In the following voivodeships: West Pomerania, Greater Poland, Lower Silesia, Warmia-Masuria and Masovia, numerous populations of slugs have been recorded. Their development is favored by heavy rainfall, which causes high humidity in crops for a long time.
- Farmers report more and more slug sightings. They damage many plants.
- They can be combated with molluscicides. However, you should pay attention to the label of approved products.
What species of snails became active after the rainfall?
As reported by IOR-PIB in Poznań, the currently active species include: common slug (Arion vulgaris), great snail (Arion rufus) and spotted slug (Deroceras reticulatum). All three begin their activity after dusk and feed mainly at night. They may be periodically active during the day, at temperatures from 6°C to 20°C, at high air humidity and after rainfall.
Which crops are they dangerous to now?
Snail feeding is dangerous for young plants, as it can lead to rot. Therefore, they can currently cause damage to, among others, cucumbers, tomatoes, spinach, beetroot, radishes and potatoes (they can also damage tubers). These pests also willingly feed on fruit crops, in particular on currants, strawberries and raspberries. The smell of the fruit can be felt by snails even from several dozen meters away. Snails bite holes in the fruit or eat it whole. Mucus and feces left on plants by snails contribute to the development of many fungal, bacterial and viral diseases.
High humidity favors them. Will they be dangerous for winter crops?
Snails can also be dangerous in late summer and early autumn, when young winter crops are emerging. They may damage germinating grain and young seedlings, leading to a reduction in plant stocking. In recent years, their population has increased significantly. They do not like sandy soils, hence they are rarely found on permeable, dry soils.
– Over the last decade, weather conditions have become more favorable for the development of snails, and their populations are becoming more numerous each year. Agricultural plants are heavily damaged by snails and this trend has been noticeable for several years. They prefer to eat germinating grain and seedlings of young plants. The spotted slug damages cereal plants throughout the entire field, while the common slug and the great slug damage mainly in the edge parts of fields. This may lead to a reduction of up to 50-60% in the size of agricultural produce – informs IOR-PIB in Poznań.
How to combat snails?
As experts from the Institute remind us, agricultural producers often notice the problem with snails too late, because on clear days with significant sunlight intensity and on rainless nights, these pests stay in their hiding places, waiting for optimal feeding conditions. The waiting period may last up to two months. Crop damage is assessed after plant emergence.
– The density of snails is determined based on the number of snails caught in traps (50×50 cm mats). The economic harmfulness threshold is 3 individuals in a trap or 6 slugs per 1 m2 in cultivation – reports IOR-PIB in Poznań.
The greatest results in protecting plants against snails will be observed when we use all available methods to combat these pests.
First of all, preventive treatments such as:
- frequent mowing of ditches and edges,
- removal of plant remains and objects located near the crop.
Agrotechnical and cultivation procedures that are necessary in the fight against molluscs include:
- energy,
- harrowing,
- rolling,
- early sowing of plants,
- destroying weeds,
- rotation of crop plants
- selection of fast emerging varieties.
You can fight chemically and biologically:
- You can also successfully use a biopreparation containing slug-killing nematodes.
- or granulated molluscicides that effectively attract snails.
According to IOR-PIB in Poznań, according to data from the Ministry of Agriculture and Rural Development from May 2024, there are 217 molluscicides available. Including 138 preparations with metaldehyde, 76 preparations based on iron (III) phosphate and 3 preparations with iron pyrophosphate. The use of preparations with metaldehyde creates many problems related to adverse effects on the environment. Metaldehyde is toxic to some farm animals and birds. Iron(III) phosphate has low toxicity to mammals and invertebrates. Molluscicides with iron pyrophosphate are already available for sale to reduce the number of snails. This substance immediately stops the snails from feeding, and after consuming the granules, the snails hide in the soil and die.
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