Baltimore, MD

Multiple species (Aphididae)

Small soft-bodied sap-sucking insects that reproduce explosively in spring. Excrete honeydew that supports sooty mold and attracts ants. Transmit viral diseases.

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.

Sylvilagus and Lepus species

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

Popillia japonica

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

Multiple species (Chrysomelidae)

Tiny black or bronze jumping beetles that put hundreds of small holes in seedling leaves. Most damaging on direct-seeded brassicas and young eggplant.

Meloidogyne species

Microscopic soil-dwelling worm that forms galls on roots, reducing vigor and yield.

Tetranychus urticae

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

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.

Pseudoperonospora cubensis (cucurbits) and others

Water mold (oomycete, not a true fungus) that thrives in cool damp conditions. Spreads rapidly through cucurbit and brassica plantings on wind-borne spores.

Pythium and Rhizoctonia species

Soil-borne complex of water molds and fungi that kill seedlings before or shortly after emergence. The single most common cause of seed-starting failures.

Cucumber mosaic virus, Tobacco mosaic virus, and others

Family of plant viruses producing mottled yellow-and-green leaf patterns. Vectored primarily by aphids; some are seed-transmitted or spread by handling tools and tobacco products.

Botrytis cinerea

Ubiquitous fungal disease that causes fruit rot during cool wet weather, often the dominant berry disease in humid regions.

Fusarium oxysporum

Soil-borne fungal disease that plugs vascular tissue and kills affected plants. Persists in soil for many years; impossible to eliminate once established.

Sclerotium rolfsii

Soil-borne fungal disease most damaging in warm humid Southern conditions. White mycelial fans and small mustard-seed-sized sclerotia at the soil line are diagnostic.

Plasmodiophora brassicae

Soil-borne disease causing characteristic distorted club-shaped roots on brassicas. Persists in soil for 10-20 years; the dominant brassica pathogen in acidic poorly-drained soils.

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.