<P> The RIFA 's introduction to the United States was in the late 1930s . Traveling in soil used as ballast on cargo ships , they came in through the seaport of Mobile , Alabama . They build mounds , usually no larger than 46 cm ( 18 in ) in diameter and 46 cm ( 18 in ) in height , although in Alabama some mounds have been reported to be over 60 cm ( 2.0 ft ) high and larger , especially in fields where cattle graze . They build on soil close to homes and other buildings , and sometimes forage indoors for food and moisture . They are a nuisance , and can threaten sleeping or bedridden individuals and pets . Occasionally , they feed on vegetable plants in home gardens . The worst damage usually occurs during hot , dry weather , when they invade flower beds while seeking warmth and moisture . If disturbed , fire ants bite and sting the intruder . </P>
<P> The RIFA 's introduction to the United States was in the late 1930s . Traveling in soil used as ballast on cargo ships , they came in through the seaport of Mobile , Alabama . They build mounds , usually no larger than 46 cm ( 18 in ) in diameter and 46 cm ( 18 in ) in height , although in Alabama some mounds have been reported to be over 60 cm ( 2.0 ft ) high and larger , especially in fields where cattle graze . They build on soil close to homes and other buildings , and sometimes forage indoors for food and moisture . They are a nuisance , and can threaten sleeping or bedridden individuals and pets . Occasionally , they feed on vegetable plants in home gardens . The worst damage usually occurs during hot , dry weather , when they invade flower beds while seeking warmth and moisture . If disturbed , fire ants bite and sting the intruder . </P>
when were fire ants introduced to the us
when were fire ants introduced to the us
in the late 1930s
in the late 1930s