Since radishes taste delicious, they are often grown in your own garden. However, it is annoying when the radishes are eaten, because some pests attack the plants.

In a nutshell

  • Pests usually infest the above-ground parts of the plant
  • Radishes themselves are rarely eaten
  • Avoiding or preventing is often easier than fighting the pests

Fleas (Psylliodes)

damage picture:

  • one to two millimeter round holes in the radish leaves (window damage); especially in young plants
  • severe infestation causes growth disturbances or total failure
  • root feeding of the larvae

Happen:

  • in the garden, especially in dry and warm weather
  • prefer a dry soil surface
  • from April to August (depending on weather conditions)

Look:

  • two to three millimeter long leaf beetles with great jumping ability
Ground flea larva. Source: Gilles San Martin from Namur, Belgium, Psylliodes chrysocephala larva (31943653745), crop from Plantopedia, CC BY-SA 2.0

Measures:

  • Sweeping over the plants with a broom or whisk causes unrest and “drives away” the flea beetle
  • Lay out the board with caterpillar glue (beetles stick)
  • fight with natural enemies: hedgehogs, shrews, leaf and caterpillar beetles
  • Keep soil moist (preventative)
  • Dust rock flour or algae lime on leaves (keeps the pests away)
  • fine-meshed culture or pest protection net, mesh size less than one millimeter; alternatively plant protection fleece (preventive)
  • regular chopping (disrupts the pupation of the larvae)
  • Mulch layer of lawn clippings or other garden waste (preventative)
  • Plant manure made from tansy or wormwood (preventive)
  • against larvae: scorching the garden soil

defensive plants:

  • Onions (leeks, garlic, onions)

cutworms

In colloquial language, the caterpillars of various owl moths (owl, "moth") are referred to as cutworms. Common types are:

  • Winter crop owl (Agrotis segetum)
  • Black-winged owl (Agrotis ipsilon)
  • Exclamation mark (Agrotis exclamationis)

damage picture:

  • leaf damage
  • root damage

Happen:

  • Young caterpillars live above ground
  • later stages underground (nocturnal)
  • Main flight time of the moths: from early summer to autumn
  • last generation overwinters in the ground

Appearance of the caterpillars:

  • gray-brown, brown, yellowish-brown
  • up to five inches long
  • short hair
Black-eyed owl (Agrotis ipsilon) caterpillar; Source: Rasbak, Agrotis ipsilon, aardrups, edited by Plantopedia, CC BY-SA 3.0

Measures:

  • collect caterpillars in the dark (flashlight)
  • keep soil surface moist
  • Bait: Mixture of bran (100 grams), sugar (10 grams), quassia (10 cc) and water (200 milliliters)
  • Nematodes (nematodes or roundworms)
  • natural predators: blackbirds, bats, chickens, hedgehogs, toads, moles. Ichneumon wasps, caterpillar flies, shrews
  • Spray young plants with wormwood decoction (keeps the caterpillars away)
  • set up light and scent traps
  • to reduce egg laying: cover with vegetable nets
  • Crush egg clutches on plants
  • when hoeing or digging: remove pupae from the ground (preventive)

Tip: Since cutworms prefer weeds, you should not remove all weeds in or just in case.

defensive plants:

  • sage
  • thyme
  • tansy

Garden slug (Arion hortensis)

Other names: garden slug, garden slug

damage picture:

  • Eating marks on radishes (underground)
  • leaf damage

Appear:

  • no seasonal cycle
  • often live in the ground
  • all stages can hibernate

Look:

  • extended to 50 millimeters long, most significantly smaller
  • Back: dark blue to black with a slight brownish tinge
  • Sole: brownish yellow, dark yellow to deep orange
  • yellowish mucus
  • strong resemblance to the common slug (Arion distinctus)
Source: Aiwok, Arion hortensis 1.ext, edited by Plantopedia, CC BY-SA 3.0

Measures:

  • Snail fences, strips or traps
  • Predators (slugs)

Notice: Collecting the garden slugs is not particularly effective due to their way of life.

Japanese beetle (Popillia japonica)

In order to contain or prevent the spread of the Japanese beetle, you should inform the responsible plant protection service about an infestation. To check, it is recommended to catch a beetle in a screw-top jar.

damage picture:

  • Leaf feeding to skeleton feeding by adult beetles
  • Browning and dropping of affected leaves
  • Traces of feeding on flowers

Happen:

  • Main flight time between mid-May and mid-August

Look:

  • eight to twelve millimeters long
  • white tufts of hair on abdomen and end of body,
  • shiny metallic copper colored wings
  • gold-green shimmering head
  • similar appearance to June or garden chafers

Notice: In the case of the Japanese beetle, it was observed that often only one plant is eaten bare, while neighboring plants were spared.

Measures:

  • attractant traps
  • Collect the beetles
  • against larvae: moles, birds, shrews, roller wasps, ground beetles, nematodes, mechanical tillage in early autumn (reduction in the chances of survival of the larvae that feed near the ground)
  • Avoiding oviposition: keep grassland dry during the main flight season

Lesser cabbage fly (Delia radicum)

Other names: cabbage root fly, root fly, turnip fly

damage picture:

  • Plants wither and die (root damage by the larvae)
  • brown burrows in the radishes
  • Barrel pupae (brownish, two to three inches long) and maggots in the root area (visible when pulled out)

Happen:

  • Flight times: April to October
  • forms several generations
  • Egg-laying on the root neck of radishes

Look:

  • similar to a housefly
  • five to six millimeters in size
  • strong hair
  • Larvae: whitish yellow, about eight millimeters long
Source: AfroBrazilian, Delia radicum 01, edited by Plantopedia, CC BY-SA 4.0

Measures:

  • Nematodes specialized on cabbage fly larvae (application from April to July)
  • Cover with fine-meshed nets (preventively)

defensive plants:

  • Mixed culture of tomatoes and celery

Notice: If a larger number of radishes are affected, you can no longer effectively fight the cabbage fly. Therefore, you should remove the plants with the roots and dispose of them in the household waste.

Large cabbage fly (Delia floralis)

The cabbage fly produces only one generation of larvae in summer in this country. Measures against the more destructive cabbage fly also help against the rarer cabbage fly.

Lesser Cabbage White (Pieris rapae)

damage picture:

  • leaf feeding of the caterpillars

Appear:

  • Flight times of the diurnal butterflies: March to the end of October

Appearance of the butterflies:

  • whitish colored
  • black spot at the tip of the forewings
  • Wingspan: 40 to 55 millimeters

Appearance of the caterpillars:

  • up to 25 millimeters long
  • greenish colored
  • yellow longitudinal lines on sides and back
  • short, dense hair

Measures:

  • Protective nets against moths (mesh size maximum two millimeters)
  • biological pesticide
  • collect caterpillars

Large cabbage weevil or large rape stalk weevil (Ceutorhynchus napi)

damage picture:

  • Eating marks on the leaves (beetles)
  • Mining tunnels in the plant stems (larvae)

Appear:

  • from a ground temperature of six degrees Celsius
  • nocturnal or twilight active beetle
  • Larvae pupate about an inch deep in the soil in late May/early June

Look:

  • beetles three to four millimeters long with large eyes and a proboscis-like extension of the mouth area, kneeling antennae
  • dark or light gray body (covered with gray scales)
  • Larvae: up to 7 mm long, yellowish white with dark head, bristles on top of head capsule

Measures against the larvae:

  • special species of parasitic wasps (Tersilochus fulvipes), ground beetles (Carabidae)

Measures against bugs:

  • Create dark retreats (upside down flower pot, wooden board), collect bugs during the day
  • collect animals at night; Spread a light-colored cloth on the ground (for better recognition of the beetles)
  • Keep soil moist (against egg laying)

Notice: The small or spotted cabbage weevil (Ceutorhynchus pallidactylus), which grows to a maximum of three millimeters, shows a very similar pattern of damage. You can fight him the same way.

Cabbage gall weevil (Ceutorhynchus pleurostigma)

damage picture:

  • Deformations of the root neck (hazelnut-sized "galls" as protective chambers for the larvae)
  • Mining burrows in roots and stem
  • withered leaves

Appear:

  • Egg-laying from April

Look:

  • two to three millimeters long
  • dark brown to black
  • "trunk" extending from the mouth

Measures:

  • remove affected plants

Tip: The galls of the cabbage weevil are often confused with clubroot (fungal infection). However, unlike the beetle's growths, these are not hollow inside.

Spanish slug (Arion vulgaris)

Other names:

  • Nasturtium
  • Large slug
  • Lusitanian slug

damage picture:

  • leaf damage

Appear:

  • from February / March to autumn

Look:

  • fully grown seven to fifteen centimeters long
  • Color highly variable: light brown, orange, reddish, light yellow, dark brown, almost black

Measures:

  • fight with predators: tiger slugs (tiger snail, Limax maximus), Indian runner ducks
  • Slug fences, protective strips (e.g.: copper tape), slug traps
  • Collect

Notice: Snails in the garden cannot be avoided, only reduced.

frequently asked Questions

Can radishes that have been nibbled be eaten?

That depends on the countermeasure. If toxic substances are used, you should refrain from eating radishes that have been eaten.

Can I avoid infestation of weevils with a net?

Plant protection nets do not help against weevils.

Can radishes also be eaten in the greenhouse?

Yes, radishes can also be eaten in the greenhouse. Woodlice, for example, nibble on the red part of the radish when they can't find any other food.

Category:

Vegetable garden