I have two mature hemlock trees left on my property after losing three to a Hemlock Woolly Adelgid (HWA) infestation last spring. I've been having them professionally treated with a basal bark application of a neonicotinoid. The arborist is very careful about applying the treatment in appropriate conditions, avoiding wind and ensuring moisture levels are just right, and we are quite a distance from any water sources. I know that HWA is persistent in my area of Southwest Pennsylvania, and while alternative treatment options like foliar oil sprays are problematic for us due to access issues, I'm curious about effective harm reduction strategies. Is it better to stop treatment and accept the loss of the trees, or should I continue treating them despite potential ecological consequences? Could underplanting with ferns instead of pollinator-attracting plants help? Any thoughts would be appreciated!
2 Answers
If you’re looking for a more ecological approach, consider purchasing some beetles that are natural predators of HWA. They can help control the pest without the use of chemicals. Just my two cents, but I've been debating whether it's worth saving my ash trees using neonicotinoids. They turn toxic and lose their ecosystem value. In a way, keeping them alive might just prolong the inevitable until we find a better solution. If there’s a biological control available, I’d go for it.
Check out resources from PA Ag Extension for solid advice on dealing with HWA. Regarding your treatment method, it sounds like you're mixing up basal bark treatments with spraying. Basal bark treatments are typically applied directly to the bark, not sprayed over the entire tree. I totally understand the reluctance against insecticides, but given that you’ve already lost three trees, it might be worth trying.