Horticultural Hardships

Floral Fungus

When it comes to plants and shrubs, especially fruit trees and landscape quality cultivars, disease can frequently be attributed to fungus.  Some of the more common fungal diseases includes root rot, cankers, black knot, anthracnose, cedar-apple rust, apple scab and various blights.  Various conditions favor disease development;  warm, damp weather can be very conducive to tree fruit diseases, certain times of year and at certain stages of growth plants will be more susceptible to disease, monocultural growth may spread disease and conversely certain species planted near each other will provide host material in multi-stage fungal growth.

Malady Manifestations

Disease can manifest as defoliation, fruit malformation, reduction in bloom, galls, leaf spot, canker formation on trunk or branches and even limb die off.

dogwood anthracnose

Anthracnose primarily affects dogwoods and sycamores. It can present as leaf spots, curling or deformation, trunk and twig cankers or defoliation. It affects developing shoots and expanding leave.

root rot

Root rot can infect roots and decay the trunk of the tree, it will cause a slow decline in the trees health and can seriously affect the structural integrity.


Cankers will form when a pathogen enters through wounds or branch nubs and cause infolding, swollen, sunken and/or discolored tissue.


Black knot is pretty much exactly how it sounds, it forms black, knotty looking galls mostly on branches or axillary twigs. Twigs will weaken from stress of extra weight and the ability to move nutrients is impeded.




cedar apple rust-cedar

Cedar apple rust needs 2 hosts to complete its life cycle. Above is the gall with extruded telia formed on the eastern red cedar. During dry conditions spores will be released.

cedar apple rust

Once spores find apple leaves they will infect causing orangish-yellow pustules


 Fight the Blight

Prevention is the key when managing for tree diseases, healthy trees will have the most resistance.  Carefully select sites for planting trees, monitor watering schedules; make sure trees are sufficiently watered during times of drought, but avoid over-watering and excessive mulching, regular fertilizations give will give an added healthful boost and adequate pruning will be beneficial.  Your landscape may require cultural practices be integrated with biological and/or chemical controls for the best outcomes.  Consult with your arborist to evaluate your property for disease and devise the optimal program for prevention, treatment and control.