Plant Health Management for Backyard Bramble (Raspberry

and Blackberry) Plantings

Prepared by

Mike Ellis Professor and Extension Specialist and Omer Erincik

Graduate Research Assistant

Department of Plant Pathology The Ohio State University

OARDC/OSUE Wooster, OH, 44691

Common Diseases on Fruit

Gray mold (Botrytis fruit rot)

Symptoms:One to several blossoms

in a cluster may show blasting (browning and drying).

Berries eventually become covered by a grayish, dusty, or powdery growth of the fungus.

Gray mold

Disease Development:Caused by the fungus Botrytis cinereaMost infections occur during bloom; however,

symptoms are usually not observed until harvest.

Temperatures between 70 and 80 °F and free moisture (water) on the foliage from rain, dew, fog, or irrigation are ideal conditions for disease development.

The disease is generally most severe in the interior areas of the plant canopy where humidity is higher and air movement is poor.

Management of gray mold

Free water (wet conditions) is required for most fungal pathogens to infect fruit. Any practice that promotes faster drying of fruit and foliage is beneficial for disease control.

Site selectionSelect a site with good air movement and

sun exposure (promote faster drying).Canopy management

Prune to keep row width between 1 or 2 feet in order to encourage air movement and faster drying.

Control timing and amount of nitrogen fertilizer to prevent excessive growth.

Management of fruit rot diseases

IrrigationIf you use overhead irrigation irrigate early

in the day, so that plants can dry faster.Handling

Harvest mature fruit promptly to avoid letting berries become overripe

Pick fruit carefully, avoid bruisingProcess and or refrigerate fruit

immediately after harvest

Common cane diseases on brambles

Anthracnose Cane blight Spur blight

Symptoms of cane diseases Anthracnose Small purple spots develop on young canes.

Eventually, they become grayish and sunken in the centers surrounded by a reddish margin.

Cane blight Brownish-purple to grayish areas, up to

several inches long usually develop around pruning or other wounds. Branches suddenly wilt and die above the blighted area.

Spur blight Reddish-brown or purplish-brown areas up to

several inches long develop at the nodes on the young canes. Eventually, the bark may split lengthwise in the diseased areas.

Cane diseases on brambles

Disease Development:Causal fungi (pathogens): Anthracnose……...Elsinoe veneta

Cane blight……….Leptosphaeria coniothyrium

Spur blight……….Didymella applanata

These three fungal pathogens survive over winter in spots or other infected areas on canes.

Spores of these pathogens spread to new canes during spring in splashing water from rain or overhead irrigation to cause new infections.

Management of brambles cane diseases

Use disease free planting stock Proper site selection

Choose a site with good air circulation and sun exposure (promotes faster drying).

Pruning (sanitation)Prune out all canes showing disease symptoms to

reduce pathogen populationRemove infected canes from the planting

Canopy Management:Avoid over fertilization, especially with nitrogenPrune to keep row width between 1 to 2 feet to

encourage rapid drying.

Common Diseases Attacking Roots

Verticillium wilt Phytophthora root rot

Verticillium wilt

Symptoms:Starting at the base of the cane

and processing upward, leaves wilt, turn yellow, and drop.

Black raspberry and blackberry canes may exhibit a blue color or purple streaking from the soil line extending up infected canes to varying heights.

Verticillium wilt

Disease Development:

Caused by the soil-borne fungus, Verticillium albo-atrum

The fungus can survive in soil for many years.

The fungus infects roots and plugs water-conducting tissues (xylem). This prevents the movement of water from the roots to the rest of the plant; thus, the plant eventually wilts, and dies.

Disease is favored by wet and poorly drained soils.

Phytophthora root rot

Symptoms:Healthy canes may suddenly decline

and collapse. Leaves may initially take on a yellow,

red, or orange color or may begin scorching along the edges.

Affected canes eventually wilt and die. On the below-ground portion of the

crown or large roots, a distinct line can generally be seen between healthy and infected tissues after scraping away the outer bark. Infected tissues are brown to brownish-red.

Phytophthora root rot

Disease development:caused by Phytophthora spp.favored by high soil moisture (saturated soil)

and cool temperatures.infection can occur throughout the growing

season if soil moisture conditions are favorable.

most destructive in heavy clay soils that are saturated with water during cool weather.

Management of root diseases

Use healthy planting stock Proper site selection

Plant in well-drained soilSelect a site that does not have a previous

history of problems with any of the root diseases.

SanitationDig up diseased plants, including roots,

and remove them from the planting.

Management of root diseases

RotationDo not replant brambles where disease

has been a problem for at least 2 years.Improve soil drainage Any practice that improves soil drainage

is beneficial to control.Plant on raised bedsTile planting areas.

Management of root diseasesUse resistant varieties for Phytophthora root rot

Phytophthora root rot is most destructive on red raspberries. Black raspberries are not immune but appear to be much more resistant than red raspberries. The disease is rare on blackberries. Although no red raspberry varieties are completely resistant, varieties vary greatly in their susceptibility. Choose red raspberry varieties with higher levels of resistance.

Diseases caused by rust fungi

Orange rust Late leaf rust

Orange rust

Symptoms: The lower surface of infected leaves

become covered with blister-like pustules. Eventually, the pustules turn into bright orange, powdery masses of spores.

Plants are systemically infected (fungus grows throughout the plant and the plant is infected for life). In years following infection, infected canes will be bushy and spindly as they emerge in the spring.

New leaves on infected canes are stunted or misshapen and pale-green to yellowish.

Orange rust

Disease development: Orange rust only affects black raspberry and

blackberry. Red raspberries are immune. In late May to early June, the bright orange

spores of the pathogen spread from infected leaves to healthy leaves by the wind and perhaps rain-splash.

When environmental conditions favorable (temperatures between 43 and 72 °F and long period of wetness), the spores (aeciospores) germinate and penetrate the leaf causing localized infections.

Orange rust

Disease development: About 45 days later the fungus produces another

type of spore (teliospores) in these infected areas. During late summer or early fall, these teliospores produce yet another type of spore (basidiospore). Basidiospores infect buds at the base of the plant to cause systemic infection.

The fungus becomes systemic, growing into the crown at the base of the infected shoots, and into newly formed roots.

Leaf late rust

Symptoms:Small chlorotic or yellow

spots form on the upper leaf surface.

Small pustules filled with powdery spores are formed on the underside of the infected leaves.

These “rust” pustules also occur on fruit.

Leaf late rust

Disease development Pathogen: Pucciniastrum americanum Disease only affects red raspberries. Black

raspberries and blackberries are immune. The small, numerous, light yellow spots seen on

the undersurfaces of the leaves are the uredinial pustules that contain the urediniospores of the fungus.

These spores are capable of causing new infections on leaves and fruit throughout the growing season.

Management of rust diseasesUse healthy planting stock Site selection

Select a site with good air movement and sun exposure (promote faster drying).

Canopy controlPrune to keep row width between 1 or 2 feet in order to

encourage air movement and faster drying.Control timing and amount of nitrogen fertilizer to prevent

excessive growth.Sanitation

Remove and destroy infected plants including the roots (important for orange rust).

Destroy nearby wild brambles that serve as a reservoir for disease.

Management of rust diseases

Disease resistance:Orange rust

Red raspberries are immune (completely resistant)

There are no resistant black raspberry varieties.

Late leaf rust Black raspberries and blackberries are

immune. No red raspberries varieties are resistant.

Using Fungicides For Brambles Disease Control

Fungicides can be important for disease control in commercial plantings; however, fungicides are generally not recommended for use in backyard bramble plantings.

Effective fungicides are usually difficult or impossible for backyard growers to obtain.

If not used properly, they are generally not effective.

For backyard growers that do wish to use fungicides in the disease management program, fungicide recommendations are available for brambles in Bulletin 780 “Controlling Disease and insects In Home Fruit Planting”.

Emphasis for disease control in backyard plantings should be placed on:

Use of the various cultural practices for disease control mentioned previously.

Use of disease resistant varieties when possible.

Selected literature for backyard fruit production and plant health management:

Bulletin 591. “Growing and Using Fruit at Home” Bulletin 780. “Controlling Diseases and Insects in

Home Fruit Planting” Bulletin 782. “Brambles Production Management

and Marketing”. Bulletin 861. “Midwest Small Fruit Pest

Management Handbook”.

These can be obtained through your county extension agent or the Extension Publications Office, The Ohio State University, 385 Kottman Hall, 2021 Coffey Road, Columbus, Ohio, 43210-1044

To get more information about plant diseases visit the websites below.

http://www.ag.ohio-

state.edu/~plantdoc/extension.php

http://www.ohioline.ag.ohio-state.edu