ISSUE 15    August 17, 2006

PLANT DIAGNOSTIC LAB SUMMARY

Below is a summary of samples diagnosed from August 2, 2006 to August 16, 2006 (research samples and seed health testing results are not included):

Host

Diagnosis

Taxonomic name

County

Apple (ornamental)

Fall Webworm

Hyphantria species

Benson

Apple (ornamental)

Scorch

Abiotic pathology

Grant

Ash; Green; red

Ash Plant Bug

Tropidosteptes amoenus

Cass

Ash; Green; red

Scorch

Abiotic pathology

Cass

Ash; Green; red

Spider Mite Injury

Abiotic pathology

Cass

Ash; Manchurian

Scorch

Abiotic pathology

Logan

Bean; Dry

Heat stress

Abiotic pathology

Cass

Beet; Sugar

Nutrional deficiency

Abiotic pathology

Clay

Bluegrass; Kentucky

Magnaporthe Summer Patch

Magnaporthe poae

Clay

Crabapple

Poor Root Development

Abiotic pathology

Cass

Densiformis Yew

Sunburn

Abiotic pathology

Stark

Elm; American

Dutch Elm Disease

Ophiostoma ulmi

Cass, LaMoure

Household

Red Flour Beetle

Tribolium species

Fauquier

Plant Id request

Cucumber; Wild

Echinocystis lobata

Adams

Plant Id request

Rocky mountain bee plant

Cleome serrulata

Adams

Rape; Canola

Environmental stress

Abiotic pathology

Slope

Soybean

Soybean Downy Mildew

Peronospora manshurica

Unknown

Spring Wheat

Environmental stress

Abiotic pathology

Norman

Spring Wheat

Growth Regulator Effect

Abiotic pathology

Clay, Norman

Spruce

Stigmina Needle Blight

Stigmina lautii

Barnes, LaMoure

Sunflower

Growth Regulator Effect

Abiotic pathology

Cass, Cavalier

Turfgrass

Ants

Family Formicidae

Mercer

Turfgrass

Soil Compaction

Abiotic pathology

Mercer

Unidentified shrub

Powdery Mildew

Microsphaera species

Hettinger

Errata: In the August 3, 2006 issue of Crop and Pest Report, Phytophthora ramorum was incorrectly reported on an apple sample. This diagnosis should have read that the result was negative for Phytophthora ramorum. The sample was erroneously included in the report, since it is part of an on-going state survey, and not a public sample submitted to the lab for diagnosis. Also, the samples listed in the August 3, 2006 issue were for the week of July 26 through August 2, 2006.

Soybean cyst nematode screening: With recent reports of new finds of the soybean cyst nematode detected for the first time in Cass county, North Dakota and Clay county, Minnesota, growers may be wondering if the pest is present in their fields. Several labs in the region, including the NDSU Plant Diagnostic Lab, are able to process soil to screen for the soybean cyst nematode. Some labs can offer race identification services (the NDSU Plant Diagnostic Lab does not offer race identification on a routine basis). General instructions on submitting soil samples for nematode screening are summarized below:

Soil samples for nematode extraction or root rot indexing:

  • Use a soil probe to collect soil samples, 6-8 inches in depth. If possible, collect samples from areas that are at the perimeter of symptomatic plants (between healthy and symptomatic plants). This is generally the area where the pest is most active.
  • If foliar symptoms are not evident, use a zigzag pattern to collect 10-20 soil cores per every 10 to 20 acres.
  • Collect cores from areas of similar soil type and crop history.
  • Dump cores from each 10-20 acre set into a bucket or tub and mix thoroughly.
  • For nematode screening, send 1 pint (2 cups) of mixed soil in a soil sampling bag or plastic zippered bag. For Aphanomyces indexing, send about 1 gallon (32 cups) of soil per 10-20 acre set. Label the bags with a permanent marker. Don't allow paper labels to come in contact with soil.
  • Store sample in a cool, dark place until shipped to a lab. It may be a good idea to call the lab your sending samples to ahead of time, for fee information and shipping instructions.
  •  

    Kasia Kinzer
    NDSU Plant Diagnostic Lab
    e-mail: diaglab@ndsuext.nodak.edu
    Telephone: 701-231-7854


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