Southern Corn Leaf Blight 1. In 1970 disease resulted in loss of corn crop in the order of billions of dollars. 2. Disease organism: Helminthosporium maydis (=Bipolaris maydis, Drechslera Rusts and Smuts maydis and Cochliobolus heterostrophus. 3. Problems that made disease so deadly were similar to those of Late Blight of Potato. 4. Topic for paper in class?

Rusts and Smuts Rusts z Introduction 1. Pathogenic on a variety of seed 1. Two of the most economically plants and some ferns. important group of fungi in 2. Species pathogenic to grains . historically well known. Reliably 2. probably known since reported on grains as far back as beginning of agriculture: 3000 years. „ Rusts recorded in Bible (Blast). 3. Common name is based on “rusty” „ Reported by Greeks and Romans. colored blotches on stems and „ Robigus and Robigalia of Rome. leaves of plants from urediospore 3. not specifically mentioned stage. until around 1700 by Jethro Tull.

Rusts 1. Pathogenic on a variety of seed plants and some ferns. 2. Obligate parasites and of significant economic importance when on grains. 3. First described by Theophrastus on grains in Historia Plantarum. 4. Actual cause of disease would not be known until mid 1800s.

1 Rusts Rusts 7. stages of Puccinia graminis: 5. Life history of rusts is unique. „ Stage 0: Spermogonium. Produces „ Up to five spore stages. spermatia and receptive hyphae. „ Can have two hosts. „ Stage I: Aeciums produce „ No fruitbody, e.g , like aeciospores. other Basidiomycota. „ Stage II: Uredium produce 6. Will use Puccinia graminis as urediospores. example of a Rust. „ Stage III: produce . „ Stage IV: produce .

Rusts Rusts 8. Normally presented in this order: 9. Has two hosts: Wheat and alternate „ Stage II: Uredium produce hosts Barberry. urediospores. „ Urediospores and teliospores „ Stage III: Telium produce occur on Wheat. teliospores. „ Spermogonium and aeciospores „ Stage IV: Basidium produce occur on Barberry. basidiospores. „ Basidiospores transitional, infects „ Stage 0: Spermogonium. Produces Barberry. spermatia and . 10.Fungus gains entrance to host „ Stage I: Aeciums produce through stomata. aeciospores.

Urediospores

Ruptured Epidermis

Stoma

Early spring, aeciospore infects wheat to start infection.

2 11.Spore stage gives plant its characteristic rusty color 12.Urediospore stage is “repeater stage”. 13.Late summer, prior to fall, uredium Continually re- converts to telium and produce infects wheat into teliospores. late summer 14. thick-walled, with two cells and black.

Basidium

15.Teliospore over winters. Basidiospores 16.Following spring, germinates to produce basidia and basidiospores.

Rusts 17. must go to Barberry. „ Produces spermogonium on upper surface of leaf. „ Spermogonium consists of receptive hyphae (female) and spermatia (male). „ Each spermogonium has a sweet sugary droplet. Barberry plant

3 Receptive Spermogonia hyphae with sugary exudates

Spermatia

Clusters of spermogonia on upper surface 18.Spermogonium with receptive hyphae of Barberry leaf (note exudates). and spermatia.

Rusts 18.Flies necessary to continue life cycle. „ Flies visit spermogonia for sugar solution. „ Takes spermatia to receptive hyphae as it visits spermogonia. „ Flies responsible for completion of sexual cycle.

Rusts 21.Aeciospore must go now to Wheat and cycle starts over.

On lower surface of Barberry, aecium with aeciospores formed.

4 Summary of Wheat Rusts Wheat Rusts 1. Wheat Rusts believed to be responsible for first famine. 2. Recorded in Bible. „ 1800 years before birth of Christ. „ Story of Joseph tells of incident. 3. Recorded during Roman Empire. „ Rome was plagued by Wheat Rust.

Wheat Rusts Wheat Rusts 4. Cato, The Elder, suggested 3. Recorded during Roman Empire planting wheat away from foggy, (continue). misty areas. „ Romans created a god, Robigus, „ Shortly after birth of Christ, for the rust god. 300 years, weather changed and „ Every spring, on April 25th., became wetter and cooler. Robigalia held honoring Robigus „ Greater problems with Wheat for 700 years. Rust occurred causing famine, hunger, diseases and discontent. „ Internal problems from within contributed to decline of Roman Empire.

Wheat Rusts Wheat Rusts 5. How Wheat Rust spread was 8. Although cause of disease was unknown. unknown, by 1600, in France, it 6. Barberry became a popular plant was realized that Barberry’s for its foliage and tasty berries, presence was somehow connected which spread the disease. with Wheat Rust. 7. Now known that you cannot 9. Law soon passed to eradicate successfully grow wheat with Barberry in Europe. Barberry present. 10. Wheat was first introduced to „ In 1920, a circular area of 10 New World in early 1500s and miles, Wheat crop was virtually Wheat Rust came with wheat. destroyed due to one Barberry plant.

5 Wheat Rusts Wheat Rusts 11. By 1726, first Barberry 11. Still a problem: eradication law enacted and still a. New strain discovered in Africa and one of means used to control Asia. Wheat Rusts. 12.Never successfully controlled b. Destroyed wheat crops in Uganda, Wheat Rust in North America by Kenya and Ethiopia, and is spreading. eradication of Barberry. Why? c. Eventually will spread to Saudi Arabia, Egypt and all of Middle Eastern 13. Breeding resistant of wheat, in countries and cause mass starvation. 1960’s, somewhat successful. d. Will take about 6-8 years to develop new resistant wheat strain.

Coffee Rusts Coffee Rusts 1. Origin of coffee is unknown, but 4. By 1700, 3000 coffee houses in many stories told of its origin. London. 2. Believed to be native to Africa „ Merchant, lawyers and business and early on introduced to Arabia. men gathered for discussion. 3. First introduced into Europe, via „ Businesses began, e.g., Lloyds of Venice, in 1615, then France, in London, started in coffee house in 1640, and England, in 1650. 1690. „ Water was often contaminated.

Coffee Rusts Coffee Rusts 5. Price became higher with 6. British planted coffee on all popularity. suitable land in Sri Lanka by 1825. „ Arabian city, Mocha, had monopoly 7. 1875, Coffee Rust, Hemileia on coffee. castatrix struck. „ Monopoly ended by 1690. „ Berkeley had recorded disease in „ Plantations first started in Java, 1869. „ then Ceylon (Sri Lanka), Sumatra Suggested immediate action be and then in the New World. taken against disease. „ By 1875, the fungus had spread to all coffee plantations.

6 Coffee Rusts Coffee Rusts 7. 1875, Coffee Rust, Hemileia 7. 1875, Coffee Rust, Hemileia castatrix struck (continue). castatrix struck (continue). „ Sulfur solution spray was tried, „ British gave up on coffee and but unsuccessfully. began growing tea in Sri Lanka. „ A remedy for disease has never „ Reason why Indian Tea is main been found. stimulant consumed by British. „ Coffee Rust eventually destroyed „ all coffee plants in Sri Lanka, Java Coffee now mostly grown in New and Sumatra and eventually to World and was free of Coffee Arabia, Liberia and Africa. Rust until 1970.

Coffee Rusts 8. Still not an effective means of treating Coffee Rusts. „ Breeding programs have produced resistant varieties, but poorer in Smuts “quality”.

Introduction Introduction z Smut, in literal sense, mean dirt z First mention of smut in 1700 by or excrement. English agriculturalist Jethro Tull.

z Presently, we use it to mean z Because of widespread occurrence on something that is filthy and grains, probably observed since obscene. beginning of agriculture. z This group of fungi is somewhat like the rusts. z Reference to rusts in some instances „ Both are classified in Basidiomycota. may actually have been smuts. „ Do not have fruiting bodies and basidia and basidiospores produced by teliospores.

7 Mathieu Tillet Mathieu Tillet z Keeper of mint, in France, by profession. z In 1755, studied smut on Wheat and determined two types of smuts were produced. „ Le Carie, Common Bunt or Stinking Smut. Contaminated grain filled with “black, foul smelling powder”. „ Le Charbon, . Plant is Common Bunt or Loose Smut covered with black powder that is Stinking Smut readily blown away by wind.

Mathieu Tillet Mathieu Tillet z In 1847, this distinction would z Regardless of soil type, when, be verified by Charles and Louis and different weather Tulasne. conditions, contaminated wheat z In order to honor Tillet, they gave rise to contaminated plants. described Stinking Smut as a new z Concluded this meant that “black genus, , after Tillet. powder” in seeds responsible for „ Species was named . smutted plants, i.e. seed borne. z z Tillet tried to demonstrate that the Also washed seeds before planting in smutted plants were caused by the cattle urine, water and lye black powdery material in the grain. suppressed disease to some degree.

Bénédict Prévost Bénédict Prévost z This line of research did z Thought sprout penetrated soft eventually lead to eliminating tissue of Wheat and destroyed stinking smut from Wheat. the seed. z About 50 years later, Prévost z Accidentally discovered means of continued with concept of washing controlling Stinking Smut. seeds to rid Wheat of smut. z did not readily germinate in z Also observed germination of spores, distilled water as they did in well which had previously not been seen. water. z Saw germination of “stubby sprouts” z Germinated spores in distilled water growing from spores. grew several hours and then died.

8 Bénédict Prévost Bénédict Prévost z Observation, however, was z Farmers slow to follow, but impractical. from 1850-1900 was z Accidentally discovered significance extensively used. of observation. z Later other solutions used: z Experiments with copper sulfate „ Formaldehyde indicated that smut could be „ Several mercury compounds. destroyed even with trace amounts of copper. „ Most recently hexachlorobenzene (=HCB). z In 1807 recommended washing seeds with copper sulfate. z Method=topical chemotherapy

Loose Smut Origin of Gingerbread z Topical chemotherapy not z What do you do with flour made from effective against Loose Smut. smutted wheat?. „ Disease systemic „ Odor, taste and appearance of bread „ Most solutions tried also killed made from such flour undesirable. fungus, but also grain. „ Odor and taste could be hidden if ginger added. „ Jensen, 1888, hot water treatment, somewhat successful. „ Color could be covered by masking it „ Systemic fungicide have since with molasses. been developed. „ Carefoot, G.L. and E.R. Sprott. 1969. Famine on the Wind.

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