ABSTRACT
Four procedures were compared in their efficacy to extract juveniles of Anguina agrostis from commercial grass seed. The procedures included those currently used by the state regulatory laboratories of Oregon and California, as well as new tests developed to determine juvenile viability for the phytosanitary certification of fumigated grass seed. Eleven seed lots of Agrostis tenuis (bentgrass) and Dactylis glomerata (orchardgrass) naturally infested with varying levels of juveniles of Anguina were individually analyzed. Only one procedure, a new live recovery test, yielded nematodes in all 11 samples and is recommended as the best method for use by regulatory agencies. In comparison, although the other three extraction procedures resulted in greater numbers of Anguina agrostis juveniles per gram of seed, they failed to yield any nematodes in as many as four seed lots with low infection levels.
ABSTRACT
Hemicycliophora biosphaera n. sp. (Nemata: Criconematidae) was found in soil from a fallow field plot within the Biosphere 2 Center, Oracle, Arizona. The nematode species is characterized by continuous and irregular breaks in transverse striae in the lateral field, smooth annules, a rounded-truncate lip region with rounded anterior margins, three lip annules, first labial annule elevated and widened laterally, dome-shaped and elevated labial disc, stylet length (76-97 (mum), VA%T value (30-59), 234-273 body annules, and tail with a terminus offset, cylindrical to slightly conoid digit. Hemicycliophora biosphaera n. sp. most closely resembles H. armandae but differs from it in body width (30-39 vs. 38-54 mum), stylet length (76-97 vs. 95-119 mum), greater number of annules between the excretory pore and esophagus base (4-16 vs. 2), length of the tail terminal spike (16-28 vs. 32 mum), lower Rvan value (9-15 vs. 16), and indistinct spetanatheca vs. distinct spermatheca.
ABSTRACT
Odontopharynx longicaudata (Diplogasterida: Odontopharyngidae) was found in soil around roots of Poa annua L. growing on a golf course in San Francisco, California. This is the first record of this species in the United States. Populations of O. longicaudata were increased in the laboratory on the free-living nematode UCD Acrobeloides No. 1 (Rhabditida: Cephalobidae). Light microscopy was used to compare the morphology of fixed specimens from California and The Netherlands. California specimens were studied in greater detail by scanning electron microscopy. Emended descriptions are given for the genus and species, as well as the diagnostic morphological characters of the juvenile stages. The species is distinguished by the number and position of stomatal teeth (seven anterior, six posterior); vulva position (41-65%), length of the paired postuterine sacs (left 35-78 mum, right 29-73 mum); size and shape of the spicules and gubernaculum, and by number and position of the preanal papillae (two subventral pairs, one ventral papilla), anal papillae (one lateral pair), and caudal papillae (one pair anterior to phasmid, four posterior pairs). A neotype is designated from The Netherland collection.
ABSTRACT
The behavior of a California isolate of the predaceous nematode, Odontopharynx longicaudata de Man, was studied in water agar culture. When feeding on an Acrobeloides sp. the predator completed its life cycle in 13 to 14 days at 25 C. Optimum temperature for reproduction of the predator was 25 C, few individuals survived at 10 C, and 30 C was lethal. Males were necessary for reproduction, and at 25 C the sex ratio was about 1:1. All postembryonic stages were voracious feeders. A single female predator consumed 30 individuals of another Acrobeloides sp. in 1.5 days. Juveniles must feed in order to complete their development. Three modes of feeding were observed depending on the prey selected. A high degree of prey selectivity occurred; 6 of 17 nematode prey species were readily consumed by the predator, but there was little or no feeding on the remaining 11 species. Predation percentage varied with prey species. Consumption of Anguina pacificae and the two Acrobeloides spp. was almost 100%, consumption of A. amsinckiae,Pratylenchus vulnus, and Trichodorus sp. was 70-78%. Difference in final predator population densities was obtained after feeding on the two species of Acrobeloides. Final predator population densities increased linearly with increasing inoculum levels of the first Acrobeloides sp.
ABSTRACT
Five grape rootstocks were inoculated with 0, 100, 1,000, and 10,000 Pratylenchus vulnus. Dogridge and Saltcreek supported low average total numbers of P. vulnus, 136-705/pot, at 12 months after inoculation. Growth of both rootstocks was not affected. Harmony, Couderc 1613, and Ganzin 1 supported high average total numbers, 6-856 times the inoculum levels. Numbers in Harmony continued to increase at all levels but reduced root weight only at the 10,000 level after 12 months. Numbers in Couderc 1613 decreased by 15-30% after 12 months, and root weight was reduced at the 10,000 level. In Ganzin 1, total nematode numbers diminished after 12 months but were still at high levels; growth reduction was proportional to numbers of nematodes added. Meloidogyne incognita, M. javanica, and M. arenaria produced galls and egg masses in Harmony and Couderc 1613 only at 36 C. Galling in Ganzin 1 increased with increasing temperature. Galls in Ganzin 1 at 18 C supported mature females after 90 days. Harmony was resistant to M. incognita in single and concomitant inoculations of P. vulnus and M. incognita. At 250 days after inoculation, total numbers of P. vulnus increased above the inoculum level and the 150-day values; increase was greatest in P. vulnus added singly. Neither nematode species affected growth of Harmony.
