Nursery Notes: Spotting hopper burn on maples
I have seen a lot of red maples recently with minor to severe cases of leafhopper damage or “Hopper Burn.” I saw a very severe case last week.
The top 6 to 8 inches of new growth did not have a leaf larger than a nickel. The internodes were short. Leaves were cupped, with brown edges.
The population was so high that I found the tiny light green critters without looking for them. I usually can not find them.
I recently learned how this tiny insect causes this major distortion in the new growth. As they remove plant sap, they inject salivary toxins that cause this reaction.
Spray with Sevin, Carbaryl, Diazinon, Dursban, Talstar, Tempo, Decathlon, Scimitar, or Tempo SC Ultra. Try a 7 to 10 interval till the new growth comes out and stays normal.
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One grower called about the white cottony lint on the trunk and branches of white pine. Pine bark adelgid can be controlled easily with dormant oil in the late winter or now with summer oil. Total coverage is essential.
Total coverage is not easy on tightly sheared pines. Total coverage has not been easy on ash being attacked by the White Peach Tree Scale. Air blast sprayer water volume must be increased from 20 to 30 gallons per acre, up to 80 or 100. One label recommended 1 gal of summer oil per 100 gallons per acre.
Four trips around a block may be required.
Crawlers (the babies) are easier to control than the adults. Determine their presence by wrapping a few stems with double sided tape and check it weekly. We have had the first generation and two more will occur this summer.
If the air blast fails, use a hand gun or back pack sprayer and spray from 4 sides. It is not essential for the solution to run down the trunks, but ready to.