LOPHODERMIUM NEEDLECAST ( Lophodermium seditiosum )
Lophodermium needlecast, is caused by a fungus and may attack all two- and three-needle pines as well as a few five-needle pines. Scots, Austrian and red pines are among the more susceptible species. Although there are many species of Lophodermium which act as secondary pathogens and saprophytes, L. seditiosum is the most serious of the group, and can be a problem in both nurseries and Christmas tree plantations.
In the spring, L. seditiosum causes yellowing and then browning of needles infected the previous year. Needles may be cast any time after this symptom appears. Symptoms are usually most severe on the lower part of the crown because that is where favorable conditions of cool temperatures and free moisture on the needles are most likely to occur and persist. In mid-to-late summer (starting about July 10 in New York), minute, black, football-shaped fruiting bodies form on the recently killed needles, and these fruiting bodies release spores after they are moistened. The spores are shot out of the fruiting bodies and up into the air where they are carried by the wind to new sites of infection on the current years's needles.
Fig 1. Yellowing and browning of needles infected the previous year
|Fig. 2 Fruiting bodies on recently killed needles|
To try to prevent a Lophodermium infection from getting started, keep weeds under control and plant on south-facing slopes. Avoid planting in valleys or other low lying areas. Good air flow keeps trees drier and helps to prevent infection. Remove heavily infected trees to limit inoculum and remove windbreak trees of the same species as your crop trees to minimize inoculum production. Resistance to this disease varies among pines. Scots pine from different seed sources show differences in susceptibility, while red pine seems to be most susceptible in the seedling stage.
Pesticides are available for controlling this disease once it becomes established in a plantation. It requires four separate treatments to control this disease, beginning in early July and continuing, monthly, through early October.
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