Sampling and handling specimens
The accurate identification of plant pests depends upon correct sampling, packaging and timely delivery of samples to an appropriate diagnostician.
Different pest types require different sampling and handling techniques. Some general guidelines are provided here; however, if you are unsure about the correct sampling procedures for a particular pest you should contact a specialist for advice.
More detailed information can be found in Plant Protection in the Pacific Islands – A Trainer’s Guide by J.C. Lowe and J.M.H. Parker (published by SPC, Noumea, New Caledonia, 1997).
Insect pests
- Collect about ten specimens that include different developmental stages of the insect if possible, particularly mature male and female specimens.
- Collect specimens that are clean and in good condition, i.e. complete with appendages such as antennae, wings and legs.
- Use a small leak-proof alcohol resistant receptacle, such as a film canister, glass bottle with air- and liquid-tight stopper, or plastic container with screw-top lid.
- If sending small and/or soft bodied insects (eg. thrips, aphids, mites and larvae): Place specimen in 70% ethanol and completely fill the container. Tape the lid securely to avoid accidental spillage. Note: do not remove mealy bugs or scale insects from the leaves or stems on which they are feeding as this will damage their mouth parts and make identification difficult. Instead, cut out leaf tissue around the insects and place this in alcohol.
- If sending hard bodied insects (eg. beetles, moths, grasshoppers and fruit flies): carefully fold specimen in tissue paper and place in a small crush-proof plastic tube or container with several holes in the lid for ventilation.
- Clearly label the container (refer to Labelling Samples section below).
- Place the container in a self-sealing bag with some absorbent material (eg. paper towel) and pack this into a small sturdy box filled with padding (such as foam chips, scrunched paper, bubble wrap, etc) for protection during transit. Clearly address the package with the recipient’s name, address and telephone number. DO NOT SEND LIVE INSECTS.
- Retain and store a spare sample using the methods described above.
Pathogens (diseased material)
- Select samples representing the full range of symptoms.
- If sending dried samples: it is useful to incubate samples at high humidity before despatch to promote sporulation. Place samples overnight in a plastic bag with a little water. Afterwards, blot samples to remove surface water and dry between newspaper, changing the paper daily over a period of a week until the samples are completely dry. Alternatively, place the samples, separated by corrugated cardboard, vertically above a 60 watt electric light bulb. In this case, the samples will dry within 24 hours and there is no need to change the paper.
- If sending fresh samples: collect samples close to the time that you intend to mail them and store in a refrigerator. They need to arrive within 1-2 days. Place samples in self-sealing plastic bags with some dry tissues or paper towel added to absorb excess moisture. Do not add any water or pack wet samples. If submitting a fruit or vegetable sample, wrap in dry towelling and pack firmly into a crush-proof container.
- Clearly label all samples (refer to Labelling Samples section below).
- Place the bag containing your sample in a padded envelope or sturdy box and seal securely. Clearly address the package with the recipient’s name, address and telephone number.
- Retain and store a spare sample using the methods described above.
Weeds
- Collect at least two weed samples.
- If sending fresh samples: submit fresh whole plants if possible, i.e. leave any flowers, seed heads, leaves or fruit attached to the stem and part of the root system, or submit representative sample portions of the plant if it is large.
- If sending dried samples: press weed samples between dry sheets of newspaper (change paper daily if necessary) using moderate pressure. Alternatively, dry using a 60 watt electric light bulb (see Pathogens). Enclose dried weed specimens with newspaper between two rigid sheets of cardboard. Note: do not tape sample to the newspaper; do not send specimens in plastic bags or with wet newspaper.
- Attach a label to the sample (refer to Labelling Samples section below).
- Place the sample in a padded envelope or box and seal securely. Clearly address the package with the recipient’s name, address and telephone number.
- Retain and store a spare sample using the methods described above.
- Note: useful guidelines for the collection of botanical specimens are provided by the Centre for Plant Biodiversity Research.
Labelling samples
- Label each sample clearly using a pencil or alcohol-proof marker.
- Secure labels to the inside and outside of the sample bag or container for insect pest and pathogen samples. For weeds, use a tag such as those used by nurseries and secure it to the plant.
- Include the following information on the label:
– site collection details
– host plant
– sample number for reference (e.g. your initials followed by the sample number)
– date of collection
– name and contact details of collector. - Include additional information to assist the identifier, as outlined in the Pest Identification Form.
Mailing samples
Before mailing a sample for identification:
- Check if there are any quarantine regulations that need to be complied with. REMEMBER: IF YOU ARE SENDING SPECIMENS OVERSEAS, ENSURE THAT YOU HAVE THE CORRECT IMPORT PERMITS AND CONTACTS.
- Check that the intended recipient will accept the sample(s).
- Check if there are any sample submission forms that need to be completed and sent with the package.
- Check if you will be charged a fee for the identification.