After tropical storms and hurricanes, there are always discussions about the trees which have fallen during the storm. Many times the trees in question have landed on a home or some other structure which resulted in multiple thousands of dollars damage.
Commonly, water and laurel oaks are the culprits. These large trees are frequently found in the panhandle area, have shallow roots, and have a relatively short life span.
The signs of these trees reaching the problem stage are many. The crowns die out, their centers decay, and fungal growths speed their decline.
The usually hardy pines have their problems too, and storms provide the ideal time for them to succumb to conditions which should be recognized and reacted to beforehand. One of those windows to the future is a bulbous gall easily observed but usually passed by.
A bulbous growth on pines is a sign of problems to come. The warm humid days of summer are ideal for its spread to many oaks, then on to new pine infections. The leverage applied by storm winds can result in breaking trunks.
Fusiform rust is caused by the fungus Cronartium quercuum f.sp. fusiforme. It has been identified as the most serious disease affecting pines in the southeastern U.S. and is killing many young trees.
It is usually found in loblolly and slash pine species, both of which are commonly found in both the wild and planted stands. Occasionally this disease is observed in longleaf pines as well.
The infections typically result in swollen galls on the branches and stems. These growths vary in appearance, but they are usually the shape of a spindle or cylinder.
Sometimes the branches and stems are killed past the gall and breakage is common. Another symptom of this condition is pitch exudation.
Pine sap leaks or weeps from the gall, giving it the moist appearance of a septic wound. Opportunistic insects and the fungus cause this condition.
Cylinder shaped galls form where the spores land and flourish. On branches they may result in breakage during wind events.
Curiously, the disease is not spread from pine to pine. The spores of this fungus are spread on the wind to the tender young leaves of oaks, with red and black oaks being particularly susceptible.
Water oaks and laurel oaks are two of the host species which are quite common in panhandle Florida. It should be noted these are the same oak species which also host the multitude of cankerous growths inflicted by the tiny oak gall wasp.
The disease is passed around among oaks through a series of different spore types until warm temperatures and high humidity develops. A tiny spore called a basidiospore or sporidia is produced and scattered on the breeze.
A pine tree’s needles and tender, succulent bark are ideal for a new infection. Only a few hours on the pine’s vulnerable surface are necessary for the fungus to become established.
If the humidity suddenly drops, the pines may be spared infection. The sporidia are extremely delicate and quickly lose there infectious ability if the environment dries out.
If the pine is infected after eight years of age it will suffer few ill effects from the disease, but can aid with the fungus’ dispersal. Even that is a bad sign.
Leave a Reply