Plant Disease Management Handbook

See:

Greenhouse Plants, Ornamental - Pythium Seed Rot, Damping-off, and Root Rot

Lily (Lilium spp.) - Basal Rot (Bulb Rot)

Rotted roots due to Pythium sp.

OSU Plant Clinic image, 2015.

Underground symptoms include rotted portions on roots and bulbs. These lesions had Cylindrocarpon, Rhizoctonia and Trichoderma.

OSU Plant Clinic, 2020.

See:

Lily (Lilium spp.) - Root Rots

Stunted plant to the left is noted in the image.

Tom Allen Collection.

The plants in the row to left of center (shorter row next to tubing) are yellowed and stunted when compared to plants in the row right of center.

Photo by Jay W. Pscheidt, 1990.

Cause Aphelenchoides fragariae has a wide host range (including Anemone, begonia, and phlox) and is a pest of various kinds of lily in northern and southwestern Oregon. Nematode infections are transferred to other areas and from one season to the next in planting stock. Plant-to-plant spread in field and greenhouse plantings occurs especially when plants are close together. Spread can be rapid even when low-volume irrigation spray stakes are used in the greenhouse.

Note the deformed shoot tip.

Photo by Kathy Merrifield, 1993.

See:

Tulip - Crown Rot

Notes Some products are registered for lily and not tulip such as the following:

  • Cannonball WG at 7 oz/A applied at planting. Group 12 fungicide. 12-hr reentry.

Cause Botrytis elliptica and B. cinerea, fungi. The former has been reported on crocus, daylily, and gladiolus but is primarily on lily while the latter has a huge host range. Botrytis overwinters as sclerotia in the debris of plant shoots that mature and decay in fall. In spring, sclerotia on or near the soil surface produce conidia that infect leaves. Conidia are windblown to healthy foliage.

Image related to Lily (Lilium spp.)-Botrytis Blight (Fire)
Image related to Lily (Lilium spp.)-Botrytis Blight (Fire)

Necrotic leaves and leaf spots due to Botrytis.

OSU Plant Clinic Image, 2014.
Image related to Lily (Lilium spp.)-Botrytis Blight (Fire)

Although copper-based products are helpful they will not remove leaf spots.

OSU Plant Clinic Image, 2014.
Image related to Lily (Lilium spp.)-Botrytis Blight (Fire)

Black sclerotia of Botrytis have developed on this leaf and serve as a survival structure for the fungus.

OSU Plant Clinic Image, 2014.

Note the necrotic blotches on the leaves.

Photo by Jay W. Pscheidt, 1990.

See:

Lily (Lilium spp.) - Root Rots

A lily bulb
A lily bulb

This bulb had many different fungi in addition to Fusarium and bulb mites.

OSU Plant Clinic image, 2020.

Cross section through the bulb from above image.

OSU Plant Clinic image, 2020.

Cause There are several organisms that have been associated with root rots of lilac including Phytophthora, Rhizoctonia and Armillaria. These diseases are generally found where plants are in cold wet soils and/or overwatered. Young, nursery-grown plants can get root rot as well as mature bushes grown in landscapes.

Image related to Lilac (Syringa spp.)-Root Rot
Image related to Lilac (Syringa spp.)-Root Rot
Plants in pots can also get Phytophthora root rot.
Jay W, Pscheidt, 2006.

Lilac root rot where both Phytophthora sp. and Pythium sp. were found. Cut midway shows transition from healthy vascular system above to discolored tissue below.

OSU Plant Clinic, 2021.

Image related to Lilac (Syringa spp.)-Root Rot
Young plants are as susceptible as older ones to Phytophthora root rot.
Jay W, Pscheidt.
Image related to Lilac (Syringa spp.)-Root Rot
Lilac with Phytophthora crown and root rot. Note dead branches in the middle of the bush.
Jay W. Pscheidt, 2006.

Cause The fungus Erysiphe syringae (formerly Microsphaera syringae) is found generally and can also infect Privet (Ligustrum spp.). Phyllactinia syringae has been reported from Idaho and E. penicillata has been reported from WA. Cultivars of S.

Note the white patches on the leaves.

Jay W. Pscheidt, 2020.

Colonies can cover the leaves.

Jay W. Pscheidt, 2020.

See:

Crabapple (Malus spp.) - Stem Rot

Phytophthora sp. was isolated from the discolored canker on this sample.

OSU Plant Clinic, 2021.

Cause Several fungi have been reported from the Pacific Northwest including Alternaria sp. (leaf spot), Ascochyta syringae (leaf blight), and Phyllosticta sp. (leaf spot). Airborne or water-splashed spores infect young leaves during wet weather, in the spring.

Symptoms Light-brown to dark-brown necrotic leaf spots and blights.