Leatherjacket and water logging problem

I am at my wits end with my lawn.

My house was a new build 2 years ago, initially the lawn was lush green grass (was laid as turf by the developer) but over the last few years each winter/spring it has died off and resulted in me having to heavily seed it in the spring/summer. I know the reason it dies off is due to leatherjackets and water logging (heavy clay soil). I have tried treating the lawn with nematodes in the spring (double strength application) and autumn but it doesn't seem to have worked.

Two days ago I covered the lawn with a tarpaulin overnight and went out the following morning to collect the leatherjackets, I was absolutely gobsmacked by the number of them I was able to collect just on the surface, problem is I was unable to sweep them up and had to pick them up which was very time consuming. The issue being that the following morning there was a similar number again, this isn't practical to do this every day and to do the whole lawn, it seems futile, does it really make much difference when you have an infestation this bad or is it a complete waste of time? Is there anything I could spray on them while they're on the surface to kill them and save picking them up?

I feel like I am going round in circles and am looking for a more long term solution.

I have a few options that I am considering but am a complete novice so am not sure how practical these are:

1) Keep treating with nematodes and reseeding- probably the least drastic option but so far hasn't proved to be effective.

2) Rotavate the whole garden and mix in compost/gravel and top soil to improve drainage (and hopefully kill some of the leather jackets off in the process!) and then re-turf. I am worried I would do all of this and the leatherjackets would survive and just eat the new turf!

3) Cover the lawn with tarpaulin for an extended period of time to kill the lawn off to remove their food source and break the cycle - drastic and unsightly for unto a year but long term should fix the issue.

4) Cover the lawn with jayes fluid - I have read it can be used to kill Grubbs. Again, I am a complete novice so unsure if this would work or if this is a terrible idea!

I also have seen some crane flies in my garden over the last few days, should I be worried as they shouldn't be out this early, does this mean I will be hit even worse next year?

I have attached some photos to show the state of my garden, how many leather jackets I collected in the 12x18 area and also one of he crane flies I caught (as it may be something else).

Any help or suggestions would be gratefully received!

thank you

 

I wish I could help because that does look like a real problem, it looks like you have thought of most of he solutions the only thing I can do is give you this link to see if it will help in your decision, sorry I can't help you more.
https://www.gardenseeker.com/lawn-care/pests-diseases/leatherjackets/

 

Did you soak the lawn before applying the nematode?
Which brand of nematode did you purchase?
Where did you purchase the nematode?
Did you check the use by date on the nematode packet, as they are a perishable item?
What do you mean by double dose, did you use 2 packets, or mix 1/2 the amount of recommended water.
And excuse me for asking this (you would be surprised) did it state specifically, the nematode was for leatherjackets?
I would be surprised if the nematodes worked with a single application, with the amount you are collecting on a daily basis fron a small area.
There are no chemicals that work on LJackets, the only way to combat them are nematode, and good drainage on the lawn, you will need to areate the lawn for drainage, scarify to remove as many eggs, and apply nematode when you know the temprature is going to remain above 12 degrees C for a month, and water the lawn before application, as the wet encourages the LJ to feed. I would areate now, and apply nematode in late April or early may if the temprature window is there, then apply another round of nematode in September. it may be a 2 or even a 3 year cycle before you win the battle. And make sure the nematode are Steinernema feltiae.

 

there is chemical control but it’s limited and is on a yearly notice, 2018 and 2019 emergency authorisation of Syngenta insecticide Acelepryn was approved for the control of chafer grubs and leatherjackets. The Emergency Authorisation is authorised for a limited window within each calendar year.
You would need to talk to someone local who’s trained ie BASIS qualified agronomist and to use such products and can obtain the above if once again permission to do so is authorised and for the purpose of approved use.
A typical use would be say an airfield where grubs attract birds and so air strikes would be a risk. The question is if it’s applicable to your lawn.

 

Authorisation will only be given if the pest is causing financial damage, or as you pointed out a safety risk, it is not available for public use, i.e the lawn, and you will not get permission.
Emergency Authorisation for Acelepryn reapproved for turf | GreenCast

 

Thanks for the reply :-)

I did soak the lawn before applying the nematodes, I bought them from nematodes direct and they were in date when I used them and were definitely for leatherjackets.
When I said double dose I meant I used twice the recommended amount in spring (as directed by the nematodes direct website) and actually applied this again at the same dosage 2 weeks later and then a single dose in Autumn.

I have used a garden fork to stab deep holes in the lawn roughly 2 - 3 inches apart to areate it, I have read I should now fill these holes with sharp sand to help with drainage, is this correct as I am worried with clay soil I’ll end up with cement!

Should I be worried I am seeing crane flies now? It seems too early based on what I have read online.

 

As good practice you would top dress once areated, but must soak the lawn pre application, and have the night and day temp of overc12 degrees C. When you see the crane flies, its a signal they may be laying eggs, so scarifying should remove most of the eggs.

 

Great, thank you.

Just out of curiosity when you say top dress once areated do you mean with compost and fertilisers?

How does scarifying remove the eggs, doesn't it just move them around the lawn? I have a leaf rake, would that be enough to scarify it?

Sorry I am a total novice!

 

Top dress can be with sand, top soil, weed and feed, depending on the job you are doing, in the nursery, it can be as easy as removing weeds from pots, then top dressing with a feed then fresh compost.
I have lots of work around the nursery to do, so have put a link to a sports pitch maintainance, which should answer most of your questions.

How to Identify & Control Crane Fly or Leatherjackets | Pitchcare iGuide

 

there is a way if you follow the guides and if it’s deemed appropriate, other chemicals under the same Ruling have been applied within domestic properties and as I pointed out you need to seek advice from one of the listed services.
there’s quite a few chemicals that have come under similar rulings in the past.

 

As of 2019, its only permitted for Amenity application.

Emergency Authorisation for new Acelepryn soil pest control ICL

 

Turf managers or owners who believe they have suffered economically damaging effects of Chafer grubs and leatherjackets are advised to contact their BASIS agronomist or ICL Area Manager in the first instance.

 

Agreed, but if the agronomist, is caught using the product on a non ameniety area, or an area outside the permitted time frame, they will lose their license, the reason being, this product works by paralising the muscles of the insect, and if this product gets into the water table, it will not effect humans, but will effect other insects, the only reason it is allowed to be used, is because other products have been banned, and this product, whilst effective, is not fully liscensed yet, but because of the financial burden to companies like turf producers, or golf courses, an infestation could cost each entity £605, 000 per annum to deal with, the other reason its not fully liscensed, is because of the chemicals full effect as a marine pollutant is not yet proven