The ladybug lifecycle is a long one. It can be as longer than 8 weeks from when an egg is laid until when it emerges as an adult. So that means that the great flush of ladybug eggs that you’ll get in late spring won’t produce the great number of adults that you hoped for until mid to late summer. But, that’s ok. Because in the meantime, their larvae are contributing more to aphid destruction than the adults ever will. So, we want to encourage that egg laying, which includes attracting and maintaining high ladybugs populations. I’ll walk you through just how to do this. You can also see all this in video form here:
Let’s take a look at the life stages of ladybugs again: Above are pictures of ladybug eggs. Notice they are yellow, tightly packed in a cluster and protrude from the leaf surface. Eggs are naturally well-protected, but belHere is the most sensitive life cycle (below). Most people will spray this off or squish it before recognizing what it is. This is the first stage larvae that have just hatched. They quickly become mobile and begin feeding and despite some size and colour variations all the larvae of the big red and spotted ladybugs tend to look the same.
But what’s brining them to your yard? Don’t buy “ladybugs” because the ones you buy are typically wild-collected hippodamia convergens. And while that native species will show up in your yard, the ones you buy were hibernating and are programmed to go back to that site. Cornell did study this extensively and did find a way to trick them into staying, but it spent weeks or different light, heat and diet variations, which made it far too burdensome to use. So when we talk about keeping ladybugs in the yard we are talking about establishing the native ladybugs.
And what’s bringing them to your yard is aphids. (Here’s everything you need to know about controlling aphids.) Yes, they eat other pests, but they do not do major damage to the populations of other pests. So the first thing you can do to promote and establish ladybugs is to stop getting rid of your aphids so quickly. I know this seems counter intuitive: you want aphids gone so you have to keep them, but hang in there, this will all make sense in a second.
I’m not saying you have to keep aphids on your favourite plants or allow them to take over. You can establish aphids on adjacent plants to feed the ladybugs. But there’s a trick. These adjacent plants and aphids have to be non-transferable aphids. What I mean by that, is a population of aphids that is host specific and will not spread to other plants. This is fairily common. In many greenhouse operations they grow wheat or oats or some other plant in the Grass/grain family, and infest it with the oat aphid…which can only feed on grass species. Then, they release their beneficial aphid predators who can feed and establish on these aphid banker plants before tackling the aphids in the crop. It’s this same principal you’ll be practicing in the garden. But in your garden, it’s called conservational bio-control. Here are some examples of plants you can use.
If you are not growing brassicas or cole crops: like broccoli, cabbage, kale, or their cousins in the mustard or turnip family, then one such aphid you can invite to your yard is the cabbage aphid. This grey aphids loves leafy green cole crops but will also attack the flowering stems of mustards. You can grow these tall yellow mustards for the flowers, or those ornamental kales if you still want them to look good. The aphids on here will attract aphid predators, increase their numbers and provide an aphid banker for your yard.
My absolute favourite is the hop. Hops get the hop aphid, which is practically non-transferable aphid. But best of all, aphid predators love the plant and multiply quickly on them. I originally started growing hops for summer shade, since they die right back to the ground each winter, when I desperately want the sun. So, if you’re into a fast growing source of shade that dies back each winter, get some hops! The hop aphid is so bad where I live that it collapsed the hop industry here, which was at one time the biggest in the British Empire. If you are growing hops for making beer or producing shade, then you might want to buy an aphid predator to help knock them down, and do so preventatively either with Aphidoletes aphidimyza or the Crazee Mite, Anystis baccarum. But if you are growing it for fun and have a fence to grow this bine, then you’ll have an effective aphid magnet and ladybug breeding area.
Another great one is to plant wheat or rye or oats. They typically get the oat aphid, and just like the greenhouse banker, it’s certainly one that won’t infect your other plants.
Finally, if you want to take this to the next level, and you’re brave, and your neighbours won’t be upset, you can try just encouraging aphids in general, even ones that can spread. The reason I say this is because as soon as you try to grow aphids, you will ultimately loose. I know this, because it’s part of my job, and even with cages and chemicals, when an aphid population gets big, and honeydew is noticeable, it will attract all sorts of predators.
So, if you’re up for it, try these plants. I grow bread poppy, which gets this terrible black aphid. However, I grow it for the seeds, so I don’t mind the aphids. In the meantime, I attract predators to the yard. I’ll grow nasturtiums with my blue berries, because even though it’s the same nasty black aphid the aphid doesn’t like the blue berries, and instead I get a huge number of aphid predators.
I grow sunflowers, which get several aphids, but this plant is loved by pests and predators alike, so you’ll have to monitor these regularly to see how it’s working.
I always have to give this disclaimer: aphids can spread viruses and disease and stunt the growth of your plants. There are some plants where you have to intervene: a blast of only water, release of commercial predators, like Aphidoletes, or removing aphids by hand are the best methods for saving your plant while not interfering with the opportunity for aphid predators like ladybugs from establishing.
But above all else, be tolerant of some aphid populations. In order to attract and maintain ladybug populations you need to have aphids. Learn to love seeing them destroyed by natural predators by attracting them to other plants in your yard. You’ll be a more patient and confident gardener because of it.
Here’s more on conservational bio-control:
Lesson 1: Which flowers
Lesson 2: Structures or habitat
Lesson 3: Lawns and “no-till”
Lesson 4: Compost and patience.