Protect carrots from FLN damage to secure yields

23.11.2018

Carrot yields were down by 15 to 30% this year at harvest due to environmental challenges faced throughout the growing season and free living nematode (FLN) damage caused further 5 to 10% yield losses where crops were irrigated.

This is a widespread issue across Europe, resulting in the market price for carrots being higher than normal. Therefore, Selchuk Kurtev, Certis IPM Manager, advises growers to implement control measures ahead of drilling to secure high carrot yields and maximise returns next year. 

Step-by-step cultural controls to reduce FLN damage

1. The key cultural control method for reducing FLN damage in carrots is to widen crop rotations. Try to implement long crop rotations of six to eight years to maintain good soil health and reduce the impacts of pests and diseases. 

2. To disrupt existing FLN populations and ensure robust root growth, soil cultivation is essential. Aim for a stone free, fine, soft tilth. It’s important to note that split roots, forced to grow around stones, are often mistaken for FLN damage. 

3. Before drilling carrots, plant deterrent crops, such as wild oats or mustard. These plants grow ahead of carrots and deter FLN from feeding on the roots of the main crop so that carrot roots have the chance to grow robustly, reducing the risk of FLN damage. 

4. Regulated irrigation helps to stop FLN moving across the soil. By identifying the key stages of crop development at risk of FLN, growers can strategically irrigate to reduce the damage, for example, between the start of germination and full canopy coverage of seed beds.

Nematicide application

In addition to cultural controls, Selchuk recommends a nematicide application to protect carrots from FLN.
NEMguard is a granular, biorational insecticide derived from garlic, applied in furrow at drilling. The granules gradually release garlic into the soil, protecting roots as they develop. 

With multiple modes of action (MOAs), NEMguard first acts as a deterrent by stopping FLN attacking roots. Secondly, excessive oxidisation occurs on contact, where the active moves through the FLN cuticle, causing septicaemia.