Loblolly Pine Tree Seedlings Are Turning Brown

Insufficient Water

• Improper watering is a common cause of browning needles on loblolly saplings, which need plenty of moisture to make it through the winter without becoming dessicated, or dried out. In the summer, keep the soil around them evenly moist. Continue regular supplemental watering throughout the fall up to the first freeze. According to Elizabeth Killinger, a horticulture extension educator in Hall County, Nebraska, you should even water seedlings in winter, as long as daytime temperatures are above 40 degrees. Killinger advises watering early in the day so moisture can soak into the ground before temperatures drop for the night. Use enough water to moisten the soil to a depth of eight inches and apply it around the drip line, the place where rainwater naturally falls from the outer tips of branches.

Needle Cast

• Loblolly pine trees are particularly susceptible to pine needle cast, in which the needles from previous seasons turn brown from the tip to the base in springtime. After browning, they drop off, leaving only the new growth. The condition is unsightly but harmless in older, established trees. However, young loblolly seedlings with needle cast can suffer from impeded growth. A webpage on the North Carolina State University website recommends removing the fallen needles promptly from around the base of the tree, while appraising the amount of needle loss. If the seedling has shed many needles, fertilize it to provide extra nutrients. The Oklahoma Forestry Service advises using a slow-release fertilizer, following label directions regarding amount. However, you should forego fertilizing loblollies after mid-August because the resultant new growth might not have a chance to harden properly before winter.

Brown Spot Needle Blight

• Brown spot needle blight, caused by a fungus called Mycosphaerella dearnessii, affects both new and older needles, and usually strikes in the late summer through fall. The disease begins with brown spots -- often surrounded by a halo of yellow -- on the needles. After developing spots, the whole needle turns dark brown and drops off, usually in the following spring. The fact that the browning starts on lower branches and moves upward can help confirm a diagnosis of brown spot needle blight. According to University of Kentucky, you can treat the disease with fungicides, including mancozeb and ferbam. Apply the sprays every two to three weeks from mid-April through June, the time during which the seedlings are most susceptible.

Annosus Root Rot

• A fungal disease called annosus root rot can also affect young loblolly pines. Caused by the Heterobasidion annosum pathogen, the disease causes reddish-brown needles and thin foliage at the top of the tree. Dark-colored fungal fruiting bodies may be seen on the tree near the soil line. Annosus root rot is fatal, with seedlings eventually dying where they stand or being blown down by strong winds. Loblolly seedlings with annosus root rot must be cut down and treat the stump with dry granular borax. The North Carolina State University webpage cautions that you must avoid planting another loblolly pine -- or pine tree of any type -- within 20 feet of the site of an infected tree.