OAK WILT. See separate page dedicated to oak wilt.
DIPLODIA TIP BLIGHT
Diplodia tip blight in pines can be controlled with trunk injected fungicides. This condition is most common in Austrian pines. Propiconazole is injected in the fall and can give 2 to 3 years of prevention of this fungal condition. Early fungicide sprays can also be used along with the injections or instead of the injections.
ANTHRACNOSE.
Anthracnose is commonly seen during wet, cool springs. It is a fungal leaf infection that causes browned or blackened areas on leaves, distortion of leaves and noticeable leaf fall in the spring. In some trees, it can cause significant thinning of the canopy and can be a real nuisance for homeowners with the necessity of cleaning up leaves in the spring.
Anthracnose seldom needs any specific treatment, but if it is severe, fungicide injections may be warranted.
Sycamore trees that have anthracnose year after year can be treated preventively with fungicide injections in late summer or fall to control the disease the next spring. With Alamo injections we often see two years of control after a single injection. With Arbotect injection, we have seen three to four years of control.
CRABAPPLE SCAB
Crabapple scab often causes severe defoliation of crabapple trees. The lesions form on the leaves in May and June and defoliation begins in July, becoming severe in August, especially with hot dry weather.
Sprays can control scab if early systemic fungicide sprays are applied (twice before the bloom). If sprays are not feasible or if sprays do not adequately control scab, injection of the fungicide propiconazole can be helpful.
In many cases, we have seen up to two years of control of scab with one injection in late September or early October.
DUTCH ELM DISEASE
Dutch Elm Disease is still with us and kills many nice American elms each year (Siberian elms have resistance). This disease can be prevented with a high degree of success with injected fungicides.
Arbotect can give two years of excellent control.
Since we do not know if a tree has been inoculated, the first injection comes with some risk that the tree is already infected and could die from DED. After the first two years, we are quite confident that the tree will enjoy long term survival with repeated two year booster injections.
CHEMICAL DURATION EFFECTIVENESS COST
Arbotect (thiabendazole) Two years 95- 99% (observed) $ 15 per diameter inch
The reason Arbotect is expensive is because it is a very expensive chemical and because it must be infused with large volumes of water and the infusion can take several hours.