Tulip Diseases & Pests
The main diseases of tulips are Bacterial Soft Rot, Botrytis tulipae (Blight), Crown Rot (So Blight), Tulip Anthracnose, Tulip Molds, and Tulip mosaic virus.
The main pests of tulips are aphids, spider mites, foliage eating catepillars, bulb flies, bulb mites, and snails and slugs.
Bacterial Soft Rot
Bacterial soft rots cause infected tissue to turn brown, become mushy, and develop an unpleasant odor. Stem tissue turns brown and deteriorates near the soil. Plants grow slowly and seedlings collapse.
Bacterial spots often start out as tiny water-soaked areas on leaves, stems, or blossoms. Spots or blotches turn dark gray or blackish as they enlarge and sometimes have yellow borders.
Initial spots are circular but may become angular and coalesce and cause plant tissue death or necrosis. Cankers may form on stems. Under wet conditions, infected tissue may exude brownish masses of bacteria. Dead tissue may tear out, leaving holes and a ragged appearance.
Botrytis tulipae (Blight)
Botrytis tulipae is a major fungal disease affecting tulips, causing cell death and eventually the rotting of the plant.
Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. It is simply a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Blight caused from Sclerotium rolfsii most often infects tulip species.
Botrytis tulipae, (which sometimes goes by the name Blight or Fire), may produce stunted or deformed leaves. Dead spots on the foliage are often surrounded by dark green circles. The spots turn yellow and may have small black spots speckled within them. Buying fungicide-treated bulbs will help avoid that fate.
Treatment with chlorothalonil (Trade name Daconil), mancozeb (Dithane) or iprodione (Chipco) can keep healthy plants healthy. Layering coarse sand above the bulb when planting can also help prevent invasion.
Crown rot (also known as Southern Blight) is sometimes a problem. Caused by sclerotium rolfsii, it produces yellowed leaves and a fibrous rot on the bulb. Plants are typically stunted and will die prematurely. Fumigating the soil can help remove the condition, but often that will have to be accompanied by discarding the diseased cultivars.
Tulip Anthracnose is a fungus that affects leaf blades and peduncles of mainly Darwin Tulips. In nature, the Reverend Eubank and Zwanenburg varieties are highly susceptible, while Clara Butt and Fantasy (a parrot type) are immune.
Blue Mold, Pink Mold, Black Mold, and mushy rot are common tulip molds. The cure is discarding infected plants, so don’t buy tulip bulbs if they show any signs of these colors.
Tulip mosaic virus
Tulip mosaic virus causes color-breaking of tulip flowers. Also known as tulip breaking virus, tulip top-breaking virus, Tulip bandbreaking virus, Rembrandt tulip-breaking virus, and Lily mottle virus, this virus is one of five plant viruses of the family Potyviridae that cause color-breaking of tulip flowers. These viruses infect only two genera of plants: Tulipa (tulips) and Lilium (lillies).
Aphids are insects that feed on and infect a wide variety of plants. The green peach aphid is a carrier of Tulip breaking disease.
Nematodes are a kind of microscopic roundworm (phylum Nematoda) that lives in the soil in warm climates where the ground seldom freezes. Nematodes are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish.
Over 28,000 have been described, of which over 16,000 are parasitic. The total number of nematode species has been estimated to be about 1,000,000. Unlike cnidarians or flatworms, roundworms have tubular digestive systems with openings at both ends.
Bulb Flies, Bulb Mites, Catepillars, Snails and Slugs, and Spider Mites can also cause problems.