Delaware
103 active alerts in this region
TreeIssues monitors plant and tree health threats across Delaware. Below you will find current alerts for pests, diseases, fungi, and invasive species that have been detected in the state. Alerts are sourced from USDA, USFS, and Delaware state agricultural agencies. Each alert includes severity ratings, affected species, symptoms, and recommended treatments.
Dutch Elm Disease
CRITICALA devastating vascular wilt disease spread by elm bark beetles that has killed millions of American elms since the 1930s. The fungus blocks water-conducting vessels, causing rapid wilting. It fundamentally changed the American urban landscape.
Affecting 45 regions
Chestnut Blight
CRITICALA fungal disease that functionally eliminated the American chestnut as a canopy tree species in eastern forests by the mid-20th century. Once numbering in the billions, mature American chestnuts are now exceedingly rare. Root sprouts survive but are re-infected.
Affecting 25 regions
Bacterial Leaf Scorch
HIGHA chronic bacterial disease that affects many shade tree species, particularly oaks, elms, sycamores, and maples. The bacterium is transmitted by xylem-feeding leafhoppers and spittlebugs and colonizes the water-conducting vessels, restricting water flow. Symptoms worsen each year as more of the canopy is affected. There is no cure.
Affecting 19 regions
Phytophthora Root Rot
HIGHA group of water-mold diseases that attack the roots and root collar of many tree species. Phytophthora thrives in wet, poorly drained soils. It destroys fine roots and can girdle the trunk at the soil line. Affected trees show a general decline that is often misdiagnosed as drought stress. Oaks, dogwoods, rhododendrons, and many other species are susceptible.
Affecting 31 regions
Emerald Ash Borer
MODERATEAn invasive wood-boring beetle native to Asia that has killed hundreds of millions of ash trees across North America since its discovery in Michigan in 2002. Larvae feed on the inner bark, disrupting nutrient and water transport.
Affecting 36 regions
Spotted Lanternfly
MODERATEAn invasive planthopper native to China first detected in Pennsylvania in 2014. While it primarily threatens agriculture (grapes, hops, fruit trees), it feeds on over 70 plant species. It excretes honeydew that promotes sooty mold growth.
Affecting 21 regions
Hemlock Woolly Adelgid
MODERATEA tiny aphid-like insect native to Asia that feeds on hemlock sap at the base of needles. It has devastated eastern hemlock populations from Georgia to Maine. Trees typically die within 4-10 years of infestation.
Affecting 20 regions
Spongy Moth (formerly Gypsy Moth)
MODERATEAn invasive moth introduced to Massachusetts in 1869. Caterpillars defoliate hundreds of tree species, preferring oaks. Repeated defoliation weakens and can kill trees, especially when combined with drought stress.
Affecting 20 regions
Japanese Beetle
MODERATEAn invasive beetle introduced to New Jersey in 1916. Adults skeletonize leaves of over 300 plant species while larvae (grubs) damage turf grass roots. They are particularly damaging to linden, birch, and fruit trees.
Affecting 35 regions
Bagworm
MODERATEA moth whose larvae construct distinctive spindle-shaped bags from silk and foliage fragments. They feed on over 100 species of trees and shrubs, with conifers being most vulnerable since they cannot regrow lost foliage as readily.
Affecting 28 regions
Cedar-Apple Rust
MODERATEA fungal disease requiring two hosts to complete its life cycle: eastern red cedar (juniper) and apple or crabapple trees. It causes economic losses in apple orchards and aesthetic damage to landscape cedars.
Affecting 34 regions
Anthracnose
MODERATEA group of fungal diseases causing leaf spots, cankers, and shoot blight on many shade trees. Sycamore, dogwood, maple, and oak are commonly affected. Cool, wet spring weather promotes infection of newly expanding leaves.
Affecting 38 regions
Asian Lady Beetle
MODERATEFound alive but in terrible shape. Was swimming around in the water bowl we put out for feral cats here. Also appeared to have had a run in with a spider web, as it had something stuck all over it. Got a lot of suggestions for fungi and parasitoids that target ladybeetles, so maybe its appearance is more a function of a disease or parasite process taking place. It was definitely having trouble getting adound, but could be due to having been in the water for a long time and/or having bits of web
Affecting 41 regions
Eastern Boxelder Bug
MODERATEA red-eyed boxelder bug chills on the sunny side of a concrete street lamp post It's a sweltering 30° C and sunny
Affecting 21 regions
turkey-tail
MODERATEsmall group growing on saw cut oak trunk in upland mesic hardwoods; funnel shaped to rosette growth, with peeling, wavy "petals"; upper surface velvety/finely hairy, concentrically zoned, blues, purplish browns & yellowish browns dominated, whitish at margin in some; lower surface with rounded pores, some becoming elongated & tooth-like, white to pale tan pore surface; rudimentary to no stalk, hairy, attached to wood centrally or laterally
Affecting 28 regions
Asian Longhorned Beetle Damages hardwood trees by tunneling deep into trunks and branches
MODERATEAsian Longhorned Beetle Damages hardwood trees by tunneling deep into trunks and branches - identified by USDA APHIS as a pest threat.
Affecting 50 regions
Reddish-brown Stag Beetle
MODERATEI was finally able to encounter a female individual of this species - however, she unfortunately appeared to be dying. I initially found her on her back.
Affecting 27 regions
Northern Masked Chafer
MODERATENorthern Masked Chafer observed in the wild. Research-grade iNaturalist observation.
Affecting 7 regions
Abbott's Sphinx
MODERATEAbbott's Sphinx observed in the wild. Research-grade iNaturalist observation.
Affecting 1 region
Oriental Beetle
MODERATEOriental Beetle observed in the wild. Research-grade iNaturalist observation.
Affecting 13 regions
Rice Beetle
MODERATEAnother great evening celebrating moth week! Tonight, we were at John Bunker Sands with around 80 other folks -- lots of excitement for bugs! :) Quite a few things showed up -- apologies for my particularly bad photos tonight though.
Affecting 13 regions
North American Wheel Bug
MODERATEHanging out in a mass of sunflower and knotweed full of Japanese beetles. Love to see it
Affecting 23 regions
Nabis roseipennis
MODERATENabis roseipennis observed in the wild. Research-grade iNaturalist observation.
Affecting 11 regions
Southern Masked Chafer
MODERATEAttracted to light at night. The plant on which the insect is resting (sweet Joe Pye weed) is located beside an exterior light that was illuminated.
Affecting 33 regions
Punctured Tiger Beetle
MODERATEPunctured Tiger Beetle observed in the wild. Research-grade iNaturalist observation.
Affecting 27 regions
Spotted Pink Lady Beetle
MODERATESpotted Pink Lady Beetle observed in the wild. Research-grade iNaturalist observation.
Affecting 25 regions
Green Cloverworm Moth
MODERATEGreen Cloverworm Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 22 regions
Three-spined Grass Bug
MODERATEThree-spined Grass Bug observed in the wild. Research-grade iNaturalist observation.
Affecting 11 regions
Grapevine Beetle
MODERATEA tremendous evening with around 75 folks to celebrate moth week! It was the hottest day of the summer so far, so it was a wonderful treat to look for bugs with so many folks. :) Great night!
Affecting 27 regions
Asiatic Garden Beetle
MODERATEAsiatic Garden Beetle observed in the wild. Research-grade iNaturalist observation.
Affecting 11 regions
False Milkweed Bug
MODERATESmall red-and-black insect crawling on the sage blooms down at the corner. ID algorithm is coming back as "lygaeus".
Affecting 20 regions
Berkeley's Polypore
MODERATEFound growing at base of large maple tree, harvested specimen is 8 inches long, 5 inches wide and 3 inches tall but the stipe extended another 4 inches before being cut. Older and larger specimen was about a foot in diameter. Sulfur scent like chicken of the woods and non-staining white flesh.
Affecting 19 regions
Ring-horned Assassin Bug
MODERATERing-horned Assassin Bug observed in the wild. Research-grade iNaturalist observation.
Affecting 17 regions
mica cap
MODERATEmica cap observed in the wild. Research-grade iNaturalist observation.
Affecting 8 regions
bladder wrack
MODERATEbladder wrack observed in the wild. Research-grade iNaturalist observation.
Affecting 9 regions
Harlequin Bug
MODERATEOn Apios americana. Mustard and cabbage plants were also nearby, but I didn't realize they laid eggs on things other than mustard and cabbage.
Affecting 23 regions
Olive Arta Moth
MODERATEOlive Arta Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 3 regions
Long-necked Seed Bug
MODERATEWhat a nice evening with around 40 folks at Cedar Hill State Park -- we put up blacklights and spotted quite a few neat bugs, despite the pretty intense heat and drought.
Affecting 22 regions
Stirellus bicolor
MODERATEMary's Creek Open Space - accessed with permission What a spectacular evening at Mary's Creek as we did some more blacklighting and nighttime surveys. Lots of neat things showed up!
Affecting 7 regions
milky conecap
MODERATEmilky conecap observed in the wild. Research-grade iNaturalist observation.
Affecting 4 regions
snow fungus
MODERATEtwo growing about 1 m apart on fallen, dead hardwood in floodplain swamp of Withlacoochee River; jelly like mass of delicate broad leafy lobes (resembling branched antlers), shiny, translucent, gummy, silvery white, turning yellowish at point of attachment (right specimen in photo is upside down to show "base")
Affecting 12 regions
flocculose inkcap
MODERATEflocculose inkcap observed in the wild. Research-grade iNaturalist observation.
Affecting 10 regions
Alfalfa Plant Bug
MODERATEAlfalfa Plant Bug observed in the wild. Research-grade iNaturalist observation.
Affecting 14 regions
Versute Sharpshooter
MODERATEVersute Sharpshooter observed in the wild. Research-grade iNaturalist observation.
Affecting 20 regions
Large Milkweed Bug
MODERATECluster of black and orange insects on milkweed plant. Warm, near sunset, slightly overcast.
Affecting 35 regions
Ash and Privet Borer
MODERATEAsh and Privet Borer observed in the wild. Research-grade iNaturalist observation.
Affecting 4 regions
crowded parchment
MODERATEcrowded parchment observed in the wild. Research-grade iNaturalist observation.
Affecting 14 regions
Swamp Cicada
MODERATEThis bug was on a stick I accidentally knocked into the water, and it couldn’t make it to dry land. I waded in and scooped it and put it on this sunny spot. It turns out it has a super bright white belly. I did not photograph it until it was settled, because being knocked into the water seemed like enough trouble. It had a bad day, but it only took about five minutes for it to compose itself and fly away.
Affecting 21 regions
Chamaesyce Rust
MODERATERust fungus on Euphorbia maculata. These plants were growing abnormally upright, just a few feet away from the ones in my previous observation; see discussion there: https://www.inaturalist.org/observations/381834381
Affecting 1 region
Eastern Hercules Beetle
MODERATEI found this deceased male Hercules beetle lying next to an office window. I wonder if he struck the window and died from impact.
Affecting 17 regions
Coker's amanita
MODERATECoker's amanita observed in the wild. Research-grade iNaturalist observation.
Affecting 4 regions
Spotted Peppergrass Moth
MODERATESpotted Peppergrass Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 4 regions
Mint-loving Pyrausta Moth
MODERATEMint-loving Pyrausta Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 11 regions
Lucerne Moth
MODERATELucerne Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 14 regions
Boxwood Leaftier Moth
MODERATEBoxwood Leaftier Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 15 regions
Smooth Ox Beetle
MODERATESmooth Ox Beetle observed in the wild. Research-grade iNaturalist observation.
Affecting 8 regions
Imperial Moth
MODERATEImperial Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 20 regions
Green Cone-headed Planthopper
MODERATEGreen Cone-headed Planthopper observed in the wild. Research-grade iNaturalist observation.
Affecting 19 regions
Green-spored Parasol
MODERATEGreen-spored Parasol observed in the wild. Research-grade iNaturalist observation.
Affecting 27 regions
Orange Virbia Moth
MODERATESaw a couple of these moths last night too but I didn't get a good pic until tonight
Affecting 4 regions
North American Tarnished Plant Bug
MODERATEOriginally collected at the University of Kentucky Arboretum alongside a Goldenrod Soldier Beetle.
Affecting 21 regions
Orthotylus flavosparsus
MODERATEOrthotylus flavosparsus observed in the wild. Research-grade iNaturalist observation.
Affecting 3 regions
Monarch
MODERATEEarly was stationary on Lima bean leaf, then on this particular Zinnia flower, nectaring, for a long while. Lots of Common and Butterfly milkweed flowers nearby but went for this zinnia.
Affecting 32 regions
Ultronia Underwing
MODERATEUltronia Underwing observed in the wild. Research-grade iNaturalist observation.
Affecting 11 regions
Citrus Flatid Planthopper
MODERATEHad a wonderful evening with the Elm Fork Master Naturalist training class -- we talked bugs and then after class, we did some blacklighting. Crazy hot and dry, and quite a bit of light pollution here, but still, some neat bugs showed up! :)
Affecting 25 regions
Yellow-fringed Dolichomia Moth
MODERATEYellow-fringed Dolichomia Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 15 regions
Agreeable Tiger Moth
MODERATEAgreeable Tiger Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 7 regions
North American Luna Moth
MODERATEHeard frantic flapping noise against window glass, opened window and let in moth. It finally settled on trim above inside door where it's rested calmly for past 25 minutes. Guessing female based on wing shape, coloring and position, thinner antennae, and bulkier body/abdomen.
Affecting 28 regions
Zabulon Skipper
MODERATEZabulon Skipper observed in the wild. Research-grade iNaturalist observation.
Affecting 3 regions
Black Vine Weevil
MODERATENow TELL ME that this isn't a freaking puppy dog. I have cuteness aggression!!!!!
Affecting 18 regions
Spotted Cucumber Beetle
MODERATEA screenshot from my friend @west87363 ‘s video. We observed the same individual insect but I wasn’t able to capture it on camera like he did.
Affecting 31 regions
Green Stink Bug
MODERATEAnother mothing try at Green Acres Farm- fortunately not windy this time, so a few little guys came out to the light, along with some stink bugs. It was still hot even after the sun went down and it got dark, and it is very dry everywhere.
Affecting 29 regions
stinky squid
MODERATESmelled it after getting this auto ID and it did smell very bad, like rotting fish
Affecting 11 regions
Pipevine Swallowtail
MODERATEPipevine Swallowtail observed in the wild. Research-grade iNaturalist observation.
Affecting 11 regions
Catalpa Sphinx
MODERATECatalpa Sphinx observed in the wild. Research-grade iNaturalist observation.
Affecting 12 regions
Linne's Cicada
MODERATELinne's Cicada observed in the wild. Research-grade iNaturalist observation.
Affecting 6 regions
Brown Prionid
MODERATEBrown Prionid observed in the wild. Research-grade iNaturalist observation.
Affecting 17 regions
Ringless Honey Mushroom
MODERATEHundreds, possibly thousands of mushrooms surrounding the base of a live Norway Maple.
Affecting 17 regions
Coppery Leafhopper
MODERATECoppery Leafhopper observed in the wild. Research-grade iNaturalist observation.
Affecting 23 regions
Blue-green Cracking Russula
MODERATEBlue-green Cracking Russula observed in the wild. Research-grade iNaturalist observation.
Affecting 8 regions
Elegant Grass-veneer
MODERATEElegant Grass-veneer observed in the wild. Research-grade iNaturalist observation.
Affecting 24 regions
Corn Earworm Moth
MODERATECorn Earworm Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 15 regions
Maple Webworm Moth
MODERATEMaple Webworm Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 3 regions
Ailanthus Webworm Moth
MODERATESpent pretty much all day today at the car dealership to get a new vehicle -- sooo, I missed out on a park visit. Anywho, I put up the blacklights in the backyard to see some local bugs. :)
Affecting 26 regions
Black Swallowtail
MODERATEBlack Swallowtail observed in the wild. Research-grade iNaturalist observation.
Affecting 17 regions
Isabella Tiger Moth
MODERATEIsabella Tiger Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 25 regions
Peach Root Weevil
MODERATEPeach Root Weevil observed in the wild. Research-grade iNaturalist observation.
Affecting 15 regions
Coral-pink Merulius
MODERATECoral-pink Merulius observed in the wild. Research-grade iNaturalist observation.
Affecting 16 regions
crown-tipped coral fungus
MODERATEcrown-tipped coral fungus observed in the wild. Research-grade iNaturalist observation.
Affecting 25 regions
Oleander Aphid
MODERATEObserved on a 15 minute walking survey at Kirk Park. This survey is part of the Paired Garden Study project associated with Biodiversity in Urban Gardens (BUG) and is run by the California Native Plant Society. This observation is from the native plant garden. My survey here ran from 4:44PM-4:59PM. More info about BUG is available at the link below (scroll down to Santa Clara Valley Research Project for more info about the Paired Garden study) https://www.cnps.org/education/bug Umbrella projec
Affecting 33 regions
Common Buckeye
MODERATECommon Buckeye observed in the wild. Research-grade iNaturalist observation.
Affecting 14 regions
Eastern Rhinoceros Beetle
MODERATEEastern Rhinoceros Beetle observed in the wild. Research-grade iNaturalist observation.
Affecting 14 regions
Smoky Tetanolita Moth
MODERATESmoky Tetanolita Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 7 regions
Phytocoris tibialis
MODERATEPhytocoris tibialis observed in the wild. Research-grade iNaturalist observation.
Affecting 10 regions
Black-staining Polypore
MODERATEBlack-staining Polypore observed in the wild. Research-grade iNaturalist observation.
Affecting 20 regions
Clover Looper Moth
MODERATEClover Looper Moth observed in the wild. Research-grade iNaturalist observation.
Affecting 5 regions
Ganoderma sessile
MODERATEGanoderma sessile observed in the wild. Research-grade iNaturalist observation.
Affecting 12 regions
Two-banded Japanese Weevil
MODERATETwo-banded Japanese Weevil observed in the wild. Research-grade iNaturalist observation.
Affecting 6 regions
Wrinkly Stinkhorn
MODERATEWrinkly Stinkhorn observed in the wild. Research-grade iNaturalist observation.
Affecting 12 regions
Luminescent Panellus
MODERATELuminescent Panellus observed in the wild. Research-grade iNaturalist observation.
Affecting 9 regions
Leptoglossus oppositus
MODERATELeptoglossus oppositus observed in the wild. Research-grade iNaturalist observation.
Affecting 16 regions
Powdery Mildew
LOWA widespread group of fungal diseases that produce a distinctive white powdery coating on leaves and shoots. It affects hundreds of tree, shrub, and plant species. Unlike most fungi, it thrives in warm, dry conditions with high humidity.
Affecting 49 regions
Leaf Spot Diseases
LOWA broad group of fungal diseases that cause discrete spots on the leaves of deciduous trees. Most are primarily cosmetic and do not seriously harm established trees. They are most common during wet spring and summer weather. Many different fungi cause leaf spots on different tree species.
Affecting 38 regions