Is late blight going to attack tomatoes this year? I've heard rumors. How can I tell if I'm seeing late blight or early blight?
Late blight disease, which devastated tomato plants in 2009, has been found in states all around Maryland, but not in Maryland yet. The late blight fungus likes cool damp conditions (think of the potato famine in Ireland — same fungus), and we had a spell of that weather.
Keep an eye out for brown blotches that start at the leaf tip or edges. Late blight also causes brown cankers on stems. Eventually tomato fruits (and potatoes) can be infected, and the entire plant dies.
Early blight, on the other hand, has brown fungal spots with a yellow "halo" or margin. These spots start on leaves at the bottom of the plant because the spores are splashed up from the soil. Infection then works its way up the plant.
Treatment is different for late and early blight. Go to our Grow It Eat It website at growit.md.edu and click on Plant and Pest Problems to see photo galleries that will help you compare late and early blight symptoms. Both of our websites have control information. Gardeners can also call us with questions. If you suspect you have late blight on your tomatoes, please notify us immediately — the University of Maryland is tracking this disease.
I had a row of beautiful dwarf Alberta spruce for years. They died, I replaced them, and those died. I've done this three times! I can't keep this up. The soil hasn't changed. I've done no construction, and the other trees nearby have continued to grow huge! What gives?
Dwarf Alberta spruce is a natural dwarf found in Canada, and in its natural range it likes full sun. In Maryland's heat and drought, it enjoys some shade, but it is not a full shade plant. We suspect that your landscape has matured over the years and now has much more shade than it previously did. Replace your dwarf Alberta spruce with a more shade-tolerant plant such as holly, yew, rhododendron or nandina. Changing landscape conditions can creep up on you!
I found a brownish gray, inch-long bug which looks like it has a buzz saw blade on its back. What is it?
You found a type of assassin bug. These predators earn their name by attacking and eating all kinds of insects. They're a big plus in your garden. The fellow you described is known as a wheel bug, because the crest on its thorax does look like a wheel got stuck in it. Generally adult assassin bugs have narrow bodies and long legs and antennae, usually in brown or black. Youngsters often sport bright red bodies or a big red backside that they wave in the air. It's best not to handle assassin bugs because they may stab you with their beak. They eat flies, tomato hornworm and stinkbugs.
University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to the website at hgic.umd.edu.
Plant of the week Oregano
Looking for an aromatic and culinary herb that is easy to grow? Try oregano. This hardy plant is a signature flavor in many Italian, Mexican, and Spanish dishes. The best variety for cooking is Greek oregano, but there are many varieties ranging in culinary intensity. Growing 12-18 inches high and wide with a creeping rootstock, oregano can be used as an edging plant or groundcover. Small varieties grow well in rock gardens. As a bonus, oregano can be used in herb and flower arrangements. Like most Mediterranean herbs, oregano requires full sun with good drainage and is happy in average soil. Start plants from seeds, cuttings, or division in the spring. Begin harvesting the sprigs when plants reach about 6 inches. You can allow some of the spikey white, purple, or pink flowers to bloom as an attractant for pollinators, but leaves are most flavorful if harvested before bloom. Pinching flowers also keeps plants bushy and prevents going to seed. Leaves can be used fresh, dried, or frozen. To prevent legginess in this perennial plant, cut out old wood at winter's end. Replace plants about every four years.
— Marian Hengemihle