Worm casts are the curse of every ground care professional and amateur alike - they are unsightly and messy and provide a superb seed bed for weed germination.
However, if you have a worm problem in the first place, you should be pleased because it means you have an active soil with good aeration and humus content.
Having said that, it is probably no consolation because your lawn in the meantime looks awful and your machinery will be suffering too.
So how do you rectify this problem?
- Avoid leaving leaves on the surface during the autumn and winter because this warm blanket of organic matter is an ideal restaurant for the worms.
- Do not allow a build up of thatch as again this decaying matter is digested by the worm which leads to casting deposits.
- keep the grass at a reasonable height.
- Avoid unnecessary watering as this leads to attracting more worms. In dry weather the worms will move deeper. By aerating regularly you can improve drainage; this will discourage worm activity.
Some of the above is counter productive to producing good turf and the finer the grass the greater the problem is likely to be. Inevitably you will need to turn to chemicals and in today's world that may be considered a problem.
The law does not permit long-life residual chemical build up in the soil. Gone are the days where a good dose of Chlordane would wipe out the worms. In fact, Chlordane probably wiped out a few groundsman too before legislation got tougher.
One product - used by most turf carers - known to be effective against worms , is Carbenzamin. This chemical was primarily produced to deal with fungal diseases such as Fusarium and Dollar Spot but as a side effect was also found to be a good repellent of worms.
Carbendzamin disrupts worms feeding near the surface by making the organic matter in which they feed on, unpalatable. Deeper feeding, non casting worms, will not be bothered by the presence of Carbenzamin in the soil, and continue to feed normally.
Applying Carbendazim for worm control products is most beneficial in Spring and Autumn and must be carried out when the soil is already wet as the chemical needs help in dispersing through the structure. It is advisable to carry out the treatment when rain is forecast within 24-48 hours but not imminently as run off may effect results as the chemical may end up next door rather than where it's intended.
Heavy infestations may need a second application after 3-4 months. Alternative lawn worm treatment - organic
For gardeners looking for an organic, non pesticide, worm treatment, take a look at CastClear.