What's different in St Marys
South Creek and Byrnes Creek
Penrith City Council's St Marys (Byrnes Creek) catchment covers about 310 hectares and includes the St Marys levee, first built to limit flooding from South Creek. Water that sits after a storm is what mosquitoes are looking for.
Mosquitoes tested nearby
NSW Health found Barmah Forest virus in mosquitoes trapped at Werrington on 25 March 2025, and Gan Gan virus there on 1 April and 8 April 2025. A virus in a trap isn't a human case, but it's a reason to cover up in late summer and early autumn.
Penrith's mosquito advice
Council says larvae live and breed in small amounts of stagnant water, so clear your yard. It also says to keep swimming pools full and well maintained, avoid going outside after dusk, and keep fly screens in good condition.
What turns up in reserves
Council's fauna box checks in May and June 2023 found ringtail possums, sugar gliders, huntsman spiders and bush cockroaches, and multiple boxes showed signs of introduced bees. Bees will move into almost any hollow, including a wall.
Rodent control in St Marys
Rats and mice want food, water and somewhere dry, and a yard by a creek can offer all three. Look for droppings along walls, gnawed containers and cables, and greasy rub marks where they travel the same route. Scratching in the ceiling at night is the classic sign.
A pest business should show you where they're getting in, then explain what they'd close up and what they'd use. Rat holes are about 80 mm across, the Victorian health department says, and mice can gnaw holes up to 20 mm wide, so small gaps still matter.
NSW Health says leptospirosis bacteria may be in rat and mouse urine and can get in through cuts. So wear gloves for any clean-up, cover cuts and wash your hands with soap afterwards.
After a big storm
Walk the yard
Tip out buckets, pot plates, toys and anything else holding water.
Check gutters and drains
Blocked gutters hold water for weeks. Clear them from a stable ladder, or get someone in if you're not confident.
Check the pool
Council says to keep it full and well maintained, so don't leave it green and low.
Look under the house
From outside, check for damp or water sitting against timber, because termites like moist wood. Get an inspector in if it's stayed wet.
What we'd do about pests in St Marys
Do the walk after every big rain. It takes minutes and it's most of the mosquito job. If you're hearing something in the ceiling, that's the time to tell us your postcode.
Want someone to look at it?
Tell us what you've seen and your postcode, and a local pest business that handles exactly that calls you to talk it through.
