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Disease Note. Occurrence of Heterodera iri in Putting Greens in the Northeastern United States. J. A. LaMondia, Department of Plant Pathology and Ecology, Connecticut Agricultural Experiment Station, Windsor 06095. R. L. Wick, Department of Plant Pathology, University of Massachusetts, Amherst 01003. Plant Dis. 76:643. Accepted for publication 11 February 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0643C. Cyst nematodes were recovered from putting green soils from 17
sites in Connecticut, Massachusetts, Maine, New York, New Hampshire,
and Rhode Island. The greens sampled were a mixture of annual
bluegrass (Poa annua L.) with creeping bentgrass (Agrostis palustris
Hudson) and/or velvet bentgrass (A. canina L.). Several of the greens
showed stress consistent with cyst nematode damage, and other plantparasitic
nematodes were also present. Cyst nematodes from seven
sites in Connecticut, Massachusetts, Rhode Island, and New York
were identified as Heterodera iri Mathews (1). In the United States,
this nematode had previously been identified only in New York and
Michigan (2). The pathogenicity and host range of H. iri remain unknown. In a preliminary greenhouse test, however, new cysts, eggs,
and juveniles were produced on roots of creeping bentgrass (cv.
Penncross) inoculated with H. iri juveniles. Mature cysts were pale
to dark brown and spheroid to lemon-shaped, with a small vulval
cone and well-developed neck. The vulval cone was bifenestrate with
a strong vulval bridge and conspicuous bullae. Fenestrae (n = 33)
averaged 44 X 25 µm. Males were numerous in samples taken in
late May but not in those obtained during the summer. Males (n
= 30) had constricted head regions and were 1,232 X 31 µm with
a strong stylet averaging 30 /-Lm long. Spicule length averaged 39 µm.
Second-stage juveniles (n = 100) averaged 611 X 23 /-Lm and had
strong stylets 25 µm long with slightly concave basal knobs. Juveniles
had true tails, 89 µm from anus to tail tip and a long (56 µm) clear
tail. Eggs containing juveniles (n = 100) averaged 132 X 50 µm. |