Please do not write
to ask "where can I get these products from?" The market changes too
quickly and governments continually remove effective chemicals from the
market. Be aware that groundskeepers have access to professional chemical
supplies, which require training to use safely.
Worms produce worm casts (small piles of digested earth), which are unsightly,
slippery, blunten lawn mowers, affect play on sports turf (e.g. bowls, croquet
and golf) and make balls, etc. unpleasant to handle.
The casts also can act as seedbeds for weeds. The action of worms can also
facilitate weed growth by pulling down seed material from the surface.
Worms are a source of food for birds and animals, many of which are undesirable
on sports or fine turf. Birds leave droppings and can damage the turf through
pecking. Burrowing animals, such as moles, can destroy huge areas of expensively
maintained turf in their search for worms.
Worms aerate the soil through their motion improving its structure and process
waste material (e.g. components of thatch).
"Castings are digested animal manure and plant matters and have five
times the nitrate, 11 times the potash, seven times the phosphorous and
three times the magnesium of the soil around them."
http://www.azcentral.com/home/garden/articles/0302worms02.html [dead link]
Worm casts can be removed mechanically by brushing, switching or using a
drag mat. Brushing is only feasible for small areas. Switching involves
using a long switch, like a fishing rod, the end of which is swept quickly
over the surface of the grass. Telescopic ones, 4-6m long, with a thin fiberglass
tip are available and large areas can be covered quickly. Whilst primarily
intended to break-up morning dew they smash or smear the worm casts. A drag
mat enables large areas to be processed.
Whilst this overcomes the immediate problem, the worm casts will be there
next morning. The alternatives are to discourage, remove or kill the worms.
Worms are not necessary for a healthy lawn; they do nothing unique.
Earthworms prefer a near-neutral soil acidity (pH), moist soil conditions
and plenty of plant residue on the soil surface.
Worms do not seek soils with high acidity (low pH = acid). There are products
that intentionally acidify the surface of the soil which claim to drive the
worm down from the surface. The acidifying agent needs reapplying at 2-4
I would raise an eyebrow at this approach. Grass, like worms, has a preferred
pH range (see diagram on right) and the viability of the grass is likely to be affected if its conditions
are modified. There are grasses however which like acidic conditions, but
they may not offer the required turf properties, e.g. hard wearing, drought
resistance, etc. Also, if you pour something on the top of soil and are
reapplying it frequently, where does it go to? Down seems the obvious answer
so the worms get driven further and further down?
The Croquet Association advises
in its publication 'Croquet Lawns: Their establishment,
improvement and maintenance', section 58:
"As the pH drops towards 5.5 the spraying will become less necessary.
The cheapest way to lower the pH is to apply Calcined Sulphate of Iron
at ¼oz (7gm) per sq. yd."
Example products: 'Worm Clear Plus' (spray) and 'Sulphur
Worm' (granules). The product 'CastClear' (2010) claims to deter worms - its principal component is ammonium thiosulphate, hence liberating sulphur and acidifying the soil.
Chemical: Various solutions can bring worms to the surface where they become
prey to birds and other predators, sweeping machines and lawn mowers. The
following quotes should act as pointers. Searching Google for ' permanganate
vermifuge -koi -fish -aquarium ' etc. can pull up information on
the use of permanganate excluding reference to its use on fish. A vermifuge is
something that flushes worms out. Solution strengths are infrequently quoted.
"The efficiency of mustard as a vermifuge for estimating earthworm
populations or collecting earthworms for laboratory studies was compared
with that of formalin, potassium permanganate and household detergent.
Mustard was shown to be as efficient as potassium permanganate and both
these substances were better than formalin. Household detergent was an
extremely poor vermifuge. Mustard does not kill earthworms as does potassium
permanganate, and unlike formalin it is not carcinogenic and does not
have phytotoxic effects on clover. Mustard would therefore appear to
be an ideal "environmentally friendly" means of estimating
earthworm populations and, for collecting healthy worms for laboratory
studies in areas where soil sampling is not feasible due to the damage
it would cause."
http://biology.bangor.ac.uk/research/publication/A1992HW93900001 [link defunct]
"Worm extraction (vermifuge, a chemical irritant to bring them to
the surface) from soils is possible with formalin, (now probably an illegal
use), with liquid detergents (4 liters per 50 x 50 cm quadrat (many worms
die)), potassium permanganate solutions, and probably least destructive
or harmful to surrounding conditions is a with a mustard solution 25
ml per liter."
http://fwie.fw.vt.edu/rhgiles/aRuralBusiness/AlphaEarth.html [link defunct]
Potassium permanganate is a powerful oxidant and its storage is a concern.
Electrical: There are a few mentions of electrical 'worm probes' or 'worm
harvesting', primarily used by fishermen to bring worms to the surface. For
"Electric Worm Harvester: The electrical current produced by the Harvester
will bring the Worms to the surface. If the current is strong enough it
will stun the Worms who will recover without harm. If the current is
too strong it will injure the Worms and white spots will show on the
skins. Such Worms may live up to 24 hours but will die, or the Worms
may remain in the ground and die."
http://www.oldphoneman.com/FSMagnetos.htm [link dead]
"CPSC is aware of more than 30 deaths involving functionally-identical
worm probes. Consumers have been electrocuted by contacting the
exposed metal shafts and shocked by touching the ground in the vicinity
of the probe."
The posh term for a worm-killing chemical is a vermicide. As indicated
in the caveat at the head of this article the chemicals available to you
depends where you are and who you are. Some products may not be available
to members of the public. The Royal Horticultural Society (UK) states:
"Pesticides for the control of lawn pests are no longer available
to home gardeners. Pesticides marketed for professional use cannot be
used on garden lawns, although it is possible have them applied to sports
turf, such as a bowling green. In that type of situation it may be worth
employing a contractor who has the necessary Certificate of Competence
to use professional pesticides on amenity turf." (link now removed by RHS)
I used to quote trade names but the products were successively pulled from
the UK market: hence I do not give advice on products, suppliers or usage;
please do not ask! As an example, the first chemical below was banned in
2003 and the second will be banned in 2006:
"As far as we are aware, thiophanate-methyl and carbendazim are the
only 2 active substances used to control worms. Under 91/414/EEC, thiophanate-methyl
is to be included in Annex I as a fungicide (although the Directive has
yet to be published). A decision has yet to be taken for carbendazim
For information on banned chemicals in the UK see http://www.hse.gov.uk/pesticides/topics/pesticide-approvals/pesticides-registration/withdrawal-and-restrictions/banned-and-non-authorised-pesticides.htm
Use the Internet to track down products available in your region given the
The good news is that there are products that are not sold specifically
as vermicides, but do reduce the worm population. Typically fungicides,
which are routinely applied to sports turf, have this beneficial side effect.
The following quote gives indications of some chemicals which are effective
at killing worms. NOT ALL OF THESE ARE SUITABLE FOR SPRAYING ON GRASS - SOME
ARE HERBICIDES AND WILL KILL IT! Caveat Emptor!
"Earthworms prefer a near-neutral soil pH, moist soil conditions,
and plenty of plant residue on the soil surface. They are sensitive to
certain pesticides and some incorporated fertilizers. Carbamate insecticides,
including Furadan, Sevin, and Temik, are harmful to earthworms, notes
worm biologist Clive Edwards of Ohio State University.(4) Some insecticides
in the organophosphate family are mildly toxic to earthworms, while synthetic
pyrethroids are harmless to them.(4) Most herbicides have little effect
on worms except for the triazines, such as Atrazine, which are moderately
toxic. Also, anhydrous ammonia kills earthworms in the injection zone
because it dries the soil and temporarily increases the pH there. High
rates of ammonium-based fertilizers are also harmful."
http://www.attra.org/attra-pub/soilmgmt.html (no longer working) and reference
4 is Edwards, Clive A., and P.J. Bohlen. 1996. Biology and Ecology of Earthworms.
Chapman and Hall, New York. p. 426
The following quote gives a comprehensive list of chemicals (and their trade
names) that will kill worms. NOT ALL OF THESE ARE SUITABLE FOR SPRAYING ON
GRASS - SOME ARE HERBICIDES AND WILL KILL IT! Caveat Emptor!
"University researchers identified other toxic chemicals that home
owners and lawn services may use [to kill worms]:
- acephate (Orthene)
- azinphosmethyl (Guthion)
- bendiocarb (Turcam)
- carbaryl (Sevin)
- carbofuran (Furadan)*
- copper sulfate
- cypermethrin (Ammo, Cymbush)
- D-D fumigant
- endosulfan (Thiodan)
- esfenvalerate (Asana)
- ethoprop (Mocap)
- fonofos (Deafened)
- metam-sodium (Vapam)
- methomyl (Lannate)
- methyl bromide
- metribuzin (Sencor, Lexone)
- phorate (Thimet),
- thiophanate-methyl (Topsin-M)
http://www.azcentral.com/home/garden/articles/0302worms02.html [link dead]
"Earthworms were killed with a pesticide
(carbofuran) which is known to affect earthworms at various rates depending
on the species and the type of soil (Lee, 1985). Due to the low hydraulic
conductivity in vertisols, we chose to apply high doses of 10 kg ha−1
a.i. The product (Trademark Furadan) was spread on the soil surface
every 2 years."
http://www.mpl.ird.fr/SeqBio/Archives/FichesPerso/Articles/Tiphaine/chevallier_ASE_01.pdf [dead link]
Example products: Rigby Taylor sells "Systemica" fungicide/vermicide
containing carbendazim. http://www.rigbytaylor.com/Shop+by+Product/Chemicals/Worm+Control/Systemic+Worm+Cast+Control+5lt_0632102-05.htm.
Look also for "Mildothane Turf Liquid" (contains thiophanate methyl).
Scotts Turfclear contains carbendazim - http://www.aitkens.co.uk.
These will become impossible to find as the bans become effective - search
Google for ' "worm control" fungicide '
There do not appear to be any biological controls on the market for earthworms.
Moles are not an option!
Disclaimer: Whilst I have attempted to gather useful information
and provide pointers, I make no representations about the accuracy of the
information quoted. Please do not email to ask "where can I buy products?" - use
4. Additional Information
Peter M Taylor writes about the above.
"An interesting and comprehensive article on the Oxford website which
doesn't seem to highlight the key points.
Worms are beneficial to lawns and will always be present they are just
an inconvenience when working at surface level which needs to be discouraged.
The best means of discouragement is the regular removal of the plant residue
by verticutting and scarifying gentle within the season i.e. down to soil
surface and severely into the underlying soil ideally in the Autumn.
Damp surface conditions also need to be discouraged by sarel (gentle spiking)
rolling during the season and deeper spiking and possible verti-draining
to remove compaction outside the season.
The use of lining marking products raises the pH (alkaline) encouraging
worms and they should be used sparingly especially towards the end of the
It would be a rare situation where repeated acidic chemical applications
to lower pH are required and pH may be lowered by regular applications
of topdressing of know alkalinity."
Peter Howells has approached (UK) suppliers:
a) Aitkens Sportsturf Ltd, 01977 681155, have a product for worms called
Ringer. 1 x 5Ltr Ringer (5Ltr treats 12,500 sq.mtr) £130.90 per 5Ltr
+ vat and carriage (2005). http://www.aitkens.co.uk
b) You can use a chemical called Carbendazim to prevent worm casts forming.
It is found in products such as Scotts Turfclear, but this only comes in
5 Litre sizes. However Nu-Turf produce a product called Nu-Turf Worm Control
which contains carbendazim and it comes in 1 Litre sizes and costs £33.00
+ delivery + VAT. (2005)
Both products are restricted and must be applied by qualified personel.
Sweepfast Ltd. 01675 470770, The Homestead, Old Kingsbury Road, Marston,
Sutton Coldfield, West Midlands, B76 0DP, https://www.sweepfast.com
Mark Homan adds [Aug 2007]
The recent correspondence about worm casts reminds me that back in September 2005 I reported:
1. Success with Carbendazim for worm suppression. I think this is now no longer an approved product, but that is not to say it is unobtainable. Old stock is still around!
2. On the subject of a preponderance of worm casts around boundary lines and the effect of lime in the liner in encouraging coarse grass I stated: 'I have done some research on.... white liner. It appears that the usual products have a PH of about 8.5. However, there is one called Elite which at 7.7 is still high, but breaks down and releases the lime more slowly so has less effect in raising PH. Also it is claimed the lines last much longer. Arsenal and Chelsea both use it.... I am going to try switching to Elite ..... and will report the results sometime next season'.
I did not in fact report the results last season as I felt that the trial was too short for the excess lime already in the soil to dissipate. Well, after two years it has. I now no longer have dark thicker grass along the lines nor any more worm casts than elsewhere on the court. Pros and cons I have observed are:
Pro: Better grass/less casts as above It seems to last longer. Hence a saving in liner and labour.
Con; Elite is more expensive than most alternatives. It is stickier than other products and clings to the lining equipment. If you wash it out this is wasteful of liner and labour. If not the box eventually gets clogged up. Whether on balance it is therefore more or less economical I cannot say.
Also remember, this is a subjective opinion based on the particular soil conditions of one court and the extremes of weather in the last two summers.
Brendan Quinn, a pharmacist and a member of Birdwatch Ireland, notes 
* Furadan also known as carbofuran is a banned Eu substance and has been linked to deliberate bird poisonings, as it has been today in Ireland. Probably best not to list it in products used to control worms.
Stan Daurio notes 
In paragraph 3.3.1, you say that 2,4d will kill worms. As part of the massive Canadian and U.S herbicide 2001-2010 recertification program, 2,4d was found safe for mice, rats, dogs, rabbits, crayfish, ducks, earthworms. honeybees and many others included in the comprehensive studies; you may want to reference the findings of the Pest Management Regulatory Authority of Health Canada for more information.