Source(s): Gary R Peiffer
Collecting a sample for identification of a pest or disease problem.
DO YOU WANT A GOOD PEST OR PROBLEM ID?
Observe the plant symptoms and collect the right sections. Then bring them in to the Extension office in good condition.
SYMPTOMS: WILTING; YELLOWING, GENERAL PLANT DECLINE could be caused by a root, stem or foliage problem.
If practical and possible: it is best to bring in the entire plant (leaves, stems and an intact root system). Dig the plant out carefully-do not pull it up or you will lose the roots.
SYMPTOMS: TWIG AND BRANCH BLIGHTS AND CANKERS wounds and dieback of the branches and their foliage.
Select specimens which show recent damage or infection. An area where there is a transition (change) from healthy to damaged (dying) or visa versa. The area where there is a wound or damage to the stem is often the point of infection and this is the area that should be examined for a correct diagnosis.
DO NOT include twigs or branches that are entirely dead, or have been dead for a while. These branches would NOT help with a proper diagnosis because several decay fungi would already have been introduced.
SYMPTOMS: FOLIAGE DISEASES can include spots, scorch, curling, mottling, marginal burning, etc.
Select leaves which show early or recent signs or symptoms of infection, not leaves that are entirely dead or long dead. Marginal burning on the edges of the leaves indicate chemical injury or a type of root disorder (physiological, organic or chemical).
SYMPTOMS: FRUIT, VEGETABLES FLESHY PLANT ORGANS often related to cultural or disease problems.
When collecting, NEVER select specimens that are showing advanced stages of decayor disease. SELECT fresh specimens which show EARLY stages of a problem-disease.
OTHER SUGGESTIONS FOR GOOD SAMPLING & HANDLING
- DO NOT allow specimens to lay around several hours or days before bringing into the Extension Office. Rotted or dried, brittle samples are worthless.
- PICK plant samples right before your trip to the Extension Service office.
- KEEP SAMPLES COOL – under refrigeration – until you can bring them in.
- DO NOT allow specimens to over-heat and be destroyed in an automobile.
- Bring your FRESH specimens in a plastic bag but wrap all plant materials in paper towels before dropping them in the bags.
- DO NOT add any moisture to these diseased samples.
- Bring samples- Monday thru Wednesday so that they can go out right away if they need to, we can forward fresh samples to the UGA laboratory. (Samples brought Thursday and
- Friday will be held until shipping, the following week – and will not be as fresh.)
- Fill out diagnostic forms as completely as you can.
- Collect them ALIVE and bring them in alive, undamaged.
- If you must kill them, place the insects in alcohol.
- Do NOT crush or smash and bring more than one for ID (bring 3-5 or more).
- IF POSSIBLE, and available on the plant or in your home, collect and bring in the various life stages of the pest: adult, larva, pupa, egg, etc.
- DO NOT mail insects in envelopes or on tape – they are impossible to ID due to the handling they receive while in the mail.
- MAKE NOTES as to where the pest resides, type of damage,host plant, types of chemicals or other controls you have tried, etc. (for ID FORM).
As of 3/5/99, there are a limited number of fees for diagnostic samples.
FEES ARE CHARGED FOR:
- SOIL SAMPLES (basic test) is $6.00. For other specialized soil tests you should call for the current cost.
- WATER TESTS: basic = $12.00. All specialized water tests, call for current cost.
- DIAGNOSTIC SAMPLES sent directly to the UGA LAB without going through the local County Agent. These samples circumventing the system are not considered educational samples and are $25 per sample. So, please go through your County Extension office and use the correct forms.
- (NO CHARGE TO HANDLE: plant ID, nematodes, disease or insect ID)
If you have questions about what can be tested, Call First!
Center Publication Number: 38