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What is needle rust?
The needle rust fungus creates multiple, unique types of spores that all play a different role in this complex life cycle and allow it to move between pine trees and plants in the aster family. All of these spore types need moisture on leaves and needles to start a new infection. The needle rust fungus survives winter within living plant tissue ...
What family is pine needle rust from?
The pine needle rust fungus needs two different host plants to complete its life cycle. One plant from the Pine family and the other from the Aster family.
How does Pine needle rust survive and spread?
Pine needle rust is caused by the fungus Coleosporium asterum. Like many rust fungi, C. asterum needs two different host plants to complete its life cycle. One plant from the Pinaceae family and the other from the Asteraceae family.
What trees are resistant to needle rust?
In areas with large numbers of wild asters, plant conifers resistant to needle rusts like spruce, white pine or balsam fir.
Where does needle rust fungus live?
The needle rust fungus survives winter within living plant tissue including infected pine needles and infected leaves at the crown of plants in the aster family.
Can pine needles re-infect other pine needles?
The spores produced on pine needles cannot re-infect other pine needles. Instead, they are carried by wind to infect the leaves of a susceptible member of the aster family.
Can pine needles be infected by spores?
These spores can only re-infect another member of the aster family and cannot infect pine needles.
What is spruce needle rust?
What is spruce needle rust? There are two fungi responsible for spruce needle rust: Chrysomyxa weirii and Chrysomyxa ledicola . While both of these fungi foster spruce needle rust symptoms in trees, they do so in slightly different ways. Most spruce species are susceptible to the disease but it is most prominent in white, black, and blue spruce.
What is the name of the rust caused by Chrysomyxa weirii?
The rust caused by Chrysomyxa weirii is referred to as “autoecious. ”. What this means is that the life cycle of the needle rust is completed without an additional host. So, it starts with spruce and ends with spruce, there is no intermediary host.
What is the host of rust?
The alternate hosts for the rust produced by Chrysomyxa ledicola are Labrador tea ( Ledum groenlandicum) and leatherleaf ( Chamaedaphne calyculata ). The fungus overwinters on Labrador tea and leatherleaf and spores are produced and released from these alternate hosts in early summer. The spores travel by wind and come in contact with spruce trees, infecting the current year’s needles.
When do needles turn yellow?
In July and August, the current year needles turn yellow and develop whitish waxy blisters filled with yellow-orange spores. The spores released from these pustules travel by wind and rain to, you guessed it, the alternate hosts, where the spores germinate and infect the evergreen leaves they overwinter on.
Is spruce needle rust heteroecious?
Chrysomyxa ledicola/Chrysomyxa ledi: The spruce needle rust wrought by these fungi is “heteroecious” in nature. This means that its life cycle is dependent on more than one host. You may wonder why you are being schooled on the life cycle of a fungi. The answer is: It’s very important for effective disease management.
Does rusting spruce kill trees?
Spruce needle rust also does not kill trees; the damage is primarily cosmetic. It also does not prevent the formation of healthy buds on the ends of branches nor the production of new needles the next year.
Can you use fungicide on spruce needles?
Even though spruce needle rust is caused by fungi, a fungicide treatment is not recommended for spruce needle rust control. Why you ask; because once the tree displays symptoms, it’s already too late.
What causes rust on a spruce needle?
Spruce needle rust, also known as Weir's cushion rust, is caused by the fungus Chrysomyxa weirii .
When do orange spots appear on needles?
In late winter to early spring, orange to yellow spots or bands appear on one-year-old needles. In late winter, the symptoms may be hard to detect, but when spring advances and bud break approaches in early to mid-May, the bands swell to produce waxy, yellow-orange pustules containing masses of rust-colored spores.
What is the best way to kill spruce fungus?
Fungicides may be practical to protect new growth and stop spread of the disease on small, high-value specimen trees. Copper hydroxide or mancozeb can be effective and is labeled for use on spruce in the landscape.
Is spruce needle rust autoecious?
Spruce needle rust is differs from other common landscape rust diseases (e.g. cedar-apple rust) in that the pathogen is autoecious; it occurs only on spruce and has no known alternate host.
What is rust on spruce needles?
Weir's cushion rust (Chrysomyxa weirii) is the only species of spruce needle rust currently found in Pennsylvania. Infected current-year needles will exhibit pale yellow bands that go completely around the needle. Orange, immature fruiting structures may be visible within the band. This is easiest to see on an overcast day or on the shady side of the tree. Mechanical damage from pricking of needles during windy weather may mimic spruce needle rust. But, mechanical damage does not encircle the needle and usually has a darkened, wrinkled spot or indentation in the yellowed area. Around bud break, the mature, orange telia form on the discolored spots. Spores are yellow orange.
What happens if you get a needle in the previous year?
Needles infected in previous year turn brown and defoliate
What to do if banding of needles is found?
If banding of needles is found, tag several trees to monitor for telia production.
What kind of spruce is in Pennsylvania?
Hosts. In Pennsylvania, most commonly reported on Colorado blue spruce and its varieties, Serbian spruce, and Sitka spruce.
Does spruce needle rust have an alternate host?
This species of spruce needle rust does not have an alternate host. All necessary spore stages are found on spruce. During the winter, the fungus is maturing inside the current year's needles and faint yellow bands with developing orange telia can easily be seen, particularly on lower branches (Figures 1 and 2).
What is rust fungus?
Rust fungi represent some of the most advanced fungal species known. Because rusts are complex diseases they can be described in many different ways. You can categorize them by their life cycles, their spore colors, their primary or alternate hosts, or the types of symptoms they cause.
What causes rust on Christmas trees in Michigan?
Basically, there are two types of rusts on Michigan Christmas trees; those that cause diseases of stems and twigs and those that cause diseases of needles. An example of needle rust is beginning to show up on spruce trees near water. Spruce needle rust overwinters on Labrador tea and leather leaf and spores from these alternate hosts have moved ...
Is Norway spruce rust resistant?
Care should be taken to plant spruce away from wetlands especially the rust susceptible Colorado blue, black and white spruce. Norway spruce is more resistant. Scouting for alternate hosts, roguing infected branches and trees and planting resistant stock can reduce the impact of many of these rust diseases.
