CSI (Crop Science Investigation) shedding new light

[Guest guest]

Perspective -- CSI (Crop Science Investigation) shedding new light

on fungus

Wednesday, November 10, 2004

http://farmweek.ilfb.org/viewdocument.asp?did=7268 & r=0.4154627

By Matt Montgomery

The Public Broadcasting Service (PBS) recently aired an interesting

episode of a program entitled " Secrets of the Dead. "

The documentary-style program highlights an ancient mystery each

week and uses modern technology, sciences, etc. to attempt to solve

those mysteries.

An episode entitled " The Witches' Curse " dealt with the mystery of

why the Salem witch trials occurred during the late 1600s.

The trial theory highlighted would be of interest to Illinois

farmers because it dealt with a fungus about which our Extension

office annually warns livestock producers.

On the program, Caporael, a behavioral psychologist with

Renasselaer Polytechnic Institute in Troy, N.Y., presented her

research related to the witch trials.

She theorized the unusual symptoms noted by the

supposedly " bewitched " persons, which resulted in death penalty

convictions on sorcery charges, may have resulted from ingestion of

a fungus.

The fungus in question is termed Claviceps pupurea, and it starts

out as small fungal fruiting bodies termed a " sclerotia. " The

sclerotia of C. pupurea are brown and strongly resemble rodent

feces.

Typically found in the soil during the early spring, the fruiting

bodies eventually produce knob-like masses on the top of

small " stalks " termed " stromata. " These stromata then give rise to

small fruiting bodies, which give rise to spores

termed " ascospores. "

Wind and rain transfer these ascospores to the florets of green

plants. The fungus then infects the florets, producing an oozing

yellow mass of secondary spores termed " conidia. "

The sticky yellow material, sometimes termed " honeydew, " adheres to

the bodies of feeding insects and drips on other florets, resulting

in further infection by the fungus.

Infected florets replace the kernel with an ovule full of fungal

material, thus forming another sclerotia that can seed the next

year's " batch " of C. pupurea fungi. Brown sclerotia are the most

noted sign of the disease and are often noted protruding from the

seed head during early/mid-summer.

Claviceps pupurea may infect many different grasses. Wheat, barley,

oats, wild grasses, pasture grasses, and rye can all be infected by

this fungus. Caporael theorized a cool, wet spring — ideal

conditions for development of this fungus — resulted in widespread

infection of the rye crop by C. pupurea in the area surrounding

Salem.

The resulting sclerotia of this fungus contain many alkaloids and

toxins. Symptoms resulting from the ingestion of such alkaloids in

contaminated grain include spasms, lameness, elevated body

temperatures, swollen joints, numbness, and reproductive problems in

livestock.

Additional symptoms in humans can include delusions, hallucinations,

and additional symptoms similar to those caused by certain drugs. In

short, infections by this fungus can be deadly and dangerous.

Many of those who were claimed by neighbors to be " bewitched " may

have been suffering symptoms derived from the toxins produced by

this fungus in their own contaminated grain.

Livestock producers know this fungus as the disease called " ergot, "

and they know that ergot fruiting bodies appear each year in their

pasture grasses.

They further recognize the symptoms in livestock, which can result

in loss of tails, etc., as symptoms of ergotism. They stop the

disease in their pastures by clipping grasses to ward off the

production of seed heads that could be infected by this fungus.

Matt Montgomery is a crop systems educator in the University of

Illinois Extension units in Sangamon and Menard counties.

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