Rapid Diagnostic Tests for Greenhouse and Nursery Crop Monitoring

Although rapid diagnostic tests have been available for a phone number of years, they have not been fully utilized by Oklahoma producers. These tests allow for fast and accurate disease diagnostics in greenhouse, greenhouse and field settings. few materials are required and the rapid results can be used to guide management decisions, including choice of the appropriate chemical for disease command .



Plants exhibiting fishy symptoms ( Figure 1 ) can be tested on-site with diagnostic test kits. Results are available in 5 minutes to 30 minutes. If the sample is sent to a plant diagnostic lab, delivery alone may take two days or more.

Plant exhibting suspicious sysmptoms

Figure 1. on-site diagnostic kits can be used to quickly test leery symptoms in greenhouse and nursery crops .


The results are highly accurate for symptomatic plant material. In some cases, the test will detect the list organism, vitamin a well as close relate pathogens. This will be indicated on the kit out instructions .

If screening asymptomatic plants, it is suggested to send plant corporeal to a diagnostic implant testing ground, since the rapid tests may not detect the pathogen in asymptomatic plants .


The tests do not require any speciate train or experience. All materials are included in the test kit, except normally available supplies including paper towels, scissors and a dull aim ( such as a marker ) .


The test materials are safe and non-hazardous. They can be stored in the refrigerator until needed .

Wide Selection

rapid test kits are available for a large count of plant pathogens. mesa 1 ( page 5 ) lists the more common plant pathogens in greenhouses and nurseries that can be tested with rapid tests. A list of U.S. suppliers is shown in table 2 ( page 6 ). Contact the suppliers or visit their websites for complete lists of rapid tests .

Good Shelf Life

Tests can be purchased in little ( 5 to 10 ) or big ( 25 to 50 ) quantities. Shelf-life is one year or more, if properly stored in the refrigerator. Desiccant packets are included to keep materials dry, therefore do not remove them from the test kits .

Low Cost

cost is $ 10 to $ 20 per trial ( including transport ), depending on the exact test and supplier. Shipping costs to the diagnostic plant testing ground or time taken to drive to an Extension office by and large cost more .


Interpretation of results

If a test yields a positive result, the kits do not provide management recommendations. Consult the local county Extension office, Extension Specialist, or chemical representative for steering .

Results are pathogen specific

The tests merely provide a convinced or negative resultant role for a single pathogen. If the results are negative, the agriculturist may need to test for extra organisms. Contact a plant diagnostic lab if extra test is needed .

Tests are not available for all pathogens

Table 1. abbreviate list of rapid, on-site diagnostic tests for greenhouse and nursery growers. *

Disease Hosts Pathogen Testing formats
Bacterial blight Geranium, Pelargonium Xanthomonas campestris pv. pelargonii Agristrip
Bacterial wilt Geranium, tomato, potato Ralstonia solanacearum Agristrip, ImmunoStrip®
Calibrachoa mottle Calibrochoa, Petunia Calibrachoa mottle virus (CbMV) ImmunoStrip®
Cucumber mosaic Many Cucumber mosaic virus (CMV) Agristrip, ImmunoStrip®
Fire blight Rosaceae (apple, pear and related) Erwinia amylovora Agristrip, ImmunoStrip®
Hosta virus Hosta spp. Hosta Virus X (HVX) ImmunoStrip®
Impatiens necrotic spot Many ornamentals Impatiens Necrotic Spot Virus (INSV) Agristrip, ImmunoStrip®
Pepino mosaic Tomato, basil Pepino Mosiac Virus (PepMV) Agristrip, ImmunoStrip®
Phytophthora diseases Many Phytophthora spp. ImmunoStrip®
Plum Pox Virus Peaches, Nectarines, Prunus spp. Plum Pox Virus Agristrip, ImmunoStrip®
Potyvirus group Many Potyvirus group viruses ImmunoStrip®
Tobacco mosaic Many Tobacco Mosaic Virus (TMV) Agristrip, ImmunoStrip®
Tomato mosaic Many Tomato Mosaic Virus (ToMV) Agristrip, ImmunoStrip®
Tomato spotted wilt Many ornamentals Tomato Spotted Wilt Virus (TSWV) Agristrip, ImmunoStrip®

*Contact supplier or view their websites for a arrant list of products .

Basic Instructions for Using a Rapid Test

Select plant tissue

diagnostic plant weave is preferred ( A and B ). Samples can be cut or torn from several plants or establish parts. If roots are used, rinse roots in water to remove territory or potting mix and blot dry on paper towels .
Selecting plant tissue

Open bag (if necessary)

Plastic origin bags are included with the kit. Some kits include bag pre-filled with extraction buffer zone. These filled bags must be opened with scissors ( C ). Hold the udder upright sol that the sample buffer does not leak from the udder .
Scissors opening a bag in front of a plant

Place plant tissue in bag

open sample bag. If two layers of plastic mesh are portray, be indisputable to insert the plant weave in between the layers ( D ). Add roughly one ( 1 ) public square column inch of plant tissue ( E ). Do not use excessively much establish tissue or the test may not work by rights .
Plant tissue in a bag and square inch of plant tissue

Add buffer (if necessary)

Follow kit out instructions and add the appropriate sum of buffer to the bag ( F ). Some companies provide pre-filled bags .
Added butter in a bag

Extract sample

Rub a blunt object ( i. pen or marker ) across the mesh until the plant weave is macerated and a green-brown melted fills the bag ( G and H ) .
A pen rubbing the plant until it is macerated into a green-brown liquid

Test the sample

Strips or cartridges for specific pathogens are included with the trial kit. Allow strips, cartridges and distill solution to warm to board temperature before running the test. Strip method: The excerpt solution may be poured into a houseclean container such as a toast cup or the strip may be immediately inserted into the cup of tea ( I and J ). Be sure to insert strips in the proper guidance and do not insert above the maximum fill line. Cartridge method: Deposit the bespeak sum of excerpt onto the test spot ( K ) .
Testing the sample with the strip and cartridge method

Interpretation of results

Wait the bespeak sum of prison term and examine the quiz leach or cartridge. If there is only one line ( C- command line ) this indicates the test worked properly, but the consequence is negative .
A negative test

If two lines are confront ( T-test line and C-control line ), the examination worked properly and the sample distribution is plus for the test pathogen .
A positive test

If no lines are stage, the test is disable and the drug user should visit the trouble-shoot guidelines listed below and included with the test kit .
An invalid test


If the test malfunctioned, please review the specific kit out instructions for troubleshooting. The most coarse errors are listed below .

1. Control line did not develop. This may occur if the sample was inserted excessively deep in the sample distribution infusion ( L and M ). This invalidates the results, so the test should be repeated .
Example of test strip malfunctioning due to be inserted too deep

2. Extract does not move into the strip or moves very slow. In most cases, this occurs because excessively much plant weave was used. The extract may be thick and gluey ( N ). Some plants have naturally syrupy blackjack and this interferes with the excerpt moving through the composition. Rerun the trial using less plant tissue or dilute the distill with extra extract buffer. Another cause may be that cold buff was used in the test. therefore, always warm kit supplies to room temperature before running the test .
An example of a test strip malfunctioning due to the extract not moving into the strip or moves very slow

3. Green or pigmented test line develops. The trial line should be a pink-purple color. If the test line appears green, it should not be considered a incontrovertible result. It is likely besides much plant material was used or the plant sap is syrupy. Rerun the test using less plant tissue or dilute infusion with extra extract buffer. Do not test orange, bolshevik, purple fruits without contacting the company ( O ). No reaction or false positive bands may appear .
Test malfunction due to a green or pigmented test line and should be reran

4. Test or control line is weak (faded). Verify that the kit has been used before the passing date. It is possible that the trial materials were leave open excessively long and they absorbed moisture. therefore, keep kit components closed and stored in the refrigerator between uses. A attenuate, watery T-test argumentation may besides indicate that the pathogen titer ( assiduity ) is broken in the establish ( P ) .
An example of a test malfunction due to test or control line is weak (faded)

5. Other concerns. If other strange results occur, contact a product congressman. They will worry shoot the problem, but the sample may need to be forwarded to a establish diagnostic lab for extra test .

Table 2. tilt of U.S. Suppliers of rapid test kits. *
*Other suppliers may be available

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