Controlling the carrot fly in carrots is nothing new for the sector. The most effective control methods have been worked on for more than 3 decades. The disappearance of the Cruiser seed coating and the active ingredient thiram puts growers on edge. During Delphy's Peendag in Nagele, there was a lot of talk about it.
Consultancy firm Delphy organized their national Carrot Day on Wednesday, October 10. This is the practical part, which was last organized at this location this year. An indoor event is organized in winter. In addition to the stands of the machine manufacturers, the growers could view tests. In addition to new varieties and fertilization strategies, the control of the carrot fly was high on everyone's agenda.
Irrigate
Little was said about the market. Prices are at a stable and high level and harvesting is taking place gradually for delivery from land (industrial carrot for Dutch buyers). More growers are starting the irrigation reel again because conditions are too dry. There is a risk of harvesting damage, especially on sandy soil, because the dry soil is abrasive. For arable farmers, irrigation in mid-October is unique. The harvesting for storage is awaited. It's too hot for that now.
What concerns the entire sector is the discontinuation of the Cruiser seed coating. The active substance thiamethoxam is banned from January 1, 2019. Damage caused by carrot fly larvae is not new, but not everything is known. A shrinking resource package means that conventional growers have to switch to organic alternatives.
On October 10, the European Commission officially withdrawn the active substance thiram published. This substance may be used for crop protection and seed coating until January 30, 2020. Thiram is used as granules to combat carrot fly maggots in the soil and fungi in the soil.
Organic alternatives
Various alternatives were shown during Carrot Day (such as onion oil and special cloths). In addition, biological agents are available. Seed coating with Nemguard, a garlic extract, Tercol and Benevia. There is also Coragen. However, all these products have their limitations, may only be used to a limited extent, are too expensive, may require special spraying techniques or have a side effect on the carrot fly.
De Groene Vlieg monitors the pressure of carrot flies in 1 plot. During the Peendag it was emphasized how important monitoring is, in order to act at the right time with the limited package of resources. The fly has various flights, which should be avoided as much as possible from the first moment.
If it is possible to combat the first flight effectively, this will have good consequences for subsequent pressure. The situation is different this growing season due to drought. Irrigation stimulates the carrot fly. Depending on the season and pest pressure, up to 10 sprayings may need to be carried out.