Seven-spot ladybirds are probably the most well-known ladybirds in our country and are among the first beneficial insects ever to be used for biological pest control.
Every gardener is familiar with the aphids (Aphidoidea), which feed on the sap of beloved plants. Luckily there is a natural opponent, namely the ladybug. This article is specifically about the seven-spot ladybug (Coccinella septempunctata).
Seven-spot ladybug: profile and way of life
Like any insect, the seven-spot ladybird has 6 legs, reaches a body length of 5 to
8 mm and, as the name suggests, has 7 spots. A special distinguishing feature of the Coccinella septempunctata is the seventh spot, which is separated by the two wings and flanked by two light, elongated spots. There are two white dots on the front part of the chest, as well as on the head between the two black eyes. The seven-spot ladybug has two feelers that it can use to "smell" and touch. Unlike other ladybird species, the seven-pointed beetle is clothed very uniformly: There are only rarely animals that differ in terms of the number of points or color of the elytra.
Coccinella septempunctata are polyphagous, i.e. they have a very broad food spectrum. In addition to aphid species, which are essential for the development of the larva, other food such as thrips (Thysanoptera), leaf beetles (Chrysomelidae) and even eggs of their own kind are eaten.
Seven-spot ladybirds, along with the two-spot ladybirds, are the most common species found in Germany and often overwinter in colonies on damp ground, surrounded by leaves, grass or moss. As soon as the temperatures rise, the mating season begins. Egg-laying begins at the end of April, with a female depositing up to 400 eggs on plant parts, most of which are already aphidsare affected. A few days later, the first seven-spot ladybird larvae hatch and prey on the aphids. After three molts, the larvae pupate, and about a week later, the pupa hatches into a seven-spot ladybird.
Seven-spot ladybirds in Germany usually form only one generation per year, in more southern countries there are quite often two generations per year. In India even 15 to 20 generations have been observed. Each individual of the seven-spot ladybird is about 12 months old.
During this time, it changes its preferred habitat: larvae grow up protected in herb layers. The beetles migrate to shrubs to feed on ripening and then hibernate on trees, in houses or on the ground. In the spring they go back to where their larvae are protected and can grow close to the ground on herbaceous plants to lay their eggs.
The seven-spot ladybird feeds mainly on its neighbors, the aphids. If the aphids are scarce, Coccinella septempunctata feeds on pollen and fungal spores if necessary or migrates to the next aphid colony. The activity of the beetle depends on the weather: from 18 °C and without rain, the eggs develop into the pupa within two months. At 25 °C, on the other hand, it only takes 15 days.
Seven-spot ladybugs as a beneficial insect against aphids
For natural and effective aphid control without any synthetic pesticides, for example, the use of our Plantura seven-spot ladybirds is possible and effective from around 18 °C. There are a few things you should keep in mind in order to be successful using Seven Spot Ladybugs.
Successful use of seven-spot ladybugs:
- Stop using chemical pesticides 6 weeks in advance.
- If necessary, remove excess ants before use.
- At the fighting site there should be at least 18 °C.
- Use in enclosed spaces such as conservatories, rooms and greenhouses is much more effective than outdoors where the beetles tend to migrate.
- The success of the application can be seen after a few days if the conditions are good.
Tip: Beneficial insects like our ladybugs are sensitive to pesticides. But some of them are less harmful to the beetles or are broken down so quickly that the waiting time between their application and the use of beneficial insects is shortened: agents based on rapeseed oil or potash soap and neem preparations such as our Plantura organic pest-free neem can last another week before obtaining the beneficials to decimate the pests.
How do seven-spot ladybugs fight aphids?
Seven-spot ladybugs lay their eggs on plants that are already infested with aphids. The newly hatched Coccinella septempunctata larvae are particularly voracious and eat up to 1200 aphids during their development period, depending on the aphid species, while adult seven-spot ladybirds only eat up to 150 aphids a day. Young larvae of the seven-spot ladybird usually also consume smaller prey by biting and then sucking them out. Larger larvae and adult beetles, on the other hand, can chew up their food completely.
Procedure for use as a beneficial insect
How to use ladybugs as beneficial insects:
- 150 bugs are enough to control approximately 10m² of infested area.
- Put the plants as close together as possible so that the seven-spot ladybugs can easily move from one plant to the next.
- Once received, apply the same evening or the following morning if possible.
- Open packaging at application site.
- Carefully remove the pieces of foil with the eggs and place them at the infested area.
- Alternatively: attach with clothespins.
- As close as possible to the aphids.
- Min. 18 °C, avoid places with strong sunlight.
- Wait, observe and check the success of the control after approx. 3 weeks.
Not only seven-spot ladybugs, but also many other animals can help you against pests. In our special article, we introduce you to 10 beneficial insects that you should know about and promote in your garden.