MSU Extension Service
Home Grown is an educational,
entertaining, question-answer column seen weekly in "News from
the Genesee MSUE Office," a weekly newsletter for Genesee
County Master Gardeners. Special thanks to the Genesee, Oakland and
Livingston county MSU Extension offices for providing this service.
01-13-05 Fungus gnats; deer protection
01-19-05 After cutting down trees: to
chip or not to chip? Also: starting seeds indoors for spring
01-27-05 Excessive plant growth in ponds;
problem trees and/or problem sites
02-11-05 Diplodia Tip Blight on Pine
trees; caring for African violets
02-14-05 Caring for Ficus in winter;
indoor pests: larder beetles
02-14-05 bonus! Fertilizer for gardens -
designer vs "regular"; why gardenias don't like our
02-21-05 vole damage in lawns & woody
plants; how to root cacti and succulents
03-04-05 tree-climbing vines; hibernating
03-08-05 deer pests in the landscape;
grain moths in kitchens
03-15-05 ants in the kitchen;
mythological apple trees
04-07-05 spring care of ornamental
grasses; little beetle in basements
04-13-05 Preventing crabgrass; flies on
04-18-05 Buying perennials in boxes; care
of perennials in early spring
05-20-05 Dogs and lawns; winter injury on
This week's HomeGrown
HOME GROWN 301
I just walked out to look at a couple of Scotch pines that I have and I was horrified. There were some little black and green wormy-things eating needles near the ends of the branches. A few needles looked tan and shredded but others were just missing. What am I supposed to do now?
First, relax and stop shaking. These are European Pine Sawfly larvae. And they are dinky. This is the juvenile eating stage. The adult sawflies are the reproducing stage. If you are horrified now, give these guys several weeks of feeding on your scotch pines and you will have to be hospitalized. If you have enough sawfly larvae, they have the potential to defoliate a small tree. They could consume everything other than this yearís needles. Pine trees that will be unwilling hosts to European Pine Sawflies are Red, Austrian, Scotch and Mugho pines. These green and black longitudinally striped larvae with black heads eventually grow to be approximately one inch long. There is a great deal of foliage to be consumed if yours are small. Kill them while they are babies and save the trees from taking a beating. Eaten needles will never be replaced. If this silly event takes place every spring for a number of years, the poor trees canít get in a decent season of growth with their valuable needles. Stressed trees can become dead trees. When these larvae are larger, they will rear up as an entire colony and do the bug version of The
Wave. To hungry birds, this looks like a large objectÖtalk to the hand. Birds just donít consume them so donít hold out hope of some magic biological control. Hereís how all this happened. Mama Sawfly flew to the new, soft needles at the tip end of the branches late last spring. She carefully sat on the needle and put some tiny slits into it. An egg was put into each slit. The needle healed over and the eggs stayed protected until this spring when they began to hatch. The herd on one branch could easily be the children on one fertilized female. Those tan, frizzled needles are the ones that they hatched from. Most people notice them around Memorial Day when they are the size of Chinese dragons. A great deal of damage has already been done and they are just about as big as they are going to get as larvae. Monitor early and kill them as pipsqueaks. You can control your guys with several products. This insect doesnít need to be killed with anti-aircraft weapons; a BB gun will do. Commercially manufactured Insecticidal Soap does an excellent job when sprayed directly on your offenders. Liquid Sevin or Carbaryl will also be effective. If there are only a few, squish them. Skip the spraying and get the
satisfaction of mashing them into eternity.
I have an entire row of burning bushes along my property line. I noticed that they didnít seem to have buds and when I looked, I knew why. The rabbits have chewed all or almost all of the bark off the shoots, close to ground level. Can I put pruning sealer on them? Or, could I prune off the branches down to ground level and they will grow back?
The best thing to do at this point would be to cancel the Burning Bush Birthday Party you had planned. It appears that the guests of honor may not be attending due to fatal health complications. Covering destroyed bark doesnít do much other than disguise the damage. Letís take a little side trip to the Cambium Virtual University. Visualize this: under the bark is a thin layer of cells that are responsible for transportation. This layer looks like hundreds of mini drinking straws, standing on end. The layer is one drinking straw thick. Some straws suck
up. They pull moisture and soil nutrients into the plant. The others pull down. They take produced sugars to the roots. When they are destroyed, nothing goes up or down. This equals death. You can try to prune off the shoots that are girdled. But burning bushes are not noted for their ability to send up new growth. Good luck. You and they are going to need it.
Gretchen Voyle, MSU Extension-Livingston County Horticulture