John A. Weidhass's Images
Title: ProfessorOrganization: Virginia Polytechnic Institute and State University
Unit: Department of Entomology
Country: United States
| 132 Images of 85 Subjects | View Subject List | View Image Details | View Thumbnails |
| Image | Subject Name | Scientific Name | Description |
|---|---|---|---|
| 1626092 | horned oak gall | Callirhytis cornigera | Horned oak galls are hard, woody swellings on the twigs. Small horns protrude through the surface of the gall, and a small stingless wasp develops in each horn. |
| 1626085 | maple bladdergall mite | Vasates quadripedes | Maple bladder galls are small globular growths on the upper surface of red and silver maple leaves. The galls can be either red or green, and they may occur singly or in clusters. |
| 1626051 | whiteflies | Immature whiteflies may be confused with scale insects, but are much smaller. | |
| 1626090 | eastern spruce gall adelgid | Adelges abietis | Immature females overwinter beneath a wax coat at the base of spruce buds. |
| 1627093 | tip moth | The tiny caterpillars bore initially into the buds and then into the twigs themselves. | |
| 1626089 | eastern spruce gall adelgid | Adelges abietis | Eastern spruce galls occur at the base of new shoots. They are found primarily on Norway spruce, but also on white, red, and Colorado blue spruce. |
| 1627057 | elm leaf beetle | Xanthogaleruca luteola | |
| 0717010 | eastern spruce gall adelgid | Adelges abietis | A common pest on both Christmas trees and yard plantings. Note the short needles on the gall. |
| 0717004 | pine bark adelgid | Pineus strobi | Feeding at the base of needles. These cotton masses are the most conspicuous but usually the least damaging. |
| 0717002 | pine bark adelgid | Pineus strobi | The pine bark adelgid is a serious pest of eastern white pine and is conspicuously noted by its cottony covering. |
| 1627054 | elm leaf beetle | Xanthogaleruca luteola | During severe outbreaks, entire trees may be covered with brown, skeletonized leaves. |
| 0718013 | roseslug sawfly | Endelomyia aethiops | |
| 1626072 | lady beetle | Ladybug larvae are relentless predators. Their colorful, but ferocious appearance often causes unknowing gardeners to assume that they must be harmful. | |
| 1627030 | pine webworm | Pococera robustella | |
| 1626009 | hemlock woolly adelgid | Adelges tsugae | Underneath the wax, adelgids resemble tiny, plump aphids without cornicles. |
| 1626035 | juniper scale | Carulaspis juniperi | Plants which have lost their normal healthy green color are often infested. Upon close inspection, numerous white scale covers with yellow-brown centers can be seen on the foliage. Heavily infested branches yellow and eventually die. |
| 1626091 | hickory gall phylloxera | Phylloxera caryaecaulis | A phylloxeran causes hickory leaf stem gall on the leaves, petioles, and twigs of hickory. |
| 1627014 | orangestriped oakworm | Anisota senatoria | It appears in midsummer and feeds gregariously. Groups of them defoliate one branch at a time eating all but the mid-vein of each oak leaf. |
| 1626088 | cooley spruce gall adelgid | Adelges cooleyi | |
| 1626026 | magnolia scale | Neolecanium cornuparvum | The largest scale insect in the United States. |
| 1627038 | European pine sawfly | Neodiprion sertifer | Colonies can cause serious defoliation on red, Scotch, and mugo pine. |
| 1627092 | tip moth | The first symptoms of tip moth attack are the dead tips of terminal and lateral branches. | |
| 1627049 | locust leafminer | Odontota dorsalis | The mines of their larvae seen here on the right are sometimes responsible for turning entire black locust trees brown in mid-summer. The adults are pests as well. Their feeding damage to black locust is pictured here on the left. |
| 1627048 | locust leafminer | Odontota dorsalis | The adult locust leafminer is a small yellow and black beetle. |
| 1627050 | arborvitae leafminer | Argyresthia thuiella | Yellow or brown tips on arborvitae indicate the presence. |
| 1626025 | oak lecanium | Parthenolecanium quercifex | Dead females on the twig and settled crawlers on the leaf. |
| 1626041 | white peach scale | Pseudaulacaspis pentagona | Males are elongate and snowy white. |
| 1627056 | elm leaf beetle | Xanthogaleruca luteola | The beetles emerge in early spring and begin laying clusters of yellow eggs on the underside of elm leaves. |
| 1627025 | fall webworm | Hyphantria cunea | The large flimsy nests of the fall webworm are a familiar sight along road sides in later summer. The nests grow larger and larger until entire branches are covered. |
| 1626061 | honeylocust plant bug | Diaphnocoris chlorionis | These stunted and deformed leaves were caused by early spring feeding. |
| 0717011 | cooley spruce gall adelgid | Adelges cooleyi | Note the long needles on the gall itself. |
| 1627004 | eastern tent caterpillar | Malacosoma americanum | Eggs are laid in distinctive shiny masses which encircle small twigs. The caterpillars hatch just as leaves begin unfolding in the spring. |
| 1627013 | walnut caterpillar | Datana integerrima | A coat of long, soft, white hairs identifies this member of the summer defoliator group. Clusters of them feed on the leaves of walnut, butternut, hickory, and pecan. |
| 0717041 | eastern white pine | Pinus strobus | newly established Christmas tree research plots. 1992 |
| 0718021 | oak leafminers | Cameraria spp. | |
| 0718057 | hemlock woolly adelgid | Adelges tsugae | |
| 1626017 | spruce spider mite | Oligonychus ununguis | Spruce mites are most active in cool weather during spring and fall. |
| 0718027 | spruce spider mite | Oligonychus ununguis | |
| 1626004 | white pine aphid | Cinara strobi | The white pine aphid feeds on the bark of twigs and branches. Heavy aphid infestations can seriously weaken small trees. |
| 1626054 | boxwood psyllid | Cacopsylla buxi | Nymphs, covered with a white waxy material, feed on the terminal leaves as they unfold in the spring. |
| 1626032 | cottony camellia scale | Pulvinaria floccifera | |
| 1626044 | mealybugs | The taxus mealybug is unusual in that it has only one generation per year. | |
| 1626099 | European hornet | Vespa crabro | Girdled branches due to removal of bark to be used for nest building. |
| 1627047 | columbine leafminer | Phytomyza aquilegivora | These winding tunnels indicate the presence of columbine leafminer. |
| 1627066 | Japanese beetle | Popillia japonica | The larvae of the Japanese beetle are call white grubs. These white, c-shaped grubs feed on the roots of grasses and are themselves serious pests. |
| 1627094 | tip moth | Pitch, frass, and dead needles soon are evident on the infested tips. Young trees are seriously deformed by repeated infestations, but light infestations may actually improve some ornamental pines by making them bushier. | |
| 1627095 | tip moth | ||
| 1627097 | white pine weevil | Pissodes strobi | Drooping leaders which eventually die on white pine or Norway spruce are the familiar symptoms of white pine weevil attack. |
| 1627099 | white pine weevil | Pissodes strobi | |
| 0717021 | spruce spider mite | Oligonychus ununguis | Note the red eggs, the clear egg shells, and the green mites. In addition, notice the spots caused by the feeding. |
| 1626008 | woolly alder aphid | Prociphilus tessellatus | Some aphids produce a protective coat of white waxy filaments. |
| 1627046 | boxwood leafminer | Monarthropalpus flavus | It is not uncommon to find half a dozen maggots per leaf. |
| 1626023 | soft scales | Parthenolecanium spp. | Wingless and legless adult scales spend their lives pressed against their hosts under tiny, protective shells. Soft scale insects have a waxy film secreted over their body wall, while armored scales are well protected beneath a separate cover secreted over their bodies. |
| 1626024 | soft scales | Parthenolecanium spp. | Female scale insects lay their eggs under their bodies or scale covers. When they first hatch, young scales have legs and are quite active. At this stage, they are called crawlers. Crawlers disperse, locate new feeding sites, and then transform into immobile adults. |
| 1626018 | spider mites | Because they are small and difficult to see, spider mite problems are often diagnosed by symptoms of the host rather than by direct identification of the pest. | |
| 1626019 | spider mites | Spider mites get their name from this ability to produce silk webbing. A hand lens is essential to determine if mites are actually present and whether they are alive or dead. | |
| 1626020 | boxwood spider mite | Eurytetranychus buxi | White or yellow stippling on the upper surfaces of leaves and the presence of egg shells and cast skins on the lower surfaces indicates a boxwood mite infestation. |
| 1626021 | southern red mite | Oligonychus ilicis | The presence of eggs and cast skins helps identify this pest. |
| 1626027 | hemispherical scale | Saissetia coffeae | An adult female and several settled crawlers are visible in this picture. |
| 1626028 | hemispherical scale | Saissetia coffeae | |
| 1626029 | wax scales | Ceroplastes spp. | Wax scale is an easily recognized pest of azalea, camellia, Chinese holly, and many other ornamental plants. |
| 1626030 | fletcher scale | Parthenolecanium fletcheri | Due to premature needle drop, infested plants become thin and a crust of sooty mold covers twigs and remaining needles |
| 1626036 | obscure scale | Melanaspis obscura | Primarily found on oaks, this pest causes dieback of branches, limbs, and sometimes entire trees. Inexperienced observers often mistake these scales for flakes of bark even at close range. |
| 1626037 | pine needle scale | Chionaspis pinifoliae | Feeding causes needles to yellow and drop prematurely. Infested trees become sparse and sickly looking. |
| 1626038 | pine needle scale | Chionaspis pinifoliae | Pine needle scale overwinters as eggs beneath the female's shell and has two generations per year in Virginia. |
| 1626039 | white peach scale | Pseudaulacaspis pentagona | |
| 1626040 | white peach scale | Pseudaulacaspis pentagona | Female white peach scales resemble miniature fried eggs. |
| 1626003 | aphids | Aphids feed in colonies. They have plump, pear-shaped bodies and two tubes, or cornicles, which project like exhaust pipes from their abdomens. | |
| 1626005 | apple aphid | Aphis pomi | |
| 1626006 | aphids | Aphid feeding often causes leaves to curl and become deformed. Once this happens, control is very difficult because aphids inside the curled leaves are protected from contact with the insecticide. | |
| 1626007 | aphids | Aphids excrete a sugary waste produce called honeydew. Notice the clear drop on the left side of this picture. Ants, bees, and wasps collect honeydew for food. Black and brown fungi, appropriately called sooty molds, cover leaves and other objects below aphid colonies where honeydew collects. | |
| 1626014 | spider mites | Spider mites are almost microscopic. Most are about the size of a period made by a typewriter. | |
| 1626015 | spider mites | This type of feeding causes a fine flecking or stippling on the foliage. | |
| 1626016 | spider mites | Where large populations exist, the injured areas coalesce and entire leaves become yellow or bronzed. | |
| 1626093 | dogwood clubgall midge | Resseliella clavula | Eggs are laid in developing dogwood buds. After hatching, their larvae work their way into the tips of the new twigs. Later, the adjacent tissue begin to swell and a gall forms. |
| 1626097 | twig girdler | Oncideres cingulata | After laying an egg beneath the bark of a twig, the beetle chews a continuous notch around the twig which girdles it. The girdled twig soon drys out and breaks off; the larva develops inside the fallen twig on the ground. Damage to the host trees including elm, oak, hickory, dogwood, and others is generally insignificant. |
| 1626098 | European hornet | Vespa crabro | |
| 1626086 | maple bladdergall mite | Vasates quadripedes | Several tiny mites live inside each gall. The white, carrot- shaped gall mites, barely visible here under high magnification, are invisible to the naked eye. |
| 1626075 | lacewings and allies | The larvae are miniature monsters when viewed at close range. They are deadly enemies of small caterpillars, aphids, and other soft-bodied insects. | |
| 1626078 | Tachinid flies | Tachinid flies are parasites of other insects. This fly has laid its small white eggs just above the legs of the caterpillar in front of it. Upon hatching, the fly maggots will burrow through their hosts skin and feed on its internal organs. The caterpillar will die just as the larvae emerge and complete their development. | |
| 1626053 | psyllids | Some species are serious pests, but many are simply nuisances because the honeydew they produce leads to unsightly crusts of black sooty mold. | |
| 1626045 | mealybugs | Nymphs and adults cluster together at favorable feeding sites. | |
| 1626046 | mealybugs | White, waxy filaments may cover entire colonies. | |
| 1626048 | whiteflies | Whiteflies often go unnoticed even when they occur in large numbers, because they congregate on the underside of the leaves. When the leaves are disturbed, the adults fly about, but they quickly settle again when the disturbance has passed. | |
| 1626049 | whiteflies | Adult whiteflies are only about 1/16 inch long. Their two pairs of broadly rounded wings are covered with a white waxy powder. | |
| 1626050 | whiteflies | Nymphs are small, non-motile, and nearly the same color as the foliage. | |
| 1626033 | euonymus scale | Unaspis euonymi | Enonymus scale has two to three generations per year and can build up until whole plants are covered by scales. |
| 1626034 | euonymus scale | Unaspis euonymi | Male and female enonymus scales are so different in appearance that they are often mistaken for different species. The males are small, narrow, and white and occur primarily on the leaves. |
| 1626042 | oystershell scale | Lepidosaphes ulmi | Lilac, willow, apple, and dogwood are among over 100 plants known to be hosts of this pest. |
| 1626055 | boxwood psyllid | Cacopsylla buxi | The familiar result of an infestation is stunted twigs and cupped leaves. |
| 1626057 | boxelder bug | Boisea trivittata | |
| 1626058 | leaf-footed bugs | Leptoglossus spp. | Several species of leaf-footed bugs, pictured here on the left, and most stink bugs, here on the right, are plant feeders. |
| 1626059 | fourlined plant bug | Poecilocapsus lineatus | Small circles of dead leaf tissue indicate the presence of four line plant bugs. |
| 1626060 | honeylocust plant bug | Diaphnocoris chlorionis | Honeylocust and black locust trees are susceptible to infestation by the honeylocust plant bug. |
| 1626063 | lace bugs | Corythucha spp. | Prior activities are confirmed by black, shiny spots of excrement and spiny cast skins on the underside of damaged leaves. |
| 1626066 | leafhoppers | There are hundreds of species of leafhoppers, all similar in size and shape. The adults are about 1/4 inch long and usually green. | |
| 1626067 | leafhoppers | Cast skins left behind each time the nymphs molt are a clue to the presence of leafhoppers. | |
| 1627039 | redheaded pine sawfly | Neodiprion lecontei | Sawflies can be distinguished from caterpillars by counting the number of fleshy prolegs they have. Caterpillars have five pairs or less; sawflies six pairs or more. The bright red heads easily identify this pest as the redheaded pine sawfly. |
| 1627041 | roseslug sawfly | Endelomyia aethiops | |
| 1627044 | boxwood leafminer | Monarthropalpus flavus | Adult females, like this one, insert their eggs through the epidermis of new leaves. |
| 1627045 | boxwood leafminer | Monarthropalpus flavus | After hatching, the maggots feed within the leaves, causing unsightly blisters to appear. |
| 1627051 | arborvitae leafminer | Argyresthia thuiella | Caterpillars are only 1/5 inch long when full grown. |
| 1627052 | arborvitae leafminer | Argyresthia thuiella | They are so small that they can feed and complete their development inside the narrow arborvitae leaves. |
| 1627059 | snout beetles or weevils | Half-moon shaped notches eaten into leaf edges are characteristic damage. | |
| 1627060 | black vine weevil | Otiorhynchus sulcatus | The black vine weevil is also called the taxus weevil. |
| 1627063 | Fuller rose beetle | Pantomorus cervinus | All individuals are females; males have never been found. They can produce viable eggs without mating. |
| 1627064 | rose chafer | Macrodactylus subspinosus | |
| 1627065 | Japanese beetle | Popillia japonica | This beetle feeds in swarms. |
| 1627005 | eastern tent caterpillar | Malacosoma americanum | Their tents, always located in branch forks, get larger as the caterpillars feed and grow. |
| 1627006 | eastern tent caterpillar | Malacosoma americanum | Full-grown caterpillars are 2-1/2 inches long with a white stripe down the back and blue spots on either side. |
| 1627008 | cutworms, loopers, owlet moths, and underwings | ||
| 1627009 | cutworms, loopers, owlet moths, and underwings | ||
| 1627011 | buck moths | Hemileuca spp. | Most of the time, this is a rare insect, but during outbreaks, large numbers can cause serious defoliation of oak trees. |
| 1627026 | fall webworm | Hyphantria cunea | Inside its web, the fall webworm caterpillars feed and grow in relative safety. |
| 1627027 | mimosa webworm | Homadaula anisocentra | Both mimosa and honeylocust are attacked by the mimosa webworm. |
| 1627036 | gypsy moth | Lymantria dispar | Larvae leave their host tree and search for hiding places in which to pupate. During outbreaks, large numbers wander through parks and picnic areas, across sidewalks and roads, and onto houses and other buildings. |
| 1627015 | greenstriped mapleworm | Dryocampa rubicunda | |
| 1627016 | red-humped caterpillar moth | Schizura concinna | |
| 1627017 | azalea caterpillar | Datana major | |
| 1627019 | imperial moth | Eacles imperialis | The caterpillar will be four inches long when full grown. |
| 1627020 | hickory horned devil | Citheronia regalis | This caterpillar. Despite its ferocious look, it is harmless to man and never occurs in large enough numbers to be considered a pest. |
| 1627021 | saddleback caterpillar | Acharia stimulea | There are a few caterpillars that should not be handled because of their stinging spines. Contacting the spines of a saddleback caterpillar is every bit as painful as a bee sting. |
| 1627022 | bagworm | Thyridopteryx ephemeraeformis | Bagworms hide themselves in silken bags covered with bits of their food plant. |
| 1627023 | bagworm | Thyridopteryx ephemeraeformis | The caterpillar inside exposes only his head and front legs as it moves and feeds carrying its bag-like house with it. |
| 1627071 | long-horned beetles | With their striking color patterns and exceptionally long antennae, long-horned beetles are a handsome lot. Their larvae are white, legless, and worm-like with somewhat swollen heads. Luckily, most species in this group infest only dead or dying trees. There are, however, a few important pests which will attack healthy trees and shrubs. | |
| 1627073 | locust borer | Megacyllene robiniae | Their larvae bore through the bark and tunnel extensively in the wood. Heavily infested trees may be so weakened that they break off in high winds. |
| 1627074 | redheaded ash borer | Neoclytus acuminatus | |
| 1627076 | dogwood twig borer | Oberea tripunctata | |
| 1627077 | flatheaded or metallic wood borer | The adult beetles have hard shells with a metallic lustre. The heads of the larvae are expanded and flattened. | |
| 1627078 | bronze birch borer | Agrilus anxius | This insect seeks out birch trees already in poor condition, then lays its eggs in bark crevices or near recent wounds. |
| 1627082 | dogwood borer | Synanthedon scitula | |
| 1627083 | American plum borer | Euzophera semifuneralis |
