Ask The Gardeners; Q&A.
Q. A few weeks ago something started chewing on the tips of our asparagus. Then tiny black spindlelike structures appeared, protruding horizontally from the stalks. What would cause such a problem? Is there a cure?
This is the work of the asparagus beetle, which feeds on the stalks for a few days and then attaches its eggs to the stem. The eggs hatch into soft-green or gray larvae which feed on the stems and ferny foliage, then they go into the soil to complete their life cycle (two generations in the North and more in the South).
Start using malathion or rotenone during the cutting season and spray the brushy growth in late summer. Clean up all debris. Ladybug larvae and chalcid wasps are good predators.
Malathion and rotenone are considered relatively safe pesticides, but be sure to wash all produce thoroughly before eating.
Q. We came back from a weekend outing and found the trunk of one of our shade trees had two huge cavities in the trunk, one near the base and one about halfway up the trunk. There were piles of wood chips on the ground. There is one dead limb on the tree, which we were going to have removed, but assume we should now remove the whole tree. Could vandals have done this?
Your tree apparently has insects working in the trunk and a pileated woodpecker (a black-and-white, crow-size, 19-inch bird with flashy red crest) has performed a search-and-destroy mission.
It would be best to remove the tree, since it would not be worth repairing with such extensive insect damage.
Incidentally, leaving dead trees standing in their wood lots invites extremely valuable members of the woodpecker family to live nearby. Sumacs make good homes for smaller species. Pileateds are native only in the Eastern United States and Canada. Its counterpart, the larger ivory-billed woodpecker, is nearly extinct.
Q. I often buy eucalyptus from a florist and have tried unsuccessfully to root the tip ends, which I thought might grow into nice potted plants. A florist told me her cut foliage comes from Australia, but she thought I could buy seeds from a garden store. I cannot find them anywhere. Can you help?
Eucalyptus trees are native to Australia, but many species have been naturalized in California. They do start easily from seeds. One source we know of is this: Park Seed Company, PO Box 31, Greenwood, S.C. 29646. They make lovely pot plants.
Although some species are supposed to survive in temperatures as low as 20 degrees F., we recommend they be planted directly outdoors only in areas where temperatures normally remain above freezing.