The Olmecs were the first major civilization in Mexico following a progressive development in Soconusco. They lived in the tropical lowlands of south-central Mexico, in the present-day states of Veracruz and Tabasco. It has been speculated that Olmec derive in part from neighboring Mokaya and/or MixeâZoque.
One of the most common types of mechanical injury to dogwoods is impact from lawnmowers. Injuries of this type can invite basal stem rot disease and insect borer infestation. Similarly, string trimmer impact can sometimes bruise or girdle the cambium (the vital layer of tissue under the bark).
Root Diseases. Root rot is a common fungal disease that affects roots of otherwise healthy trees. Armillaria is a common fungal root disease in maple, oak and ornamental trees. Phytophthora root rot affects smaller nursery and landscape deciduous trees in areas with poor soil drainage.hyronectria is a fungal canker that affects woody ornamental trees and plants, fruit trees and forest trees. Seiridium canker causes infected twigs to turn brown, forming a sharp contrast against the healthy green foliage of the tree. Hardwood trees such as aspen and oak are susceptible to hypoxylon canker.