Emerald Ash Borer Awareness Week

The United States Department of Agriculture and the governor of New Hampshire, Maggie Hassan, have declared May 18-24 Emerald Ash Borer Awareness Week in New Hampshire. Citizens are encouraged to learn the signs of infected trees, learn more about the insect, and ways to slow the spread of the emerald ash borer (Agrilus planipennis), a destructive insect introduced from Southeast Asia.

One telltale sign on the ash tree is bark ‘blonding’ where woodpeckers remove the top layer of bark exposing a lighter color of the cambium. Now is a good time to spot affected trees before the leaves fully emerge.

Tens of millions of ash trees have already been lost in the midwest, eleven of them at my son’s home in Ohio. He sent the photos below of tunnels left by larvae beneath the bark, tunnels that disrupt the transport of nutrients and water and eventually cause the demise of the tree.

Emerald Ash Borer on Ashemerald ash borer signsThe camping season will be getting underway on Memorial Day weekend. We all need to be aware that the larvae can be spread by transporting infested firewood. Campers can do their part by using firewood that is close to your campsite.

To learn more about the emerald ash borer, click HERE.

It’s a small, small, small world…

I have a few aphids on some of my beautiful Shasta daisies (Leucanthemum ‘Becky), daisies that have flowered profusely throughout the summer. I know aphids can overtake and cause havoc in the bed of daisies but I needed to know how much of a problem I had.

Shasta daisies

Insects buzzed and circled around my head yesterday as I knelt to check out the aphids that traveled along stems beneath the blooms. These insects will suck the sap out of leaves, tender stems and the flowers, and they will transmit diseases like fungus and mold. I saw no signs of wilting leaves or buds. And I saw very few aphids. Now the question, “Should I treat these flowers with an insecticide?” That’s a question that every gardener faces when insect pests invade their gardens. Insecticides would certainly take care of the aphids, but….

… what damage would the insecticide do? The answer to that question comes by observing your garden. There is a small world of insects living there, good ones and pests. Insecticides will kill all insects, benign insects as well as insects that are the natural predators of pests such as ladybugs, praying mantis, assassin bugs, spiders and more.  Let’s take a closer look at the small world around these daisies.

Hover Fly - click photo

The hover fly is a common fly in our area. It gets its name from their ability to hover in midair, then dart here and there, sometimes backwards. The adult does not sting and feeds on pollen and nectar and they are important pollinators but their larvae are very important predators of aphids, thrips, and other caterpillars. These are excellent insects for the garden. Insecticides would eliminate them.

Green Bottle Fly - click

The green bottle fly (Lucilia sericata), also called a blowfly, is a scavenger of all things decomposing and will lay eggs in carrion, thus cleaning up what other animals cannot eat. Unless this fly invades your house or garbage and causes problems, it is not a threat to humans in the garden. It’s a natural pollinator attracted to the nectar of the daisy.

miniature ants - click photo

Almost too small to be identified as ants by my eyesight, the camera zoomed in on these miniature ants who are after food, too. These are benign insects that do no harm to the daisies and are food for other insects and birds.

Skipper Butterfly - click photo

This little butterfly could be the Yehl Skipper (Poanes yehl), a fairly uncommon skipper that is seen along the coast at this time of year, but I prefer my IDs to be confirmed by an expert. This fella would be done in by an insecticide.

Soldier Beetle - click photo

This soldier beetle or Pennsylvania leatherwing beetle (Chauliognathus pensylvanicus) is a cousin to the lightning bug. They are common in the garden and beneficial as a pollinator and a predator of aphids and other small insects.

sweat bee - click photo

A variety of bees visited the daisies and we all know we need those pollinators. Although the sweat bee can be a nuisance when it seeks out the salt in our sweat, it is considered a benefit in the garden due to pollination.

mystery insect - click photo

These tiny insects were unknown to me. These winged insects were the size of pepper flakes to the naked eye. I watched them through the camera lens become the meal of a few hungry crab spiders that lived around the petals.

The answer to the original question about insecticides is IPM (Integrated Pest Management). IPM is a sustainable method of management using biological, cultural, physical and some chemicals to minimize environmental damage. Using a insecticide for the aphids indiscriminately will have a negative and damaging effect on all insects that depend on this small ecosystem for life.  Because there is no sign of damage to the plants and the insects are a part of the food chain for predator insects, I will allow the aphids to live in the daisy bed and permit the natural system to work. But I will monitor the flowers for signs of disease or damage. If I must interfere, I will learn about the life cycle of the insect, how best to control it physically, such as picking off or pinching the colonies to kill them. My next step will be to spray soapy water beneath the blooms. And if all else fails, the very last attempt would be a careful use of pesticides, preferably the newer natural pesticides derived from botanicals.

It’s better to become familiar with IPM techniques and implement a regular monitoring program before using any biological controls. Read more about IPM here.

Ann Hohenberger, The Garden Club of Gloucester