management plans in the future." - Brianna Shepherd, Park Ranger,  Allegheny County Parks 

"I really enjoyed the Invasive Species Scavenger Hunt. It made me aware of invasives that may not be in my area yet, but could become a problem in the future. Forewarned is forearmed." - Barbara Ritzheimer,  Pennsylvania Master Naturalist 

"I really liked the Invasive Species Scavenger Hunt because it helped to introduce me to some invasive species I didn't know about yet. Generally, by the time I am familiar with an invasive species, it's because it has invaded beyond all hope of combatting it. But the Scavenger Hunt made me work to become more aware and identify species that are on the radar, but are not yet overwhelming. Perhaps if myself and others can learn to identify these species before they get a firm foothold, we have a better chance of limiting their spread. I would never know on my own how to prepare for what might be coming next, but given a finite list of species to focus on makes surveying a little less overwhelming. Many of the species on this year's list I could not find at all, but the event got me in the habit of looking for them... and if I ever see water soldier or an Asian longhorned beetle, I'll be all over it!" - Adele Philippides, Pennsylvania  Community Scientist 

What questions do you have? Type them into the webinar Chat box and they will be answered in the order they are received.

Contact Amy Jewitt, Invasive Species Coordinator at the Western Pennsylvania Conservancy, for any Scavenger Hunt related-questions you have after today's training.

• Email: ajewitt@paconserve.org (preferred)
• Phone: 412-586-2305