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Pine Needle Blight and Casts



P_pinenbltcst

Pine Needle Blight and Casts

Usually appear in

All Year


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Caused By:-     Several Fungi

Description

Pine Needle Blight and Casts can affect all pines. Needle cast fungi often are quite host-specific and can be an indication of the fungus involved. These diseases are caused by several fungi some of which are Bifusella linearis, Cyclaneusma minus, Elytroderma deformans, Lophodermium spp,Mycosphaerella pini, Mycosphaerella dearnessii, Rhizosphaera kalkhoffii. Throughout the range of hosts pines the most severe attacks are near bodies of water where there is high humidity such as when there is frequent fog or mist or in a very wet year.
Established and older pines usually outgrow the infection, but young plants are very susceptible and likely to be killed. Some of these fungi can even cause Witches Broom and other deformations to occur.
Needles are infected early in their development from the spring to autumn. Although new needles are infected during their first year of growth, at this time there is little visual evidence of infection apart from banding or yellow spots on the individual needles. Damage occurs in the needle tissue over the Autumn and winter and then the needles turn red in the spring to summer when spores are produced on dead and dying needles ready to infect new needles when these spores are spread wind or water.
Usually it is the interior needles that are affected whilst the new needles on the tips of the branch remain green. This is because the disease infected older needles during wet weather the previous summer. Young needles of the current year are not yet infected, since sporulation usually occurs on late spring to autumn.
When pine needles turn reddish-brown in early summer, several things could be the cause. It could be beetles in the trunk, compaction damage to the roots. Similar damages which cause general decline in conifers, such as root disease or drought, mimic the symptoms of needle cast. Scale insects, and winter desiccation can be confused with needle cast. Identification of which fungi needs a specialist tree doctor or a laboratory. Picture by USDA Forest Service Archive, USDA Forest Service, Bugwood.org.


Control

Control of needle cast in urban forest trees is usually not necessary as infected trees, if otherwise healthy , usually survive. Positive identification of needle cast fungi, and information on control can be obtained from a specialist tree doctor or a laboratory.
If necessary, cut and remove severely infected trees, particularly old, diseased pines. Prune healthy trees first to reduce the fungal spores and promote better air movement through the pines. Do not prune infected trees during wet weather. Avoid planting susceptible stock into areas which favour disease conditions.
If fungicides are needed, apply them at the proper time to get best results.
Collect and destroy fallen needles where fungi is suspected as the fungi produce spores on dead plant material. Often natural foliar shed of needles in the fall can be confused with needlecast diseases, but needles dropping due to needlecast diseases occur in early to mid summer.


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