Pests & Diseases
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Earthworms eat organic matter, breaking it down into smaller pieces, allowing bacteria and fungi to feed on it and release the nutrients
and are responsible for some of the fine crumb structure of soils. Earthworms play an important role in
breaking down dead organic matter in a process known as decomposition. This is what the earthworms living in your compost bin are doing and earthworms living in soils also decompose organic matter. Decomposition releases nutrients locked up in dead plants and animals and makes them available for use by living plants. Earthworms do this by eating organic matter and breaking it down into smaller pieces, allowing bacteria and fungi to feed on it and release the nutrients. Earthworms are also responsible for mixing
soil layers and incorporating organic matter into the soil. Charles Darwin referred to earthworms as ‘nature’s ploughs’ because of this mixing of soil and organic matter. This mixing improves the fertility of the soil by allowing the organic matter to be dispersed through the soil and the nutrients held in it to become available to bacteria, fungi and plants. Earthworms also have a positive effect on
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The USGA started researching tea seed meal in autumn 2007 to determine if it could be used to reduce earthworm casts on playing surfaces
128 I PC FEBRUARY/MARCH 2017
bacteria and fungi in soils. Where earthworms are present, there are more bacteria and fungi and they are more active. This is important as bacteria and fungi are key in releasing nutrients from organic matter and making them available to plants. They are also an important source of food in their own right for many other animals that live in soils. There are twenty-eight species of
earthworm native to the UK, as well as a number of non-native species brought in by accident through the actions of humans - for example in the soils of imported exotic plants. Each species exhibits unique behavioural and physiological characteristics, their distribution being influenced by soil pH, soil texture, organic matter, mode of feeding, life style and their location within the soil profile. Maybe surprisingly, only a small number of
species actually produce the casts which are deemed such a nuisance on sports turf. The most abundant of the casting species is Lumbricus terrestris, which is also the UK’s largest species at 90-170mm in length. This
earthworm is nocturnal and forms a permanent vertical burrow opening onto the soil from which it forages for food. It is this beast of the underworld that
causes so many problems to groundsmen and greenkeepers and, come the end of August, there will be no legal control for casting worms.
Carbendazim was withdrawn from sale at the end of February 2017, with all stocks having to be applied by the end of August. After that, there is nothing, ziltch, diddly squat etc. Or is there? Recent posts on the Pitchcare
forum have been suggesting that a product being marketed as a soil conditioner is having an affect on casting worms, either as an irritant or by killing them; the jury is still out, but the latter does also appear likely. Postees discussed the product at some length and argued that it contained either tea seed meal or mowrah meal (a once popular treatment for worms), along with other ingredients such as seaweed and poultry manure.
The USGA started researching tea seed
meal in autumn 2007 to determine if it could be used to reduce earthworm casts on playing surfaces. One of the authors of the research, Daniel A. Potter, had attended a sports turf conference in Beijing, China in 2007 where he learned of another natural substance used there to suppress earthworms and casting on sportfields. The method involves applying a by-product of tea oil manufacture. Tea seed oil, pressed from seeds of the Chinese tea oil plant, is used for cooking in eastern Asia, and in soaps and shampoos, margarine, ointments and other products. Although tea oil websites claim efficacy for earthworm control, a 2007 search of the worldwide scientific literature found no references or data supporting that claim. Most of the early trials were done on a
large, predominantly Penncross creeping bentgrass push-up green at the University of Kentucky’s A.J. Powell Jr. Turfgrass Research Center, near Lexington. Other trials were done in fairway-height creeping bentgrass and on a
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