Leaf Spot and Melting Out Flashcards
Leaf Spot and Melting Out
Cause:
Drechslera poae
Drechalera Poae
Host:
Poa pratensis
Poa annua
Drechslera poae
Symptoms:
- 1/8” leaf lesions
- “football” shaped
- Purple border, Tan center
- Reddish-brown rot of crowns
- Spotted leaves senesce and turf thins
Drechslera poae
signs:
- Conida on condiophore
- Conida are long and has many septa and able to produce many germ tubes
When does the fungus reproduce?
When does it infect the plants?
When does the plant die?
- reproduces in cool, wet weather
- infects plant when it gets warmer (spring)
- plant dies when it gets hot/dry (summer)
Brown Blight
Cause:
Drechslera siccans
Drechslera siccans
Host:
Lolium perenne
Net Blotch
Cause:
Drechslera dictyoides
Drechslera dictyoides
Host:
Fesuca spp.
Drechslera dictyoides
symptoms:
- Net-like leaf lesions or purple stripes
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Drechslera siccans
symptoms:
- 1/8” leaf lesions
- “football” shaped
- Purple border, Tan center
Red Leaf Spot
Cause:
Drechslera erythrospila
Drechslera erythrospila
Host:
Agrostis spp.
What time of year is Drechslera erythrospila active?
How is this different from other Drechslera diseases?
It’s active at higher temperatures, it’s more of a summertime disease instead of a spring or fall disease like the others.
Leaf Spot Diseases
Predisposing Factors:
- 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
Leaf Spot Diseases
CHemical Control:
- Local Penetrants and Contacts
- Acropetals will make it worse
Leaf and Crown Rot
Cause:
Bipolaris sorokiniana
Bipolaris cynodontis
Bipolaris sorokiniana
Host:
- Agrostis
- Poa
- Lolium
- Festuca
Bipolaris sorokiniana
symptoms:
- 1/8” oval leaf lesions
- “football” shaped
- Purple border with tan center
What is the difference between the Conidia of Bipolaris and Drechslera?
- Bipolaris conidia only germinate from the poles (the ends of the spore)
- Drechslera germinates from every cell of the spore
Bipolaris cynodontis
Host:
Cynodon spp.
Zoysia spp.
Leaf and Crown Rot
Predisposing Factors:
- Warm conditions
- Extended leaf wetness
- Drought stress
- Thatch
- Low HOC
- Excess WSN
- Use of Horomonal type fungicides
Fading Out
Cause:
Curvularia spp.
Curvularia spp.
Host:
All
Curvularia spp.
signs:
“curvy” Conida with “fuzzy” conidiphores
Curvularia spp.
Predisposing factors:
- Insulting your turf
- Warm to Hot temperatures
- Thatch and compaction
- Extended leaf wetness
- Low HOC
Using certain fungicides can make the Drechslera diseases worse. what fungicides are they?
DMI’s (except heritage) and Thiophanate-methyl
