The genus Ditylenchus has been divided into 2 groups: the Ditylenchus triformis-group, and the Ditylenchus dipsaci-group based on morphological and biological characters. A total of 18 populations belong to 5 species of Ditylenchus was studied: Ditylenchus africanus, Ditylenchus destructor, Ditylenchus myceliophagus and dipsaci, Ditylenchus weischeri, the first 3 belong to the Ditylenchus trifo...

ABSTRACT The stem nematode Ditylenchus dipsaci is of great economic importance worldwide as a parasite of agricultural crops and horticultural plants. The internal transcribed spacer (ITS) of rDNA from 23 populations of the D. dipsaci complex from various host plants were amplified and sequenced. Seven previously studied populations were also included in the study. The phylogenetic analysis of ...

The alfalfa race of Ditylenchus dipsaci parasitized and caused characteristic symptoms on nonhost seedlings of sweet clover, onion, tomato, sugarbeet, and wheat in controlled growth-chamber studies. Although the nematode was unable to reproduce on any of the cultivars, it caused plant mortality ranging from 20% on sugarbeet and tomato to 100% on onion.

Ground and whole Ditylenchus dipsaci maintained on onion callus contain no culturable micro-organisms when tested with five check media. Healthy onion callus does not produce pectolytic enzymes. Pectolytic enzymes are present in infected callus. These enzymes are, however, associated with resident nematodes and not host tissues. These results suggest that D. dipsaci is the actual source of the ...

Ditylenchus dipsaci larvae survived in soil without a host plant for at least 242 days when held at 15 C and 21 C. Larvae held at 15 C remained infective for 212 days. Moisture levels within both clayey and sandy soils did not appreciably affect recovery of larvae. Active nematodes recovered from soil are not necessarily infective. Temperatures of -12, 0 and 4 C had little adverse effect on lar...

Transmission of Corynebacterium insidiosum (McCull.) Jensen (cause of bacterial wilt in alfalfa) by the stem and bulb nematode Ditylenchus dipsaci (Kiihn) was demonstrated by Hawn (3) . Disease development in plants where D. dipsaci was the vector was comparable to that in the controls where wilt was induced by the root-ball soak method devised by Cormack, Peake and Downey (1) . Furthermore, th...

White flagging of alfalfa, Medicago sativa 'Ranger, found associated with Ditylenchus dipsaci in the Columbia River Basin was observed in northern Utah during 1971. This is a report on chloroplast changes, induced by D. dipsaci in alfalfa leaves, as observed with an electron microscope. Leaves from alfalfa plants infected with D. dipsaci were either devoid of normal pigmentation or displayed va...

Field population densities of Ditylenchus dipsaci associated with shoot tissue of Phlox subulata were monitored during two consecutive growing seasons and intervening periods of overwintering and plant storage. The population density increased significantly through four peaks during the first growing season, and decreased significantly during storage at 5-7 C or overwintering in the field. Duri...

Ditylenchus dipsaci showed an affinity, in relation to infection, for the temp at which it had been acclimated. The optimum infective temp was also correlated with field temp when collections were made during different seasons and from climatically different geographical areas. Nematode developmental stage did not influence infectivity.

Simultaneous inoculations of alfalfa with Meloidogyne hapla larvae and Ditylenchus dipsaci at 16, 20, 24, and 28 C did not depress penetration of either nematode in 'Nev Syn XX' -a selection resistant to M. hapla and D. dipsaci, 'Vernal 298' -a selection resistant to M. hapla and susceptible to D. dipsaci, 'Lahontan' -a cultivar resistant to D. dipsaci and susceptible to M. hapla, and 'Ranger' ...