Combating Japanese Beetles

Japanese Beetle (Popillia japonica)

Japanese Beetle (Popillia japonica)

Japanese Beetles (Popillia japonica) are especially prolific this summer, voraciously consuming the leaves, flowers and buds of herbaceous (non-woody) plants, shrubs and trees. They were first discovered at a nursery in New Jersey in 1916, probably introduced here with imported nursery stock. Now widespread east of the Mississippi River in the United States and southern Canada, these insects are destructive pests in North America because the natural predators with which they evolved are not present here to keep them in check.

Red Chokeberry (Photinia Pyrifolia) leaves skeletonized by Japanese Beetles

Red Chokeberry (Photinia Pyrifolia) leaves skeletonized by Japanese Beetles

What can you do to combat these critters? Enlist the help of some predatory insects that are native to North America.

Scolia dubia on Boneset (Eupatorium species). Scolia dubia is known to prey on the larvae of Japanese Beetles.

Scolia dubia on Boneset (Eupatorium species). Scolia dubia is known to prey on the larvae of Japanese Beetles.

Scoliid wasps prey on the larvae of scarab beetles to feed their own larvae. Japanese Beetles are a species of scarab beetle. Female Japanese Beetles burrow a few inches into the ground to lay their eggs. Their larvae, often called grubs, develop underground and feed on the roots of plants. Female scoliid wasps find and enter the underground burrows of Japanese and other scarab beetles, and lay an egg on each grub. The wasp larva hatches and consumes the grub.  Two species of scoliid wasps are shown in this post, Scolia dubia and Scolia bicincta.

Scolia dubia on Grass-leaved Goldenrod (Euthamia graminifolia)

Scolia dubia on Grass-leaved Goldenrod (Euthamia graminifolia)

How can you entice these beneficial wasps to patrol your property? They can be bought with food. The adult wasps drink nectar from flowers, usually flowers that have short tubes, arranged in dense clusters that provide a landing platform for the wasp. Mountain mints and many aster family members fit this description. They seem especially partial to goldenrods and bonesets, in addition to the mountain mints.

Scolia bicincta on Hoary Mountain Mint (Pycnanthemum incanum). Scolia bicincta may also be a Japanese Beetle predator.

Scolia bicincta on Hoary Mountain Mint (Pycnanthemum incanum). Scolia bicincta may also be a Japanese Beetle predator.

These beneficial wasps are hairy, helping to make them to be effective pollinators of the plants they visit for nectar. The pollen is likely to adhere to their hairy bodies and be carried to another plant for deposit.

Scolia bicincta on Hoary Mountain Mint (Pycnanthemum incanum).

Scolia bicincta on Hoary Mountain Mint (Pycnanthemum incanum).

You may be worried about having wasps around, because of their reputation for stinging. While that reputation may be deserved for some social wasp species, like the Yellowjackets, it’s more a case of guilt by hasty generalization for solitary wasps like the scoliids. Social wasps live in colonies, which they aggressively defend from intruders. But scoliids, like many wasp species, are solitary. So there is no colony to defend. Stingers are really ovipositors (egg laying structures) that can be used for two purposes. Females may use the ovipositor to sting and subdue their prey, and also to lay their eggs. Male wasps and bees don’t lay eggs, so the don’t have ovipositors, and can’t sting. Solitary wasps like the scoliids are quite gentle, and would generally have no reason to sting a person.

Eastern Yellowjacket (Vespula maculifrons) on Goldenrod (Solidago species)

Eastern Yellowjacket (Vespula maculifrons) on Goldenrod (Solidago species)

The Wheel Bug (Arilus cristatus) is a type of assassin bug that is happy to devour adult Japanese Beetles. Wheel Bugs hunt their prey by blending in with a plant. They wait for a hapless victim to come close enough to grab it with their somewhat hairy and sticky front legs, then stab it with their beak, injecting enzymes that paralyze and then liquefy their victim’s innards. The Wheel Bug then slurps up the resulting insect smoothie, with the victim’s exoskeleton acting as a to-go cup.

Wheel Bug (Arilus cristatus) preying on Japanese Beetle; more Japanese Beetles continue to eat in upper left.

Wheel Bug (Arilus cristatus) preying on Japanese Beetle; more Japanese Beetles continue to eat in upper left.

Japanese Beetle grubs (larvae) are especially fond of eating the roots of lawn grasses. As a result, lawns are the favored location for Japanese Beetles to excavate a burrow for their eggs. Replacing as much lawn as possible with a mix of herbaceous plants, shrubs and trees will minimize the habitat available to Japanese Beetles for reproduction. Reduced habitat means fewer Japanese Beetles.

Japanese Beetles (Popillia japonica)

Japanese Beetles (Popillia japonica)

What can you do to combat Japanese Beetles?  In order to attract beneficial insects like those shown here, be sure you have a variety of plants native to your area. Take away the Japanese Beetle’s preferred habitat by minimizing the size of your lawn. There will be a corresponding reduction in the number of Japanese Beetles you see.

Spicebush (Lindera benzoin) leaf skeletonized by Japanese Beetles

Spicebush (Lindera benzoin) leaf skeletonized by Japanese Beetles

 

Related posts

Mountain Mints are Pollinator Magnets!

Asters Yield a Treasure Trove

Fall Allergies? Don’t Blame Goldenrod!

 

Resources

Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America. 2007.

USDA Japanese Beetles

Beneficial Insects in the Garden

 

 

Pearl Crescents: A Flirtation Consummated

Animal species instinctively behave in ways that help further the survival of their species. Inevitably, this means spending much of their time eating and reproducing. Recently I had the opportunity to observe such behavior in Pearl Crescent butterflies.

Pearl Crescent sipping nectar from Indian Hemp (Apocynum cannabinum)

Pearl Crescent sipping nectar from Indian Hemp (Apocynum cannabinum)

Pearl Crescents are named for the crescent shaped marking near the center of the submargin of their hind wing. They can often be seen together in groups, nectaring on a variety of flowers, feeding on minerals, and flirting.

Pearl Crescent female (top) with two males hoping to capture her interest; on Butterflyweed (Asclepias tuberosa)

Pearl Crescent female (top) with two males hoping to capture her interest; on Butterflyweed (Asclepias tuberosa).

In the photo below, a male Pearl Crescent is doing some serious courting of a female.  Ignoring him, she sips nectar from Indian Hemp (Apocynum cannabinum) flowers, a species of Dogbane, and  an important nectar source in June and early July.

Do you come here often?

Pearl Crescent male (right in photo) to female (left), “You look lovely in this light! Do you come here often?”

Still in search of food, the female Pearl Crescent flew off to find more nectar, stopping on another Indian Hemp plant.  The male followed closely behind. Still drinking, she turned to let him make his case.

Pearl Crescent male (right in photo) to female (left), "You won't find a finer specimen of Pearl Crescent manhood!" Unimpressed, she continued to drink nectar.

Pearl Crescent male (right in photo) to female (left), “You won’t find a finer specimen of Pearl Crescent manhood!” Unimpressed, she continued to drink nectar.

A few seconds later she flew off again, finally turning toward him with fluttering wings; a sign of rejection, at least for now.

Pearl Crescent female (left) to male (right), "I'm not ready to commit yet!  I'm still shopping around to see if I can do better."

Pearl Crescent female (left) to male (right), “I’m not ready to commit yet! I’m still shopping around to see if I can do better.”

Later, I spotted a female Pearl Crescent with her wings open.  She appeared to be basking. Then I noticed the two other butterflies with her.

Pearl Crescent female mating with one male while another continues to plead his case

Pearl Crescent female mating with one male while another continues to plead his case

She was mating with one male, while another, undeterred, continued to lobby for her favors. She remained steadfast.

Pearl Crescent female, above right, mating with male below her.  Male Pearl Crescent on left, "Hey baby, why don't you drop that loser and fly away with me?!"

Pearl Crescent female, above right, mating with male below her. Male Pearl Crescent on left, “Hey baby, why don’t you drop that loser and fly away with me?!”

The rejected male flew off, remaining close by in case the female changed her mind.

Rejected male to female, "I'll be waiting over here when you come to your senses."

Rejected male to female, “I’ll be waiting over here when you come to your senses.”

But she elected to stay with her original choice.

Mating Pearl Crescent butterflies

Mating Pearl Crescent butterflies

When they are finished, the female Pearl Crescent will seek out the select aster species that her offspring caterpillars will be able to digest. Among the acceptable species are Heath or Awl Aster (Symphyotrichum pilosum), Calico Aster (Symphyotrichum lateriflorum), Panicled Aster (Symphyotrichum lanceolatum), and Smooth Aster (Symphyotrichum laeve).

Pearl Crescent on aster

Pearl Crescent on aster

These bright little butterflies are active from April through November in the northern parts of their range, producing multiple broods.  In the south, they are active year-round.

Pearl Crescents can be found in most of the eastern two-thirds of the US; they are very common in the east.  Their range extends into Canada from southeastern Alberta to southern Ontario, and to the south in northeastern Mexico. Look for them in a meadow or garden near you!

Related Posts

What good is Dogbane?

Romance in the Meadow – Baltimore Checkerspots

Resources

Butterflies and Moths of North America

Cech, Rick; Tudor, Guy. Butterflies of the East Coast. 2005.

 

 

First Monarchs of the Season

Monarch butterfly on Butterflyweed (Asclepias tuberosa), in the meadow at Pennswood Village, Newtown, PA

Monarch butterfly on Butterflyweed (Asclepias tuberosa), in the meadow at Pennswood Village, Newtown, PA

In the past week, I’ve seen Monarchs in three different locations.  (This is the only one that would pose for me!)  Cause for optimism?  Have you seen any Monarchs this summer?

What Do Juniper Hairstreaks and Cedar Waxwings Have in Common?

Juniper Hairstreaks are sprightly little butterflies with varying color forms that predominate in different parts of their range.  Where I live in the east, the ‘Olive’ Juniper Hairstreak is present, sporting a sparkling bright green and brown coloration.  The Juniper Hairstreak is named after its caterpillar food plant, which is Eastern Red Cedar in much of the eastern two thirds of the United States, east of the Rocky Mountains.  To understand the origin of the butterfly’s name, it helps to know that this plant is actually a juniper, reflected in its scientific name, Juniperus virginiana.

Juniper Hairstreak nectaring on Short-toothed Mountain Mint (pycnantemum muticum)

Juniper Hairstreak nectaring on Short-toothed Mountain Mint (pycnantemum muticum)

Juniper Hairstreak’s distribution is sometimes described as ‘locally common’, because this butterfly is usually found in close proximity to its caterpillar food plant.  Male Juniper Hairstreaks spend their time perched on the branches of their caterpillar food trees, waiting for a receptive female to appear.  Eggs are laid singly on the tips of the tree branches.

Juniper Hairstreak nectaring on Narrow-leaved Mountain Mint (Pycnantemum tenuifolium)

Juniper Hairstreak nectaring on Narrow-leaved Mountain Mint (Pycnantemum tenuifolium)

Adult Juniper Hairstreaks visit flowers of many perennials for nectar, but this is most often in the vicinity of their caterpillar food plants.  In my area, they seem especially fond of nectaring at Mountain Mints, but I have also seen them feeding on coneflowers and other aster family members.

Juniper Hairstreak nectaring on Black-eyed Susan (Rudbeckia hirta)

Juniper Hairstreak nectaring on Black-eyed Susan (Rudbeckia hirta)

Eastern Red Cedar is an evergreen tree with a shape that is generally pyramidal or columnar.  It usually grows to a maximum height of about 40 feet (12+ meters), although in the right conditions it can grow taller.  It does best in full sun.  Eastern Red Cedar can tolerate moist to dry soils but is especially well adapted to dry conditions, making it a good candidate for locations where drought is a concern.  It is effective alone as a specimen tree, or on larger properties it can be used for privacy screening or to line a driveway.  Its deep root system enables Eastern Red Cedar to stand up to strong winds, so it also makes an effective windbreak. It can even stand up to tropical storms.

Eastern Red Cedar (Juniperus virginiana)

Eastern Red Cedar (Juniperus virginiana)

The evergreen foliage of Eastern Red Cedar provides year-round visual interest.  It is accented by the changing color of its fruit, which begin to develop in pale shades of grayish blue by mid to late spring, ripening throughout the summer to a deep blue.  Often some fruits will remain on the trees through much of the winter.  While these fruits look like luscious berries, they are actually cones.  Although there are occasional exceptions, Eastern Red Cedar is generally has male and female reproductive parts on separate plants.  At least one male is needed in the neighborhood to produce pollen.  Only the female trees will have the showy berry-like cones.  Eastern Red Cedar relies on wind to achieve pollination.

Eastern Red Cedar (Juniperus virginiana) cones

Eastern Red Cedar (Juniperus virginiana) cones

In addition to being a caterpillar food plant for Juniper Hairstreaks, Eastern Red Cedar is great for birds.  The berry-like cones provide food from late summer through much of the winter for many bird species.  The social Cedar Waxwings, for whom fruit is a larger part of their diet than it is for most birds, were named for their love of these cones.  Eastern Red Cedar’s dense foliage provides good coverage for small to medium sized birds who are looking for a place to perch safely out of view and reach from larger predators.

Cedar Waxwing

Cedar Waxwing

Eastern Red Cedar is a hardy tree that reproduces readily.  It is sometimes referred to as a pioneer species, since it is often one of the first tree species to appear in fields and meadows.  This is usually the result of its seeds passing through the digestive system of birds, a process that increases the chance that the seed will germinate successfully.

What do Juniper Hairstreaks and Cedar Waxwings have in common?  Both depend on Eastern Red Cedar for food.  Juniper Hairstreak caterpillars rely for their survival solely on this tree species .  Cedar Waxwings have a strong preference for the cones of Eastern Red Cedar, but also eat many other fruits.  The names of both of these animals reflect the strong association between them and Eastern Red Cedar.

Watch to see how many different bird species dine or take shelter in Eastern Red Cedar.  If there are good nectar plants nearby, you’ve found a hospitable home for Juniper Hairstreaks, too.

Juniper Hairstreak on Hoary Mountain Mint (Pycnanthemum incanum)

Juniper Hairstreak on Hoary Mountain Mint (Pycnanthemum incanum)

 

Resources

USDA Eastern Red Cedar Plant Fact Sheet

USDA Eastern Red Cedar Plant Guide

Lady Bird Johnson Wildflower Center

Butterflies and Moths of North America

Sibley, David Allen.  The Sibley Guide to Bird Life and Behavior.  2001.

 

 

Late Spring in Stowe, Vermont

Spring unfolds more slowly in northern Vermont than it does where I live in the mid-Atlantic.  So we were able to catch some late spring action in the Stowe area recently.  The show started in the gardens at Trapp Family Lodge, where an Eastern Chipmunk foraged among the Wild Columbine (Aquilegia canadensis) and Wild Bleeding Heart (Dicentra eximia),

Eastern Chipmunk with Wild Columbine (Aquilegia canadensis) and Wild Bleeding Heart (Dicentra eximia)

Eastern Chipmunk with Wild Columbine (Aquilegia canadensis) and Wild Bleeding Heart (Dicentra eximia)

while a Groundhog family watched nearby.

Groundhog family in the garden at Trapps

Groundhog family in the garden at Trapps

The woods at Trapps and the other natural areas we visited were lush with ferns, with a bounty of other diverse plants peaking through them.

The woods from Fox Track trail at the Trapp Family Lodge

The woods from Fox Track trail at the Trapp Family Lodge

Narrow Beech Fern (Phegopteris hexagonoptera) with Foamflower (Tiarella cordifolia) and Hooked Crowfoot (Ranuunculus recurvatus)

Narrow Beech Fern (Phegopteris hexagonoptera) with Foamflower (Tiarella cordifolia) and Hooked Crowfoot (Ranuunculus recurvatus)

Bunchberry (Cornus canadensis) at Wiessner Woods

Bunchberry (Cornus canadensis) at Wiessner Woods

Pink Lady’s Slippers (Cypripedium acaule) shyly raised their heads for our viewing pleasure.

Pink Lady's Slipper (Cypripedium acaule)

Pink Lady’s Slipper (Cypripedium acaule)

Pink Lady's Slipper (Cypripedium acaule)

Pink Lady’s Slipper (Cypripedium acaule)

Goldthread (Coptis trifolia) had finished blooming, and was setting fruit.

Goldthread (Coptis trifolia) with Canada Mayflower (Maianthemum canadense) leaves

Goldthread (Coptis trifolia) with Canada Mayflower (Maianthemum canadense) leaves

Canada Mayflower (Maianthemum canadense) shown in the sun’s spotlight,

Canada Mayflower (Maianthemum canadense)

Canada Mayflower (Maianthemum canadense)

while the delicate blossoms of False Solomon’s Seal (Maianthemum racemosum) lit the trails.

False Solomon’s Seal (Maianthemum racemosum)

False Solomon’s Seal (Maianthemum racemosum)

A White-tailed Deer was unfazed by our visit to her domain.

White-tailed Deer

White-tailed Deer

Foamflower (Tiarella cordifolia) was in various stages of its bloom cycle in different locations. We often found it close to water.

Foamflower (Tiarella cordifolia)

Foamflower (Tiarella cordifolia)

In the woods, most of the potential pollinators were flies of various species.  In the photo below, the fly on the Foamflower is harvesting pollen, a food source for some fly species.

Fly harvesting pollen from Foamflower (Tiarella cordifolia)

Fly harvesting pollen from Foamflower (Tiarella cordifolia)

Bluebead Lily (Clintonia borealis) was just beginning to bloom, often visited by the fly shown here.

Bluebead Lily (Clintonia borealis)

Bluebead Lily (Clintonia borealis)

 

Bluebead Lily (Clintonia borealis) with flower visitor

Bluebead Lily (Clintonia borealis) with flower visitor

A Robber Fly, better know for its diet of other insects than for drinking nectar, visited Dwarf Ginseng (Panax trifolius) flowers.

Dwarf Ginseng (Panax trifolius) with Robber Fly

Dwarf Ginseng (Panax trifolius) with Robber Fly

Dwarf Ginseng was popular with another fly visitor who unknowingly gathered pollen on its hairy body for possible dispersal to other flowers.

Dwarf Ginseng (Panax trifolius) with potential pollinator

Dwarf Ginseng (Panax trifolius) with potential pollinator

Near Stevenson Brook in Little River State Park,

Stevenson Brook at Little River State Park

Stevenson Brook at Little River State Park

Virginia Waterleaf (Hydrophylum virginianum) bloomed a deep violet, pictured here with a flower visitor coming in for a landing.

Virginia Waterleaf (Hydrophylum virginianum)

Virginia Waterleaf (Hydrophylum virginianum)

Southern Pygmy Clubtail dragonflies rested on a fern at Sterling Falls Gorge.

Southern Pygmy Clubtail dragonflies

Southern Pygmy Clubtail dragonflies

Sterling Falls Gorge

Sterling Falls Gorge

Bluets (Houstonia caerulea) brightened  a meadow at Trapps, the yellow nectar guides at their throats attracting a variety of visitors, incuding Bumble Bees, Eight-spotted Forester moths, Bee Flies and a Mustard White butterfly.

Bluets (Houstonia caerulea)

Bluets (Houstonia caerulea)

Bluets (Houstonia caerulea) with Bumble Bee

Bluets (Houstonia caerulea) with Bumble Bee

Bluets (Houstonia caerulea) with Bee Fly (Bombylius major)

Bluets (Houstonia caerulea) with Bee Fly (Bombylius major)

 

Bluets (Houstonia caerulea) with Mustard White butterfly

Bluets (Houstonia caerulea) with Mustard White butterfly

The Mustard White was a new butterfly for me.  Its numbers have diminished in recent years because of habitat loss, and possibly also due to the increase of the invasive Garlic Mustard (Alliaria petiolata).  Mustard White caterpillars rely for food on our native mustards, such as Toothwort (Cardamine diphylla) and Cut-leaved Toothwort (Cardamine concatenata).  Toothwort is present along the trails near the clearing where we saw the Mustard White, and Garlic Mustard was nowhere to be seen.

Back in the woods, two crane flies mated, doing their part to ensure that the show will continue.

Crane Flies mating

Crane Flies mating

 

Related Posts

Cut-leaved Toothwort