Treating cottony maple leaf scale

Can you tell me what these little creatures are? They have completely taken over my backyard, on my fences, on my pool cover and on my shed. They are about 1/4-inch long, and some are orange and white and others are purple and white. Pictures are attached. I have a 40-foot silver maple in my backyard, and these things are growing only under this tree, and there is sap everywhere. Can I use liquid Sevin or liquid malathion [to get rid of them]?-- Bob Zambri, Bethpage

What you're dealing with is cottony maple leaf scale, which wreaks havoc on trees and can lead to a premature loss of foliage as well as dieback of some branches. The insects, which use their piercing-sucking mouthparts to extract sap from leaves, excrete a lot of honeydew (droppings), upon which the black sooty mold grows. The mold eventually blackens leaves and sometimes branches, and then everything under the tree.

Bonnie Lynn Klein, my expert contact at the Cornell Cooperative Extension of Nassau County, says the pest is showing up here in large numbers this year. Treatment is dependent on "growing degree days" (GDD), a formulaic system used to determine precisely when different insects reach stages of maturity. Because different stages are vulnerable to different control methods, this is important to know. The Suffolk County Cornell Cooperative Extension posts updates of GDD information for different parts of Long Island and NYC on its website: ccesuffolk.org/ assets/GDD-Reports/2010-Daily-Weather-Email.pdf.

Your first line of attack ordinarily would be horticultural oil applied at the summer rate (read the package for instructions and follow them precisely). But treatments are effective only if applied from 802 to 1,265 GDD.

As of this writing, all of Long Island was prematurely outside of the range because of the recent heat wave, so there isn't anything you can do right now.

Julie Seghrouchni, the Nassau CCE's horticulture educator, says you can help prevent a reoccurrence next year by applying spring dormant oil in late March to early April.

The best thing you can do for your trees right now, she says, is to keep them healthy: Don't forget to keep watering trees - even well-established ones - during drought, and don't fertilize them.

My dad is 89 and living in Manorville, where soil is a little sandy. What are the best flowers to plant for minimum care? - A reader

Sandy soil usually is low in organic matter, so no matter what you plant, be sure to mix in a generous helping of compost before planting. Asclepias tuberosa (butterfly weed), Baptisia australis (false indigo), Coreopsis species, Echinacea purpura (coneflower), Hemerocallis (daylily), Rudbeckia (black-eyed Susan) and sedum (stonecrop) are good choices that will tolerate sandy soil and require little care once established.

Will chamomile do well in planters?

Tammy Remsen, Mastic

Absolutely. Enjoy!