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Government of

Information and public services for the Island of Jersey

L'înformâtion et les sèrvices publyis pouor I'Île dé Jèrri

Plant health control

Plant health

Plants can suffer from:

  • bacterial
  • viral
  • fungal
  • pest attack

This leads to weakening or killing the plant's cellular activity, meaning, it will die without proper prognosis and treatment.

The Plant Science Laboratory at Howard Davis Farm provides:

  • specialist diagnosis of plant pests and diseases
  • analysis of soil and water
  • plant samples for:
    • farmers
    • growers
    • Plant Health Inspectorate
    • States departments
    • the public

   Ash dieback disease symptom guide

Plant pathology (plant disease) and entomology (insect) identification and advisory service

Between April and September, the laboratory monitors a range of insect pests relevant to Jersey crops and the results are available weekly. We combine physical trapping data from the Island with that from Warwick Horticulture Research International (HRI)  and ADAS forecasts to provide up to date information on:

  • pest activity
  • risk to crops
  • treatment thresholds

The insects monitored include:

  • the major potato aphids
  • cutworm
  • cabbage root fly
  • carrot fly
  • Colorado beetle
  • large narcissus fly
  • gypsy moth
  • diamond back moth

If you would like to receive this information by fax or email, contact the laboratory.

Soil, water and tissue analysis

The laboratory tests over 2,500 fields annually for Potato Cyst Nematode (PCN) and nutrient status (NPK), plus hydroponic feed samples.

These analyses allow the grower to make informed decisions about the nutrient requirements of crops and pest status of soils and whether or not fertilisers and pesticides are required for the next crop.

General Laboratory Analysis form for Potato Cyst Nematode, Soil Nutrient and Plant Tissue analysis

Colorado beetle

The Colorado Beetle presents an annual threat to potato production in Jersey via invasion from France. Under international plant health laws, both the UK and Jersey are protected zones for this pest. This means the beetle is not present in the area. Should Colorado Beetle become established in Jersey, not only would it devastate the potato crop but it would affect the export of the crop to the UK.

Beaches and potato crops in Jersey are monitored for the pest when certain climatic thresholds are reached. These include:

  • easterly winds exceeding 20 knots (which may carry the flying beetles across the sea to the Island)
  • greater than 6 hours of direct sunshine
  • temperature exceeding 20°C
  • high climatic instability (thermal activity)
  • high beetle flight activity on the adjacent French coast

The Meteorological Department transmits its data to the laboratory on a criteria based system. The first criterion is wind direction. If the wind direction is not sufficient to pass the criteria  no more information is required. If the direction is suitable (NE - SE) the next criterion becomes speed (more than 20 knots) and so on.

The French / Jersey climatic information is supplemented by flight information and warning faxes from the Service Regional De La Protection Des Vegetaux (SRPV).

Through continued liaison with the French plant protection authorities and monitoring of suitable weather conditions, the system monitoring risk periods in Jersey from Colorado Beetle continues to operate well.

Where to get plants checked for disease

The laboratory at Howard Davis Farm in Trinity provides specialist diagnosis of plant pests and diseases for the general public. Private garden queries will incur a charge of £25 unless there is a public health or statutory issue.

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