In the rapeseed field, tiny beetles cause serious crop failures. Indoors, rape beetles will target flowering houseplants. Read here how to recognize the pests by their appearance. Tried-and-tested tips and tricks reveal how to get rid of pollen beetles in the home. This is how poison-free control in the garden succeeds.

Rape beetles cause great damage

Table of Contents

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  1. the essentials in brief
  2. Rape beetle appearance
  3. Why Pests?
  4. Get rid of in the house
  5. Fight in the garden
  6. frequently asked Questions

    7. the essentials in brief

    • Oilseed rape beetles are oval, 2 mm small, have a blue, green, black or violet shell with a metallic sheen.
    • Home remedies against rape beetles in the apartment are lemon scent and a yellow trap with water and washing-up liquid.
    • Biological control agents in the garden are rock flour, (14.13€) collecting, shaking off and yellow peeling as well as the predators parasitic wasps (22.99€) and ladybugs.

    What do rape beetles look like?

    Rape beetles (Brassicogethes aeneus) belong to the family of pollen beetles and are usually called pollen beetles. The beetles can be recognized by an oval body with a length of 1.5 to 2.5 millimeters. A metallic, shiny chitin shell that shimmers blue, black, green or violet is striking. The legs and club-shaped antennae are brown.

    Yellowish-white larvae are slender, 4 millimeters long and sport short bristles. Three short, black and brown legs on each side of the body and a brown head characterize the appearance. Rape beetle larvae hatch from milky-white, tiny eggs and molt several times.

    Why are rape beetles harmful?

    Rape beetles are accused of two habits. Menus and family planning nip any sympathy in the bud among farmers, hobby and indoor gardeners. A look at the way of life makes it clear why the shiny mini beetles are assigned to the pests:

    Disastrous propagation strategy

    Rape beetles lay their eggs in buds

    Oilseed rape beetles become active from a cool 10° Celsius soil temperature and leave their winter quarters under a layer of leaves or turf. Famished, the beetles fly to young plants for ample nourishment from leaves, flowers, pollen and nectar. On warm spring days with 18° Celsius and more, mass flights with a plague character are not uncommon. Immediately afterwards, pollen beetles devote themselves to their fatal reproduction strategy in these steps:

    1. Mating females bite a hole in buds
    2. 1 to 6 eggs per bud are laid on stamens and pistils
    3. The larvae hatch within 4 to 7 days
    4. Maturation feeding of larvae on nectar and pollen for 27 to 30 days
    5. Symptoms: eaten, dried up, empty buds, premature flowering, stunted, puny pods

    Adult larvae drop to the ground, burrow two to three centimeters deep and pupate. After about two weeks, the young oilseed rape beetles hatch from their pupa cradle. This process takes place in June, just before or during the rapeseed harvest. The young beetles complete their maturing feeding on various wild and cultivated plants before they go to their winter quarters in August.

    Numerous food and host plants

    Roses are also attacked by rape beetles

    Oilseed rape is the preferred plant, although not the only one, that rape beetles cast a covetous eye on. Cruciferous plants with yellow or white flowers are primarily affected. The following table lists typical useful and ornamental plants that suffer from a plague:

    crops botanical name ornamental plants botanical name wild herbs botanical name
    canola Brassica napus roses pink goose cress Arabis
    turnips Brassica rapa gold lacquer Erysimum suffruticosum White Mustard Sinapis alba
    radish Raphanus raphanistrum scented stone rich Lobularia maritima bittercress Barbarea vulgaris
    radish Raphanus sativus candytuft flowers iberis shepherd's purse Capsella
    vegetable cabbage Brassica oleracea night violets Hesperis Schöterich erysimum

    The actual damage is caused by adult oilseed rape beetles when they eat the buds in spring or bite holes in the bottom of the buds. Larvae only feed on pollen and nectar, which does not seriously damage the affected plants.

    tips

    Yellow panels are useless for the purpose of determining infestation and combating pollen beetle. The beetles are attracted by the bright yellow color. In contrast to cherry fruit flies and other pests, oilseed rape beetles do not stick to the special glue with their chitin armour. For this purpose there are extra yellow bowls with a close-meshed grid as a cover so that bees and other insects do not fall in.

    What to do against rape beetles in the house?

    Rape beetles are stubborn fellows who don't like to be chased away. The beetles often get into the house well hidden in the bunch of wild flowers you have picked yourself. If you have discovered pollen beetles in the apartment, you do not have to tolerate the uninvited guests. The following two home remedies have proven to be effective for fighting without poison. How to get rid of oilseed rape beetles indoors:

    lemon scent

    The persistent research of experienced entomologists (insectologists) is to be owed the knowledge that a lemony scent can repel oilseed rape beetles. The following home remedies drive away the pests never to be seen again:

    • lemongrass
    • lemon slices
    • Bowls filled with lemon juice
    • Citronella products, such as soap, candles, scented oil

    A positive side effect: other nuisances and pests in the house, such as ants, spiders or mosquitoes, run away from the lemon scent.

    The following video impressively demonstrates why lemon scent has a deterrent effect on oilseed rape beetles:

    youtube

    Make your own rape beetle trap

    Their fondness for the color yellow becomes the fate of rape beetles when a self-made trap is used. The trap is copied from the yellow shell that farmers use to determine infestation in the rapeseed field. Take a yellow bowl, either plastic or glass. Fill the bowl halfway with water and add a drop of dish soap to break surface tension. If you place the trap near infested plants, the beetles cannot resist the lure for long and fall into the water and drown.

    What helps against rape beetles in the garden?

    The manual removal of rape beetles is tedious but effective

    Rape beetles don't mind if there is no rape growing in the garden. If the favorite plant isn't available, the beetles immediately set their sights on useful plants and beautiful flowers. Primarily cruciferous plants, in particular types of cabbage, are very popular with the pests as a source of food and nursery. Rape beetles unscrupulously feed on rose petals in the flower bed. Insecticides are not approved for the home garden and do not achieve any significant results anyway. What really helps against oilseed rape beetles in the garden is summarized in the following overview:

    • collect: early in the morning, pick off the rigid rape beetles with two fingers
    • Shake off: Spread out the foil and shake off crawling beetles
    • rock flour: lightly dust infested plants with rock dust
    • engage predators: birds, parasitic wasps, ladybugs

    A straw mulch layer reflects the sun's rays and irritates approaching pollen beetles. The effectiveness of vegetable oil solutions as a natural control agent is the subject of heated debate in private allotment gardens. Buds sprayed with oil-water stick together, making it difficult for them to open. The milk of lime propagated as a control agent in some instructions is tricky to use because it is lime dissolved in water, which is primarily used as a wall paint and has no place in a natural garden.

    digression

    Attract parasitic wasps - end the rape beetle plague

    Ichneumon wasps are a miracle weapon in the fight against oilseed rape beetles

    Ichneumon wasps are the secret heroes in the fight against a plague of oilseed rape beetles. The filigree insects parasitize the larvae and reduce the infestation pressure in fields and beds by up to 50 percent. So far, nine species of parasitic wasps are known in Europe that help farmers and hobby gardeners to combat pollen beetle. In order for the beneficial insects to find their way into your garden, it is important to consistently avoid using all kinds of pesticides. Umbelliferous plants invite parasitic wasps to linger, such as parsley, fennel, carrots or hogweed. The delicate natural beauties cannot resist a home-made insect hotel (€11.33).

    frequently asked Questions

    How to get rid of rape beetles in the apartment?

    Lemon scents have proven to be effective in driving rape beetles out of the home. Lay out lemon slices, add lemon juice to the cleaning water or put lemongrass in the house and rape beetles will flee. A tried-and-tested household remedy against rape beetles in the home is yellow bowls that you fill with water and a drop of washing-up liquid.

    How long do rape beetles live?

    As a rule, rape beetles live for about 14 months. Rape beetles spend the winter in leaf litter and loose layers of soil once in their lives. In early spring, the beetles leave their winter quarters and first devote themselves to ripening rape and spring flowers. Mating females soon lay their eggs in buds and flowers. Once a lady beetle has laid her 250 to 400 eggs, her life is coming to an end.

    Can rape beetles bite?

    Oilseed rape beetles have powerful mouthparts for feeding and laying eggs in buds. Considering a body size of 2 millimeters, the teeth are tiny. For a bite into delicate blossoms and young leaves, the biting teeth are enough. The attempt to bite human skin is of course doomed to failure for the rape beetle.

    What helps against a rape beetle plague in the rose garden?

    If hordes of rape beetles invade the rose garden, we recommend an XXL version of the yellow trap, which has proven itself well in the apartment. Buy one yellow bucket for every 10 to 20 square meters of infested area. Fill this bucket two-thirds full with water and one to two tablespoons of dish soap. Cover each bucket with a close mesh (8mm x 8mm) to prevent bees from falling into it. Rape beetles are attracted by the yellow color and sink into the water because the detergent breaks the surface tension. Replace dirty water.

    Can rape beetles fly?

    Yes, oilseed rape beetles have a well-developed flight apparatus. The shiny metallic chitin armor protects transparent wings that carry a pollen beetle up to 3 kilometers through the air. This is one of the main reasons why home gardens near rapeseed fields often have to deal with a beetle plague in vegetable and rose beds.

    tips

    Seven-spot ladybirds (Coccinella septempunctata) like to eat rape beetle larvae. Have there been too few of the red ladybirds with the distinctive spots in your garden? Then you can increase the population of beneficial insects and breed ladybugs yourself. Breeding farms and specialist dealers offer complete breeding sets with eggs or ladybird larvae.

Category:

Animals in the garden