Phenol extraction and cesium trifluoroacetate ultracentrifugation were compared for efficiency in the extraction of DNA from eggs and second-stage juveniles of four species of Meloidogyne. The second method proved to be more satisfactory in that it yielded larger amounts of DNA, shortened the extraction period, and reduced sample handling by eliminating phenol and ether extraction and RNAse tre...

Winter survival of Meloidogyne incognita in six soil types (Fuquay sand, Norfolk loamy sand, Portsmouth loamy sand, muck, Cecil sandy clay loam, and Cecil sandy clay) was determined in microplots at one location from November 1981 to May 1982 and from November 1982 to March 1983. Survival, based on second-stage juveniles (J2) of M. incognita, from November 1981 until May 1982 ranged from 1% in ...

Heterodera avenae is an important soil-borne pathogen that affects field crops worldwide. Chemical nematicides can be used to control the nematode, but they bring toxicity to the environment and human. Trichoderma longibrachiatum has been shown to have the ability to control H. avenae cysts, but detailed microscopic observations and bioassays are lacking. In this study, we used microscopic obse...

Walleye is a very common recreational fish in Canada with a strong cannibalism tendency, such that walleyes with larger sizes will consume their smaller counterparts when food sources are limited or a surplus of adults is present. Cannibalism may be a factor promoting population oscillation. As fish reach a certain age or biological stage (i.e. biological maturity), the number of fish achieving...

Seventeen leguminous species common to the Pacific Northwest were evaluated as potential hosts of the pea cyst nematode, Heterodera goettingiana, in both greenhouse and field experiments. In all experiments, juveniles of H. goettingiana penetrated roots of these 17 species with the exception of greenhouse-grown chickpea. Nematodes molted and developed into swollen third-stage or fourth-stage ju...

the effect of salicylic acid (sa) on induction of resistance against root-knot nematode (meloidogyne javanica) and the effect of m. javanica to induce biochemical defense responses in tomato (solanum lycopersicum l.) roots at six-leaf stage were investigated. meanwhile, the effect of different concentrations of sa on mortality of second stage juveniles of m. javanica was examined. changes in th...

Psychopath. The word alone evokes powerful emotions and images. Attaching that label to a juvenile offender is a serious charge, and should be done so with caution, especially given that the standard assessment tools for psychopathy were originally developed for adults, not juveniles. As the MacArthur Research Network on Adolescent Development and Juvenile Justice has shown, and as the U.S. juv...

Gracilacus wuae n. sp. from soil associated with cow parsnip in Ontario, Canada is described and illustrated. Morphologically, females have a long stylet ranging from 80 to 93 µm long, the lip region not offset from the body contour, without lateral lips but with large and flat submedian lobes, the mouth opening slit-like elongated laterally and surrounded by lateral flaps, the excretory pore i...

changes of ions (na+, cr, k+), osmolarity and water concentration of body tissue, size and number of gill chloride cells as well as mortality percentage of the juveniles caspian roaches in weight groups of0.2, 0.5 & 1g water satiny stress were studied. the salinities tested  were 0 (fesh water), 7, 12.5 & 16g/lit and the assessments were completed 0, 12, 24, 48 & 72 hours after exposure. result...

The dynamics of a predator-prey system, where the predator has two stages, a juvenile stage and a mature stage, are modelled by a system of three ordinary differential equations. The mature predators prey on the juvenile predators in addition to the prey. If the mortality rate of juveniles is low and/or the recruitment rate to the mature population is high, then there is a stable equilibrium wi...