Pests & Diseases
The previously popular mowrah meal method involved applying powdered product from seeds of Bassia latifolia, the butter tree of India
perennial ryegrass golf fairway. The initial tests were with crude tea seed
meal pellets (3.2mm diameter; 5-8mm long) and powder obtained from a source in China. The latter, essentially a dust, proved awkward to apply, so later work focused on the pellets. Application of tea seed meal at 6lbs of material per 1000ft2
, followed by irrigation,
quickly expelled as many as 200 worms per 10ft2
on the pushup green. Most of the
expelled worms dried up and died on the turf surface.
A single tea seed meal application in early
April 2008 reduced castings in replicated plots on the push-up green by more than 95% for at least five weeks. In another trial on the push-up green, application of tea seed meal in early October reduced casts by 98% after two days, and 83% after thirty days. Finally, a sequence of lab trials confirmed that the chemical basis for tea seed meal’s activity on earthworms is the natural triterpene saponins found in tea seeds. The previously popular mowrah meal method involved applying powdered product from seeds of Bassia latifolia, the butter tree of India, after the edible oil had been pressed out. Natural components in mowrah meal irritated the earthworms, causing them to come to the surface where they were raked into piles, shovelled into wheelbarrows, and hauled off the site. The method, established by British
greenkeeper Peter W. Lees during the 1890s, was so effective that it had become the mainstay for earthworm suppression on European and United States golf courses by the 1920s.
The method is regarded as among the most
important historical innovations in turf management, in part because it allowed expansion of British golf courses on upland soils previously ill-suited for golf because of the unplayable putting green surfaces caused by earthworms. At one time, at least a dozen proprietary fertilisers and other products containing mowrah meal were marketed for earthworm control on golf courses. The use of the method declined in the late 1940s and
1950s with the development of chlordane and other earthworm-toxic synthetic pesticides. Mowrah meal is rich in saponins, natural soaps or surfactants found in the leaves and seeds of oats, spinach, alfalfa, chickpeas, soybeans, ginseng, tea and hundreds of other plants. Although saponins were never confirmed as the earthworm-active component in mowrah meal, it is highly likely that their detergent-like irritation of the earthworms’ mucus membranes was the basis for its effectiveness. Mowrah meal is no longer marketed for earthworm management. So, is Purity (or similar product), the cavalry galloping over the horizon to save the turfcare professional troubled by casting worms? Most that have used it for that purpose reckon so, although some have seen no results. Either that, or they had no worms in the first place, which seems unlikely. Remembering that these products are
marketed as ‘soil conditioners’ only, is the groundsman or greenkeeper right to be using it for another purpose? What if the pesticide police get wind of this extraneous use? More importantly, what damage is being done below the surface where hundreds of harmless worms are going about their daily lives, enriching your soil beyond most mechanical methods you employ or products you apply? What if these worms are being killed off too, which would seem likely? Are you really going to able to work with dead soil in a couple of years time? Until such times as a machinery
manufacturer comes up with a machine to ‘thoop’ up worm casts, employing the vacuum method, perhaps we are all going to have to simply put up with them from September onwards. We’re off to give James Dyson a call to see if he can help us design the Super Thooper!
With thanks to the Earthworm Society of Britain
www.earthwormsoc.org.uk and the USGA
www.usga.org
”
Remembering that these products are marketed as ‘soil conditioners’ only, is the groundsman or greenkeeper right to be using it for another purpose?
” PC FEBRUARY/MARCH 2017 I 129
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