Every grower has dealt with the frustration of a plant disease that they simply can’t get rid of. We are often contacted by farmers who are seeing symptoms such as wilting, yellowing, stunting, dieback, damping off, leafspots, and cankers, and who ask us, “What is wrong with my plants? What’s causing this, and how do I get rid of the problem?”
How We Diagnose Plant Diseases
At Sunburst, we strive to help growers by identifying the source of crop ailments, and providing solutions. When you send a plant, soil, seed, or grapevine sample to our laboratory in Turlock, California, our specialists subject these samples to sophisticated diagnostic tests such as:
- Pathogen selective media plates, which involves placing samples in multiple petri dishes with very specialized nutritional media, which are designed to only allow very specific organisms to go. This process of elimination can allow us to identify infectious pathogens.
- Microscopy, in which samples are subjected to visual examination under a microscope.
- ELISA (enzyme-linked immunosorbent sssay), in which samples are tested for the presence of antibodies signifying the presence of specific viruses.
- Real-time and reverse transcription PCR (polymerase chain reaction), a rapid means of amplifying and detecting DNA or RNA sequences indicative of certain pathogens or viruses.
- Gene sequencing, in which the DNA of pathogens are ‘read’ using a DNA sequencer, allowing us to directly identify the pathogen.
By selectively using one or more of the above diagnostic processes, we can identify a wide array of disorders caused by fungi, bacteria, viruses, phytoplasma, nematodes, as well as nutritional deficiencies.
Once we have identified the causal agent(s) responsible, we develop a remedial program designed to treat the specific ailments and deficiencies affecting the health of your plants, and ultimately improve the quality and yield of your crops.
Diseases We Diagnose
Just a few of the many pathogens and diseases we test for include, for the following crops:
Xanthomonas campestris pv. campestris – Black Rot
Phoma lingam – Black Leg, Canker, Dry Rot
Xanthomonas campestris pv. carotae – Bacterial Leaf Blight
Alternaria dauci – Leaf Blight of Carrot
Acidovorax avenae ssp. citrulli – Bacterial Fruit Blotch
Cucumber Green Mottle Mosaic Virus
Melon Necrotic Spot Virus
Squash Mosaic Virus
Lettuce Mosaic Virus
Peronospora farinosa f.sp. spinaciae – Downy Mildew
Verticillium dahliae – Verticillium Wilt
Xanthomonas campestris pv. vesicatoria – Bacterial Leaf Spot
Clavibacter michiginensis ssp. michiginensis – Bacterial Wilt and Canker
Pepino Mosaic Virus
Tobamoviruses (TMV, ToMV)
If you have any questions about the diseases we test for, contact us for more information.
Checklist for Collecting Plant and Soil Samples
- Collect sample(s) according to our sample submission guidelines.
- Place in sample bags, either:
- Double-bagged in Ziploc bags
- In our special sample bags
- Label sample bags.
- Fill out submittal sheets. Be sure to fill out sections indicating the type and age of the plant(s), and a description of the problem.
- Enclose necessary permits:
- CDFA Permit for shipping within California
- USDA Interstate Permit for those outside of California
- USDA Importation Permit for those outside of the United States
- Attach CDFA shipping label.
- Overnight the samples to Sunburst Labs. Do not use slower shipping options.
We understand that the sample collection and submission process can be a little overwhelming for those unfamiliar with the process, and even for those that are familiar with it! If you ever have any questions about collecting or submitting samples, please call us at (209) 667-4442, or send us a message using our online contact form. Our representatives will be more than happy to walk you through the process.
“I have used Sunburst Plant Disease Clinic for close to 20 years now and I’ve been very satisfied with the level of their performance year in & year out. I have trusted their lab testing expertise in many of my soil samples for disease diagnostics and the results I receive from these soil tests are vital to many of my decisions out in the field. I have learned to trust quite a lot of the results that their lab produces. Their office staff also communicates very well & are very responsive to our questions or needs. I have always received excellent service from Sunburst in all departments & look forward to continued business with them in the future.”