Once outdoor ant trails have been located, targeting them with a granular product is one way to ensure successful bait uptake.

Prior to the introduction of baits using actives with ‘viral’ transfer capabilities, the first directive for ant management used to be “find the nest!” Whilst this task remains important, the emphasis when using modern baits has shifted to “follow the trail”. Trails are generally far easier to spot than the nests themselves and indeed success with baiting requires bait placement near active trails, to maximise the chances of discovery.

Ants work as a social unit, building the nest, providing care for the brood, queen and reproductives, and foraging for the colony. Not all forager ants in a colony will leave the nest to forage at the same time. It is generally recognised that around 10% of the ants in a colony are foragers, with the oldest workers mostly employed in this task to secure nutrients for the rest of the colony.

Ant colonies require sugars, oils, and proteins at various times during their life cycle. Most common pest ant species develop well defined foraging trails that are marked by pheromones; as each ant moves along the trail, more pheromones are released from the base of the abdomen. The continual release of pheromones keeps the trail scent powerful, which allows other workers to determine the value and direction of the trail. Pheromones are highly volatile, which is why they need to be continually boosted.

Foraging trails may be built through lawns or other vegetation to provide a direct route to the food source. Trails also may become subterranean – this is often seen with nests partially buried in landscaping timbers. Trails may also follow the roots of trees. Finding these trails is more challenging. When seeking out ant trails, advice from the homeowner may assist in guiding you to areas where the ants are commonly observed. Check carefully around fences, wiring and plumbing leading to the structure, as well as trees, shrubs and plants that are in contact with building.

Once trails have been located, Ensystex regional director, Steve Broadbent, advises managing the infestation with Hymenopthor Ultra Granular Ant and Cockroach Bait. It is a complex blend of two proteins, two oils and two sugars, which targets all species of ants, including red imported fire ants, Pharaoh ants, meat ants and Singapore ants as well as all species of cockroaches, large and small.

“To ensure high palatability, Ensystex moved away from the traditional de-fatted corn grits used by most companies and went with a highly absorbent, free-flowing baked corn cereal with a high honey content,” explained Mr Broadbent. “The cereal is crushed through a double roll mill to create a small granule that is 1-3 mm in size to better ensure targeting of all ant species.

“Ensystex’s patented, non-repellent fipronil moves through the colony between nestmates. The ants will survive for up to 24 hours, allowing for the fipronil to be transferred through the colony and for total elimination to be achieved.”

Mr Broadbent believes that the efficacy of Hymenopthor Ultra arises from Ensystex’s ‘Liquid oil phase release’ technology. This effectively creates a liquid gel around the granules. This is created by dissolving the fipronil in the oils, and then coating the granules with the oil. It means that when worker ants use their legs and mouthparts to physically carry the granules back to the nest – for the larvae to digest and feed to the colony – the bait is not diluted before it reaches the nest, since the workers do not consume it. So the entire granule with all the active is taken into the colony.

“In contrast, with straight gel baits, the worker ants ingest the gel including the toxicant. So when they later return to the colony to pass it to nestmates by trophallaxis, there has been a dilution of the toxicant, due to it having been absorbed into the worker’s body,” he explained.

“We know that worker ants are generally liquid feeders. Importantly, our ‘Liquid oil phase release’ technology allows workers to feed directly on the Hymenopthor Ultra and receive a toxic dose of the active, as well as feeding on the pre-digested liquids from the larvae. To feed liquids to the larvae, workers apply their mouthparts to those of the larvae and the liquid food is regurgitated from the adult ant’s crop. This is referred to as stomodeal trophallaxis and has been observed in nearly all major ant families.

“More importantly, unlike the adults, the larvae can externally digest solid food brought back by adult ants, producing soluble proteins which are in turn sought from the larvae by the adult ants. The larvae regurgitate this digested food to the workers in a liquid form. This has led to the concept that ant larvae might serve as specialised digestive castes.”

Ensystex’s extensive trial program has shown that optimal uptake of a granular bait is achieved when the bait is sprinkled along a trail rather than placed in a heaped mound.

“For optimal results, follow the trails – then bait the trails,” he concluded.