Viruses will also reduce the yield of winter wheat

Wirusy ograniczą także plon pszenicy ozimej

Winter crops are heavily infected with viral diseases not only in barley plantations, but also in wheat.
Infected wheat produces much lower yields and is also thinned out.

Early wheat sowings were very vulnerable to viruses

We reported on the virus infection of numerous winter wheat plantations in March and April. This year's season is unique in this respect, as such a large infection in winter crops has never been recorded before. Especially since we are talking about a high level of viral infections not only in winter barley, but also in wheat. This is not new, although the scale is surprising, because infected plantations are not isolated phenomena.

While in the case of winter barley, severe symptoms of infection were observed already at the beginning of spring, in the case of wheat, the infection could initially be inconspicuous. Or in other words – damage to the site or weaker plants were observed, but it seemed, at least at the beginning, that the problem was, among others, on the side of soil deficiencies.

Certainly, the higher risk of virus infection in winter wheat is influenced by, among others, sowing date. In the ongoing 2023/2024 season, many winter wheat plantations were established already in the second half of September. And considering the course of autumn, it was a very early date. Aphids attacked plantations for an exceptionally long time, from the earliest development stages. Meanwhile, few plantations were protected with insecticides. Viral diseases, such as wheat dwarf virus, are also transmitted by leafhoppers. With such early sowing dates in the coming season, there will probably be a need to protect against pests. It is their high pressure that contributes to the level of virus infection. And in fact, only such prevention – protection with insecticides in autumn – allows us to avoid infection.

Why can you suspect virus infection in some plantations?

If the wheat was discolored at the beginning of spring (towards red and orange shades), we can assume with a high degree of certainty that the virus appeared on the plantation. However, confirmation of any assumptions is only possible based on tests performed in the laboratory.

Significant thinning of the canopy may also indicate virus infection. Some of the plants "fell out" and stopped their development at the beginning of spring. Those that survived, but were infected at least to some extent (lower virus concentration) may mature prematurely. There we will notice ears that are much more mature than healthy plants, they are exposed to, among others, to a greater extent to blackening. Additionally, at first glance, the grain is of lower quality and is often severely wrinkled. The ear itself is weak.

Let us add that it could happen that more than one virus appears on the plantation – it is not uncommon to have a specific combination of various factors resembling infection with them. Remember that wheat may also be affected by BYDV (barley yellow dwarf virus) and more.

The virus itself is destroying plantations, but the drought has helped

The virus infection itself reduces yields, and droughts, frosts, etc. they additionally enhance the effect of paralysis. It is difficult to determine the degree of yield reduction. The research results are not clear, but there is at least a 10% reduction in the case of minor paralysis. However, with a strong infection, losses may exceed even 30% in the case of wheat dwarf virus infection. However, at the moment it will be difficult to determine to what extent the virus contributed to the reduction in yields and how much to drought. Both phenomena are directly related. The lack of water intensified the virus infection, and the virus itself significantly reduced the plant's tolerance to even short-term water shortages. It happens that in case of a strong infection, the plants die completely (after the previous symptoms in early spring), although a smaller infection reduces the yield (due to much worse grain, ear and thinning of the plantation), but this is not the case with wheat.