Apple

Gymnosporangium juniperi-virginianae

Two-host fungal disease alternating between apple and eastern red cedar. Severe pressure in regions with abundant cedar.

Erwinia amylovora

Devastating bacterial disease that can kill trees rapidly. Most severe in warm wet springs.

Venturia inaequalis

The most widespread apple disease in humid regions. Reduces fruit quality and defoliates trees.

Podosphaera leucotricha

Surface-feeding fungal disease that distorts new growth and reduces yields.

Physiological disorder

Damage from direct intense sun exposure on fruit or bark, particularly on plants suddenly exposed by pruning, defoliation, or hot weather. Distinct from sunburn (which is reversible).

Agrobacterium tumefaciens

Soil-borne bacterium that enters plants through wounds and induces tumor-like galls on roots, crown, and lower stems. Galls reduce vigor and shorten plant lifespan; on Rubus the disease is often fatal.

Cydia pomonella

The most damaging pest of apple worldwide. Larvae tunnel into developing fruit, ruining the crop.

Conotrachelus nenuphar

Native weevil that lays eggs in young stone and pome fruit, causing characteristic crescent-shaped scars.

Popillia japonica

Defoliating beetle introduced to North America in 1916. Skeletonizes leaves of many fruit trees, berry canes, and pecan.

Halyomorpha halys

Invasive stink bug from Asia that pierces fruit, causing corky tissue and surface dimpling.

Tetranychus urticae

Tiny mite that feeds on leaf undersides, causing stippling and webbing during hot dry weather.

Odocoileus species

Whitetail and mule deer browse can devastate orchards and gardens, particularly in winter when food is scarce. Antler rub on young trunks kills saplings outright.

Microtus species

Field voles and meadow voles girdle young fruit-tree trunks under snow cover during winter and chew root crops. The leading cause of mysterious orchard losses.

Sylvilagus and Lepus species

Cottontails and jackrabbits strip bark from young fruit trees in winter and graze tender garden vegetables year-round, especially seedlings.

Lygus lineolaris

Mottled brown sucking bug that probes flower buds and developing fruit, causing 'cat-facing' deformities on tomato, peach, and strawberry. Wide host range and rapid generations.

Frankliniella occidentalis

Tiny slender insect that rasps leaf and flower surfaces. The primary vector for Tomato Spotted Wilt Virus and Iris Yellow Spot Virus, which makes it more damaging through disease transmission than direct feeding.

Lycorma delicatula

Invasive planthopper from Asia first detected in Pennsylvania 2014, now spreading through the Eastern US. Direct feeding weakens trees; honeydew supports sooty mold and reduces fruit quality.

Quadraspidiotus perniciosus

Tiny armored scale insect that encrusts bark, branches, and fruit. Heavy infestations weaken trees and produce red haloed spots on fruit at harvest. Persistent year-over-year if not controlled.

Eriosoma lanigerum

Aphid that feeds on apple roots and aerial wood, producing distinctive cottony white wax. Root colonies cause galls that reduce vigor; aerial colonies disfigure new growth.