Diseases and pests of cruciferous vegetables
Young seedlings are affected by a fungal disease called brassica seedlings or the black leg. It is manifested by browning and narrowing of the root neck and the ground part of the stem. Plants fall over and die. This disease is most common in frames, in which plants grow too densely and are not sufficiently ventilated. Sick plants should not be planted, for they will soon die.
Also, downy mildew of brassica is present on seedlings, which can also infect older plants. It is a fungal disease, which we can recognize from the gray fluffy coating on the underside of young leaves. More severely infected leaves curl and dry up.
Serious illness, mainly attacking the cabbage, kohlrabi and cauliflower, as well as turnips and swede, there is cabbage syphilis. This disease occurs on the roots of older plants in the form of numerous tumors of various sizes, initially hard and lightly colored, then darkening and rotting. The plant withers and dies.
At various stages of development, cabbage can be attacked by a disease called vascular bacteriosis (black bacterial rot). It manifests as yellow spots on the leaves, rapidly darkening and drying out and blackening of the leaf veins and stems. A dark ring can be seen on the cut petiole or stem, from which drops of mucus are released, containing bacteria. Infested plants turn yellow and die.
In order to avoid and combat the diseases mentioned above, it is necessary to:
– apply crop rotation of cruciferous crops yes, lest they follow each other and other members of the cruciferous family more often than what 4-5 years in the same field;
– liming the soil (15-20 kg of quicklime per 100 m2) in order to prevent its acidification;
– carefully destroy crop residues, remove noodles (under no circumstances should you dig them);
– perform thermal or chemical disinfection of seed boxes, inspects, land used for sowing and quilting;
– dress the seeds before sowing with seed dressing T. (4 kg in 1 kg of seeds) or hot water against blackleg and bacteriosis;
– do not compact the sowing and protect it against weed infestation;
– spray the seedling from time, when the plants will have 2-3 leaves, 2-3 times what 7-10 days with fungicides.
The most dangerous pests of cruciferous seedlings are earth fleas. They gnaw holes in the leaves, and with a mass occurrence, they can completely destroy the seedling. They are tiny beetles, which fleeing scared, they jump high like fleas. Adult insects hibernate under plant debris or stones. Immediately after noticing the pests, catch them using a trap made of a piece of plywood painted on both sides with orchard glue or any kind of slow-drying glue.. In the event of a large pest infestation, the plants are sprayed with preparations: Determined 2,5 EC – 0,05% or Gardon 24 EC – 0,3%.
In addition to fleas, cruciferous fish have numerous enemies, which cause serious damage to their crops, especially if the change and careful tidying up of our garden are not followed. Common ones include those listed below.
Cabbage cream. It is an insect similar to our housefly. In the spring, it lays several eggs at the root of the cabbage or early cauliflower. The eggs hatch white, legless larvae, which penetrate the roots and the stem. Affected plants wilt initially, and then they wither away. Chemical control of this pest consists in treating the roots of seedlings in an aqueous suspension of Primicid 30 DP immediately before planting. One liter of water is equal to 30 g of the preparation and mix thoroughly. Plants are immersed in the liquid up to the root collar, then plants.
Cabbage aphid is dangerous to varieties of medium early and late cruciferous vegetables. The first symptom of the presence of a pest on a plant is the discoloration of the leaf, a little later, the leaves with the aphids are twisted in a spoonful, and inside they are greenish, aphids covered with gray waxy coating. With a small number of plants, you can destroy the aphids by hand with more – is sprayed with Pirimor 50 DP in concentration 0,05% with the addition of Jorovit moisturizer 2 w 10-14 days from the moment you notice the first aphids on the plant.
The cruciferous mantis is a butterfly, whose caterpillars initially bite on the leaves of the so-called. windows, formed by eating the lower leaf skin and crumb without disturbing the upper skin; later you can see the little ones, irregular buttonholes. The caterpillars are small (do 1 2 mm in length), light green; first generation foraging in June, the second – at the end of July and in August, and the third – in August and September. When growing a few plants, it is enough to harvest them by hand. With greater occurrence, starting at the end of May, if we spot the first caterpillars of this, as well as other pests, preferably sprayed with bacterial preparations: Bactospeine Garden -0,5%, Bactospeine WP 16000 -0,1% with the addition of Jorovit moisturizer 2 or chemical preparations: Determined 2,5 EC – 0,05% or Gardon 24 EC – 0,3%
White cabbage plant is the most dangerous pest of cruciferous plants, widely known. There are two generations of this butterfly in Poland, the second of which is much more numerous, foraging for quite a long time (15-30) in July and August. Caterpillars bluish green with numerous black spots grow up to 4 cm in length. They are fought in the same way as the crucian mantis.
Bielinek rzepnik – caterpillars of this species, unlike cabbage moth, they forage one by one, causing similar damage.
Older caterpillars bite into the heads of cabbage and cauliflower roses, additionally polluting them. They are intensely green, velvety, with three longitudinal yellowish stripes on the back. They grow up to 3 cm in length. They are controlled similarly to the caterpillars of the previously described pests.
Cabbage pie – caterpillars of this butterfly, length approx 5 cm, of different color: from gray-green through brown to black (on the dorsal side of the body they have two yellowish stripes running longitudinally and yellow transverse stripes), initially they bite small on the leaves, irregular holes (then they are still tiny and green), and then bite deep into the heads or roses of the cauliflower, contaminating the gnawed pavements with faeces. Caterpillars of the first generation forage in late June and July, second generation – in August and September. Therefore, starting from mid-June, the plants should be systematically inspected and the caterpillars destroyed, and in the case of greater infestation, spray with preparations: Determined 2,5 EC – 0,05% or Gardon 24 EC – 0,3%.