All things green, outdoors, and nature-y. Whether it's animals in their natural habitat, hiking trails and mountains, or planting a little garden for yourself (and everything in between), you can talk about it here.
See also our Environment community, which is focused on weather, climate, climate change, and stuff like that.
(It's not mandatory, but we also encourage providing a description of your image(s) for accessibility purposes! See here for a more detailed explanation and advice on how best to do this.)
This community's icon was made by Aaron Schneider, under the CC-BY-NC-SA 4.0 license.
If I have enough aphids, they're kind of already enough of a lure. The plan of let them run wild until the ladybugs show up only really works if they're on mature plants that won't die in the meantime.
But also, I have better luck keeping them around for longer if I make sure to spritz some water all over the plants every morning/evening after release (until I find eggs on a leaf at least). If they've got food and easy to access water, like droplets on leaves, they tend to stick around.
If you can buy them as larva you might have a better chance of them sticking around. They don’t have wings but still love eating aphids and other little pests.
You are right that they will just fly away, usually just after 1 day of hanging around.
But it's really not good to purchase ladybugs anyway. They're not raised in an insectary, they are taken from their native homes. Also, their immune systems are hyper-localized so when the purchased ladybugs inevitably fly away, they breed with the local populations and end up weakening the immune systems of the subsequent generations.
I've never tried a "ladybug lure" but you can attract them yourself by planting native, or at least localized, flowering plants.
You can however purchase green lacewing larva from insectaries or their distributors. The lacewing larva are known as "aphid lions" and they certainly live up to their name. A cheaper option, although a bit slower, is to purchase assassin bug eggs. They come on little paper cards that you hang on your plants and will hatch after a week or so.