Leaf Spot and Melting Out

Question 1

Leaf Spot and Melting Out

Cause:

Answer 1

Drechslera poae

Question 2

Drechalera Poae

Host:

Answer 2

Poa pratensis

Poa annua

Question 3

Drechslera poae

Symptoms:

Answer 3

• 1/8” leaf lesions
• “football” shaped
• Purple border, Tan center
• Reddish-brown rot of crowns
• Spotted leaves senesce and turf thins

Question 4

Drechslera poae

signs:

Answer 4

• Conida on condiophore
• Conida are long and has many septa and able to produce many germ tubes

Question 5

When does the fungus reproduce?

When does it infect the plants?

When does the plant die?

Answer 5

• reproduces in cool, wet weather
• infects plant when it gets warmer (spring)
• plant dies when it gets hot/dry (summer)

Question 6

Brown Blight

Cause:

Answer 6

Drechslera siccans​

Question 7

Drechslera siccans

Host:

Answer 7

Lolium perenne

Question 8

Net Blotch

Cause:

Answer 8

Drechslera dictyoides

Question 9

Drechslera dictyoides

Host:

Answer 9

Fesuca spp.

Question 10

Drechslera dictyoides

symptoms:

Answer 10

• Net-like leaf lesions or purple stripes
  *

Question 11

Drechslera siccans

symptoms:

Answer 11

• 1/8” leaf lesions
• “football” shaped
• Purple border, Tan center

Question 12

Red Leaf Spot

Cause:

Answer 12

Drechslera erythrospila

Question 13

Drechslera erythrospila

Host:

Answer 13

Agrostis spp.

Question 14

What time of year is Drechslera erythrospila active?

How is this different from other Drechslera diseases?

Answer 14

It’s active at higher temperatures, it’s more of a summertime disease instead of a spring or fall disease like the others.

Question 15

Leaf Spot Diseases

Predisposing Factors:

Answer 15

• Cool Temperatures
  
  • Except RLS…RLS= Hot Temps
• Extended leaf wetness
• Thatch
• Low HOC
• Excess WSN
• Use of DMI or Thiophanate methyl will make it worse
  
  • Heritage is okay
• Infected plants dies from heat stress

Question 16

Leaf Spot Diseases

CHemical Control:

Answer 16

• Local Penetrants and Contacts
• Acropetals will make it worse

Question 17

Leaf and Crown Rot

Cause:

Answer 17

Bipolaris sorokiniana

Bipolaris cynodontis

Question 18

Bipolaris sorokiniana

Host:

Answer 18

• Agrostis
• Poa
• Lolium
• Festuca

Question 19

Bipolaris sorokiniana

symptoms:

Answer 19

• 1/8” oval leaf lesions
• “football” shaped
• Purple border with tan center

Question 20

What is the difference between the Conidia of Bipolaris and Drechslera?

Answer 20

• Bipolaris conidia only germinate from the poles (the ends of the spore)
• Drechslera germinates from every cell of the spore

Question 21

Bipolaris cynodontis

Host:

Answer 21

Cynodon spp.

Zoysia spp.

Question 22

Leaf and Crown Rot

Predisposing Factors:

Answer 22

• Warm conditions
• Extended leaf wetness
• Drought stress
• Thatch
• Low HOC
• Excess WSN
• Use of Horomonal type fungicides

Question 23

Fading Out

Cause:

Answer 23

Curvularia spp.

Question 24

Curvularia spp.

Host:

Answer 24

All

Question 25

Curvularia spp.

signs:

Answer 25

“curvy” Conida with “fuzzy” conidiphores

Question 26

Curvularia spp.

Predisposing factors:

Answer 26

• Insulting your turf
• Warm to Hot temperatures
• Thatch and compaction
• Extended leaf wetness
• Low HOC

Question 27

Using certain fungicides can make the Drechslera diseases worse. what fungicides are they?

Answer 27

DMI’s (except heritage) and Thiophanate-methyl