More and more frequent beet aphid attacks are observed on sugar beet plantations, including extensive colonies of these pests. The leaves are twisted and the beetroot loses vigor.
- There are more and more aphids on sugar beet plantations.
- We recommend inspecting the plantation and, after exceeding the economic harmfulness threshold, carrying out a protection treatment.
Aphids in beets always portend problems. First, the so-called raids are recorded. migrants (winged aphids). They establish numerous colonies. Each individual, whether a larval or an adult, sucks sap from plants, weakening them.
There are more and more aphids, which is favored by the weather (moderately warm and no rain). In such conditions, they multiply quickly. In the center of the country, on some plantations, virtually all sugar beet plants are infested with the pest.
The leaves are curled, notched, and characteristic black pests are visible underneath. Ants and ladybugs often appear nearby. The former are attracted by honeydew, the latter are a natural enemy of aphids and they eagerly feed on such colonies.
Damage caused by the feeding of beet aphid
Two types of damage can be indicated, as experts from Pfeifer&Langen remind us in a message addressed to sugar beet growers: These are damages:
- direct – resulting from puncturing the leaves and sucking out plant juices, which results in reduced growth, deformation and yellowing of the leaves. Plantations over-fertilized with nitrogen are particularly susceptible to damage. Long-term severe damage to young plants may result in a yield reduction of over 30%.
- indirect – resulting from the transmission of viruses causing plant diseases, e.g. necrotic beetroot yellowspot or mild beetroot yellows. Moreover, sooty molds grow on the honeydew produced by aphids, limiting access to light and thus photosynthesis.
The harmful threshold for beet aphid is at least 15% of inhabited plants or 15 non-winged aphids/plant. In order to prevent viral diseases, the first winged aphids should be combated.
The effectiveness of the treatment is important
Aphids are not easy to control because they live on the underside of leaves. Contract agents (e.g. pyrethroids) do not have a satisfactory effect on numerous colonies. Systemic measures dedicated to combating aphids in sugar beet cultivation must be used. It can be administered with the addition of an adjuvant dedicated to insecticides.
However, be careful with tank mixtures. The use of systemic agents in mixtures with herbicides, fungicides and foliar fertilizers may reduce the effectiveness of the treatment. Therefore, it is best to use the insecticide alone. How to combat aphids? We have already written about this in previous articles:
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