Initial morphometric data and descriptions of males and the four juvenile stages of Xiphinema coxi coxi Tarjan, 1964 collected from soil about the roots of alfalfa (Medicago sativa L.) at Gainesville, Florida, and from a greenhouse microplot at Fayetteville, Arkansas, are given. Males were similar morphometrically and in shape to females and had 3-5 preanal supplements. The four juvenile stages...

In Arkansas wheat is commonly grown either in rotation or double cropped with soybean. Surveys from 1986 to 1988 identified 18 phytoparasitic nematode species in Arkansas wheat fields. The frequency of occurrence, as a percentage of the total number of samples (199), for the following nematodes was Heterodera glycines 43%, Quinisulcius acutus 40%, Pratylenchus scribneri 37%, Helicotylenchus pse...

The 18S ribosomal DNA (rDNA) and cytochrome oxidase I region of mitochondrial DNA (mtDNA) were sequenced for 24 Xiphinema americanum-group populations sourced from a number of geographically disparate locations. Sequences were subjected to phylogenetic analysis and compared. 18S rDNA strongly suggested that only X. pachtaicum, X. simile (two populations) and a X. americanum s.l. population from...

The effects of four soil types, soil porosity, particle size, and organic matter were tested on survival and migration of Xiphinema americanum. Survival and migration were significantly greater in silt loam than in clay loam and silty clay soils. Nematode numbers were significantly greater in softs planted with soybeans than in fallow softs. Nematode survival was greatest at the higher of two p...