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Scary-looking cicada killers are primarily interested in their prey
By Kathy Huber | July 6, 2012 | Updated: July 13, 2012 11:22am
Q: Last year I had a number of cicada killer wasps, and recently, I noticed a couple of them flying around. I've started soaking the flagstone and pea-gravel area with water daily in hopes of deterring them. I read that another solution is to pour ammonia down their holes after they return at night. Would ammonia damage tree roots? If so, do you have any other solutions to get rid of them besides waiting two months for them to leave?
A: Cicada killers are 1½-inch predator wasps that look frightening, but males can't sting, and females don't sting humans or other animals unless provoked. A female will sting a cicada, then drag it to its ground nest. She lays an egg on the paralyzed cicada, and when the larva hatches, it eats the cicada.
Male cicadas are the insects we hear droning away during the summer. The females make slits in tree bark and lay their eggs in rows in the wounds. Their presence attracts the cicada killers. Cicadas aren't especially damaging to trees in this area, and cicada killers are considered beneficial insects. Try to let them do their thing before moving on. Otherwise continue drenching with water as the big wasps don't like wet soil.
Ammonia is used in fertilizer and some homemade insecticides, but too much can burn. Pest experts at the Texas Forest Service say 1 cup per hole should not be a problem.
Q: In January, my neighbor and I had our 7-year-old live oaks professionally moved from near our garages to our front yards. Their roots were pruned before moving. My tree is clearly infected with bacterial wet wood/slime flux; my neighbor's tree is beginning to show signs of the same.
I've read bacterial wet wood/slime flux has no specific treatment. Arborists recommend careful watering and fertilizing but don't consider drilling holes and inserting drainage tubes effective. What do you recommend? If we need to replace the trees, is there a disease-resistant variety?
A: Although the drought is over, we're seeing long-term effects, such as wet wood or slim flux, says Mickey Merritt of the Texas Forest Service. He agrees that no specific treatments are available but says your trees may pull through with good care.
Wet wood or slime flux is a bacterial disease associated with wounding and environmental stress, including drought, according to studies. Gas produced by bacteria fermentation produces pressure in the wood. This pressure forces sap to ooze through cracks in branch unions and through other wounds. The flux darkens when exposed to air, and areas of the bark appear water-soaked.
Prevent wounds and stress to avoid wet wood. Treatment for infected trees is typically cosmetic. Trees will compartmentalize around the affected area, limiting wet wood spread, says the University of Tennessee Extension Service.
"I'm not sure the transplanting of the trees would be the cause of the slime flux," he says. "Hopefully, the root pruning and transplanting were done correctly, and an adequate irrigation program is in place. That will be one of the largest factors in determining whether or not the trees survive."
Merritt says slime flux affects many species of hardwoods, and he doesn't know of any resistant to the problem.
Q: My sprekelia bulbs have grown well in the ground for three years but almost never bloom. I'd like to move them to pots since they're supposed to bloom better when crowded. What do you advise?
Also, I'm surprised that my neighbors' alyssum are still blooming. Is this normal?
A: Sprekelia formosissima, aka Jacobean lily, Aztec lily and St. James lily, is an amaryllis relative native to Mexico. The orchidlike, 6-inch rich-red blooms appear late spring and fall, especially after rains. This naturalizing bulb needs at least five hours of sun for good blooms, so if yours are in a shady spot, you might move them to encourage better performance.
However, Aztec lily does flower well in crowded containers. You could enjoy them on a patio or sink the planted pots in the ground where there's adequate sunlight.
Perhaps your neighbors have one of the newer, more heat-tolerant alyssum cultivars that bloom later. This annual also holds up longer if not in full sun during the hottest months.