Pythium Flashcards
What are the Symptoms of Pythium Foliar Blight?
- irregular spots
- blighted grass w/ “grease spots”
- Will be Dead grass
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What are the Signs of Pythium Foliar Blight?
- Cottony, aseptate mycelium
- Reproduce sexually w/ Oogonaia and Antheridia
- Reproduce asexually with sporangia
Why is Pythium Foliar Blight able to rapidly move nutrients from one area of the fungi to another?
aseptate mycelium has no walls so it can move nutrients quicker. Makes it very versitile and fast moving.
Pythium is part of what kindom and phylum?
Kingdom: Stramenopila
Phylum: Oomycota
Predisposing Factors for Pythium Foliar Blight:
- Hot weather
- 85F daytime / 70F night
- Extended Leaf Wetness
- +90% Relative Humidity > 10hours
- Poor air circulation
- shade
- Excess Nitrogen input
- Seedlings are very susceptible
- High Seeding Rates
How do the predisposing factors change when you’re dealing with seedlings?
Temperatures and humidity can be lower and it will still show up.
Can Pythium grow across bare earth?
Yes, becuase it has aseptate mycelium and can travel long distances without plants being present.
Pythium Fertility management
Spoon feed to not overstimulate
Keep it dry!!!!!!
- drainage
- irrigation practices
- fans
- prune
Chemical Control for Pythium
- Use penetrants on a preventive basis
- Use contacts for “short term” knockdown
What are the two root diseases caused by Pythium species?
Pythium Root Rot
Pythium Root Dysfunction
what time of year does Pythium root rot occur?
Any time of year
What conditions does Pythium Root Rot thrive?
Poorly drained and saturated areas
Symptoms of Pythium Root Rot?
- Overall general thinning or yellowing
- irregular patters, sometimes spots or patches
Pythium Root Dysfunction symptoms:
- distinct circular patches
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Pythium Root Dysfunction is most common in areas that drain well. True or False.
True
What time of year does Pythium Root Dysfunction usually occur? When do the symptoms show up?
- Spring and Fall
- Symptoms show up in the summer
- Grass begins to decline from heat/drought stress
the standard Pythium fungicides are effective for treating pythium root dysfunction. true or false?
False. They are not highly effective
What are the differences in the two pythium root diseases?
- Root Rot can happen all year while Root Dysfunction occurs in Spring and Fall
- Root Dysfunction likes well drained areas while Root Rot likes it really wet.
- Root Rot occurs in irregular patterns while Root Dysfunction is more “patchy”
- Root Rot responds well to standard pythium fungicides while Qoi and Qii fungicides are most effective on Root Dysfunction
Pythium Root Rot symptoms
General thinning of turf in irregular patterns. many times in stress areas. Often follows drainage patterns
Are you ever going to see mycelium in pythium root diseases?
No
How does Pythium Root Disease kill plants?
They invade the roots, reproduce and cause the plant to overwork itself to surive with the mycelium and spores invading its space. It can’t function properly and when it’s too stressed out, it dies.
Predisposing factors of Pythium Root Rot:
- Cool to Hot weather
- Excess Soil Moisture
- Poor Drainage, Compaction
- Poor Site Conditions
- shade
- poor air circulation
Pythium Root Rot disease Management:
- Avoid Drought but keep as dry as possible
- prune
- fans
- improve drainage
- aerify
- KEEP IT DRY!!!
Pythium Root Rot chemical control:
- Preventive: propamocarb in the root zone
- Curative: ethazole w/ penetrant 3-5 days later to get into root zone
Pythium volutum responds to _______ while the others dont.
insignia
Pythium Root Dysfunction reduces the plants ability to do what?
Absorb water and nutrients
Predisposing factors for Pythium Root Dysfunction:
- Spring and Fall (=cooler temps)
- 50 - 75F Soil Temperatures
- Most severe on new construction
- will kill seedlings 3 months after seed is down
- Low fertility
- low mowing heights
- thatch & layering
When controling Pythium Root Diseases with chemicals, what do you want to implement into your program?
- Rotation products
- Preventative Treatments
- every 21 - 28 days when soil temps are to - 75 degrees
- Curative Treatments
- every 14 - 28 days as needed based on symptoms
