Now that spring is here, and the plants are lush and green, the new succulent foliage is prime for insects and diseases. When the weather is cool and moist, the disease pressure is highest. It’s important to maintain good sanitation and properly care for your trees. Our Thrive Advance – Evergreen Conifer Care Program is designed to prevent and manage populations of insects and diseases of Italian Cypresses, Pines, and other juniper like species.
Evergreen conifers make up a large group of trees. In North Texas this is primarily junipers, cypresses, and pines. The most common evergreen conifer trees planted in the DFW are Italian Cypress, Eldarica Pines, Arborvitae, and Eastern Redcedars. These trees host to many pathogens. I would say the most sensitive is the Italian Cypress, followed by the Eldarica Pines.
The Italian Cypresses have been in decline for the past couple of years. This is most likely due to the rapid fall in temperatures and prolonged winter freezing temperatures. These freezes can kill off living tissue, providing a site for the infection, also known as a disease court. Fungal spores can enter the plant through injuries and infect the plant. The damage is accelerated by other pests, such as spider mites and bagworms. Over time, cankers develop, spores are splashed to nearby infection courts, and diseases can spread like a wildfire.
Photo 1: Branch infected with Seiridium Canker
The Texas Plant Disease Diagnostic Clinic at Texas A&M University has not been able to isolate a single pathogen that contributed to the species decline. Seiridum canker, Botryosphearia canker, Cercospora blight, and Phomopsis blight were the most common diseases found killing cypresses and juniper species. The optimal temperatures for these pathogens are around 75-85 degrees Fahrenheit.
Photo 2 and 3: Flagging branches, visual symptom of Seiridum Canker
Pines in the DFW can be the host to a few pathogens as well. The two most common pine diseases in North Texas are Diplodia Tip Blight (Sphaeropsis sapinea) and Dothistroma needle blight (Dothistroma septosporum). Other diseases that we have identified include Pitch Canker (Fusarium circinatum).
Photo 4: Infected pine shoot and needles.
Regular applications of fungicides, insecticides, and miticides is the best chemical management of the pathogens listed above. These products should reduce the disease inoculum and lessen the amounts of infections that occur. Diseased branches should be removed back into living tissue. We sanitize our tools between each cut at Fannin Tree Farm.
Photo 5: Sanitation pruning is the most important management method
We find it helpful to get to know your tree species. Most of these evergreen conifers are dry climate species. This meaning they do not prefer prolong periods of soil saturation. Make sure that your irrigation controller is turned off before, during and after a rain event. Waterlogged soils can be favorable to Phytophthora, a root rot pathogen. If the soil has a foul odor, a soil applied fungicide with mefenoxam may be necessary.
Watering these Italian Cypresses and Pines can be tricky when you have a landscape with a mixed water requirement. Improving drainage and modifying irrigation systems may be necessary when you are growing these trees in your garden. Also seek advice from professionals like certified arborist, horticulturist, and licensed irrigators.
If you have evergreen-conifers, contact Fannin Tree Farm to see how we can develop a custom program for your trees. Our team of certified arborist is trained to identify these pests and prescribe treatments. Contact us today at 972-747-9233.