Cabbage flies are among the most important pests of cruciferous vegetables such as oilseed rape and cabbage. They can visit their home garden if they find suitable food plants for their larvae there. Since it is difficult to combat, you should take appropriate measures to prevent an infestation.

The cabbage fly is one of the few pests that attack cabbage plants

Table of Contents

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  1. the essentials in brief
  2. Control cabbage fly biologically
  3. detect damage
  4. prevent infestation
  5. Overview of species
  6. frequently asked Questions

    7. the essentials in brief

    • Cabbage fly larvae feed on plant tissue where they are well protected from pesticides. Affected plants should be discarded. Beneficial insects prevent the hatched larvae from burrowing into the root neck.
    • Larvae leave burrows in various cabbage plants in which droppings and food crumbs are present. Over time, affected plants will wilt and eventually die.
    • Infestation can be prevented by thorough tillage, mixed cultures and crop protection nets. Two species can appear in the garden: the greater cabbage fly is less harmful than the lesser cabbage fly.

    Can I fight cabbage flies with home remedies?

    In most cases, the infestation is only discovered when it is too late for treatment

    If the vegetables are eating cabbage fly infested, you should dig up the affected plants and examine the extent of the damage. If the infestation is in the early stages, you can collect the maggots from the roots and replant the plant. If the stem tissue has already partially died off, the only solution is to completely dispose of the plant.

    To prevent further spread:

    • no composting
    • Compost offers cabbage fly larvae optimal living conditions
    • Disposal of infested plant parts in household waste

    Natural regulation by beneficial insects

    The natural enemies of the cabbage fly include predatory insects such as ground beetles and spiders. The rove beetles of the genus Aleochara parasitize the pupae of the flower flies, while the parasitic wasp Trybliographa rapae preys on the larvae. It is therefore advisable to plant species-rich border biotopes to promote such beneficial insects.

    create a fringe biotope

    Sow the seed mixtures in autumn on a finely crumbly seedbed. The seeds are incorporated lightly so that they are no more than 1.5 centimeters covered by the substrate. Light and dark germs find favorable germination conditions at this sowing depth. To increase the germination rate, you can press the seeds with a board. Avoid fertilizing to suppress unwanted and competitive weeds. In the first two years you should weed spontaneous weeds such as thistle, sorrel and couch grass.

    Beneficiaries feel at home here:

    • Mixture as 50 to 60 percent crest, sedge and upright brome
    • a maximum of two percent of legumes such as clover and sweet peas
    • Corn poppy, field larkspur, corn radish and cornflower as showy flowering annuals
    • biennial pioneer species such as evening primrose, wild carrot, viper's bugloss and white campion

    Do pesticides help?

    Cabbage flies are among the mining insects. Their larvae eat into the plant tissue, where they are well protected from pesticides. Even in commercial horticulture, combating the plant pest is difficult because the larvae are not affected by the toxins.

    This is how you can recognize the harmful symptoms of the cabbage fly

    In spring, the infestation often extends beyond the edge rows. This first generation does the most damage. Seedlings that grow between March and May until the first pair of leaves develop are at risk. As the season progresses, the pests penetrate into the interior of the crop.

    • Feeding tunnels in the root neck, stems and cotyledons
    • Food crumbs and droppings in the corridors
    • Plants wither and rot
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    affected plants

    Cabbage fly maggots cause damage to cabbage plants that grow close to the ground. Cauliflower is particularly susceptible. The insects are considered dangerous pests on oilseed rape. In the private garden, they are guided by the seasonal availability of various food plants. While fast-growing vegetables such as radishes are attacked by the first generation from April, the second generation feeds primarily on Chinese cabbage, but also radish and kohlrabi in midsummer. In autumn, late-ripening species such as Brussels sprouts and swedes are on the menu for the third generation.

    Combating the cabbage fly larvae that minate is extremely difficult.

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    This is how cabbage flies reproduce

    Females orientate themselves with the help of their senses. They use visual stimuli or scents to find a suitable place to lay their eggs. Pressed swede juice or the mustard oil glycoside sinigrin have a strong attraction. The female takes a close look at the potential food plant, first crawling on the leaves and then down the stem to the ground. The eggs are laid on the root neck.
    • oval eggs are about a millimeter long
    • about 100 eggs are produced per female
    • first maggots hatch after four to eight days
    • bore into the root neck and penetrate to the root
    • Feeding activity extends over three to four weeks

    This is how you prevent an infestation

    Wood ash spoils the appetite of cabbage flies

    Since there are no pesticides for private use and the effectiveness of home remedies quickly reaches their limits, you should counteract the spread of the plant pest through optimal gardening. Thorough tillage is a must before each sowing. After the harvest, no stalks or leaves should remain on the bed, as cabbage flies prefer to overwinter here.

    • Early and late sowing avoids the main flight time of flower flies
    • Place wood ash in the planting hole and sprinkle on the soil
    • Sprinkle rock flour (€14.13) around the root neck
    • Spread a mulch layer of fern leaves
    • vegetable fertilizers increase the attractiveness of the soil for females

    Ecological balance through mixed culture

    An important measure to prevent pest infestation are mixed seeds in which opponents appear naturally. Tomatoes and celery are good partners for cabbage plants, as their intense scent keeps cabbage flies at bay.

    suitable partners unsuitable neighbors
    canola Clover, vetch, grain pea mustard
    radish carrot, parsley Cucumbers, Chinese cabbage
    cauliflower Phacelia, bush beans garlic, onions
    Chinese cabbage Spinach, beans, lettuce radish, radish
    Kohlrabi Borage, dill, leek, black salsify cabbage
    radish Nasturtium, spinach, lettuce Chinese cabbage, cucumbers

    Protect crops with a net

    Since cabbage flies fly into a plant stand, a protective net is considered the safest method to ward off the pests. It should be particularly tightly meshed so that the flies, which can be up to five millimeters in size, cannot access the food plants. The crop protection nets ideally have a mesh size of 1.8 millimeters. They are stretched over the bed immediately after sowing susceptible species and remain there until harvest.

    tips

    There are special cabbage collars that are placed around the stems of the young plants. They prevent cabbage flies from laying their eggs on the root neck. Made of felt or cardboard, the collars are removed and composted just before harvest.

    What types of cabbage flies are there?

    The small cabbage fly actually looks harmless

    Cabbage flies belong to the genus Delia within the flower fly family. Well-known pests are small and large cabbage flies. While the cabbage fly is active from April, the cabbage fly (Delia floralis) only flies between August and September. It produces one generation per year and is therefore less harmful than the related species. Delia floralis mainly uses radish and radish as host plants.

    Look

    The small cabbage fly is reminiscent of a miniature version of the house fly. It grows up to five millimeters long and feeds on nectar and pollen. Their larvae develop near the roots. They are white in color, legless and headless. Their pupae appear brown and barrel-shaped. They are found in the ground and are carried away by ants.

    tips

    The predatory nematode species Steinernema feltiae is considered an effective regulator of root fly larvae. So far, however, the beneficial insect has hardly been used against cabbage flies.

    way of life

    The first generation of cabbage fly hatches in spring. The chestnut blossom, which takes place in the Palatinate at the end of April, serves as a guide. In such mild regions, three to four generations can hatch per season. Egg development is favored by warm temperatures under foil and fleece.

    • April: oviposition
    • May to June: Larvae hatch, feed and pupate after two to three weeks
    • July: oviposition
    • July to August: Development of the second maggot generation
    • September: oviposition
    • September to October: Third generation larvae hatch and leave feeding damage until pupation

    frequently asked Questions

    Are there white cabbage flies?

    Adult cabbage flies are not white in color. Their appearance is reminiscent of the appearance of a housefly. Their larvae do not live under the leaves but in secret and are only visible when you pull infested plants out of the ground. If you spot whiteflies on the plants, they are probably whiteflies.

    Risk of confusion:

    • Whitefly: white flies on the underside of the leaf, fly up when touched
    • Cabbage White: first lays greenish and later yellow eggs on the underside of leaves
    • cabbage moth: green caterpillars eat leaves
    • Mealy cabbage aphid: powdered aphids suck on the underside of leaves

    Why do cabbage flies attack cabbage plants?

    These insects have specialized in cabbage plants, because here they compete with a few food specialists. Many cruciferous vegetables contain mustard oil glycosides, which have antibacterial and antimicrobial effects. This protects plants from potential predators, but cabbage flies can digest the substances.

    What harm can cabbage flies do?

    Because of the high reproduction rate and rapid development, the cabbage fly is one of the most dangerous pests on oilseed rape. She is capable of completely destroying a crop. Since the flies are extremely mobile, they are hardly affected by insecticides. Their larvae develop protected in the root tissue. Since the largest plants are more heavily infected than less developed plants, early sowing shows a greater infestation than late sowing.

    Do plant manure made from garlic or nettle help against cabbage flies?

    Plant brews are used to strengthen weakened plants. Since cabbage fly larvae prefer to burrow into vigorously growing plants, self-made manure does not provide reliable protection against infestation. Because of their intense smell, brews can be administered as a support.

Category:

Animals in the garden