The mycotoxin is widely categorized as a vomitoxin. It can induce vomiting if ingested in high enough concentrations, but prolonged exposure can also cause gastronintestinal damage, harm the immune system and inflame the central nervous system.

In animals, repeated exposure to the mycotoxin in food can decrease their growth and weight, and livestock can develop an immune response to the toxin that can harm their ability to reproduce.

The US Food and Drug Administration has issued advisory levels, basically limits for the amount of mycotoxin considered a health hazard in grain products.

Since barley and wheat are important as food for humans and livestock, harvested grain is routinely tested when farmers bring their crops to grain elevators for sale. Entire loads of grain may be rejected if they're found to have mycotoxin concentrations above the FDA limits.

Wheat can be treated to remove scabby kernels. If mycotoxin levels aren't too high, it could also be used for livestock feed. The advisory threshold for the mycotoxin is higher for adult cattle and chickens, at 10 parts per million, than it is for humans, at 1 ppm.

These risks are why importing and even moving plant pathogens within the US is regulated by the US Department of Agriculture's Animal and Plant Health Inspection Service, or USDA-APHIS, through the Plant Protection Act of 2000.

Federal law restricts the movement of plant pathogens, including bacteria, fungi and viruses, even for research purposes, as well as their release into the environment. A scientist who wants to move a plant pathogen, either within the US or from outside the US, must go through a permitting process with USDA-APHIS that can take up to six months to complete.

The goal of these rules is to reduce the risk of introducing something new that could be even more destructive for crops.

Even with Fusarium graminearum, which has appeared on every continent but Antarctica, there is potential for introducing new genetic material into the environment that may exist in other countries but not the US and could have harmful consequences for crops.

Fusarium graminearum infections generally occur during the plant's flowering, rainfall and periods of high humidity during early stages of grain production.

Wheat in the southern US is conducive to infection during the spring. As the season progresses, the risk from scab progresses north through the US and into Canada as the grain crops mature across the region, with continued periods of conducive weather throughout the summer.

Between seasons, Fusarium graminearum survives on barley, wheat and corn plant residues that remain in the field after harvest. It reproduces by producing microscopic spores that can then travel long distances on wind currents, spreading the fungus across large geographic areas each season.

In wheat and barley, farmers can suppress the damage by spraying a fungicide onto developing wheat heads when they're most susceptible to infection. Applying fungicide can reduce scab and its severity, improve grain weight and reduce mycotoxin contamination.

Sign up for one of our free newsletters

• The Daily Report Start your day right with Asia Times' top stories
• AT Weekly Report A weekly roundup of Asia Times' most-read stories

However, integrated approaches to manage plant diseases are generally ideal, including planting barley or wheat varieties that are resistant to scab and also using a carefully timed fungicide application, rotating crops, and tilling the soil after harvest to reduce residue where Fusarium graminearum can survive the winter.

Even though fungicide applications may be beneficial, fungicides offer only some protection and can't cure scab. If the environmental conditions are extremely conducive for scab, with ample moisture and humidity during flowering, the disease will still occur, albeit at reduced levels.

A discussion of Fusarium head blight in the northern Plains. Andrew Friskop/NDSU Extension.

Plant pathologists are making progress on early warning systems for farmers. A team from Kansas State University, Ohio State University and Pennsylvania State University has been developing a computer model to predict the risk of scab.

Their wheat disease predictive model uses historic and current environmental data from weather stations throughout the US, along with current conditions, to develop a forecast.

In those areas that are most at risk, plant pathologists and commodity specialists encourage wheat growers to apply a fungicide during periods when the fungus is likely to grow to reduce the chances of damage to crops and the spread of mycotoxin.

Tom W. Allen is associate research professor of plant pathology, Mississippi State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sign up here to comment on Asia Times stories Or Sign in to an existing accoun

Thank you for registering!

An account was already registered with this email. Please check your inbox for an authentication link.

• Click to share on X (Opens in new window)
• Click to share on LinkedIn (Opens in new window) LinkedI
• Click to share on Facebook (Opens in new window) Faceboo
• Click to share on WhatsApp (Opens in new window) WhatsAp
• Click to share on Reddit (Opens in new window) Reddi
• Click to email a link to a friend (Opens in new window) Emai
• Click to print (Opens in new window) Prin