PATH 3010 Exam 2

True

True or false: Coffee plants that are resistant to rust are available, but the quality of the beans is not as good.

An alternative host for soybean rust is...

kudzu, clover, pea

The alternate host of soybean rust is...

kudzu

For soybean rust, the most effective disease control method is:

fungicides

True or false: Four different plant species in Australia are threatened with imminent extinction due to myrtle rust.

True

Why is myrtle rust a major concern in Australia?

There are at least 358 Australian hosts already identified for myrtle rust, the myrtacae play very important roles in the ecosystem of Australia, and it moves by airborne spores so there is no easy way to stop it from spreading.

What do tree diseases do?

Attack leaves and kill bark: block the xylem (blocking water) and girdle the tree by large cankers (blocking food).

What are the hosts for Laurel Wilt?

Redbay Laurel, Swampbay, Sassafras, Avocado

What fungus causes laurel wilt?

Rafaela Lauricola

What is the vector for laurel wilt?

Redbay ambrosia beetle

Was laurel wilt introduced?

Yes

What are the hosts for sudden oak death?

Oak trees, tan oak, beech

What causes sudden oak death?

Phytopthora ramorum

Does sudden oak death have a vector?

No

Was sudden oak death introduced?

Yes, but not sure where from

What is the host for Dutch Elm Disease?

American Elm Trees

What is the fungus that causes Dutch Elm Disease?

Ophiostoma ulmi or O. novo ulmi

What is the vector for Dutch Elm Disease?

3 species of bark beetle

Was Dutch Elm Disease introduced?

Yes, from Asia to the Netherlands to Ohio

What is the host for Dogwood Anthracnose?

Pacific and flowering dogwoods

What fungus causes Dogwood Anthracnose?

Discula destructiva

Does dogwood anthracnose have a vector?

No

Was Dogwood anthracnose introduced?

No

What is the host for Chestnut Blight?

American Chestnut, European and Chinese Chestnut

What fungus causes Chestnut Blight?

Cryphonetria parasitica

Does Chestnut Blight have a vector?

No

Was Chestnut blight introduced?

Yes, from China or Japan

What fungus causes Wheat Stem Rust?

Puccinia Graminis

What is the primary host for wheat stem rust?

Wheat

What is the alternate host for wheat stem rust?

Barberry

What is the alternative host for wheat stem rust?

None

Does sexual reproduction occur in wheat stem rust?

Yes, on barberry

How is wheat stem rust controlled?

Eliminate alternate host, plant resistant varieties

Where is the native origin of wheat stem rust?

Fertile crescent

What fungus causes coffee rust?

Hemileia vastatrix

What is the primary host of coffee rust?

Coffee

What is the alternate host for coffee rust?

None

What is the alternative host for coffee rust?

None

Does coffee rust sexually reproduce?

No

How is coffee rust controlled?

Planting resistant coffee varieties, remove overstory, fungicide

What is the native origin of coffee rust?

East Africa (Sri Lanka was first major outbreak)

What fungus causes soybean rust?

Phakopsora pachyrhizi and P. meibormiae

What is the primary host for soybean rust?

Soybeans

What is the alternate host for soybean rust?

None

What is the alternative host for soybean rust?

Kudzoo, clover, beans, pea

Does soybean rust sexually reproduce?

No

How is soybean rust controlled?

Fungicide

What is the native origin of soybean rust?

Asia

What tree diseases are known as "The Classics"?

Dutch Elm Disease, Chestnut Blight

What is the biggest concern with laurel wilt?

It's a threat to the avocado industry in Florida

What are some other costs of laurel wilt?

Removal of dead trees is expensive, decreased property values, nurseries losing money due to quarantines, lost money from firewood and mulch, fire hazard due to dead trees

How can laurel wilt be controlled?

quarantine, watch and control vector, sanitation, and public education

What is the dispersal mechanism for P. ramorum?

Rain and wind, rivers and streams, human activities, and animals.

Another disease caused by Phytopthora ramorum (other than sudden oak death) is...

Ramorum blight

What are the hosts for Ramorum blight?

Bay laurels, Rhododendrons

How is Dutch Elm Disease controlled?

Control beetles by pruning or insecticides, fungicide injections, or root graft breakage.

What are the symptoms of sudden oak death?

Bleeding cankers and dieback of foliage

What does ramorum blight infect?

Nursery plants, landscape, and forest

How does P. Ramorum attack?

Above ground but also survives in soil and infects roots.

What are some consequences of sudden oak death and ramorum blight?

Dead oak trees worsen fire hazard, wildlife affected, decrease property value

What is a biotroph?

Must have a living host for nutrition to survive

Why do wheat rust spores have thick walls with yellow coats?

To resist drying and protect them from UV light

Rust fungi have ___ features that distinguish them from other fungi.

structural

Soybean rust is being ___ and ____ for control.

scouted and monitored

What fungus causes ergot in grasses?

Claviceps purpurea

What are some things that claviceps purpurea cause?

St. Anthony's fire, was likely responsible for the Salem Witch Trials, and can caused a person's limbs to fall off

On claviceps purpurea, where are spores produced?

Clubheads

What is the structure of an ergot alkaloid?

Ringed compounds containing nitrogen

What effect does ergotamine have?

Vasoconstrictor

What effect does ergonovine have?

Causes spontaneous abortion

What effect does ergine have?

LSA, causes hallucinations and uncontrollable muscle spasms

What was the name of the scientist that synthesized LSD from ergot fungus?

Albert Hofmann

What are some methods of ergot management?

Crop rotation, fall plowing, and rigorous inspection

What are some benefits of ergot alkaloids?

Migraines, childbirth, Parkinson's, and psychotherapy

What causes tall fescue?

Festuca arundinacea

What does epichloe sp. cause?

Fescue foot in animals

What are endophytes?

Symbiotic fungi living within plant tissues but cause no symptoms or disease in the plant

What are some symptoms of fescue toxicosis?

Lower feed intake, lower weight gain, higher respiration rates and body temp, lower milk production, rough hair coats, and reduced reproduction

What are mycotoxins?

Produced by a fungus and toxic to humans and animals when accidentally ingested

Are mushroom toxins classified as mycotoxins?

No, because they're eaten intentionally

What is the most carcinogenic compound made by a living organism?

Aflatoxin

What fungus produces aflatoxin?

Aspergillus flavus

What is the primary site of action for aflatoxin?

Liver

What is the short term effect of aflatoxin?

Acute toxicity

What is the long term effect of aflatoxin?

Chronic deterioration, cancer

When does aspergillum produce more toxin?

When the plant is stressed

What foods are most affected by aflatoxin?

Corn and peanuts

What is the main animal affected by aflatoxin?

Turkeys

What is the effect of zearalenone?

Mimics the action of estrogen and causes abnormal development of reproductive organs

What fungus causes zearalenone, trichothecenes, deoxynivalenol (DON), and fumonisins?

Fusarium

What effect does trichothecenes have?

Causes alimentary toxic aleaukia, symptoms include skin pain, vomiting, diarrhea, complete degeneration of bone marrow, and eventually death.

What are the symptoms caused by deoxynivalenol (DON)?

Nausea, fever, headaches, vomiting

Where is fumonisin found?

Corn

What does fumonisin cause in pigs?

Pocrine pulmonary edema

What does fumonisin cause in humans?

neural tube defects and esophageal cancer

What does fumonisin cause in horses?

hole in the head disease

What is ochratoxin caused by?

Penicillium

What does ochratoxin cause?

Cancer, chronic kidney disease

Where is ochratoxin found?

Coffee, juice, tree nuts, grapes

What are some reasons for fungi to produce mycotoxins?

Increase competitiveness, avoid consumption by insects, enhance survival