Very often small maggots or worms appear in the garden bed or in flowerpots. These are different beetle larvae. Recognizing and determining them correctly is not always so easy.
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Identify and distinguish larvae
If plants in the garden bed or in the flower pot grow stunted and even die in the end, the beetle larvae living in the soil are responsible in most cases. Their appearance is very often reminiscent of thick whitish maggots or worms. Depending on the beetle species, there is a classification into
- grubs, beetle larvae of scarab beetles (Scarabaeidae) and
- Wireworms, beetle larvae of click beetles (Elateridae).
Distinguishing and determining is not always easy. Beetle larvae in the soil can damage plants by feeding on their roots, such as the May or June beetle, but they can also be useful helpers in the garden, such as the rhinoceros beetle and rose beetle . Below is a small list of beetle larvae, which should serve to identify and recognize them.
List of common beetle larvae
Sometimes grubs and wireworms are not always clearly recognizable and distinguishable. In such a case, the knowledge of a professional should be used to identify the beetle larvae. Especially the grubs of the May, June and garden chafers are difficult to distinguish:
B to G
Blattrandkäfer (Sitona)
- pest
- Size: 0.6 to 1 cm
- Colour: creamy white
- Characteristics: brown head capsule, no legs, C-shaped crooked posture
- Occurrence: Meadows, fields, farmland
- Food: only root nodules of legumes such as clover, lupine , vetches, peas, beans
- Development time: one generation per year
- Special feature: Severe infestations can lead to crop failures.
Garden leaf beetle (Phyllopertha horticola)
- pest
- Size: 1.5 to 2 cm
- Colour: white to yellowish
- Characteristics: brown head, three pairs of breastbones, dark abdomen with dung sack and two rows of thorns, C-shaped curved body
- Occurrence: 10 to 15 cm under the ground in fields, beds and lawns, crawling even deeper into the ground when pupating
- Food: Roots of various plants
- Development time: 1 to 3 years
- Special feature: stretched in prone position moving
Gefurchter Dickmaulrüssler (Otiorhynchus sulcatus)
- pest
- Size: 1cm
- Colour: white with brown-yellow markings
- Characteristics: brown head, no legs, body surface covered with hairs, body of even thickness with a tapered rump, belly-curved posture
- Occurrence: preferably in the soil with rhododendrons , geraniums and hydrangeas
- Food: Roots and tubers, signs of feeding on the root neck and fibrous roots
- Development time: 1 to 2 years
- Special feature: crawling locomotion
Ribbed curlew beetle (Amphimallon solstitiale)
- pest
- Size: 3 to 5 cm
- Color: cream colors
- Characteristics: brown head capsule, three pairs of sternums, curved C-shaped body shape
- Occurrence: prefers sandy, light soil, under bushes and lawn plants
- Food: small roots, plant remains
- Development time: 2 to 3 years
- Special feature: locomotion by crawling on its stomach
Glossy beetle (Selatosomus aeneus)
- pest
- Size: 1.5 to 2.5 cm
- Colour: light yellow
- Characteristics: elongated, maggot-shaped body, dark head, three-part antennae, sickle-shaped jaws (mandibles), angled legs, finely hairy abdomen, cylindrical body cross-section
- Occurrence: in loose soil, also behind bark, deciduous and coniferous forests, fields and meadows
- Diet: Plant roots, soil insects, beetle larvae living in the soil
- Development period: 3 to 5 years
K to N
Kartoffelkäfer (Leptinotarsa decemlineata)
- pest
- Size: 1 to 2 cm
- Color: young larvae red-brown, older specimens yellowish
- Characteristics: black head capsule, black spots on sides of head and body, elongated body shape
- Occurrence: Nightshade plants such as potatoes, peppers, tomatoes, aubergines
- Food: Leaves of these plants are very hungry
- Development period: two to three generations per year
- Special feature: crawling locomotion
Little July Beetle (Anomala dubia)
- pest
- Size: 1.5 to 2 cm
- Colour: yellowish white
- Characteristics: Brown head capsule, rump slightly thickened and darker with short rows of brown spines, C-shaped curved posture
- Occurrence: prefers sandy and loamy soils, forest edges, gardens
- Food: Roots of grasses, cereals and woody plants
- Development time: 1 to 3 years
Maikäfer (Melolontha)
- pest
- Size: 6cm
- Colour: light cream to yellowish
- Characteristics: brown head capsule, powerful jaws, three pairs of strong and long sternums, body of even thickness, C-shaped hunched posture
- Occurrence: in the soil under vegetable beds, perennials, shrubs, lawns
- Food: roots, tubers, bulbs
- Development period: 3 to 5 years
- Special feature: hunched posture when crawling, in the young larval stage easy to mix up with June beetle larvae
Mistkäfer (Geotrupidae)
- beneficial
- Size: 1 to 2 cm
- Color beige
- Characteristics: broad body, slightly transparent, dark head, flattened forehead, tripartite antennae, three pairs of breastbones, C-curved posture
- Occurrence: in compost heaps, forest, fields, meadows
- Diet: Feces of herbivores
- Development time: 1 to 2 years
- Special feature: meandering locomotion, feed on the droppings and dung of herbivores, nutrients get into the soil, rarely occurring
Nashornkäfer (Oryctes nasicornis)
- beneficial
- Size: 2.5 to 10 cm
- Colour: whitish yellow with brown spots
- Characteristics: light brown head capsule, three long, brown pairs of breastbones, segmented body, divided into separate plicae (ringlets), slender, cylindrical body, curved C-shaped posture
- Occurrence: in compost
- Food: dead plant material
- Development period: 3 to 5 years
- Special feature: stretched and moving on the back
R to S
Rosenkäfer (Cetoniinae)
- beneficial
- Size: 4 to 5 cm
- Colour: yellowish-beige with black-grey shades and reddish-brown spots on the sides
- Characteristics: brown head capsule, thin-skinned, small stubby legs on the chest, slender front part, thickened posterior part, stocky body covered with brown hair, in supine position C-shaped posture
- Occurrence: Common in compost heaps
- Food: dead plant parts, remains of wood
- Development time: 2 to 3 years
- Special feature: moving on the back, stubby legs stretched out in the air
Red-brown leaf beetle (Serica brunnea)
- pest
- Size: 0.8 to 1 cm
- Colour: white to slightly yellowish
- Characteristics: brown head capsule, three pairs of breastbones, curved brown bristles on the anal segment, C-shaped body posture
- Occurrence: prefers sandy soils, garden beds, lawns
- Food: Roots of various plants and grasses
- Development time: 2 years
Saatschnellkäfer (Agriotes lineatus)
- pest
- Size: 1.7 to 2 cm
- Colour: yellow-orange
- Features: dark head capsule, round, elongated body shape, three pairs of sternums, chitinous exoskeleton, last body segment conically pointed
- Occurrence: Meadows, fields, gardens, heath
- Food: Roots and shoots of potato and cereal plants, corn, sugar beets, carrots, onions, tomatoes, grass, lettuce
- Development period: 3 to 5 years
Sandlaufkäfer (Cicindealinae)
- pest
- Size: 1.1 to 1.6 cm
- Color: yellowish-beige with dark shades and black spots
- Characteristics: large head rounded at the sides, sclerotized fore chest and head, short legs, forward-facing mouthparts, flattened slender body, six large dotted eyes
- Occurrence: preferably in sandy soil, under trees and shrubs
- Food: insects
- Development time: 2 to 3 years
Silvery somersault beetle (Hoplia philanthus)
- pest
- Size: 2cm
- Colour: creamy white
- Characteristics: brown head capsule, three pairs of sternums, black-grey abdomen, back and abdomen end with dense brown bristles, C-shaped curved posture
- Occurrence: under lawns
- Food: roots of grasses
- Development time: 2 to 4 years
frequently asked Questions
There are plant pests in these beetle larvae that should be fought so that they cannot cause any damage. In addition, various grubs are also useful for the ecosystem, as they eat pests, among other things. It should not be forgotten that some of these larvae are also protected and therefore must not be killed.
The first signs can be seen in a stunted growth. Over time, the plants will die as the roots have been eaten. However, you should not wait that long. The pot can simply be placed in a bucket filled with water. After one to two hours, the little animals appear on the surface of the earth because they don’t like the cool water. The grubs can then simply be collected.
The simplest control is the use of nematodes from the genus Heterorhabditis bacteriophora. These can be added to the irrigation water. The nematodes then kill the beetle larvae in the soil. In addition, flower pots should never be placed in the garden without saucers. A geranium offshoot in the flower pot can also be helpful. The larvae abhor its smell. Larkspur has the same effect.
The addition of nematodes of the genus Heterorhabditis bacteriophora to the irrigation water is also very effective here. When spreading, the outside temperature should be at least 12 °C. The lawn can be watered with it from July to September. Alternatively, buckets filled with compost or horse manure can be buried to 10cm below the rim near lawns. They are filled up with soil. These should be replaced after a year.
