- IOR – PIB, after inspecting winter rapeseed plantations in Winna Góra, warns against the pressure of autumn pests.
- After exceeding the economic harmfulness threshold, chemical treatment is recommended, which in this situation is a treatment that saves the stock or plants from losing the assimilation surface and vigour.
High temperatures and windless weather are ideal conditions for pest invasions. Yellow vessels exposed in rapeseed are filled with various species, and various damages appear on rapeseed leaves. Most often, these are holes, scraped-off pulp, and even bark. However, these are not the only symptoms of pest feeding. Aphids, for example, carry viruses, and cabbage root fly larvae destroy rapeseed roots. Daily inspections will help detect the threat in time. What species of pests are already present in rapeseed fields?
A bonehead can lead to a dead end
As reported by IOR-PIB in its phytosanitary communications, larvae of the rapeseed beetle have been observed on the underside of the leaf blade of many winter rapeseed plants.
– Monitoring for the presence of this pest should be carried out from the emergence of winter rapeseed plants, because the larvae are very voracious and, if present in large numbers, can destroy an entire plantation within a few days. Young larvae bite small holes, while older ones eat entire leaves, leaving bare leaves – advises IOR-PIB.
IMG_7615.jpeg Rapeseed beetle on mustard in catch crop Photo AK
Currently, in intercrop crops, especially mustard, one can find plantations completely infested with the larvae of this pest.
We would like to remind you that the economic damage threshold for the rapeseed beetle is:
- emergence period (BBCH scale 10-12) – on average 1 larva per 1 winter rapeseed plant;
- late spring (June) – on average 4 larvae per 1 spring rapeseed plant.
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What treatments should be used in the 4-6 leaf phase of rapeseed?
Flea beetles and the diamondback dandelion are making holes in the leaves
Damage caused by flea beetles and diamondback moth caterpillars was observed on many winter rapeseed plants.
Symptoms of rapeseed flea beetle feeding include visible holes chewed on the cotyledons and leaves.
– The feeding of larvae of this pest in petioles, leaf veins and shoots of winter rape plants is more harmful than the feeding of beetles. Damaged plants freeze more easily in winter – informs IOR-PIB in Poznań.
The economic damage threshold for the rapeseed flea beetle is 3 beetles per 1 linear meter of plant row or 1-2 larvae per 1 plant.
The harmful stage of the diamondback moth are the larvae, which feed on the leaf blades, gnawing away the pulp, leaving the upper or lower skin.
Economic damage threshold: on average 1 caterpillar per plant (BBCH scale 13-19).
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When to regulate rapeseed and in what doses?
Aphids establish colonies. There are also whiteflies
Hemiptera also appear. They suck plant juices, weakening the plants' vigor. Indirect damage is related to the transmission of viruses, e.g. turnip yellows virus.
– Both winged and non-winged forms of aphids were observed on the underside of the leaf blade – reports IOR-PIB in Poznań.
Economic damage threshold: aphids – vectors, first individuals noticed in autumn.
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When to apply boron in rapeseed?
Slugs are still a threat
In areas with more rainfall and where soils are compact, clayey, snails are still a problem. Like the gnathus, they cause extensive damage to the leaf blade, including defoliation. Traces of slime will indicate their presence.
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Slugs in rapeseed will be a big problem. How to combat them?
The grasshopper flies and lays eggs
A major threat at this stage is cabbage leaf miner. The flies of the 3rd generation are already flying around, threatening young rapeseed plants. They lay eggs, the larvae hatch, which damage the root system. As a result, this important organ becomes under-productive, which takes its toll practically until the end of the rapeseed vegetation.
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Cabbage fly is already attacking rapeseed