Professional turf is a close-knit grass sward with seemingly few openings and opportunities for invasion by weeds, but a surprisingly large number of plant species continue to invade, establish and grow. Turf weed achievement is governed by a range botanical attributes alongside breaches in turf integrity that allow these dicotyledonous (broad leaved) plants to exploit the environment and ecosystem. Turf weeds are simply green plants in the wrong place at the expense of fine turf grasses. At first it was a successful move. At the August 2012 share sale, MBII shares rose about 50%, valuing the company at $345 million. The company’s growth and successful share sale was considered a validation for Pam Marrone after she missed out on an IPO in 2001 for AgraQuest, another biological pest management solutions company she founded in 1995 from which she was ousted as CEO.
Keeping a low profile
The meristems (growing points) of grass plant species are sufficiently low to miss the mower’s blades which is the essential factor underpinning the creation and maintenance of turf. Broad leaved weeds with intrinsically higher growing points should be dispatched by the low cutting heights required to maintain sports turf in a playable condition, but in practice many do escape to survive and thrive as weeds. Weed plant populations contain a range of biotypes especially of those species with a high seed production potential. Short interval, close cutting over a long time period will select out the most prostrate individuals which then go on to generate more of the same.
A classic example in this context is the Dandelion (Taraxacum officinale) often seen on tightly managed golf tees and still producing yellow flowers virtually at ground level. But a cut too low can be just as damaging as a cut too high, with Common Daisy (Bellis perennis)
and Greater Plantain (Plantago major) being two common weeds which thrive in ‘shaved’ and compacted turf. The capacity of broad-leaved plant populations to adapt to a ‘life’ in turf is clearly shown by those plant species displaying a prostrate growth habit when growing in turf but a more ‘generous’ growth form and habit in the wider environment.
Creeping Buttercup (Ranunculus repens) hugs the ground with its running stems slipping unobtrusively through turf to root at regular intervals. Contrast this to uncut grassy situations where creeping buttercup grows up to 45-60 cm high. Self-Heal (Prunella vulgaris) is one of the most prostrate of turf weeds but can grow up to 20 cm high in hay meadows. Bird’s Foot Trefoil (Lotus corniculatus) behaves in the same way using long grass stalks for support.
This is an extract of the full article published in International Pest Control – May/June 2016 issue.
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Author: Terry Mabbett*
* Terry Mabbett Consultants