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Turfgrass Diseases > Final - Section 2 > Flashcards

Final - Section 2 Flashcards

1
Q

What three things do we need for disease to occur?

A

Host

Environment

Pathogen

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2
Q

Compare Disease and Injury:

A

Disease is is a result of injury

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3
Q

Compare and contrast symptoms and signs:

A

Symptom- Observable condition of abnormal physiology in the plant.

Sign- physical presence of the causal agent

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4
Q

List four things that cause plant diseases:

A

Fungi

Bacteria

Nematodes

Viruses

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5
Q

What type on fungi has spores in sacs?

A

Ascomycota

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6
Q

describe the dollar spot leaf lesion.

A

Tan/white with a reddish brown border. It go across the entire leaf and looks like a bowtie.

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7
Q

list two environmental factors that promote dollar spot.

A

Heavy Dew

Warm Days/Cool Nights

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8
Q

Dollar spot can be resistant to many fungicides, name two.

A

Azoxystrobin

Pyraclostrobin

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9
Q

What turfgrass is resistant to dollar spot?

A

007 is most resistant

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10
Q

what fertilizer strategy can be used to control dollar spot?

A
  • 3-5 lb N /1000 -
  • Slow release granular in spring and fall
  • spoon feed in summer
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11
Q

Name the sign characteristic of Anthracnose?

A

Setose acervulus w/ lunate conidia with oil drop.

Black stroma w/ appresoria on crown or stolons

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12
Q

Name the primary symptom of Anthracnose.

A

thinning of turf

poa = yellow

bent = bronze

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13
Q

Why has Anthracnose become more common over the last few years?

A

Lower HOC and Low Fertility Input

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14
Q

How do you know if you have Anthracnose Basal Crown Rot?

A

When you pull the infected plant from the ground, it will have Black Stroma on the crown and/or Stolons

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15
Q

Name the favored host for Anthracnose.

A

Poa annua

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16
Q

Describe the leaf lesion for Leaf Spot and Melting Out.

A

“football” shaped….Small, oval lesions with a tan center and purple border.

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17
Q

What effect does Nitrogen have on Leaf Spot and Melting Out of KBG?

A

It creates favorable conditions for the pathogen to infect the turf by overstimulating the turf.

18
Q

What effect does close mowing have on Leaf Spot and Melting Out of KBG?

A

It creates unfavorable conditions for the plant and results in the plant being more susceptible to disease. Mowing stresses the plant - removing leaf tissue makes the plant have to work hard to replace it and cannot allocate resources to fend off disease pressure.

19
Q

What type of fungicides make Leaf Spot and Melting Out of KBG worse?

A

DMI’s and Thiophanate-methyl

20
Q

Draw the conidia of Drechslera poae.

A

.

21
Q

Name two hosts for Summer Patch.

A

Poa spp.

Festuca spp.

22
Q

What must be done to get good fungicide control of Summer Patch?

A
  • DMI & MBC (ex. Prostar Plus)
  • Begin treatments when soil stabilizes @ 65F - 2” depth
  • Use High label rates
  • Tank Mix and Rotate
  • Apply 3-5 gal. of water per 1000 sq. ft
  • Repeat at 28 day intervals
23
Q

Describe the sign for a root-infecting patch disease.

A

ectotrophic runner hyphae with hyphopodia

24
Q

What time of year do we usually find Take-All?

A

Spring and Fall

25
Q

What fertility approach can we use to reduce the severity of all patch diseases?

A

Use slow release granulars in Spring and Fall and Spoon Feed WSN in summer.

***ADD Manganese

Avoid Nitrate forms of N

Make sure you know your soil pH and choose the right fertilizer to keep it between 5.5 and 6.2

26
Q

What other fertilizer strategy can we use to control Take-All?

A
  • N-P-K in a 3:1:2 ratio
  • Add extra Manganese
  • Maintain Soil pH (5.5 - 6.2)
  • Avoid Nitrate forms of N
27
Q

Why is Take-All more prevalent on new golf course construction?

A

New seedlings are very susceptible to Take-All and sandy soils are low in nutrients to support plant health.

28
Q

How does mowing height affect summer patch?

A

Low mowing heights make the turf more susceptible to disease because Summer Patch is a root infecting disease and the lower you mow, the weaker that plant can get and the roots suffer. Short Shoots = Short Roots.

29
Q

List the causal agent of Take All.

A

Gaeumannomyces graminis.

30
Q

Describe the main symptom of a patch disease.

A

Unthrifty, thinning of turf

31
Q

Where do Smut fungi usually penetrate the plant?

A

the root cap

32
Q

What group of Fungi do the smut fungi fungi belong to?

A

Basidiomycota

33
Q

Why are penatrant fungicides the only choice for Smut diseases?

A

Because the pathogen attacks the plant from within the plant tissue.

34
Q

What is the main symptom for smut?

A

Shredded turf leaves

35
Q

In what grass do we usually find Smut?

A

Poa spp.

36
Q

What is the best management practice for Red Thread?

A

Provide adequate fertility.

3-5lbs N /1000

37
Q

What are the Red Threads?

A

“antler-like” pseudosclerotia

38
Q

What is the most susceptible host grass for red thread?

A

Perennial Rye - Fine leaf tissue

39
Q

compare the mycelium of Laetisaria spp. and Limonomyces spp.

A
  • Laetisaria spp. has septate mycelium without clamps that breaks into arthroconida and spreads easily
  • Limonomyces spp. has septate mycelium with clamp connections and spreads very slowly
40
Q

What time of year is Red Thread active?

A

Mostly all year long

32 - 86 degree temperatures

41
Q

Describe how a fairy ring might kill turf.

A

The fungi release hydrogen cyanide, when released in ghi amounts, it can kill the turf. Because they are saprophitic, this provides them with dead plant material to eat. They also can have a thick mycelial mat that is hydrophobic, the plants that are growing in this mat are unable to get water to survive and often die of drought stress.

42
Q

Briefly describe each type of fairy ring.

A
  • Type 1
  • Most Severe - kills or badly damages turf
  • Produces higher concentrations of hydrogen cyanide than the other types (= dead turf)
  • Fruiting bodies may form
  • Type 2
  • Overstimulates the turf - causes dark green color
  • produces moderate amount of hydrogen cyanide and ammonia
  • fruiting bodies may form
  • Type 3
  • No impact on turf
  • Simple ring of fruiting bodies

Turfgrass Diseases (22 decks)

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