Cause The fungus, Pleospora bjoerlingii (syn. P. betae = Phoma betae) can cause leaf spots and root rot of table beet, sugar beet, Swiss chard, and other Beta species. The fungus is seedborne. During the spring time, windblown ascospores are released from sexual fruiting bodies (pseudothecia) which developed the previous season on infected plant debris remaining on the soil surface.
A saclike cell in which meiosis occurs and which generally contain eight spores each.
Image shows blue stained asci with ascospores of Anisogramma anomala and rounded pollen of hazelnut.
Stephanie Hechert, 2011.
Injury to aboveground plant parts (leaves, bark, flowers, and fruit) caused by excessive exposure to solar radiation. Associated with high temperatures but not necessarily lack of soil moisture.
Rhododendron sunburn resulting in chlorotic areas near the leaf midribs and some necrosis.
Photo courtesy Jim Green.
Damage by freezing or below freezing temperatures when plants are dormant. See also frost injury.
A temporary state of suspended animation or greatly reduced metabolism. Used in reference to nematodes.
