Weeds, Pest & Diseases


When reseeding grass, weed problems come into roughly two categories: –

  1. After arable crops (mainly cereals) the weeds are likely to be:
  • Redshank
  • Daynettle
  • Charlock
  • Furnitory
  • Chickweed
  • Corn spurrey

These are annuals and can easily be controlled by topping them at an appropriate stage or by mob-stocking.  Once they have been suitably suppressed by either of the above techniques, they should disappear and the grass/clover prevails thereafter.

When sowing grass after arable crops (August/ early September) there is much less of a weed burden at this time of year as many of the annuals only germinate in the spring and autumn sown grass generally gets off to a comparatively weed free start.

2.  After grass or forage crop the weeds are likely to be: –

  • Spear Thistle
  • Creeping Thistle
  • Chickweed
  • Dockens

These are more difficult to control and spraying with herbicide is the most effective way to control the above.  This being the case, the clover component of the mixture can be omitted at reseeding and once effective weed control has been carried out the clover can be scratched into the young grass sward.  CAST coated clover (exclusive to Watson Seeds) is particularly effective in this situation.


The most likely to be encountered in grass are slugs and leatherjackets.  Whilst established grass can withstand both above pests, newly sown grass is very vulnerable and awareness is required to pre-empt and avoid serious damage.  Slug damage is particularly prone in heavy soils with damp hollows.  Typical slug damage to young grass is that the leaves appear to be shredded at their edges by the rasping action of the slugs grazing.

Leatherjacket numbers vary from season to season.  There is no doubt that they tend to be more prevalent following a mild winter.  Generally the farming press publish forecasts of predicted leatherjacket problems.  On-farm do-it-yourself kits are available that include liquid expellant to bring larvae to the surface of soil cores for counting.


The main diseases of ryegrass are crown rust, drechslera, rhynchosporium and ryegrass mosaic virus.  In the current National List testing procedures, varieties are exposed to these using disease inoculation techniques to measure their resistance.

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