Page Intro: Harmonia axyridis, also known as the multicolored Asian or Halloween lady beetle and will devour aphids and some scale insects. On this page you will find a description, life-cycle info, benefits, drawbacks, scouting info, advisories, usages, beyond the page, and other good stuff such as release rates.
Description
Many of you are already pretty familiar with these beetles. Especially those of you along the eastern seaboard, the mid-west and in the pacific-northwest. H. axyridis are the beetles which have, for the past few years, been invading people’s homes for the sake of comfy, protected overwintering. The “comfy, protected” parts I’m throwing in because the actual reason, to the best of my knowledge, is that these beetles naturally overwinter in the nooks and crannies of cliffs and other vertical surfaces and, thus, confuse the nooks and crannies of people’s homes with such natural overwintering locations. As in the case of houses, though, these nooks and crannies go on forever and the beetles end up being inside the homes. They really make their presence known, at least inside, in the spring when the beetles try like heck to get back outside. Unfortunately they aren’t able to retrace their steps.
Now don’t be alarmed, commercially only small quantities of these beetles are made available for interior uses and, unlike their wild brothers and sisters, these beetles are not wild-collected, they’re insectary reared just for the purposes specified.
Halloween ladybugs, with their shiny, rotund red, yellow or orange bodies may potentially clean up large populations of scale insects. Moreover, as most beetles are, H. axyridis can be very opportunistic and will eat pests other than scales: whiteflies, mealybugs, insect eggs and, in profound numbers, aphids. Moreover, these beetles may consume European red mites. We do recommend trying these beetles for other pests, especially aphids. We believe control of other pests may be obtainable with typical releases. Coincidental cross-predation should be regarded as a bonus of the application and may be more. Mass aphid consumption, in addition to scale insect control, should be expected.
Harmonia axyridis are shipped in small lots as pre-fed, pre-mated adults and sometimes as larvae. Some popular prey of these beetles is suspected to include: the scale insect species listed as hosts for Aphytis melinus and Metaphycus helvolus and other related species as well, plus a wide assortment of aphids. Moreover, very early releases in hemlocks may help control the hemlock woolly adelgid (Adelges tsuga). [Intro]
Life-style
These large and beautiful 8 mm. Asian, adult female beetles lay their eggs amongst pest colonies, averaging up to 700 eggs each; one female beetle laid over 1500 eggs in one test! The eggs hatch into black and orange larvae similar to that of Hippodamia convergens. These, too, the larvae, are fierce predators, growing up to 1.5 cm. long and consuming a great number of pests.
The life-span of these predators is roughly 3-3½ weeks in their immature stages, then up to three years as adults (probably less under most conditions). The conditions for optimum performance will be between 70-85°F with a relative humidity of around 70%. But these are optimum conditions, and not necessarily a prerequisite of successful implementation. Please note, however, significantly cooler or warmer temperatures and humidity fluctuations may hamper reproduction and development a certain degree. [Intro]
Benefits
These predators should provide outstanding results in the long-term. Canadian interiorscape trials of scale insect control have proven quite successful thus far. Initial 1996 and 1997, trials were quite favorable. Numerous recoveries, especially larval, were made.
Another significant benefit to using these beetles is the way they’re supplied: insectary-reared. pre-fed, pre-mated. Oviposition or egg-laying can potentially occur very soon after release. These same beetles, if wild collected, would probably perform poorly unless released much the same way H. convergens are. The commercially supplied larvae are probably the best way to get them as they can’t fly off at all and, yet, are still big eaters. [Intro]
Drawbacks
I have limited practical experience with these predators. However, past and present research is somewhat promising. I strongly suggest growers and interiorscapers try this species, but to do so not out of desperation.
In 1997, the first year these beetles were offered commercially, I discovered that they tend to be flightier than originally suspected. Growers should be thinking long-term when employing these beetles. It is very possible, in anything but a closed system, that few beetle recoveries will be made. Some folks who have tested them said that they only retained one or two “token” beetles. At what time of day releases are made may be critical to the successful implementation of these critters (see Advisories for details).
These beetles are a bit on the pricey side. This will probably be the case until production peaks at some point in the future. This hinges on steady demand. I suspect that the results may far outweigh the price issue, but that remains to be seen. Plus the application rates are nowhere near where they are for Hippodamia convergens (see Release Rates) [Intro]
Scouting
Adult beetle presence, larval presence, reduction of pest numbers and new, clean plant growth. These are all signs that Halloween ladybugs are hard at work.
I have nothing more to offer at this point in time. [Intro]
Advisories
Aside from misting the site with water before releasing and doing so in the late evening (even in interiors), there are other things you can do to ensure the maximum number of beetles perform. Flowering, pollen producing plants on site are a big plus.
Pollen isn’t the only thing these beetles will eat. They will also consume aphid and scale insect honeydew. A honeydew substitute product may help encourage the beetles.
Ants, if present, might need to be controlled. They will defend pests from predators and parasites to protect their honeydew/excrement food, gag! Use barrier products or boric acid products to control the ants.
You may want to try releasing these beetles (as adults) into trees the way I am suggesting to try for Cryptolaemus montrouzieri: Find a long bamboo or wooden pole with an approximate diameter of three-sixteenths to one-quarter-inch; insert one end of the pole through the pre-manufactured hole in the bottle’s lid and into the bottle of beetles, being careful not to injure any of them; the beetles will climb up the pole to the other end — if it’s not too hot, in which case they may fly off the pole, but should still make it to the foliage eventually — which should be tucked into the tree’s foliage.
Yellow sticky traps may present a problem with these beetles. I am unsure of this and ask that you exercise cautious observation when the traps are in use. If predator numbers on the traps get too high, remove the traps or use them for only two or three days per week.
Based on 1997 results, plan on making your H. axyridis releases after nightfall to minimize the fly-off and increase the likelihood of retention. [Intro]
Usages
I’m not certain of every possible use. I suggest trying them in greenhouses and interiorscapes mainly. However, orchard and garden uses may yield satisfactory results, especially if being used for aphids. Using them in hemlocks, if the timing is right, may yield good results as well. [Intro]
Beyond the Page
Harmonia axyridis is known, as mentioned in the text above, for entering dwellings as is its nature. The public outcry over this has been so tremendous, the USDA has had no choice but to outlaw them. They are no longer allowable as a biocontrol agent on the commercial level thus some of the text below is no longer accurate — but it should still be useful. I strongly recommend you collect them (perfectly legal and environmentally responsible) from their various overwintering spots and refrigerator-store them. Release them in bits during the growing season. Enjoy their benefits for free. They are really good at what they can do and they’re free so it simply makes sense. [Intro]
Rates, Instructions, and Purchase
Need more information? Check out our release rates or our short-term storage, handling, and release instructions. These predators aren’t commercially available. [Intro]
