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United States Department of Agriculture

Agricultural Research Service


item Inserra, R
item Duncan, L
item Dunn, D
item Kaplan, David
item Porazinska, D

Submitted to: Nematologica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Weeds can serve as alternate hosts for important crop pests. In Florida, wild asters are common and often support lesion nematode populations. Lesion nematodes are important economic pests of many crops. A lesion nematode that attacks citrus is very similar in appearance to a lesion nematode species common on aster. The citrus-parasitic lesion nematode is not wide-spread and if found at a citrus nursery or proposed nursery site, the site cannot be used as a state-certified nursery site. This article reports comparison of morphological traits of taxonomic significance that distinguish the two nearly-identical lesion nematode species. These findings are in use by the Florida Department of Agriculture and Consumer Services, Department of Plant Industry, the agency responsible for nursery site certification. Application of these findings prevent sites from being de-certified incorrectly.

Technical Abstract: Pratylenchus sp. from Florida, Japan (P. pseudocoffeae), Costa Rica and Guatemala (P. gutierrezi), and Indonesia (P. coffeae) were studied to compare the morphologies. Pratylenchus coffeae from citrus in Florida differed from all other populations, including P. coffeae from coffee in Indonesia, in having medial and lateral lips that were fused rather than separate, when viewed en face with scanning electron microscopy. Pharyngeal overlap length and distance from the base of the oesophageal gland lobe to the head end were the only morphometric characters of diagnostic value to separate female P. pseudocoffeae from P. gutierrezi and P. coffeae from Indonesia. Pratylenchus pseudocoffeae females also had subhemispherical or hemispherical tails with smooth termini vs subcylindrical tails with bluntly rounded an sometimes coarsely annulated termini for P. gutierrezi. The Pratylenchus population from aster in Florida most closely resembled P. pseudocoffeae based on tail and en face lip morphology, long pharyngeal overlap, long distance between the base of the oesophageal gland lobe to the head end and multivariate analyses of morphometric variables. The head pattern of P. coffeae from coffee in Indonesia differed from patterns previously attributed to this species.

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