Could there be anything more delightful and helpful to us than our beloved Ladybugs? Every child knows what they are, and without a doubt the vast majority of Americans, at one time or another, has carted one around in our hands to appreciate this friendly little critter that so benefits our garden. Perhaps some of you even have been fortunate enough to have seen the incredible winter gatherings of ladybugs, perhaps in protected canyons in your local hills. I have seen this in the Santa Cruz Mountains in northern California - millions upon millions of ladybugs, in piles and layers 5 or 6 beetles deep, in clouds flying around in the clearings when the day warmed up enough to get them stirring.
The "ladybug" is one name for the beetles that are in a family called the Coccinellidae, or "lady bird beetles". Virtually all of them are carnivores. That is, they eat meat, and that meat is in the form of some of our most reviled garden pests - aphids. Both the larva and the adult of ladybugs feed on aphids, along with other plant pests such as whiteflies, scales, and mealybugs. Several species of ladybugs have been instrumental in stopping major agricultural pests, such as The Vedalia Ladybug that was introduced to control Cottony Cushion Scale in California, essentially saving the Citrus industry from certain destruction.
There are a great many different species of ladybugs in the United States and around the world. While our most familiar kind is the Convergent Ladybird Beetle, a medium sized species with orange wings and black spots on the wings, there is a wonderful variety of sizes and colors in this group. They range in size from the head of a pin to around ½" across. Their colors are from orange to red to black to white. Variations are white with black spots, black with red spots, red with black spots, red with no spots, gray with red head, and others.
The larvae of ladybird beetles may be even more amazing. The larva is the "baby" ladybug, or the early stage that hatches from the egg. As it grows through its various stages it has an incredible appetite, and crawls all over plants looking for other bugs to eat. Quite often we may see these larvae and not recognize them for what they are - a highly beneficial and desirable visitor to our garden - and, not knowing any better we may kill them. I often am asked what the little bugs are that look like "alligators", and these are ladybug larvae. They may create their next stage - the pupa - on the wall of your house or the trunk of a tree, and these too should be left alone to live and help us.
One species of ladybug is called "The Mealybug Destroyer" because of its fondness for these ugly plant pests. This ladybug larvae has evolved a very different appearance, very much the same as the mealybugs on which it feeds, and effectively blends in with its food as protection from its own enemies. We need to learn to identify these critters so we can properly deal with insects in the garden.
So What's the Problem?
With all these incredible credentials and positive attributes could we EVER think of ladybugs as "pests"?
In its best definition a "pest" is something where we don't want it to be. Unfortunately, there are times when even ladybird beetles find themselves in situations where their presence simply cannot be tolerated, and they must be controlled, even to the point of killing large numbers of them possibly.
In the United States we enjoy an extraordinarily high level of sanitation in several important areas, two of which are:
- Hospitals and medical labs
- Food manufacturing plants
In these kinds of buildings it is a huge liability to allow even our precious ladybugs to roam about at will. Imagine the lawsuit if someone is served food in a restaurant and finds dead ladybugs in the food. Imagine the horror of finding ladybugs crawling on a loved one confined to a hospital bed, or landing on a patient on whom surgery is being performed. And yet, these are the kinds of situations that are experiencing more and more problems from the presence of ladybugs inside buildings.
The problem has escalated greatly since 1990, as a new species of ladybug has entered the United States. Actually, "entered" is not entirely accurate, as The Asian Ladybird Beetle really was brought into this country many years ago, and released in many states, from California to Maryland to Louisiana to Washington, as a biological control for agricultural pests. It did very well, finding food outside of agriculture in the forests as well, and its population grew. Now, there are huge numbers of them and the problems have begun.
Tell me something about them.
All insects make it through the winter somehow in cold parts of the country. In warm states, of course, they may simply keep on working and moving about in the outdoors, but where it is cold they will die unless they are able to tuck themselves away somewhere. Ladybird beetles over-winter as adult insects, and often they find the interior of buildings to be ideal places to hide and protect themselves from the killing cold weather. They tend to gather in large masses for this hibernation, so it isn't just a few beetles that wander into the hospital walls, it may be many thousands of them massing there.
Now, one of two things can happen from this point on. The beetles may confine themselves to some hidden places, such as wall voids, attics, or false ceiling voids, and exit to the outside when it again warms up in the spring. Or, they may get warmed up sufficiently inside the building to become active, particularly on winter days when a bright sun warms the walls and the air inside, and start crawling around looking for a way out. If that way out happens to be light fixtures on the ceiling, or other openings into a room, the potential is there for large numbers of ladybugs to be flying and crawling around in that room, hitting people, hitting the lights, crawling into food or onto people who are working or being served there.
At this point, no matter how much we may love them, they are a problem, and must be dealt with. If we go back to our scenario that the circumstance is a hospital or a plant that manufactures food products, the urgency is extremely high to eliminate the ladybugs as quickly and thoroughly as possible. Even if they are beneficial they are not necessarily clean, and ladybugs crawling on sterile gauze can spread bacteria. It is a 100% guarantee that the person finding a ladybug floating in their bowl of soup at a restaurant will NOT spoon the bug into their mouth and say "It's okay - they're beneficial you know".
What should be done about them?
Most situations, such as in your home, do not necessarily qualify as "critical" situations, and ladybugs emerging in your home should be herded outside if at all possible. If it is really cold outside they may not survive the winter, but if you kill them inside it is guaranteed that they won't survive the winter. Vacuuming is an option for quick cleanup, but obviously the beetles will die. Long-term control of these kinds of problems includes:
- Sealing up as many possible cracks, holes, or other entry points on the outside of your home as possible. This prevents the beetles from entering to begin with.
- Install screening ("20-mesh" maximum) over vent openings and exhaust pipe outlets, and use door sweeps on the bottoms of doors leading to the outside.
- Ensure all window screens and door screens are in good repair.
- Hire a Licensed Pest Control Company to evaluate the problem and to see if a chemical application within the voids and hollow spaces where they hide is warranted. Fogging around inside the living quarters of the house will do almost no good.
So, just a few thoughts on Ladybird Beetles. If you are one of those plagued by huge numbers of them I can understand the frustration of having them crawling along the back of your neck at the dinner table. However, they are an animal that is better left alive, so keeping them out of the structure is the first step in keeping them from being called "Pests", and catching and releasing them back outside is the best method of dealing with it if at all possible.