Pythium

Question 1

What are the Symptoms of Pythium Foliar Blight?

Answer 1

• irregular spots
• blighted grass w/ “grease spots”
• Will be Dead grass
  *

Question 2

What are the Signs of Pythium Foliar Blight?

Answer 2

• Cottony, aseptate mycelium
• Reproduce sexually w/ Oogonaia and Antheridia
• Reproduce asexually with sporangia

Question 3

Why is Pythium Foliar Blight able to rapidly move nutrients from one area of the fungi to another?

Answer 3

aseptate mycelium has no walls so it can move nutrients quicker. Makes it very versitile and fast moving.

Question 4

Pythium is part of what kindom and phylum?

Answer 4

Kingdom: Stramenopila

Phylum: Oomycota

Question 5

Predisposing Factors for Pythium Foliar Blight:

Answer 5

• 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

Question 6

How do the predisposing factors change when you’re dealing with seedlings?

Answer 6

Temperatures and humidity can be lower and it will still show up.

Question 7

Can Pythium grow across bare earth?

Answer 7

Yes, becuase it has aseptate mycelium and can travel long distances without plants being present.

Question 8

Pythium Fertility management

Answer 8

Spoon feed to not overstimulate

Keep it dry!!!!!!

• drainage
• irrigation practices
• fans
• prune

Question 9

Chemical Control for Pythium

Answer 9

• Use penetrants on a preventive basis
• Use contacts for “short term” knockdown

Question 10

What are the two root diseases caused by Pythium species?

Answer 10

Pythium Root Rot

Pythium Root Dysfunction

Question 11

what time of year does Pythium root rot occur?

Answer 11

Any time of year

Question 12

What conditions does Pythium Root Rot thrive?

Answer 12

Poorly drained and saturated areas

Question 13

Symptoms of Pythium Root Rot?

Answer 13

• Overall general thinning or yellowing
• irregular patters, sometimes spots or patches

Question 14

Pythium Root Dysfunction symptoms:

Answer 14

• distinct circular patches
  *

Question 15

Pythium Root Dysfunction is most common in areas that drain well. True or False.

Answer 15

True

Question 16

What time of year does Pythium Root Dysfunction usually occur? When do the symptoms show up?

Answer 16

• Spring and Fall
• Symptoms show up in the summer
  
  • Grass begins to decline from heat/drought stress

Question 17

the standard Pythium fungicides are effective for treating pythium root dysfunction. true or false?

Answer 17

False. They are not highly effective

Question 18

What are the differences in the two pythium root diseases?

Answer 18

• 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

Question 19

Pythium Root Rot symptoms

Answer 19

General thinning of turf in irregular patterns. many times in stress areas. Often follows drainage patterns

Question 20

Are you ever going to see mycelium in pythium root diseases?

Answer 20

No

Question 21

How does Pythium Root Disease kill plants?

Answer 21

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.

Question 22

Predisposing factors of Pythium Root Rot:

Answer 22

• Cool to Hot weather
• Excess Soil Moisture
  
  • Poor Drainage, Compaction
• Poor Site Conditions
  
  • shade
  • poor air circulation

Question 23

Pythium Root Rot disease Management:

Answer 23

• Avoid Drought but keep as dry as possible
• prune
• fans
• improve drainage
• aerify
• KEEP IT DRY!!!

Question 24

Pythium Root Rot chemical control:

Answer 24

• Preventive: propamocarb in the root zone
• Curative: ethazole w/ penetrant 3-5 days later to get into root zone

Question 25

Pythium volutum responds to _______ while the others dont.

Answer 25

insignia

Question 26

Pythium Root Dysfunction reduces the plants ability to do what?

Answer 26

Absorb water and nutrients

Question 27

Predisposing factors for Pythium Root Dysfunction:

Answer 27

* 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

Question 28

When controling Pythium Root Diseases with chemicals, what do you want to implement into your program?

Answer 28

* 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