N THE parasitic wasp Habrobracon juglandis (Ashm.), when a cross of I unrelated stocks is made, males (haploid) come from unfertilized eggs and females (diploid) from fertilized eggs. When the parental stocks are closely related, not only males from unfertilized eggs but also males (diploid) from fertilized eggs appear. That such biparental males should be produced was puzzling until WHITING br...

S early as 1911 0. HERTWIC demonstrated two types of behavior of irA radiated Amphibian sperm. One of these, the dominant lethal effect, resulted in death of embryos due to fusion of injured sperm nucleus with egg nucleus. The other, inactivation of sperm, stimulated the egg to develop gynogenetically since injured sperm entered it but took no part in development. PACKARD (1914) observed, in ad...

Xanthomonas arboricola is a plant-associated bacterial species that causes diseases on several plant hosts. One of the most virulent pathovars within this species is X. arboricola pv. pruni (Xap), the causal agent of bacterial spot disease of stone fruit trees and almond. Recently, a non-virulent Xap-look-a-like strain isolated from Prunus was characterized and its genome compared to pathogenic...

We investigated the basis for fruit drop in walnut (Juglans regia L.) following bloom period applications of streptomycin as a potential control treatment for walnut blight, a bacterial disease incited by Xanthomonas campestris pv. juglandis (Pierce) Dye. Experiments were conducted on streptomycin-treated field plots of ‘Vina’ walnut. Four streptomycin treatments were applied at different times...

Novel species of fungi described in this study include those from various countries as follows: Antartica , Cladosporium austrolitorale coastal sea sand. Australia Austroboletus yourkae on soil, Crepidotus innuopurpureus dead wood, Curvularia stenotaphri roots and leaves Stenotaphrum secundatum Thecaphora stajsicii capsules Oxalis radicosa. Belgium Paraxerochrysium coryli (incl. gen. nov.) Cory...

The health, sustainability, and commercial viability of eastern black walnut (Juglans nigra) are currently under threat from thousand cankers disease. The disease is caused by an invasive bark beetle species, the walnut twig beetle (Pityophthorus juglandis), and its associated fungal pathogen (Geosmithia morbida). Range expansion of the beetle and pathogen has likely been facilitated by transpo...

The Virginia landscape supports a remarkable diversity of forests, from maritime dune woodlands, swamp forests, and pine savannas of the Atlantic Coastal Plain, to post-agricultural pine-hardwood forests of the Piedmont, to mixed oak, mesophytic, northern hardwood, and high elevation spruce-fir forests across three mountain provinces in western parts of the state. Virginia’s forests also have b...