DESPITE frequent and extensive applications of slug pellets in the autumn and early winter, agronomists and growers are reporting continuing evidence of slug damage in their crops. What is the best way to tackle this pest at this time of year?
1 RECENTLY-hatched slugs could be quite easily found in December and early January on all but the lightest soils in late-sown crops in central, northern and southern areas.
Colder/frosty conditions alternating with mild, damp weather has, however, meant considerable variation in slug activity on the soil surface. Growers should continue to check later sown crops for plant losses due to slugs or vertebrate pests.
Any further applications of slug pellets should, however, be targeted carefully in advance of conditions that will favour slug movement on the soil surface. Colder conditions may make treatment unnecessary.
2GROWERS should first make sure their crops are at risk from slugs. If they are well tillered and in good condition then that will be low risk. Really the crops at risk are those that have gone in late or have been checked by the weather. In the eastern region right now I would also be concerned about wheat bulb fly.
If crops are definitely at risk then there will be opportunities for pelleting during mild conditions when temperatures are above 5íC during the day and preferably not under 1íC at night. Slug activity can also be reduced when it is windy and dry.
If the weather is wet we would recommend using a carbamate such as Genesis (thiodicarb) for which there is a maximum of three treatments per crop permissible.
We have had ideal slug egg-laying in the spring and autumn of 1998, so if we get good slug weather this spring I think populations will be bad for potatoes and rape going in this year. We could be in for two bad years of slugs.
NEW Groundwater Regulations have been introduced to cover growers disposing of pesticides on their land. How will the requirement for licences affect arable farmers carrying out normal spraying operations?
AFTER 1 April, 1999 farmers disposing of pesticides and sheep dips on their land are not allowed to do so unless they hold a licence from the Environment Agency. There are exceptions but any other farmer missing the end of March deadline for a licence must stop disposals until they have a full authorisation from the Agency.
Normal crop spraying, including spraying out tank washings on to the crop (in accordance with label requirements) will not require an authorisation, as the pesticide is being used and not disposed of.
Any disposal of pesticide, as opposed to standard applications on to target crops, will require an authorisation, including the application of unused spray mixture or tank or sprayer washings on to uncropped land. Existing areas of "uncropped land of low wildlife value" as described in the pesticide users Green Code may well be suitable for this disposal but will now need a formal authorisation under the Groundwater Regulations.
Other pesticide disposal operations from fruit, bulb or flower dipping will also need an authorisation.
Fertiliser and manure applications, although they contain ammonia which is an "identified substance" in the regulations will not require an authorisation as long as they are applied to land to utilise nutrients in accordance with crop requirements and adhere to the appropriate codes of practice.
The Groundwater Regulations require "prior investigation" to be undertaken before any authorisation can be granted. This will consider: the hydrogeology of the area; the suitability of the soil and subsoil to break down chemicals; the possible environmental impact; the risk of pollution to groundwater, including the possible impact on neighbours water sources. Farmers will have to confirm they have contacted neighbours who may have water supplies drawn from around or close to the disposal area.
Applications for small-scale, infrequent disposal (less than five cu metres (1,110gal) a day on no more than six days a year will be charged at around £84. Larger or more frequent disposals carry the full £589 charge. A further annual charge will be made to recover associated ongoing Environment Agency costs.
Growers who think they are affected by the Groundwater Regulations should contact their local Environment Agency office on 0645 333111 as soon as possible to discuss their proposals before starting work or submitting applications. In Scotland they should contact the Scottish Environmental Protection Agency (SEPA).
director of environmental protection, The Environment Agency, Peterborough, Cambs.