Blog



Testing for Fusarium Wilt on Canary Island Date Palm

June 10th, 2015
Padma Sudarshana, Ph.D. - Senior Scientist/Account Manager

Canary Island date palm is a popular ornamental tree of landscapes throughout the world. Fusarium wilt caused by Fusarium oxysporum f. sp. canariensis is the most destructive disease affecting palm trees and reported to be widespread. The Fusarium wilt is a soil borne disease and the pathogen is transmitted mechanically through pruning tools (Feather et al. 1979). Symptoms initiate as one side of leaflets turn yellow to brown and the other side remains green. Extensive discoloration occurs along the petiole and the internal vascular tissue appear as pink to reddish brown (Hodel, 2009). Infected palms die rapidly in hot and dry conditions. Current methods of disease control include prevention of pathogen introduction through infected material and removal of infected trees. In the absence of effective prophylactic measures, screening palm trees, nursery materials and seed lots for the presence of pathogen is essential to limit disease spread (Plyler et al. 1999).

Fusarium wilt diagnosis involves isolation of the fungus from affected plant tissue and culturing on agar media. Because several non-pathogenic Fusarium oxysporum isolates are associated with diseased palms, fungal cultures are isolated and further tested by PCR methods. The culture based method requires 8-10 days to complete. CSP Labs has developed a Bio-PCR method for faster and sensitive method for the detection of F. oxysporum f. sp. canariensis isolates and the test can be completed within 5-7 days. The sample submission forms can be found here.

canariensis

Fusarium oxysporum f. sp. canariensis. Left on TPDA agar. Right on Komada agar.

 

References

  1. Feather, Tolbert V., Howard D. Ohr, and Donald E. Munnecke. “Wilt and dieback of Canary Island palm in California.” California Agriculture 33.7 (1979): 19-20.
  2. Hodel, 2009. Palm diseases in the landscape. UC ANR Publication 74148
  3. Plyler, T. R., Simone, G. W., Fernandez, D., and Kistler, H. C. 1999. Rapid detection of the Fusarium oxysporum lineage containing the Canary Island date palm wilt pathogen. Phytopathology 89:407-413.




Pistachio Bushy Top Syndrome

June 3rd, 2015
Padma Sudarshana, Ph.D. - Senior Scientist/Account Manager

In the recent years, a large number of pistachio trees in California and Arizona orchards have exhibited symptoms such as shortened internodes, twisted roots, stem galls and bushy top. The abnormal growth symptoms were observed with pistachio rootstock, UCB-1 and known to affect 10% to 90% of the trees in an infected orchard (Stamler et al. 2014). A bacterial pathogen, Rhodococcus fascians was identified as the causal organism of the pistachio bushy top syndrome. The California Department of Food and Agriculture (CDFA) assigned a pest rating-C to the pathogen based on the knowledge that R. fascians infections could lower crop yield and result in serious recurring economic losses to the pistachio industry. R. fascians survives as an epiphyte on plant surfaces and favors moist conditions and moderate temperatures. The bacterial transmission occurs primarily through the use of contaminated plant material and can also spread through irrigation water (Chitambar, 2015). R. fascians has a broad host range and survives in soil in the presence of host tissue. The use of disease free plant materials for propagation can be an effective control strategy to limit pathogen spread.

CSP Labs has validated a PCR test for the detection of R. fascians. The instructions for sample submission and forms can be found here.

References:

  1. Stamler, R. A., J. Kilcrease, R. J. Heerama, C. E. Kallsen, and J. J. Randall. 2014. Rhodococcus sp. associated with Pistachio Bushy Top Syndrome in California and Arizona. Plant Disease (accepted for publication).
  2. Chitambar, J. 2015. Rhodococcus fascians. CDFA’s Division of Plant Health’s Pest Ratings and Proposals.




CGMMV Testing by Seed ELISA and qRT-PCR

Sukhi Pannu - Director, Testing Services

December 10th, 2014
Sukhi Pannu - Director, Testing Services

Cucumber Green Mottle Mosaic Virus (CGMMV), a quarantine pathogen that infects a number of cucurbit crops, has been found in the U.S. and Australia over the last two years. In an effort to help control the occurrence of the disease the American Seed Trade Association (ASTA) has published a brochure in which it’s recommended that seed lots be tested by the National Seed Health System (NSHS) approved and International Seed Testing Association (ISTA) validated method. The method is an enzyme linked immunosorbent assay (ELISA) in which 1,500-2,000 seeds, or 10% of the total for smaller lots, are tested. Australia’s Department of Agriculture, Fisheries and Forestry (DAFF) is requiring that 9,400 seeds are tested by ELISA, and may soon require that a real-time RT-PCR (qRT-PCR) method is used.

You can find more information regarding causes, diagnosis, and control of CGMMV in the ASTA CGMMV brochure.

CSP Labs continues to run seed ELISA and qRT-PCR assays, both in a high-throughput fashion, capable of fast turnaround even for the large sample sizes (9,400 seeds) as required by DAFF.

Please contact us regarding your testing needs by calling or emailing Sukhi Pannu at (916) 655-1581 or sukhi.pannu@csplabs.com.




Hybrid purity assay with SNP markers by using HRM (High Resolution Melt)

Sukhi Pannu - Director, Testing Services

June 18th, 2012
Sukhi Pannu - Director, Testing Services

CSP Labs has developed SNP-HRM assays to determine hybrid purity. These assays are inexpensive when compared to other methods including isozymes, total proteins, grow outs, RAPD and SSR markers available for hybrid purity. SSR markers are very reliable but are relatively expensive.
Our SNP-HRM assays allow us to process a large number of samples in less time. Since our cost to run these assays is significantly lower as compared to other DNA marker tests, this gives us the ability to pass the savings on to our customers. Our customers will not only pay less for the tests but they will also get better turnaround time.
At this time our SNP-HRM assays are working well for tomatoes. Assays for other crops including watermelon, melon, pumpkin, squash and pepper will be available in the near future.
Click here for more information.

Please contact Sukhi Pannu at sukhi.pannu@csplabs.com for any questions you might have.