Leather Jackets are a common lawn pest and can cause devastating damage to UK lawns. Incredibly there are over 300 species in the UK alone.
Since 2016 all effective pesticides to control Leather Jackets have been banned from the UK in both the horticultural and agricultural sector, therefore there is no longer any chemical control available. Organic or mechanical approach is currently the only option.
Lawntech recommend the most effective treatment is to carry out mechanical lawn renovation during late spring or summer to repair the damage caused by these hungry critters. Lawn renovation consists of scarifying, aeration and over-seeding to bring the lawn back to good health once the larvae have become inactive. Frogs, birds, bats and fish all consider crane flies suitable meals, in fact some countries consider the larvae (Leather Jackets) a real delicacy. If that hasn’t given you pause for thought, consider that due to the huge increase in numbers for every person in the UK there were close to three thousand daddy long legs running riot!
As we go from winter into spring we should be regularly checking our lawns for signs of leather jacket larvae damage. An infestation can utterly destroy a lawn so reducing the potential for damage by checking for grubs during the winter months through to the spring is recommended. Leather jackets range in size between 1-3cm, are a blackish/brown colour, and can easily go unnoticed as they live just under the surface until they emerge as adult crane flies during August-October. The primary source of food for leather jacket larvae is the roots and stems of grass, so they really love lawns. Having these black grubs munch away at those roots can badly stress the grass, making it wither and deteriorate,
Here are our top tips for identifying and controlling these pesky critters:
- The easiest way to check for the larvae is to dig a series of small test holes with a fork, to a depth of about three inches below the lawn surface.
- Pay particular attention to any areas of turf which appear stressed or thinning, particularly around the edges in shady areas, next to a fence or wall etc. If your lawn has been affected you will notice that the root structure will be very weak.
- Where possible try to eliminate the grubs from the lawn before they cause any more damage. The most effective solution is to either cover the whole lawn (or just the affected area) overnight with black plastic sheeting – this encourages the grubs to come to the surface so they can be brushed off and destroyed.
If a lawn has become extremely bare the grubs will need to be eradicated before re-seeding or turfing is carried out. This might take some time, so try rotovating and leaving the soil so birds and other natural predators can feed on the grubs. Lawntech’s sister company Hewlett Turf & landscapes Ltd can rotovate your lawn quickly and easily to assist with this.
As we move to becoming a pesticide free nation, the best form of protection is prevention. Recent changes in EU legislation have restricted the use of pesticides but you can employ organic solutions which don’t require a pesticide certificate. These are called ‘nematodes’, which are microscopic worms. They enter the grubs and infect them with a bacterial disease which kills them. Nematodes are available from various horticultural suppliers, but be warned; timing, soil moisture and the age of the larvae are all critical if the treatment is to be successful. In our experience, results tend to be very poor so Lawntech does not offer this as a service.
Here is our guide for using Nematodes and other organic methods
The Nematodes (or Steinernema Feltiae) should be watered onto the lawn between August and October, when the ground temperature is still warm. The soil should also be moist, so the nematodes can be at their most effective. This treatment may also be effective on very young grubs during April and May, once the soil temperature is above 12 degrees.
Another way to remove Leather Jackets from the lawn is to cover the area with a large black plastic sheet overnight. This will encourage the larvae to come to the surface of the lawn, so they can be brushed off and destroyed once the sheet is removed in the morning.
Although adult Daddy Long Legs only live for around three days, the larvae can be lurking under the surface of your lawn for quite a while and finding them isn’t always easy. Lawntech has experts who can quickly identify the larvae – and if you are currently participating in an annual lawn care programme from a professional company, your lawn care technician should be looking for them as part of his regular schedule