Knowledgebase
Eastern Hemlock and other Tree pests #750371
Asked May 17, 2021, 11:48 AM EDT
Two questions:
1. In addition to horticultural spray, are there any tree inoculants, other treatments, that are best for either woolly adelgid or leaf scale for Eastern Hemlocks (my big one is losing needles little by little)
2. For the BLS (bacterial leaf scorch) or anthracnose, are there inoculants, soil amendments, other approaches that are in use/in trial phase to try to save trees before they are infected or that make them unpalatable to insects carrying this disease??
Thank you.
Prince George's County Maryland
Expert Response
1. Yes, there are other options for control of hemlock woolly adelgid. We trust that you have had these positively id'd. If not, please send us photos so that we can be sure to target the correct pest.
Here is our webpage on hemlock woolly adelgid, with several control options besides horticultural oil. Read closely, as there are many. Timing and product are crucial: https://extension.umd.edu/resource/hemlock-woolly-adelgid-trees
The systemic insecticides should also give your trees protection from the scale.
2. Again, if you have not gotten a positive identification of the problem/pest, please send us photos.
Here is our page on bacterial leaf scorch: https://extension.umd.edu/resource/bacterial-leaf-scorch-trees We are not aware of accepted methods to protect from infection. Infected trees nearby can be removed to lessen the chances of spread by insects. Over-fertilization with nitrogen often makes plants more attractive to insects and is not necessary in established trees anyway.
The impact of anthracnose can depend on the tree species. Let us know what species you are dealing with. Shade trees usually put out new growth and suffer no permanent damage: https://extension.umd.edu/resource/anthracnose-diseases-shade-trees
Ellen
Glad we could help.
