Ants on or around a vegetable garden are more of a nuisance than a threat. Most common ants are hanging out for other reasons and are not interested in your zucchini. Fire ants, however, can cause minimal vegetative harm to zucchini plants. Of more concern are the ants' stings when you try to harvest the squash. Many ants will cluster on a zucchini plant as farmers of the aphids that live there.
Ants live in colonies with a highly structured society of specialized jobs. Their home is an underground labyrinth of tunnels and a nest where the queen resides. Worker ants forage all day to bring food back to the nest. Ants are omnivorous and will eat vegetation and other insects, not to mention any human food that comes their way. The mounding habit of their nests can cause lumps in a lawn or garden that make management difficult. Ants lay a scented trail when they go off to forage so they can find their way back home. Many of their routes are well-traveled and become common paths for the worker ants.
Ant Aphid Farming
A favorite food for ants is honeydew, which is secreted by aphids and scale insects as a waste product. It is a sticky substance that eventually will mold and turn into sooty mildew. Aphids are sucking insects and often are found on foliage plants. They suck plant juices from stems, leaf ribs, tender leaf and new fruit buds. Ants can destroy developing growth and baby zucchini, and reduce plant vigor. Ants secrete chemicals that affect aphid movements and will even bite off the wings of the aphid to keep it nearby. A proximate aphid population provides the ant colony with a ready and plentiful supply of honeydew, while the aphids feed on your zucchini plant and destroy its health.
Fire Ant Damage
Fire ants create a different type of problem. They feed on the vegetation and fruit of plants, but the damage is negligible in most cases. They nest in mulch around tree trunks and in lawns. Any non-tilled area is a potential nesting site. The real problem with fire ants is the sting, which will burn and last for quite a while. One sting isn't too bad, but if you run afoul of an entire nest, repeat stings could land you in a hospital.
Check the zucchini plant for aphids. If they are visible, these soft-bodied critters can be removed with short blasts of water. Without their easy food source, the ants should move away. Baits are the most common method of control in other situations. Piles of debris and garbage need to be removed from a 5- to 8-foot range around the zucchini plant. These piles are good nesting sites and may provide supplemental food. Set baits where there is evidence of nests. Chose a bait that is specifically sold for use around edibles, and treat early in the zucchini's life. Refresh the bait and apply according to package directions.