Butterflies Are Cabbage Pests

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

How to deal with butterflies - cabbage pests

Many types of cabbage can be damaged during the growing season. Among them are cruciferous bugs, rape sawfly, polyphagous pests (slugs, meadow moth, gamma scoop and others). But now we will focus on cabbage phytophages - butterflies: cabbage and turnip whites, cabbage scoop.

Cabbage white (cabbage)

Caterpillar of the white-headed cabbage

The butterfly is widespread and is probably familiar to every gardener under the name "cabbage". In size, these are rather large butterflies with white wings. At the apex of the front pair of their wings, there is a black wide crescent-shaped border. In addition, the female has two black rounded spots on them, which the male has only on the lower pair of wings.

The beginning of the departure of butterflies falls on 2-3 decades of May. They fly during the daytime (most active on sunny and hot days). Their greatest number is observed from mid-summer to late autumn.

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Butterflies feed on the nectar of flowers of various plants, but still give preference to cruciferous plants (both cultivated and wild). Some time after emergence, females begin to lay eggs on the leaves of cabbage and weeds (rape, wild radish, etc.).

Females place in piles on the underside of the leaves, bottle-shaped, yellow eggs, clearly visible to the naked eye. Caterpillars harm plants. The first time after hatching, they are grouped together, later they spread out. While moving through the leaves, the caterpillar makes a path of silk for itself, so it is difficult to remove or shake it off the leaf, firmly attached to this path and the head of cabbage.

The caterpillars of the cabbage whites have a special cervical gland that secretes a rather caustic liquid substance that can cause not only allergies in the form of redness on the hands, but even burns (hands swell). Adult caterpillars are yellowish-green in color with transverse rows of black dots and a light stripe along the back, with yellow stripes on the sides, with a black head, up to 4 cm long; their body is covered with bristles and hairs. They eat the leaves roughly, usually from the edges.

Caterpillar of the white-headed cabbage

With a high number, they can eat up all the pulp of the leaf, leaving only thick veins and eliminate the cabbage head in 2-3 days. Having finished feeding, the caterpillars crawl onto the walls of houses and fences, the trunks of trees and bushes, where they pupate. Young butterflies appear in two weeks.

They cause the greatest damage to cabbage in the second half of summer. Pupae overwinter on fences, walls of buildings, tree trunks, on bushes, etc.

Fungal and bacterial diseases of caterpillars and pupae play an important role in the decrease in the number of cabbage. The reproduction of this pest is also restrained by parasitic insects, which are attracted to the garden by the odorous substances of such plants (dill, various honey plants and nectar plants). Of greatest importance in the destruction of caterpillars is the parasite-rider apanteles, which sometimes lays up to several dozen eggs in the body of each caterpillar.

Hatching from them, its larvae feed on the tissues of the host caterpillar. In some years, it is capable of infecting more than half of the cabbage caterpillars. Experts advise to leave riders' cocoons (ovoid yellow, silky, about 4 mm long), which are located around the dying caterpillars when manually collecting pest caterpillars.

Cabbage also damages rutabagas, radishes, turnips and other crucifers, does not neglect nasturtium, mignonette.

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Turnip white butterfly (turnip)

Repnitsa is very similar to "cabbage", but it is smaller. The female "repnitsa" has two black spots on the front wings, and the male has one. The hindwings are white dorsally with a black spot on the anterior margin, yellowish beneath.

The biology of turnip and cabbage whites is approximately the same. Their difference is manifested in the fact that the first-generation moth usually lays eggs on cruciferous weeds, but the hatching larvae soon move to cabbage plants. They eat its leaves, often climbing into the head of cabbage. The next 2-3 generations of the pest feed on cabbage until late autumn. Measures to combat the turnip are the same as with the cabbage.

Cabbage scoop

Cabbage scoop

A ubiquitous species (damages over 70 plant species), although it is less known to gardeners than "cabbage". It hibernates pupae (2.5 cm, brown, with two spines) in the soil at a depth of 9-12 cm. The butterfly appears in about the 3rd decade of May.

The wingspan of the cabbage scoop reaches 5 cm, its front wings are grayish-brown with a yellowish-white wavy line and two dark spots at the front edge, the hind wings are dark gray. She flies at night, and during the day she hides in various secluded places (in the grass, under leaves, in buildings).

Butterflies of the cabbage scoop are very fertile, they lay eggs in heaps on the underside of cabbage leaves - hemispherical, ribbed, yellow. Having hatched, the caterpillars are first located in groups and eat away the pulp from the underside of the leaf, then colonize the entire plant. Adult caterpillars are greenish-brown with a wide longitudinal yellowish stripe on the sides, up to 5 cm long. Adult caterpillars are characterized by high voracity and eat through holes in leaves.

In a tied head of cabbage, they gnaw through the passages and pollute it with excrement: such heads of cabbage quickly rot, become unsuitable for human consumption and are not suitable for long-term storage. Older caterpillars (there are 6 instars in total in the cabbage scoop) penetrate the head of cabbage. Damage to cabbage by this pest in some years reaches 25-40%. In our zone, this pest gives one generation. In addition to cruciferous crops, the cabbage scoop also damages peas, beets, onions, lettuce, rapeseed, sunflowers and other plants.

Pest control measures

To get away from active colonization of plants, it is better to plant cabbage seedlings early. You should also carefully destroy weeds. At the time of summer, butterflies are caught for molasses and beer wort, poured into the bottom of cans; attracted to bonfires. This procedure is carried out early in the morning or in the afternoon in cloudy weather. To reduce the harmfulness of the pest, after harvesting the cabbage, the soil is well dug up with subsequent harrowing.

The easiest way to deal with caterpillars is manual collection by examining the cabbage leaves from the bottom (every 3-4 days) from the beginning of the appearance of the butterflies themselves in the gardens and the destruction of the laid eggs, as well as young caterpillars, especially while they stick together and have not climbed deep into the heads of cabbage … Carefully look through all the leaves of the cabbage, since it is much more difficult to collect adult caterpillars when they spread throughout the plant.

More than once I had to make sure that many gardeners cannot determine exactly where the pest is hiding (especially if it moves through the plant). As a rule, each caterpillar, feeding, leaves behind light green (fresh) excrement, which turns brown after 2-3 days, depending on the air temperature. Therefore, when light green excrement is found, they begin to carefully examine the leaf surface next to these excretions, not neglecting large ("old", almost lying on the ground) leaves. And if they do not find it there, then they carefully begin, without breaking, to unfold the leaves close to the coverts. Please note: if the excrement is fresh, then somewhere on the plant the caterpillar is sure to hide, and you must find it by all means.

After finding the pest, wash off these excrements with water from the watering can on the ground: you will water the plant, and you will wash away the dirty waste from the caterpillar from the head of cabbage. But the next time you inspect the cabbage, you will already know for sure by fresh excrement whether a new caterpillar has appeared on the plant.

Sometimes a rather troublesome way of dealing with cabbage is advised - to lay brushwood near cabbage plantings during pupation of caterpillars. Then the bundles of brushwood, into which the caterpillars are willingly taken, are recommended to be collected and burned after pupation.

Against young cabbage larvae, some gardeners advise sprinkling cabbage heads with a solution of lime and salt (3 parts of salt and 2 parts of lime are taken for 100 parts of water). From biological products against caterpillars of younger (1-2) ages of each pest generation, Lepidocid, Bitoxibacillin, SP (4-5 g per 1 liter of water at a flow rate of 0.5-1 liters per 10 m2), Fitoverm (4 ml per 1 liter) can be recommended water) - 3-4 treatments with an interval of 7-8 days.

With a high population of cabbage with caterpillars of these species of butterflies, they use double treatment (after 10-12 days) with solutions of chemical preparations - 25% Arrivo, EC, 25% Cymbush, EC, 5% Kinmins, EC, 10% Fury, EC and others - this will be more effective.

For better adhesion of the drug, add 20 g of soap per 10 liters of this solution. But it should be taken into account that microbiological and chemical preparations act on older caterpillars much weaker than on younger ones. The leaf surface of plants should be sprayed not only from above, but also from below, since the caterpillars often parasitize on the lower side, hiding from direct sunlight. Cabbage treatments are calculated in such a way that the required waiting time before cutting the cabbage is observed. If you have to spray shortly before harvesting, you should use rapidly decomposing (biological) products.