By Russell T. Nagata
University of Hawaii at Manoa College of
Tropical Agriculture and Human Resources Komohana Research and Extension
Center/Hilo
One of the best-kept gardening secrets of the University of Hawaii at Manoa College of Tropical Agriculture and Human Resources is the Agricultural Diagnostic Service Center (ADSC). The ADSC conducts analyses and diagnostic test for ongoing UH-Manoa research, other government agencies, businesses, farms and for the gardeners of Hawaii.
The analysis that the ADSC performs can be listed under the general heading of plant disease identification, insect identification, feed and forage analysis, chemical analysis of soil, chemical analysis of plant tissue and chemical analysis of water and nutrient solutions. The menu of services and the cost for different analyses can be found on the ADSC website at www.ctahr.hawaii.edu/site/ADSC.aspx, or do a web search for ADSC Hawaii.
While 35 analyses are listed, most of us will use only a few of the services. The most widely used services are disease and insect identification, soil pH and extractable nutrients.
The service center is headquartered on the University of Hawaii at Manoa campus and is staffed by a group of dedicated individuals. On the Big Island at the Komohana Research and Education Center in Hilo, we have Brian Bushe, who is an award-winning diagnostician. Brian handles disease and insect identification for the Big Island, as well as coordinating soil and plant tissue sample deliveries to Oahu for analysis. As for the award, Brian was selected for the State of Hawaii Governor’s Award in the category of the best individual state employee for 2009-2010.
When submitting a sample, it is very important to submit a properly collected sample, one that will be representative of the analysis needed. For insect identification, collect more than one insect, if possible, and collect different growth stages, if available. Additional information like host plant, and where insects are found on the host plant, will be beneficial to the identification.
For plant disease samples, it is best to submit samples that express the disease symptoms, but are not fully dead. A common mistake is to submit samples that are dead and beginning to rot. Identification of the primary plant pathogens from rotting plant material is made more difficult, if not impossible, due to the exponential growth of opportunistic organisms.
For diseases that cause rots, the best place to identify the causal disease organism is the zone between healthy tissue and the diseased tissue. In this intermediate zone, the disease organism can be isolated without the opportunistic organisms. Sample size should be appropriate and proportional to the sample of the host plant being submitted. A few leaves is fine for a foliar disease, but a section of a tree trunk and/or roots may be more appropriate when finding out what killed your tree. It’s always a good idea to place your insect or diseased sample in a bag or sealed container to prevent their spread.
For a good soil test it is important to get a representative sample for the location you wish to evaluate. Divide the plot into fairly uniform soil type. Each soil type will need a separate test in order to correctly recommend the amount of needed fertilizer. The submitted soil sample will need to be 2 cups, which is about half of a quart storage bag. To begin, use a shovel to dig out a section of soil 6 inches deep and place it to the side. Cut a second section about an inch thick and place the middle 2 inches of the section into a clean bucket. Repeat in several other locations and mix soil sample well and place 2 cups of soil in a plastic bag. If you have more than one sample to submit, remember to label each bag.
To submit any sample for analysis, bring it by any of the Cooperative Extension Service offices on the Big Island. The Hilo office is located in the Komohana Research and Extension Center, phone 981-5199. The office in Waimea is located in the Public Safety Complex next to the Hawaii Department of Health, phone 887-6183. In Kona soil samples are accepted by the Kona Experiment Station staff by appointment. To submit a soil sample in Kona, call Marc Meisner at 322-4896. The Experiment Station is located up the hill from the Cooperative Extension Service Office in Kainaliu, opposite the Aloha Theater. Payment can be made by cash or check. Credit cards are not accepted at this time.
For more information on this and other gardening topics, please visit the CTAHR electronic publication website at http://www.ctahr.hawaii.edu/Site/Info.aspx or visit any of the local Cooperative Extension Service offices around the island. I can be reached at russelln@hawaii.edu.
