Nursery Notes: Steps to prevent maple tip borers
I hope you’re not reading this too late. I did mention this pest briefly several weeks ago.
Spray Talstar when the second pair of new leaves have come out and each leaf is about the size of a nickel. More than 2 sprays have been useless on cultivars. Seedling trees will require 2-3 sprays, 5-7 days apart, because of the variability in development. (Some trees can be in full leaf while a few may still be in tight bud.)
The window of opportunity to spray is very narrow. Timing is everything in killing this insect. One spray timed properly can do it on red maple cultivars. If you spray too late, the critter is protected by the stem that he tunnels into.
Talstar Flowable should be sprayed at 12 fluid ounces per 100 gallons of water; 1.2 fl oz per 10 gallons; 14ml or 1 Tablespoon per 4 gallons; 10.5 ml per 3 gallons; or 3.5 ml per gallon.
Talstar 10 percent WP should be sprayed at 0.96 ounces by weight per 10 gallons of water or 9.6 ounces by weight in 100 gallons of water.
This shoot boring caterpillar, Proteoteras aesculana, overwinters in a hollowed-out bud in red maples. You must kill it after it emerges, while it crawls about the terminal, surface feeding, but before it bores into the tender shoots and kills the terminal, requiring extra work to train a new central leader.
We have learned that the larvae hatches July-August from an egg and feeds before overwintering in hollowed out buds. Occasionally, terminal feeding damage is actually noticed by a few observant growers. Spray at the first sign of damage in the terminal during July-August.
The tiny, naked caterpillar overwinters in a hollowed-out bud. It is extremely surprising that they can survive our typical winters. I wouldn’t want to try.