I live in one of those older houses facing south with light-coloured, wooden siding where ladybugs apparently love to hibernate over winter. Pheromones apparently draw them back year after year. Starting about February and continuing for weeks, dozens, if not hundreds of ladybugs can be found on our southern windows and windowsills. There’s no future for them indoors or out at that time of year so we just vacuum them up. Fast forward a few months. Here we are in mid-June and still being rained on since mid-May by a major infestation of aphids in our 2 dozen or so Garry Oak trees. Perhaps coincidentally, many perennials in the garden have their own populations to deal with. Everything is covered with honeydew – cars, decks, even windows. So, where are those ladybugs now I ask?
How frustrating! I've had some problems with aphids in my Italian plum tree in past years, and in spite of the dormant spray which I applied in February, they are worse this year, and also colonizing my apple-pear and bartlett pear trees even though I didn't get so far as fertilizing them this year (I did put a layer of compost around them last fall though). I've blasted them a number of times with the hose and just once with a teaspoon of dawn per liter of water. At least the hose blasts seem to have reduced the honeydew and I haven't seen any sooty mildew develop. However, this week I just found a number of ladybug larva on the plum tree so I haven't sprayed since. I've never seen more than a couple of ladybugs on my trees in previous years, and never any larvae before. They only seem to be on one side of the tree, so I'm wondering if it's ok to continue blasting the other parts of the tree. Nah, it's going to rain over the next couple of days, so I probably won't bother.
I take encouragement from knowing that you have been seeing ladybug larvae on your trees. Hopefully they'll arrive soon in my garden and the rain will help wash the sticky honeydew off everything.
hm, do you mean I should just let the aphids be and wait for the ladybugs to eat them? the poor tree looks so sad and the fact that the aphids are getting worse every year worries me.
One of the tenets of IPM (Integrated Pest Management) is to allow insect predators time to move in to attack and hopefully eliminate the pest population. I have to say though that my patience is wearing thin, not that I can do a darned thing about it. With roughly 3 dozen Garry Oaks and Arbutus trees reigning / raining over my garden, everything is still covered with aphid honey dew after 6 weeks at least. An article in our local newspaper gives me some consolation that I am not alone. https://www.pqbnews.com/news/parksville-program-combats-aphids-on-oak-trees/
Hi Margot, Well, you're absolutely right. The ladybugs did chow down on the aphids on my plum tree, and with the rain the other day, the leaves are barely sticky with honeydew any more. There are very few to be found now, they have all moved on, except for those that are pupating. I don't see any juveniles that look like my avatar any more, and the adults have disappeared. All of this in a matter of about a week. I was meaning to catch a few and transport them over to my apple pear, but I just might be out of luck. Hopefully some will migrate your way soon. Mother Nature certainly does take care of her own as long as we don't try to outsmart her!
Hi Joan - if any of your ladybugs still look hungry after devouring the aphids on your trees, please send them over to me. None have shown up here, many weeks into this current infestation.
Margot, it's too late to improve your current situation, but I noticed a good source for ladybugs in my garden yesterday while weeding. I allow dill to self-sow all over my garden and then harvest as needed while removing the surplus to the compost pile. Aphids invariably attack the plants by late spring; so I remove the worst affected plants. That's what I was doing yesterday when I noticed clusters of tiny, bright yellow eggs on some of the dill plants and assumed that they were ladybug eggs, since I also saw lots of ladybugs among the dill weeds. A quick Google search confirmed that they were ladybug eggs. I moved the eggs to other plants that might have aphids before tossing the dill weeds into the compost bucket. If you don't already have dill growing in your garden, you could plant some and see if it works as an attractant for both aphids and ladybugs. If that works, it would be easy to move egg clusters to plants that need ladybugs.
That's a great suggestion, Vitog! I would never have guessed dill was a particular attractant for aphids. Funny, I was thinking just today how much I like it so I will plant lots next year and see if that helps increase the ladybug population in my garden. Thank you.
Another suggestion (for next year): you could order some ladybugs from a local nursery. A co-worker of mine recently received a box of ladybugs from Garden Works in Burnaby. A box of 250 for about $12. She ordered them a few months ago. You have to pre-order in the off-season (just like honeybees, mason bees, and leafcutter bees.) I am sure nurseries in the Nanaimo area would offer them too.
Buying ladybugs sounds like a good idea at first but several problems have come to light since they became available several years ago. First is that the ladybugs on sale at garden centres, etc. are not our native species and there is a risk that the imported ladybugs may carry parasites and diseases that they could spread to the native types. All too often, purchased ladybugs fly away to other gardens after being released. I can't find anything to corroborate this bit of information - that imported ladybugs are known to bite people whereas the native ones do not. Finally - again unsubstantiated - is that it is the non-native ladybugs that are prone to infest houses like mine every year. For some reason they are drawn to older, south-facing houses with light coloured wood siding, hibernating until January or February when they make their way inside and congregate on windows and windowsills. So, I'm going to concentrate on planting more plants that attract ladybugs, such as dill, mentioned by Vitog. PS I have complained before of a huge aphid infestation in my garden and in surrounding Garry Oak and Arbutus trees this year. After almost 3 months, we are still putting up with honeydew on our decks, cars, windows . . . and nary a ladybug in sight.
The inconvenient truth is, they are in your vacuum cleaner. If allowed to live, after awakening from hibernation they would leave your house exactly the same way they got inside. Or you could help them to find the way out, wouldn't it be nice? BTW, there are many other insects that keep bad bugs in check: hover-fly larvae, lacewing larvae, predatory midge larvae, parasitic wasps, earwigs, predatory beetles. They don't look that cute but they all feed on aphids. It looks like they, too, are not abundant in Nanoose Bay. If you read the information in the articles in the link in my previous post you could learn that insects are on decline not only in Nanoose Bay. They are on decline around the world due to the habitat loss and the war the human species fight against them. According to the info on the Net "Over 1 billion pounds of pesticides are used in the United States (US) each year and approximately 5.6 billion pounds are used worldwide ". And in that war, as you know from your own experience, pesticides are not the only weapon. According to the research, while some of the most important insect species are in retreat, a small number of species are likely to be able to adapt to changing conditions and do well. "Fast-breeding pest insects will probably thrive because of the warmer conditions, because many of their natural enemies, which breed more slowly, will disappear, " said Prof Dave Goulson from the University of Sussex. "It's quite plausible that we might end up with plagues of small numbers of pest insects, but we will lose all the wonderful ones that we want, like bees and hoverflies and butterflies and dung beetles " Insect decline may see 'plague of pests' In case of aphids each female produces between 50 and 60 young per generation, and there are about 20 generations annually, while in case of ladybugs, within a year there can be only as many as 5-6 generations. Go fig.
It is very troubling to know that so many insect species - especially those that we consider beneficial - are on the decline. I would be happy to escort my ladybug guests back outdoors but I doubt think they'd survive in the cold winter temperatures.
No, not in the cold winter temperatures. As I said in my previous post, in Spring, after they awake from hibernating in your cozy, welcoming house.
The thing is that they start coming into the house mid-January and continue until early March. Temperatures don't often go below zero C here but it's still pretty cold at that time of year.
Temperatures must go well below zero for several days, to kill a ladybird beetle. I think, if you released those bugs outside, then they'll have much higher survival rate, compared to staying trapped in your vacuum cleaner. Ladybug Frequently Asked Questions: Get the Facts
True - and just as easy to empty the hand-held vacuum outside. If I knew how, I'd band their legs and track their progress . . .
Emptying in the cold winter weather a vacuum cleaner full of ladybugs with broken wings, even if with no tied legs is not a good idea. Definitely you were not there for them when they needed you.