Conifer Trees Clearwater, Fl
Ambrosia beetles – The ambrosia beetle infests both conifer and hardwood trees that are severely stressed. The adult beetle bores a round hole approximately 1/16 on an inch in diameter through the trunk tissue near the base of the tree and create a series of tunnels or “galleries” where they will live and reproduce. Once in the tree the adults and larvae feed on a fungus brought into the galleries by the beetle. Signs of an ambrosia beetle infestation are fine fluffy boring dust accumulating around the base of the tree and small entrance holes with dark stains. Seek professional assistance to determine the source of the stress.
Black turpentine beetle – Pine bark beetles such as the black turpentine beetle and the ips bark beetles are deadly insects that kill individual pine trees as well as entire forests of southern pines (slash, loblolly, longleaf and sand pines). They are attracted to trees that have been stressed by natural causes such as wildfire, drought, flooding, lightning or trees that have been damaged by manmade causes such as soil compaction, root damage, pH problems and physical injury. The best way to avoid their attack is to keep your trees healthy. If they are discovered soon after an infestation they can be controlled with an approved insecticide. If the pine’s foliage is turning to a reddish color it is too late. Once a tree is beyond treatment the entire tree should be cut down and buried at an appropriate landfill and the stump ground below ground level to eliminate the beetles and their larvae. Pine bark beetles left in a tree will emerge and can attack nearby trees. The beetle can successfully attack stressed trees and sometimes even healthy trees.
The black turpentine beetle bores through the bark in the lower trunk section and feeds on vascular tissue thus disrupting the flow of water and nutrients within the tree. The signs of a black turpentine beetle attack are pitch tubes in the lower trunk. A pitch tube is created when the beetle bores into the vascular system and saps mixes with boring dust and oozes out the boring hole and forms a reddish blob about the size of a nickel around the boring hole. As you will probably not see the insect the best method of identifying pine bark beetles is the presence of pitch tubes. If your pine tree has been struck by lightning or appears stressed seek professional help immediately.
Ips pine bark beetles – Ips pine bark beetles are the #1 killer of southern pine tree species including slash pine (Pinus elliottii), loblolly pine (Pinus taeda), longleaf pine (Pinus palustris) and sand pine (Pinus clausa). (See the information on pine bark beetles above under black turpentine beetle for a more detailed explanation of the significance of the beetles). They typically attack the trunk and upper branches of stressed native pine trees. The stressed pines undergo a physiological change and emit a scent that attracts the flying beetles. The beetles bore through the pine’s bark and feed on vascular tissue carrying food and kill the tree in the process. The signs of attack are pitch tubes on the trunk. If pitch tubes are discovered on the trunk early enough the pine can be treated with an approved insecticide. If the tree is dying it should be removed and buried in a landfill and the stump ground below grade as the beetles will emerge and fly to other trees. Adjacent trees should be sprayed as a precaution. The best preventative is to keep your pine trees healthy. If your pine is struck by lightning or if you think it is stressed consult with a professional immediately.
Pine sawflies – Sawflies are actually non-stinging wasps that cause the defoliation of pine tree branches. Sawflies common to Central Florida include the redheaded sawfly, blackheaded sawfly and slash pine sawfly. The damage is caused by the feeding of the sawfly larvae. Symptoms are small reddish stubble at branch tips where the sawfly has chewed the pine needles almost back to the fascicle (point of attachment). The sawfly can be controlled with an approved insecticide.
Spider mites – Spider mites are not true insects but are arachnids and closely related to spiders. They can cause serious damage to southern red cedar (Juniperus silcicola) and Italian cypress (Cupressus sempervirens)particularly in hot dry weather. Signs are a browning of the foliage. An approved miticide will control spider mites.
Disease problems for Trees
Heart rot – Heart rot is a disease caused by the fungus Fomes pini. The fungus spores that cause heart rot are windborne and enter the tree through old dead branch stubs left on the tree. The signs of attack are the presence of sporophores on the trunk. The sporophores can be large shelf like sporophores up to eight inches across or smaller bracket like sporophores. The sporophores are usually gray or brownish black with a white margin. The disease is not deadly but slowly destroys the heartwood leaving the tree more susceptible to failure. Consult with a professional if you observe sporophores on the trunk.
Juniper blight – A disease caused by the fungus Phomopsis juniperovora, infects southern red cedar, Italian cypress, arborvitae and many ornamental junipers. The signs are blight (dieback of foliage) on the tips of the branches causing the foliage to turn reddish. The disease advances into the stem killing the xylem tissues. The infection occurs usually during spring when warm wet weather is prevalent and the plant is adding new succulent growth. It has similar symptoms of spider mite damage and consequently the plant should be checked by a professional to determine the treatment. Sometimes the plant is being infested by juniper blight and spider mites simultaneously. An approved fungicide can control this disease.
Pitch canker – A disease caused by the fungus, Fusarium lateritium, shows up as dead branches in the crown of our native pine trees. The fungus does not produce a sporophore but if the bark is peeled away from the canker (dead stem tissue usually discolored and shrunken) the xylem will be soaked and stained with resin. The spores of the fungus enter the tree through wounds and infect the tissue. Chemical control is not recommended. Try to prevent unnecessary wounds on your trees.
Miscellaneous problems of conifer Trees
Galls – Galls are swollen areas on stems or leaves that are caused by abnormal growth of plant cells induced by insects, nematodes or by pathogens such as fungi and bacteria. The primary cause of galls is caused by insects such as wasps that wound plant tissue and lay eggs in the wounded area. The plant grows tissues in response to the wounding that encases the eggs. The larvae will hatch in the gall and feed off of plant material within the gall until the insect becomes an adult. The adult will bore a hole in the gall and emerge to complete its life cycle. Some insects that cause galls to form include wasps, aphids, psyllids and midges. Galls come in a variety of shapes, sizes and colors. Some galls appear as a fruit hanging from a stem, other galls appear as a very small dot on a leaf. Galls do not cause serious damage to trees and control is not generally recommended.
Pine chlorosis (yellowing of pine foliage) – The yellowing of our native pine trees is a serious problem in Tampa Bay and is worse every year as more forest land is converted to residential. It is common in the Tampa Bay area to observe pine trees with yellowing foliage. Most often the pine tree is succumbing to a soil pH problem. The three pine species native to Tampa Bay are the slash pine (Pinus elliottii), longleaf pine (Pinus palustris) and the sand pine (Pinus clausa). All three species require an acidic based soil and the majority of inland soils are acidic. Florida’s bedrock is composed of limestone which is alkaline when dissolved. Soil is composed of mineral material (eroded limestone particles), organic material (decaying plants and animals), water and oxygen. Even though the bulk of Florida’s soils are composed of particles eroded from the alkaline bedrock material, the soils are acidic due to the tremendous amount organic matter that grows and decays into the soil. The sub-tropical climate allows vegetation to grow most of the year and consequently the organic plant matter which is acidic dominates the soil.
Pine trees need iron to help manufacture chlorophyll, the green pigment that is a constituent of photosynthesis. Plants absorb nutrients such as iron only after they have been chemically changed to a liquid. Iron is converted to a liquid in the soil primarily when the soil is acidic. When a new home is built and the existing pines retained for landscaping they cope fairly well if their root systems are protected. But many residents observe that ten or fifteen years later the pines start turning yellow. The cause is irrigation from well water. Rainfall is essentially pH neutral but water pulled from an irrigation well has been changed to alkaline. Soil water picks up dissolved calcium carbonate from the eroding limestone as it percolates through the soil. When that water is pumped back to the surface as irrigation water it begins to raise the pH level of the soil. A property called buffering capacity resists the change in pH but after many years the soil pH will eventually change from acid to alkaline. As this occurs iron is becoming increasingly less available to the pine tree. The first symptoms are the yellowing of the needles. It happens so gradually that it is rarely noticed at first.
Squirrels – The gray squirrel damages trees by chewing the bark and stripping it from branches. Squirrels normally feed on acorns or other nut like fruit but if food is scarce they may feed on the bark of a tender young shoot. They can girdle (chew the bark all the way around the branch) the entire branch causing it to die. They also chew the bark in the crotches of young branches causing wounds and weakening the branch. There is no recommended control – squirrels and trees have co-existed for centuries.