Twig Blight

Diaporthe vaccinii

67 host plants · Fungal

Last updated

Data Maturity Structured

This profile synthesizes data from multiple published sources. Expert field review is in progress.

In blueberry fields and ornamental plantings, twig blight announces itself through wilting and red-flagged shoots appearing in summer, often accompanied by cankers at the base of infected canes. The fungus Diaporthe vaccinii produces tiny fruiting bodies embedded in the bark that ooze spores during wet weather, and when moisture is high, you may see silvery-looking tissue speckled with black dots around the infection site. The disease starts by infecting flowers during bloom and spreads down into shoots and twigs as the season progresses.

The reason twig blight has become increasingly important in British Columbia blueberry blocks is its ability to infect through both flowers and wound sites, giving it multiple entry routes into your plants. If you grow blueberries, start with certified, disease-free planting stock and prune out infected branches at least 5 to 6 inches below visible symptoms, disinfecting tools between cuts. Some cultivars like Rubel show better resistance than susceptible varieties such as Duke and Legacy, so choose wisely when replanting. Most importantly, maintain good plant spacing and canopy management to keep foliage dry and promote air circulation, which reduces the wet conditions Diaporthe needs to thrive.

Quick Reference

Agent Type
fungal
Causal Agent
Diaporthe vaccinii
Host Plants
67
Favorable Conditions
Spring; cool wet conditions (50-62°F) with 8+ hours continuous leaf wetness. ...

Management

Vulnerability Window

Spring through early summer (April-June); peak during active shoot elongation (BBCH 14-18). New tissue most susceptible.

What Triggers Infection

Spring; cool wet conditions (50-62°F) with 8+ hours continuous leaf wetness. Rain-splash dominates. Optimum: 55-60°F with high humidity.

Cultural Controls

  • Purchase healthy planting material and/or do not use plants with injured branches.
  • Prune out, remove, and destroy infected and dead branches.
  • Prune 5 to 6 inches below symptoms.
  • Avoid wounding or injuring plants.
  • Encourage plants to harden off in winter to avoid frost damage.
  • Provide adequate plant spacing and manage canopy size to promote good air circulation.

Host Plants (67)

Cotoneaster apiculatus Cranberry Cotoneaster Daphne burkwoodii Burkwood Daphne Daphne caucasica Caucasian Daphne Daphne cneorum Garland Daphne, Rock Daphne, Rose Daphne Daphne genkwa Lilac Daphne Daphne laureola Spurge Laurel Daphne lawrence Daphne, lawrence Daphne mezereum February Daphne, Mezereon Daphne odora Fragrant Daphne, Winter Daphne Juniperus occidentalis Western Juniper Microbiota decussata Russian Arborvitae, Siberian Cypress Pinus albicaulis Whitebark Pine, Scrub Pine, White Pine Pinus aristata Bristlecone Pine, Rocky Mountain Bristlecone Interior Bristlecone Pinus attenuata Knobcone Pine Pinus banksiana Jack Pine, Scrub Pine, Banksian Pine, Hudson Bay Pine Pinus bungeana Lacebark Pine, Whitebark Pine, Baipi Song Pinus canariensis Canary Island Pine Pinus cembra Swiss Stone Pine Pinus contorta Lodgepole Pine Pinus contorta var. contorta Shore Pine Pinus contorta var. latifolia Rocky Mountain Lodgepole Pine Pinus coulteri Coulter Pine, Bigcone Pine Pinus densiflora Japanese Red Pine Pinus edulis Pinyon Pine, Piñón Pine, Two-needle Pinyon Colorado Pinyon Pinus elliottii Slash Pine, Swamp Pine Pinus flexilis Limber Pine, Rocky Mountain White Pine Pinus halepensis Aleppo Pine, Jerusalem Pine Pinus heldreichii Bosnian Pine, Snakeskin Pine Pinus jeffreyi Jeffrey Pine, Western Yellow Pine, Bull Pine Pinus kwangtungensis Kwangtung Pine, Guangdong Pine Pinus lambertiana Sugar Pine Pinus leucodermis Bosnian Pine Pinus monophylla Singleleaf Pinon Pine, One-leaved Pine Pinus monticola Western White Pine Pinus mugo Mugo Pine Pinus mugo var. pumilio Mugo pine, Dwarf Mugo pine Pinus nigra Austrian Pine Pinus parviflora Japanese White Pine Pinus parvifola Pinus parvifola Pinus pinaster Maritime Pine, Cluster Pine, Turpentine Pine Pinus pinea Italian Stone Pine, Umbrella Pine Pinus ponderosa Ponderosa Pine, Western Yellow Pine Pinus pumila Japanese Stone Pine, Dwarf Siberian Pine Pinus radiata Monterey Pine Pinus resinosa Red Pine Pinus sabiniana Gray Pine, Foothill Pine Pinus strobiformis Southwestern White Pine, Mexican White Pine, Chihuahua White Pine Pinus strobus Eastern White Pine Pinus sylvestris Scots Pine, Scotch Pine Pinus thunbergii Japanese Black Pine Pinus virginiana Virginia Pine, Scrub Pine, Jersey Pine Pinus wallichiana Himalayan Pine, Bhutan Pine Pinus yunnanensis Yunnan Pine Platycladus orientalis Chinese Arborvitae, Oriental Arborvitae Thuja occidentalis Eastern Arborvitae, American Arborvitae Eastern White-cedar Thujopsis dolabrata Elkhorn Cedar, Deerhorn Cedar, Hiba Arborvitae, False Arborvitae Vaccinium angustifolium Lowbush Blueberry Vaccinium corymbosum Highbush Blueberry Vaccinium crassifolium Creeping Blueberry, Thick-leaved Whortlberry Vaccinium macrocarpon Cranberry American Cranberry Vaccinium membranaceum Big Huckleberry, Mountain Huckleberry Thinleaf Huckleberry Vaccinium ovalifolium Oval-leaf Blueberry Vaccinium ovatum Box Huckleberry, Evergreen Huckleberry Vaccinium parvifolium Red Huckleberry, Red Whortleberry Vaccinium sikkimense Sikkim Blueberry Vaccinium uliginosum Bog Blueberry, Bog Bilberry Vaccinium vitis Vaccinium vitis