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United States Department of Agriculture

Agricultural Research Service

Related Topics

Fire Ant Disease
USDA Agricultural Research Services Web site on area wide suppression of fire ants.


Thelohania fire ant disease

Fire ant disease weakens fire ant colonies and results in 60 percent fewer ants per acre.

Researchers place infected larvae on the fire ant mound. Ants adopt and raise infected larvae. The disease spreads to workers and the queen.
Researchers place infected larvae on the fire ant
mound. Ants adopt and raise infected larvae. The
disease spreads to workers and the queen.

In the queen, the disease multiplies, causing the abdomen to shrink. This is a healthy queen, left, and a diseased queen, right.
In the queen, the disease multiplies, causing the
abdomen to shrink. This is a healthy queen,
left, and a diseased queen, right.
Diseased queens have dark cysts in their ovaries and produce 90 percent fewer eggs. These queens are dissected to show healthy ovaries, left, and diseased ovaries.
Diseased queens have dark cysts in their ovaries
and produce 90 percent fewer eggs. These queens
are dissected to show healthy ovaries, left, and
diseased ovaries, right.

The few eggs the queen produces are diseased. Only a few larvae and workers develop. The workers in the healthy colony, left, greatly outnumber workers in the diseased colony.
The few eggs the queen produces are diseased.
Only a few larvae and workers develop. The
workers in the healthy colony, left, greatly
outnumber workers in the diseased colony.

A diseased, weak, colony cannot defend itself. Stronger, raiding colonies, left, carry off and adopt the diseased larvae.
A diseased, weak, colony cannot defend itself.
Stronger, raiding colonies, left, carry off and
adopt the diseased larvae.
Strong colonies which produce many winged ants, left, eventually become diseased and weak, producing only a few winged ants, so ant infestations do not spread.
Strong colonies which produce many winged ants,
left, eventually become diseased and weak,
producing only a few winged ants, so ant
infestations do not spread.

Map of southern US, North Carolina to Texas, showing sites where fire ant disease was inoculated and/or established.
Areawide cooperators have successfully established Thelohania solenopsae
throughout the imported fire ants' range within the United States.


Areawide Suppression of Fire Ants main menu

Last Modified: 7/24/2014
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