From Issue  Fall 2015

Dr. Tom Allen

Dr. Tom Allen is an associate professor and plant pathologist at the Delta Research and Extension Center in Stoneville, Mississippi.

By: Vanessa Beeson



Current Research

I have numerous foliar fungicide trials in corn, cotton, rice, soybean, and wheat to determine the efficacy of commercially-available fungicides on important foliar diseases in the Mississippi production system. In addition, my research includes seed treatment trials in corn, cotton, and soybean to determine the impact of seed-applied fungicides as well as seed-applied nematicides. I also work closely with colleagues in other states on several regional and national projects in soybean to specifically address the yield loss associated with charcoal root rot, yield losses associated with green stem of soybean and management of Cercospora blight through fungicide application as well as determining the specific yield loss associated with Cercospora leaf blight in different varieties. A large research effort, funded by the Mississippi Soybean Promotion Board, is attempting to determine the specific organisms that cause seed quality losses in years when the environment remains hot and wet and may delay soybean harvest beyond physiological maturity. Graduate student projects look at managing charcoal rot of soybean as well as determining the potential yield loss associated with fungicide-associated phytotoxicity, a malady that has been widely observed in Mississippi soybean over the past three seasons. In addition, large field projects off-station included site-specific nematode management in cotton using a fumigant to determine the yield benefit in situations where high concentrations of nematodes are present in continuous cotton situations.

Name A Specific Time When Your Research Was Applied

I, along with several colleagues, served on a project sponsored by the Corn Promotion Board, which determined whether or not a single fungicide application made at a specific growth stage in the absence of foliar disease would be economically beneficial. Fungicide applications made at a specific growth stage rather than when disease threatens or could produce a yield loss, are widely marketed as producing a yield benefit on the order of 13 bushels/acre. The large plot trials conducted over three years used farmer’s corn fields to determine the benefits associated with automatic fungicide applications in large, replicated strip plots. The results of the project determined that automatic fungicide applications were not economically beneficial. Additional research over the years has continued to support this result and indicate fungicides are most economically beneficial when applied when foliar diseases threaten to reduce yields. Additionally, in an ongoing soybean research project, we are determining how widespread fungicide resistance within the frogeye leaf spot fungal population is throughout Mississippi. Over a two year period, we were able to collect fungal isolates from 73 counties and determine that the fungus has developed resistance to one of the main fungicide classes used in soybean production systems (strobilurins). Additional field research determined that applying that specific class of fungicides would not provide the economic benefit that had been observed in the past due to the resistance.

How Did Your Research Benefit Producers?

Many farmers utilized the corn research findings and dropped an automatic fungicide application following the results. The soybean research has caused many farmers to alter fungicide application practices given that fungicide resistance within the frogeye leaf spot population is so widespread. Instead of making an automatic fungicide application with the product class exhibiting fungicide resistance, farmers have chosen to use multiple modes of action fungicide products. In addition, farmers see the benefit of frogeye leaf spot resistant soybean varieties.

Provide An Example Of A Great Partnership

Mr. Kenneth Hood is a large corn, cotton, and soybean farmer. He has been a pioneer in the use of site-specific technology on his farm in Perthshire, Mississippi, mostly to manage insects. Site-specific technology uses global positioning and georeferenced points within fields to manage pests in a small area, rather than implementing a management strategy on a whole farm. Several years ago we worked together to use site-specific management technologies to implement nematode management practices with a fumigant on his farm in cotton production systems. The specific protocol on his farm used several different management zones, relying on soil classification differences as well as digital elevation information to build a management “zone” for treatment using the fumigant. In areas of Mississippi where rotation has been poorly utilized in cotton production systems, nematodes can result in large yield losses. Results from the trials conducted during 2010 at Mr. Hood’s farm determined that a 200 lb. increase in seed cotton could be realized by applying the nematicide and placing the product in the right management zone even in a situation where a root-knot nematode tolerant variety was planted.


Many farmers in Mississippi rely on the unbiased information that we provide through research as well as extension resources. The service that we’re able to provide through the university system is invaluable.


How Does Your Research Help Inform Your Extension Role And Vice Versa?

Conducting research greatly aids my extension programming by providing important results to discuss with farmers. In addition, the extension role that I have allows me to make numerous field visits in an attempt to aid farmers, consultants, dealers, and distributors throughout the state and provides me with valuable information to initiate important field research.

What Research Are You Looking Forward To On The Horizon?

First and foremost, continuing to conduct meaningful resistance screening within the fungal pathogen population in Mississippi will greatly contribute important information to our row crop farmers. Foliar fungicides are important management tools and need to be maintained through careful stewardship. Understanding the biology involved in fungicide resistance as well as documenting where the shifts in pathogen populations occur over time is extremely important and will continue to help us benefit farmers who rely on this information. Over the past two years, we have successfully conducted some resistant monitoring/screening within Mississippi to determine how widespread strobilurin resistance was within the frogeye leaf spot fungal population. Continuing this type of research will enable us to determine shifts in fungal populations and provide valuable information to farmers for the future of disease management.

Is There Anything Else You Would Like To Add?

Many farmers in Mississippi rely on the unbiased information that we provide through research as well as extension resources. The service that we’re able to provide through the university system is invaluable.



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