Q: Our place is almost entirely lawn and we want to convert the yard into a biodiverse, native habitat for birds and butterflies. Since it is almost fall, do we cover the grass areas with newspaper and then mulch on top or leave it until spring? How do we prepare the ground for planting in spring? Can we plant things now?
Answer: If you already have decided on the beds or habitat areas, then killing the grass now is an excellent idea. Mow as low as you can. Newspaper and mulch (especially leaf mulch available in fall) should work well. Use several layers of newspaper under the mulch. Do a soil test now. Fall is a great time to plant woody plants and herbaceous perennials. However, unless you must plant now (gift plants, donated plants), you may want to wait until you have a planting plan designed for each bed. Winter is an excellent time to plan.
Have you noticed the large webbed sacs in the trees along the sides of the road lately? They do prompt questions to the Home & Garden Information Center’sAsk an Expert service. Often they are referred to as bagworms which causes some confusion because bagworms are a different insect.
So what are webworms and bagworms? Will they cause damage to trees? Let’s take a look at them both.
Fall webworm (Hyphantria cunea)
Fall webworms show up every year but their populations can vary in size. Often they are insignificant in number and not too noticeable, but every so often there is a large population. The sacs can be numerous and quite large, leading one to assume they will devour an entire tree’s worth of leaves.
But, thankfully, beneficial insects such as parasitoids and predators such as birds, who love to eat the caterpillars, keep populations in check and spraying is not necessary. Granted, the webs are not pleasing to look at. If they are within reach they can be pruned out and destroyed.
Fall webworm facts
There are two generations each year. One is active in May and the second larger population is active starting in late summer into the fall. However, the sacs can be noticeable in the trees all winter.
They feed on over 100 species of trees. Preferred hosts include walnut, oak, hickory, willow, apple, and other fruit trees.
The adult is a ¾ inch-long moth, white or white with black spots.
After eggs hatch on a host tree, the caterpillars produce a fine web over the ends of branches. They feed only within the web.
Mature caterpillars are about an inch long with noticeable long, silky hairs. They come in two colors, the ones with black heads are yellowish-white and the red-headed ones are brown.
By far bagworms are the more destructive of these two insects and need to be managed. They have voracious appetites and devour the needles of evergreens– particularly arborvitaes, junipers, Leyland cypresses, and cedars. We hear the cries of desperate residents wanting to know if the dead areas on their trees will regrow. Unfortunately, that answer is no.
Bagworm damage. Photo: UME / Ask an Expert
Bagworm damage. Photo: UME / Ask an Expert
There is one generation per season.
In addition to conifers, they will feed on deciduous trees (ones that shed their leaves in the fall) such as sycamore, maple, locust, boxelder, and linden, but the damage is not as significant.
Eggs hatch in late May or early June. Caterpillars feed and create bags made from pieces of the plant they are feeding on. The bags enlarge as the caterpillars feed during the summer.
The caterpillars pupate in late summer. Adult male moths emerge and fly to female bags that contain wingless female moths, then mating occurs. Females can lay 200-1,000 eggs which overwinter in the female bag.
Fall, winter, and spring: Remove and destroy bags containing overwintering eggs. Pinch them at the tip or use a small clipper to remove the ones you can reach from the tree. Do not drop them on the ground near the trees. Dispose of them in the trash.
Beginning in late May into early June. Begin to look for small caterpillars moving on the trees. As they feed, small bags will form. The best time to spray is when the caterpillars have just emerged and are small. Bacillus thuringiensis (Bt), an organic insecticide, will help to control the young caterpillars.
By mid-July the caterpillars will be too large for Bt to be effective. Look for a registered insecticide labeled for bagworms at a plant nursery or hardware store. Contact an arborist or landscaper to treat large trees or if the bags are located high up in the trees.
Other tent-making caterpillars
There are two more tent-making caterpillars that are sometimes mistakenly referred to as ‘bagworms’. They are eastern and forest tent caterpillars. Both are active in the spring and not in the summer or fall.
By Debra Ricigliano, Lead Horticulturalist, University of Maryland Extension Home and Garden Information Center
Besides being super important for controlling pests, since most of them are predators, wasps also can contribute to pollination. In some cases, that pollination is so specialized that plants won’t be able to set fruit if the wasps are not around! But don’t let me get ahead of myself… let’s start from the beginning. What are wasps and how to distinguish them from bees?
Is this a wasp or a bee?
Are you confused about the differences? That’s normal! It’s because bees and wasps are closely related and, in the same way that we tend to look like our close relatives, wasps and bees look similar as well. Like bees, wasps have a lot of diversity, displaying different shapes, sizes and colors. Also like bees, wasps can be social (like hornets or yellow jackets) or solitary (like those that make little mud vases or that dig small burrows in the ground).
Taxonomically, there are two groups of wasps: those that have a wasp waist, and those that don’t. Because the former are the ones that we usually refer to when we think of wasps, let’s focus on those. When we think about those wasps, wasps tend to be less hairy than most bees and tend to fly with their legs extended. The legs of bees are usually wider than those of wasps, and while they fly one can see bees rubbing their legs with one another to transfer pollen, while this will not be the case with wasps. Finally, most social wasps fold their forewings when they are at rest, which makes the wings look long and thin.
What do wasps pollinate?
Wasps are involved in different types of pollination interactions, with many being generalists (they visit many different types of flowers) and some very specialized (involving only a very small number of plants).
Even though the vast majority of wasps are predators (they prey on your garden pests!), they also need to supplement their diets with sugar, which is eaten by adults but is also required for the proper development of the offspring. For this reason, many solitary and social wasps visit flowers and collect nectar throughout the flowering season, but in particular during the fall, when other sources of sugar become harder to find. During those visits, they often enter in contact with the flower anthers (the flower part where pollen is presented), and thus passively collect and then transfer pollen when they visit another flower.
Most of these wasps have very short tongues, so they are only able to obtain nectar from flowers that are not too deep. Further, most of these wasps can’t see red colors but can see UV light. Because of all this, most flowers wasps visit are open and not too deep, and white- or yellow-colored. If you would like to attract and observe these pollinators and biological control agents, you can plant flowers of the Apiaceae family (carrot and parsley family) and you won’t be disappointed!
In addition to generalist wasp pollinators, there are some very specialized wasps that only pollinate specific types of plants. Next month, we’ll take a closer look at specialized wasps and the ones in particular that are essential for pollinating some delicious fruits — figs!
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park
It seems like a while ago, but it was only 5 weeks ago that we were experiencing a fairly gentle start to summer. We even had a few days in June with highs in the 60’s and it made for pretty easy lawn growing weather.
Flip the calendar to mid-July and it has been a different story. All of us knew summer would arrive eventually, and now we are dealing with high temperature and high humidity conditions very typical of mid-summer in Maryland.
For those with warm-season grass lawns, like zoysiagrass, the lawn should be thriving, as these grasses enjoy the heat. For most homeowners who have tall fescue, summer is always a challenge to minimize the heat stress and disease pressure on the lawn. Tall fescue is best adapted to growth when low temperatures are in the 50’s and highs are in the 70’s to around 80. Through July, we have had many days near or above 90 and many nights where the temperature didn’t drop below 70.
There are a few different reasons your tall fescue lawn may be going brown or declining this time of year—the most common are related to drought stress, soils that are too wet, or brown patch disease. Typically, growth slows down a bit in mid-summer anyway as part of a grass’s natural growth cycle as it uses more carbohydrates (food reserves) than it makes. So when the grass does experience stress or disease it is slower to recover. Drought-stressed plants exhibit a purple to grayish hue, a narrower or “curled up” leaf blade, and footprints are visible for several minutes after walking across a drought-stressed area. Continue reading →
Spotted lanternfly adults may be found feeding on many hosts, especially tree of heaven(Ailanthus altissma). Report any finds to the Maryland Department of Agriculture immediately, collect a sample or take digital photos of what you have found.
Bagworm caterpillars are now very active. Look for little bags crawling around on evergreen trees and shrubs and be prepared to spray infested trees with the microbial insecticide, Bt by mid-July. Mature bagworms are not well controlled with Bt They are best collected by hand and destroyed or sprayed with insecticides containing spinosad.
Proper lawn mowing is critical to help it survive the summer. “Mow ‘em high and let ‘em lie” should be your mowing strategy. Cut your cool-season turf (fescues and bluegrass) to a height of 3-4 inches and leave the clippings on the lawn where they will naturally decompose.
Sow seed for fall transplants of broccoli, kale, turnip, and cauliflower in flats or containers by the 3rd to 4th week in July. Late crops of squash, beans, and cucumbers can be direct sown into your garden through the end of July.
Gardeners, naturalists, researchers, conservationists, politicians — everybody talks about pollinators these days. It seems that pollinators need our help and we need to help them help us. However, it is really hard to protect something that we don’t fully know. So let’s take a look at our insect pollinators, how and when to look for them, and how to tell them apart.
Bees are one of the most important groups of pollinators. Aside from the well-known non-native honeybee, bees are very diverse in terms of size, ecology, and coloration. In our area, bees range from very small (like our metallic sweat bees) to large (like our carpenter bees and bumblebees), and display different colors and even metallic shines. Bees can be recognized because they have two pairs of wings, ‘elbowed’ antennae, and usually hairy legs and bodies. Bees fly and visit flowers both during daytime and dawn, and can be seen on flowers of different colors (e.g., pink, purple, blue, white, yellow).
Butterflies have ‘conflictual’ relationships with their preferred plants: while in their caterpillar stage they feed on the leaves and stems, they pollinate flowers in their adult butterfly stage. Maryland butterflies span different sizes, colors, and shapes. You may be familiar with the impressive Monarchs, who feed on milkweed and are able to migrate hundreds of miles, our very own state insect the rare Baltimore Checkerspot, or the beautiful swallowtails. Because of their special mouth shape with a rolled ‘tongue’, butterflies prefer flowers that have long tubes. Butterflies are diurnal and are usually attracted to red, orange, yellow, purple and mauve flowers.
Moths are relatives of butterflies, but from a pollination perspective, they differ because the majority of them are active at dusk and into the night. Like butterflies, moths have long tongues that they use to collect nectar from flowers, and thus their preferred flowers are somewhat tubular. Moths can be small or large, but the vast majority of them are attracted to flowers that bloom in the evening, produce strong and sweet scents, and are usually whitish. While some pollinating moths are fair fliers, the impressive hawkmoths can hover and are easy to recognize because they are very hairy and fly like hummingbirds. Even though most moths are nocturnal (active at night), some hawkmoths are diurnal (active during the day), such as hummingbird moths.
I hope that after reading this, you will appreciate these little guys as much as I do. Despite hoverflies contributing to a VERY large part of the pollination of both crops and wild plants, they are unfairly overseen, so let’s set the record straight! Hoverflies are relatively small (about half-an-inch). They are flies and thus have only one pair of wings that they carry openly as a ‘T’. Hoverflies often are confused with bees and wasps because many of them have yellow stripes on their abdomens. However, it is relatively easy to tell them apart because they have two wings (versus four in wasps and bees), they hover and make very fast movements when they fly, they usually have huge eyes, and their antennae are very short. Hoverflies are diurnal pollinators and prefer white, yellow and greenish flowers.
Certain families of this very large group of insects visit and pollinate flowers while feeding on pollen. Beetles that pollinate can be minute to large. One can recognize them because of the hard ‘shield’ that covers their backs and the usual hair that covers at least part of their bodies. Beetles can be active during the day and night hours and prefer flowers that are greenish, white and relatively dull. In Maryland, most of our pollinator beetles are soldier and longhorn beetles. Next time you are around flowers, I invite you to take a close look and I am sure you will have no trouble finding these guys!
This is definitely a pollinator but I still don’t know what it is!
Have you found an insect on your flowers, but you can’t figure out what it is? There is a great tool to identify it, and it is just one picture away! This magical tool is a phone app called iNaturalist. After taking a picture of the insect in question you can upload it to the app and submit it for identification. This app will let you know what is likely to be the species you have seen. It also will let other users like you learn from your observations and help you identify them. Also, besides letting you visually search for observations close to you, the app/website is simple to use, and the users are friendly and helpful. To learn how to use this app/website, refer to this very good tutorial on iNaturalist.
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park