Viburnum leaf beetle, an introduced pest

The viburnum leaf beetle (Pyrrhalta viburni) was introduced accidentally along with non-native ornamental viburnums from Europe and Asia. It took perhaps a hundred years for it to become settled and to start multiplying in noticeable numbers. By then it had found out that native viburnums, such as arrowwood, were good to eat and lacked defenses against them. The consequences were, perhaps, unavoidable; the beetle is spreading across North America ravaging native viburnums.

Adult viburnum leaf beetles © Beatriz Moisset

Read the whole article:
Viburnum under siege
Viburnum under siege. Part 2

Leaf damage caused by the larvae on arrowwood viburnum  
© Beatriz Moisset

Larva and leaf damage. © Beatriz Moisset

Egg cases © Beatriz Moisset

Egg cases © Beatriz Moisset

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Ladybugs, good and not so good

Polished ladybug, a native one

We all love ladybugs. Some children’s books tell charming little stories about them. Even schoolchildren know that ladybugs eat bad insects. Five states, Delaware, Massachusetts, New Hampshire, Ohio and Tennessee, have chosen these handsome little beetles as their official state insects. Most ladybugs or ladybeetles deserve our esteem. They eat countless numbers of insects that damage our plants, so we are grateful.

Beetles, just like butterflies, go through a complicated life cycle. When they are growing up they look completely different from the cute little round buttons we are most familiar with. They start as larvae or, if you prefer, as grubs. Ladybug larvae are so ugly that you would want to squash them in disgust if you found them on your plants. Please, don’t! Remember that they clean up your garden from pests.

How can I describe them? They look like tiny alligators, longish, usually dark and with six stumpy little legs. They grow bigger and eventually, they curl up, become rounder, go to sleep and emerge from this stage as shiny new ladybugs. Both adults and larvae devour aphids or other little bugs with gusto.

What could be bad about ladybugs, or about some of them? It turns out that not all are worthy of our unconditional applause. Some have been brought to this country or to Europe, with the best of intentions, to fight unwanted pests. While they are quite good at this job, sometimes they wear out their welcome.

The first ladybug introduced in North America was the “vedalia” beetle. It was brought from Australia to combat the cottony cushion scale, a nasty insect that was decimating orange groves in California by sucking the plants vital juices. It was a stunning success; the beetle brought the pest under control to the great relief of citrus growers. This species of ladybeetle specializes on cottony cushion scale, which in turn specializes only on plants of the citrus family. So it never became a problem by not going beyond its boundaries. This is not the case with many other introduced insects.

Asian ladybeetle

After such success several other imported ladybugs joined the ranks of pest fighters. The most common and better know is the Asian ladybeetle or multicolored ladybug. It has spread so widely throughout North America that it is the ladybug you are most likely to see nowadays. It is not a picky eater, so its diet includes many kinds of aphids as well as other small soft bodied insects.

Infestation of Asian ladybugs in winter

And this is part of the problem; it is quite capable of eating other ladybugs or to out-compete them by its proficiency. As a result it may be driving some native ladybugs toward extinction. It also can become a nuisance to us because of its inclination to search for warm, comfortable places to spend the winter.

Convergent ladybeetle, a native one

It often finds shelter in garages, outbuildings or even our homes. Entire hordes of shelter seeking multicolored ladybeetles may invade our residences much to our annoyance. It seems that the crowds keep getting bigger each year.

Spotted ladybug, a native one

We still can’t appreciate the impact of this ladybug on some of the native species and on the ecosystems. But it doesn’t sound good. We continue to observe the development of events rather helplessly. In Europe the multicolored Asian ladybug has been declared a pest. It is too late for that here.

See:
Ladybugs
Asian ladybeetle
Good bugs gone bad
Beginners Guide to Pollinators and Other Flower Visitors

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“Locavore” Birds. Grow your own Birdseed

Are we being a bit unrealistic about this business of buying bird seed? I don’t quite understand all this farmland devoted to growing bird seed. I assume that the farmer has to prevent birds from ruining his crop. So, all and all, I don’t think that we are truly helping the birds this way. Instead, we are bringing them to our yard for our own selfish pleasure and depriving them of habitat somewhere else.
If we really wanted to feed birds in our backyards we should grow our own birdseed, rather than buying it from other sources.
I know that bird seed has become a big business in recent years. It was a very good idea at the beginning and feeding the birds continues to be an educational tool that helps people appreciate wildlife. But perhaps it has gone too far. What we really need right now is to start growing plants beneficial to birds in our own backyards: the ultimate in “eating locally”.


I began to ask myself these questions and soon realized that I am not the first one. I simply googled “grow bird seed” and found out people who grow gardens from bird seed. I also found those who despair because spilled seed keeps growing where it isn’t wanted. They seem to miss the irony on feeding the birds and fighting against growing bird seed. “Buy only shelled seed”, “nuke it in the microwave oven” they say.
Fortunately the ones that choose to grow bird seed have a lot of good advice, from discussing the benefits of growing only native seeds to the money saving aspects of such gardening. I am sure that a little planning would be very helpful. Not all the bird seed that you buy will grow in your area and not all would look pretty in your garden, but there are some that can really enhance the beauty of your garden, plus being beneficial to pollinators as well as birds.

Yes, let us grow our own bird seed! Let our visiting birds become locavores!

Feed the birds with native plants

Seed-Bearing Flowers for Birds

Don't buy birdseed -- grow it

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A river of birds

I keep an old National Geographic map posted on my wall. It is a map of the Americas with the flyways of migratory birds, long undulating arrows, some stretching from Canada and Alaska all the way to the southern tip of South America.

I was stunned the first time I saw that map and became instantly a bird watcher. I wanted to know more about this amazing phenomenon. Every autumn, these tiny feathered creatures develop the urge to move south. Some are veterans that have done the journey several times before; others are novices, with no knowledge of where they are going.

They know nothing beyond the nest where they were born just a couple of months before and the piece of land surrounding that nest. Now they are taken by this uncontrollable need to move. Are they following their parents or some ancestral instinct imprinted in their genetic material? In either case, they are inexorably pushed forward grueling hour after grueling hour, day after day. Most fly by night and choose higher altitudes to avoid being cooked alive by the heat of exertion and, perhaps, to escape predators.

So, they fly over meadows and forests, valleys and mountains and, most remarkably, over open ocean. An early Spanish explorer sailing through the Caribbean described a river of birds passing overhead.

Many know that they have arrived when they see the verdant forests of the Amazon and settle there for a few months, until the urge to move again brings them back to northern latitudes. Others keep going, on and on, five thousand miles and more, all the way to the Argentinean Pampas and to Patagonia. Only then they rest.

The roster of these long distance travelers is impressive. Starting with the most famous one, the peregrine falcon, the list goes on to smaller fliers: plovers, sandpipers, gulls, swallows, even a nighthawk and the tiny red eyed vireo. They all leave Canada and the United States in the late summer or fall, cross the equator and reach the Pampas at the start of the southern summer. There, they rest and wait until it is time again to start moving north in their quest to raise a family.

What captured my imagination the first time I saw that National Geographic map was the realization that the same bird I saw here in Pennsylvania in the summer may be arriving a couple of months later at my home town in Cordoba, Argentina. I told my family: If you see a bobolink, a swallow or a sandpiper, say hello to them. They are carrying my greetings from here.


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In praise of bare spots in the garden

Eastern tailed blue butterfly on clover

Some gardeners consider any exposed earth as a blemish in need of a cure, be it mulching or reseeding the lawn and watering. But in a well balanced ecosystem even bare spots have a place, and a very important one at that.
How so? Because they provide habitat and housing for an array of unappreciated garden helpers. We should know more about them. The list is long, so I will not try to cover them all, just illustrate a few interesting ones.


Butterflies. We all love butterflies and associate them with flowers and nectar drinking, but the fact is that after they fill up their tummies with nectar; they still need other nutrients, salts. One way of getting the needed salts is to take them from moist soil. It is not uncommon to see a group of butterflies, either all of the same species or several species amiable mixed together, basking in the sun while sticking their long tongues on the wet soil to extract some minerals or drink some water. Many gardeners attract butterflies by providing flowers for nectaring and plants for feeding their young. It helps to go a step further and provide them with some much needed bare ground.

Clustering of bee nests next to a parking lot

Bees. Bees are the most important pollinators, not just honey bees but the countless species of solitary bees. Most species of bees don’t make hives like honey bees. Instead they lead solitary lives, each one tending her own brood. Some nest in hollow twigs or similar holes, but the great majority nest in tunnels underground. Sometimes they cluster their nests near each other creating veritable towns; other times they take advantage of any small patch of bare soil and build their nests there. In general they prefer sunny and well drained spots.

Square headed wasp at her nest

Solitary wasps. Just like bees there are numerous species of solitary wasps that nest in the ground. Many wasps visit flowers for nectar and perform some pollination. But, perhaps more importantly, they hunt for insects to feed their young. A healthy population of solitary wasps would cut down the need for pesticides significantly. Solitary wasps, as well as solitary bees, are not likely to sting and even if they do so when molested their sting is very mild.

Tiger beetle stalking its prey

Tiger beetles. Another form of pest control is the very colorful metallic green tiger beetle. Tiger beetles belong to a group called ground beetles for obvious reasons. They spend most of the time on or in the ground. Tiger beetles are ferocious hunters of insects. If you provide them with some bare soil you can count on them for keeping pest populations down.

In summary, bare spots contribute to the balance of the garden ecosystem. They provide food or habitat for a number of garden helpers, namely pollinators and pest controls. When you consider all their benefits you wonder why we are so unwilling to tolerate them. Shouldn’t we look at them as an integral part of the garden? There are some gardeners that intentionally make some sand piles and make sure that no pesticides get to them.

Beginners Guide to Pollinators and Other Flower Visitors


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How much is a bat worth?

Who would think of putting a dollar value on a bat? Well, it turns out that some researchers have done just that. I am not talking about a baseball bat but about that creature of the night so loathed by some. We tend to associate bats with witches and demons rather than with crops.

Is there a reason for putting an economic value on a bat? The answer is: Yes. Bats feed on flying insects at night. Many of those insects are pests that damage our valuable crops. So it turns out that bats are valuable to farmers.

A group of scientists have been trying to estimate the numbers of insects bats eat and the possible impact on agriculture and forestry if bats stopped supplying this pest control. They published their conclusions in the scientific journal, Science. Through a number of complex calculations of pesticide application and crop losses they came up with a range between $3.7 billion and $53 billion a year in the United States alone. It is not possible to be more precise when considering so many variables. Anyway the numbers are impressive.

It is worth mentioning that these maligned creatures have other functions in addition to the pest control discussed in this study. They are pollinators of many night blooming flowers. Cacti, in particular, are dependent on bats for pollination. Many cacti of the West synchronize their blooming time with the migration of some species of bats. Try to imagine what the West would be like without cacti. Another service, especially in the tropics is seed dispersal. Bats eat the fruits of many trees, such as fig trees and pass the seeds far from the mother trees.

Unfortunately, in recent times, bats are encountering serious problems. There is one disease in particular that is decimating the populations of bats in the United States. This fungal disease, called "white nose syndrome", weakens and kills large number of bats, especially during the winter. Not much is known about this illness, nor there is a cure in sight yet. It is for this reason that the researchers decided to investigate how the loss of bats would affect agriculture. Even lacking more accurate numbers the results are alarming; the losses to crops and forestry could be very serious.

The web of life is very intricate and often we don’t know enough about all the threads that make this tapestry. This is another example of a creature whose value we fail to recognize. It took a threat to the welfare of bats, such as the white nose syndrome for the world to stand up and take notice. We are only now beginning to appreciate the value of the free services provided by these creatures: pollination, seed dispersal and pest control. We have to look at bats with renewed respect. Let us develop a kinder attitude towards our friends, the bats.

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The sounds of nature

I remember starry nights at our summer house in Argentina. We would lie on reclining chairs or directly on the grass, contemplate the stars and enjoy the sound-filled air, a harmony of tiny voices, not at all like the man-made cacophony of cities. Chirps and tweets and peeps and murmurs and trills and purrs and an occasional distant bark or snort created a richly embroidered tapestry of sounds. We spoke softly or not at all to better savor the views and sounds.

Many years later, my memory of those long gone peaceful nights was jogged by a lecture with the title: “The Great Animal Symphony”. The speaker, Dr. Bernie Krause, has been collecting recordings of the so called nature soundscapes; not just the voices of specific animals, but the intricately complex combination of sounds that characterizes each locale on Earth.

He explained that the members of an animal community talk to each other in distinctive voices to avoid confusion with the many other voices nearby. Thus, each one has been refining its special signature of pitch, spacing of sounds and timing.

The result is rich and full of subtlety, in sharp contrast with the jarring dissonances of cars, planes, lawnmowers and similar noise makers found near any human habitation nowadays. Dr. Krause, urged by the rapid loss of nature soundscapes, keeps traveling to remote areas to record the remaining sounds of nature before they are gone.

I wish I had paid more attention to the magical night music at our country house. I could have tried to identify some of the members of that finely tuned orchestra. It is possible that some are already lost because of planes flying overhead and trees being cut down.

I realize now that the members of that orchestra had been polishing and rehearsing their symphony for many thousands of years. Can they cope with the intrusion of alien sounds? Are we destroying in a matter of decades what took eons to develop?

Dr. Bernie Krause: The Great Animal Orchestra

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Squirrels, Managers of the Forest

A squirrel approaches a mushroom growing under a pine tree. It sniffs it and breaks off a piece. It scrambles up the tree carrying its treasure, finds a comfortable branch to sit on and proceeds to eat the snack to the last crumb. Then it wipes its whiskers daintily, shakes its fur and scurries away to go wherever it is that squirrels go when they feel full and contented.

This vignette is more than a trivial episode; it is forest management at its best. It is a fine example of the intricate web of life of the forest. How so?

Let us unravel the links of this chain. The chunk of mushroom that the squirrel just snacked on contains numerous spores which will travel intact through the entire digestive system of the little fellow. The spores will come out at the other end, fall to the ground, some of them will germinate and eventually produce new mushrooms.

There is a fungus under that very same tree where the squirrel enjoyed its meal. You don’t see it because it is underground. It is made of a myriad thin threads spreading in all directions in the darkness of the moist soil. It intertwines again and again making tangles and becoming one big network. It seeks the rootlets of the tree; when it senses one it approaches it, penetrates it and proceeds to grow inside the rootlet. The tree fights this invasion at first, producing little knobs at the entry point, but it soon surrenders. The fungus hungrily absorbs nutrients from the root. And then a miraculous thing happens: this fungus gives as much as it receives. It is more efficient than the tree at collecting water and salts and it passes some of these much needed commodities to the plant. The fungus becomes an extension of the tree, reaching hidden pockets of soil that rootlets cannot access. Thus it is called a mycorrhiza, which means fungus-root.

Periodically, the mycorrhiza produces “fruits”, although the more appropriate word is “fruiting bodies” since they don’t carry seeds but spores. These fruiting bodies are mushrooms that sprout from the ground almost overnight and almost magically. A mushroom is like an apple and the whole “apple tree” is the fungus buried underground. This is the mushroom that the squirrel ate and whose spores the little animal will spread unwittingly and not very elegantly somewhere else.

So the green foliage above takes the sunshine and turns it into molecules of life, sugars and other nutrients, and sends them down to the roots. There they also nourish the fungus which, in return, supplies the tree with water and minerals taken from the soil. The squirrel, blissfully ignorant of its job as keeper of the forest, scampers away with a belly full of spores that will keep the fungus-tree partnership going for many years to come thus ensuring the survival of its own home, the entire forest.

Trees, truffles, and beasts: how forests function By Chris Maser, Andrew W. Claridge, James M. Trappe

The Living Constellations Beneath our Feet
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Feed the Birds

Goldfinches at feeder

You think that you love birds. Every week you pick up your binoculars and go birdwatching with others who share your interest. You have one or two birdhouses in your properties and, of course, bird feeders that you can see from your window while you drink your morning coffee. Yes, you are very much a bird lover.

But what would you think if I told you that you are probably dooming some birds to death and starvation through your gardening practices? Let us say that you decide to buy a new tree for your yard, you love the color and shape of Japanese maples and that is what you choose. Later on, you take a look at azaleas and rhododendrons and find out that there are some Chinese cultivars which you find extremely attractive. You bypass the native varieties and choose one of those.

These innocent actions have deplorable consequences for the birds that visit your yard. Birds have no use for those foreign plants. Well, you say, “I have seen them use those branches for nests, what could be wrong with such plants?”

Until just a year ago I would have thought exactly the same. I didn’t know the bad consequences of using non-native plants as long as they weren’t invasive. But reading a book by Doug Tallamy (Bringing Nature Home) opened my eyes to a whole new perspective and a new appreciation of how food chains work, not just in nature preserves and remote parks but in our own backyards.

A nutritious caterpillar feeding on native wild ginger

Numerous insects are adapted to native plants and find your Japanese maple and alien azalea totally inedible. So what? Who needs insects, anyway? You say. –Birds need insects; that is who! Ask yourself: what do birds eat? Particularly, baby birds with their voracious appetites and fast growing bodies? They need lots of proteins; that is why their parents spend several hours a day hunting for insects, because insects are little packages of protein. If your plants are non-native there isn’t much insect protein to be found on them and the birds have to search somewhere else.

So to put it in a nutshell, each time that you plant an exotic tree or shrub you are dooming some baby bird to hunger and death. Or, if it makes you feel better, each time that you plant native plants you are helping the birds you love, perhaps even more than you do with your bird feeders.

A handsome looking native shrub, mountain laurel

Nature centers and wildflower preserves as well as some arboretums sell native plants and can provide information on them. You can also find these regional native plant lists useful: Pollinator Friendly Planting Guide. They are intended for pollinator gardens but they can apply to all wildlife.

For the area I am familiar with, the Atlantic seaboard:
Delaware Native Plants for Native Bees

And of course, the book mentioned above: Tallamy, Doug: Bringing Nature Home and the website: Bringing Nature Home

Caterpillars are for the Birds

Have you ever seen a caterpillar hanging from a thread when you were walking through the woods? You probably have, more than once; it happens often enough that, although caterpillars are very small and not easy to see, everybody sooner or later gets a chance to see this peculiar scene.
Did you ever wonder where it was going? Certainly not up, most likely down. But, down where and for what reason?
Many caterpillars feed high on the canopy, devouring tender leaves and growing very fast. After they are done growing they start getting ready for the big transformation, called metamorphosis, which will turn the rather shapeless, wormy thing into a winged marvel, a moth.


Where you find a caterpillar there may be hundreds or thousands, all of them gleefully feeding on the same tree. Look up at the tree’s foliage above your head; there doesn’t seem to be much damage and this is very fortunate. Part of the reason is that there are many hungry creatures who regard the caterpillars as very tasty and very nutritious morsels of food. Among them you can count some of your most beloved birds, warblers, wrens, sparrows. You see them fleeting about and they may be picking up some of your caterpillar’s brothers and sisters. They will be taking them to their growing brood and ramming them down their hungry throats.
Let us get back to our question: where is the caterpillar going? It may be looking for a secluded place in the leaf litter, safe from winged predators (although not entirely safe for there are other hungry creatures in the soil too). Once on the ground it probably won’t go very far. In most cases it tries to find some leaf litter and it proceeds to bury itself in it. There it will begin spinning a cocoon using a special kind of saliva that changes into silk, strong and supple, as soon as it gets in touch with air.


It may proceed to undergo a big transformation in just one or two weeks to become an adult moth, or if it is the end of the season, it will wait until next year; hunkering down through a long and cold winter and will emerge only when the trees are already leafing out.


During that time it grows wings and legs and antennae and becomes a pretty moth ready to find a mate and to start the cycle all over again. If it is a female it will lay eggs after searching very diligently for the same kind of trees where it fed as a caterpillar.
Most caterpillars are very particular about their food; they can feed only on one kind of tree or perhaps a handful of related trees, for instance, only sugar maples or only several varieties of maples, but not oaks or ash trees. Others will choose only oaks or ash trees. They are so particular that many of the ornamental trees brought from overseas for their beautiful foliage or interesting shape are useless to them. The indirect consequence of a landscape with only imported plants is: no caterpillars - no food for the birds. If you love birds you may want to plant native trees to ensure that birds can find food hidden in their foliage.

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