Large population of painted lady butterflies this year

Just about everyone knows what a monarch butterfly is and its amazing migration to and from Mexico. But not nearly as many people have even heard of a painted lady butterfly; until this year that is. Reports of painted lady butterflies seem to be all over the twittersphere. The most popular one I’ve seen is the weather radar in Colorado picking up a huge swarm of the migrating butterflies.

In a garden that I tend, I’ve been seeing lots of painted ladies during the past week or so. Although there’s many more than normal, they’re not in radar-detecting numbers, that’s for sure. Since it is the middle of October, most of the plants in the garden are done for the season.  There are however, a couple of hundred late-planted zinnias still going strong. That seems to enough to convince the butterflies to stop by the garden to tank-up on zinnia nectar before continuing their journey south. I’ve noticed there is a wide size variation in the ones I’ve been seeing, some are only less than three-quarters the size of the larger ones. Apparently, the larger insects had much better feeding conditions when they were caterpillars than did their smaller companions.

Although not as big as monarchs, painted ladies are one of our larger butterflies

A quick search online shows not much is known about this species compared to the the intensely studied monarch. They’re still figuring out how they find their way south and what triggers them to migrate. Unlike the monarchs that take more than one generation to migrate, the painted ladies make the entire trip as a single adult. They’re often found in their southern range all beat up from the long flight, yet they still search out just the right plants on which to lay their eggs.

All round the country the same thing is happening: a large expansion of the painted lady butterfly population. Some scientists are so impressed by some of the reports that they are comparing this rare event to this summer’s total eclipse. If you don’t want to be left out of what is possibly a once in a lifetime occurrence, find a place that still has a few flowers in bloom and take part in some fun butterfly viewing. You probably won’t see clouds of painted lady butterflies around here but you certainly won’t have to look very hard to find them.

Bob

Hoverflies are beneficial insects

As mentioned in an earlier post on this blog, I planted a fairly large plot of buckwheat adjacent to our vegetable garden this spring. The main idea behind planting buckwheat was to provide forage primarily for honeybees and for any other pollinators that might be around to take advantage of it.

As it turns out honeybees are in the minority. When surveying the buckwheat plot, I noticed for every one honeybee I saw there were ten or twenty other pollinators. They included butterflies, small wild bees, small wasps, many kinds of beetles, flies and hoverflies.

Hoverflies are especially good to have in the garden. The adult hoverfly is a very agile flyer able to hover in one spot then zoom away, stop on a dime and hover in place again — they can even fly backwards.  They don’t have teeth or mandibles so they can’t chew or tear into things. Their mouth parts are spongy and are designed to soak up nectar and other liquids as well as picking up small particles such as pollen. That is why they’re so attracted to the buckwheat flowers.

Hoverflies have a superficial resemblance to bees.
Hoverflies have a superficial resemblance to bees.

Hoverfly larvae on the other hand are insectivores that eat small soft-bodied insects. In the garden that means mostly aphids, thrips, leafhoppers and scale. All four of these common garden pests have a stage in their lifecycle when they are soft-bodied.

After mating the adult female hoverfly buzzes around looking for a likely spot to lay her eggs, someplace where her young will have easy access to food. How does she know where the best spot is? Aphids and those other insects get all their nutrition from plant juices. They can only use part of the sugar in plant sap so they excrete the unneeded sugar as a syrupy liquid called “honeydew”. It’s the honeydew that attracts the female hoverfly: where there’s honeydew, there are insects for her young to feed on.

During the larval stage, each individual hoverfly will eat up to 400 aphids and other insects giving it the needed protein to go on to further development.

Since they are such good flyers, it’s very easy for female hoverflies to fly from the buckwheat to our vegetable garden and back again. The habitat that buckwheat provides enables the beneficial insect population to grow much larger than it would otherwise. That is a good lesson about the advantages of encouraging beneficial insects with plants instead of trying to maintain a garden in the middle of a sterile environment like a mowed lawn.

Bob

 

Pruning milkweeds

I saw my first Monarch butterfly several days ago. I know they were here much earlier because I found a caterpillar on my milkweed plants. That means there had to be a female butterfly around before that.

It takes around four days for a Monarch egg to hatch. The caterpillar stage lasts around a week and a half to two weeks. Since my caterpillar was almost fully grown, the female Monarch that laid his eggs arrived nearly two weeks ago. How did she sneak into the yard without me seeing her?

This monarch caterpillar has by now formed a chrysalis.

Most of my milkweed plants are on the verge of blooming. The plants are maturing and the leaves and stems are beginning to stiffen and get tougher in order to hold up the flowers and seed pods. Although female Monarchs will lay eggs on any milkweed, they prefer the more tender leaves toward the top of the plant.

A gardener I know suggested that I cut back my some of my milkweed plants to stimulate new growth and leaves. Theoretically, those new leaves would make my plants more attractive to the butteries than others in the area. I just snipped off the plant just above the existing leaves. That caused some milkweed sap to ooze out of the cut. That sap is poisonous and irritating so make sure you don’t in your eye.

Cutting the milkweed just above the leaves allows secondary leaf buds to sprout and grow.

This is the first time I’ve tried this with milkweeds. I’ll let you know how it turns out.

Bob

Check those plants you moved indoors for scale insects

With Christmas and other hectic, holiday happenings over, now is a good time to check those plants you brought inside for winter.

When potted plants live outside during the summer, they become susceptible to infestations of all kinds of insects. Usually, if they are in reasonably good health they can tolerate a moderate insect attack. And natural predators like lady bugs and lace wings will keep the bad insect population to a minimum. But when plants are moved indoors, they loose the protection of those natural predators which can allow the insect population to grow.

Scale insects are the ones I have the most problem with. When I start to find a sticky coating, called “honeydew”, on the lower leaves, table, nearby furniture or floor, I know that the scale insects are ramping up their feeding. They can get out of hand quickly at that point and do some real damage to the plant– not to mention the mess they make. Honeydew is sometimes mistakenly called “sap” because the plant owner thinks it is the plant leaking sap all over the place. It’s not always easy to spot a scale infestation if you’ve never seen it before.

The brown ovals are the outer shells of the scale insects. The clear substance is honeydew.
The brown ovals are the outer shells of the scale insects. The clear substance is honeydew.

Scale feed by poking their “beak” into the the plant and feeding on the nutrients from the plant juices. Like most other animals, they excrete waste. In this case it is in the form of that sticky, syrupy  honeydew. Honeydew contains a high concentration of sugar. But how and why do scale insects produce so much sticky residue? The answer is that they pick their feeding spot very carefully. If you remember from middle school biology, plants have two basic types of tubes inside. Those that carry water from the roots up into the plant are called xylem. The other tubes that carry nutrients manufactured by the leaves to the rest of the plant are called phloem.

It is the phloem where the scale insects like to poke their beaks. If they pierced a xylem tube by mistake, all they would get is mostly water and some dissolved minerals. The phloem sap contains sugars for energy, proteins for growth and other things necessary to sustain plant and animal life.

The scale can’t use all of the sugar dissolved in the phloem juices so they excrete the excess sugar which then falls all over the immediate area. Since it is primarily sugar, it is water soluble and fairly easy to clean up with a damp cloth. Small plants can be rinsed off in the sink or bathtub.

My citrus trees are way too big to rinse off in the bathtub and too heavy for me to move to the shower. Instead I use a damp cloth — or even my bare fingers– to rub off the scale from the leaves and branches whenever I find them. I find that if I do a few leaves every day, I can usually keep up with the multiplying insect population, especially if I remember to start early. If you wait too long, it can turn into a tedious, frustrating job.

One other by-product of honeydew is sooty mold, a black, powdery mold that grows om the surface of leaves and other surfaces. All of that sugar provides food for sooty-mold fungus which will grow and leave sticky surfaces with an unsightly black film that can rub off onto clothing.

Even though you may feel overwhelmed by the holiday rush, remember your plants, they will thank you for it.

Bob

 

Look for squash bugs on pumpkins and squash

The squash crop is looking pretty good so far but has had its share of problems.

Earlier in the season we were worried about squash vine borers moving in. Now we have a new pest that we need to take care of, squash bugs. A few days ago I spotted a very familiar sight, squash bug eggs. Once you’ve seen them, you’ll have no trouble finding more.

The eggs are small, shiny, metallic-looking usually found on the underside of the leaves. Many egg clusters I’ve seen this year however, are appearing on the top side of the leaf. Usually, the female lays clusters of eggs that follow the outline of the veins of the leaves giving the clusters a roughly triangular shape.

Here's a couple of squash bug egg clusters. Down in the whorl of the leaf is a group of squash bug nymphs.
Down in the whorl of a squash leaf is a group of squash bug nymphs. To the left and right of the nymphs are two small egg clusters.

Squash bugs can do a lot of damage to your vine crops if you are not careful. Several years ago I had nearly half an acre of pumpkins that became infested with squash bugs. We tried battling them with the first line of attack, crushing their eggs whenever we came across them. After crushing literally hundreds of egg masses, it became apparent we were not going to be able to keep up with the insects. We ended up having to resort to applying an insecticide to save the crop.

The eggs hatch about ten days after being laid. The young newly hatched nymphs have a very soft “skin” making them very susceptible to contact insecticides. Spraying the nymph stage is your best chance to control these pests since the adult bugs are very tough and hard to kill.

Bob

Squash vine borer defense

Squash vine borers are one of the most insidious insect pests in the garden. They attack many vine crops in the vegetable garden especially pumpkins, winter squash, summer squash such as zucchini yellow crook neck, and gourds. Sometimes they will infest muskmelons, watermelons and cucumbers. I’ve had many times in squash and only once in cucumbers.

Although the adult stage of the borer is a moth, it doesn’t look like or act like a moth. Unlike most moths it flies during the day. And instead of fluttering around like a moth, it flies quickly, like a wasp.

The female adult lays its eggs on the base of the main vine, the eggs hatch and the baby borer eats its way into the vine and keeps feeding for about four weeks. It’s very possible that our squash and pumpkin vines have borers in them right now even though they are not exhibiting any visible symptoms.

At first it’s easy to confuse borer symptoms with drought. The plants wilt on hot, sunny days then recover overnight. If left alone, eventually the plants suddenly and completely collapse. The most startling symptom of a squash borer infestation is seeing healthy vigorous vines one day then seemingly the next day they are collapsed, wilted and dying.

I would hate to lose my squash vine at this point.
I would hate to lose my squash vine at this point.

You can help your vines minimize borer damage by taking advantage of  vine growth habits. You’ve probably noticed that squash and  other vines sometimes root themselves further away from the base of the plant. Those roots are actually functional and contribute to the vines growth. By encouraging rooting along different places along the vine, you can minimize the damage the borers do since the vine can get still get water and nutrients from the soil because of the extended root system. If the plant had to depend only on the roots at the base, no water would be able to reach those parts of the vine past the area damaged by the borer.

Rooting happens at the nodes.
Rooting happens at the nodes.

Rooting takes place at the nodes of the vine; those swollen spots on the vine from where the leaves grow. To encourage rooting, cover several nodes with a shovelful of garden soil. The secondary roots that form will support the plant even if the primary vine is destroyed by borers.

Bob

Local lacewings in your garden

While inspecting my garden today I ran across some very cool looking structures on the underside of a leaf. I could tell immediately that they were lacewing eggs. The thin stalks, each holding up a tiny white egg on its end, was the giveaway.

Lacewing eggs are held up on tiny stalks about 1/4" to 3/8" tall.
Lacewing eggs are held up on tiny stalks about 1/4″ to 3/8″ tall.

Lacewings are a good ally to have in your war against insect pests because they are a major predator of aphids and other soft-bodied insects like mealy bug, mites and even small, newly hatched caterpillars among others.

It is the larva stage of the lacewing that terrorizes the other small insects, especially aphids.

If left alone, aphids can rapidly overwhelm a plant by sucking the juice out of a plant's leaves and stems.
If left alone, aphids can rapidly overwhelm a plant by sucking the juice out of a plant’s leaves and stems.

Lacewings eat so many aphids that entomologists have nick-named them “aphid lions”. A single lacewing larva can eat over 200 aphids a week. The adult on the other hand, eats only nectar and pollen.

Depending on the weather conditions, the lacewings will stay in the larval stage for about two to three weeks devouring small insects all the while. When the time is right, they then spin a cocoon and emerge five days later as an adult. The adults mate and the females lay their eggs on the underside of a leaf or other sheltered spot. About four or five days later the eggs hatch and the cycle starts over again.

Watch for lacewing eggs on your plants and avoid spraying insecticide when you find them. Let them do their work and they will reward you by building up their population and eating even more insect pests.

Bob

Look out for cabbage worms

Earlier this week I spotted some small, white butterflies flitting around in our garden.  They were the easy to recognize adult stage of the imported cabbage worm larva. Now, a few days later,their larvae are voraciously eating our cabbage.

Typical signs of cabbage worm infestation: holes in the leaves and caterpillar droppings called "frass".
Typical signs of cabbage worm infestation: holes in the leaves and caterpillar droppings called “frass”.

Curiously, I haven’t seen any on the broccoli or kale yet, but they will show up there soon too. These pests eat any and all plants in the cabbage family including broccoli, cauliflower, kale, turnip and rutabaga. They are said to attack radishes as well but I’ve never seen it in all my years of gardening. Maybe it’s because our local population would rather eat the other plants if given the choice.

BTW, it’s not the baby caterpillar that makes the choice what to eat, it is its mother. The female butterfly flies all around looking for the ideal spot to lay her eggs so her offspring have the best food to eat. That way they can grow up to be big and strong and healthy. That is good for the cabbage worms but can be disastrous for a garden.

Farmers know that within days a few cabbage worms can chew so many holes into a cabbage that it will be unfit for market. Even in a home garden cabbage worms will ruin large portions of a cabbage.

There are a couple of different species of cabbage worms in our area, one is the imported cabbage worm, the other is the cabbage looper. They are both green and color and do the same damage. Imported cabbage worms are very slow and sluggish when they move. Cabbage loopers move along like inch worms.

If left alone, this young imported cabbage worm will quickly grow and cause lots of damage.
If left alone, this young imported cabbage worm will quickly grow and cause lots of damage.

Both species of cabbage worm are easily controlled by insecticides labeled for chewing insects on vegetables. Bacillus thuringiensis, or Bt, is a favorite worm killer among organic gardeners. It is made up of spores from a bacteria that infects only caterpillars and is harmless to other insects.

Controlling them now while they are still small is much easier than waiting until they get bigger and really start chewing away large chunks of your crop.

Bob

Join the Million Pollinator Challenge

While you’re deciding on what plants to add to your garden and landscape this year, think about pollinator friendly plants. By now most gardeners are aware of the steady decline in the number of pollinators over the past several decades. Bees, butterflies, moths, beetles and other pollinators have all taken a hit.

A large percentage of the foods we eat, over thirty percent, depends on pollinators. Plus, add to that, all of the different wild plants that depend on pollinators and you can see why it is such a problem. Even the federal government has acknowledged it be a matter of national security.

Planting even a few pollinator friendly plants in a garden will help, however more is better in this case.

Even though the situation is serious for pollinators, helping them doesn’t have to be a drag. The National Pollinator Garden Network has come up with a fun way to help us help pollinators. It’s called the Million Pollinator Garden Challenge. The organization hopes to register one million gardens, both existing and new,  that are pollinator friendly.

They suggest six simple to understand guidelines to help you with your pollenator garden. And if you want to take it to the next step, their website has loads of information to guide you.

Our own Michigan State University has been scientifically studying the pollinator decline and has a wonderful website tailored to the three general ecosystems in our state: Southern Lower Peninsula; Northern Lower Peninsula; and Upper Peninsula.

When you register with the Million Pollinator Garden Challenge, your garden site is pinned to a map of North America. It’s fascinating to see all of those pins on that map and where the gardens are.

Our area of southeastern Michigan looks under represented to me. I’m not sure if it’s because of a lack of gardens or if it’s because gardeners are unaware of the program.

Let’s make our gardens pollinator friendly this year, get pinned on the map and show the world how much our region cares about helping pollinators.

Bob

Help monarch butterflies by encouraging milkweeds

It wasn’t your imagination, there really were more Monarch butterflies this fall and it wasn’t just because we were looking for them anymore than usual. The folks at Monarch Watch have evidence that the monarch migration is shaping up to be somewhat larger this year than last.

As more gardeners and homeowners become aware of the importance of milkweeds and start encouraging the plants instead of eradicating them, the monarch butterfly population should rise in proportion.

One statistic I saw was that there are 113 million gardeners in the USA. Now just think for a minute if each gardener added only one or two milkweed plants in their yards how many more places there would be for monarchs to grow and develop.

In a few growing seasons, a single milkweed plant can quickly turn into a sizable local population.  Like so many other “weeds” milkweeds produce a lot of seeds. In my yard I counted about 80 seeds in just one milkweed pod. That small plant had seven or eight  pods growing on it. That’s around 500 seeds per milkweed plant. In more fertile locations, a milkweed plant can produce 20 pods that contain over 400 seeds in each pod!

Milkweed seeds grow in rows inside the pod.
Milkweed seeds grow in rows inside the pod.

Collecting and planting seeds is the best option for propagating milkweed. Just keep in mind that milkweed seeds require a cold treatment  — called stratification — before they will germinate. In the wild this occurs naturally each winter as temperatures drop below freezing. The easiest way to provide the cold treatment is to plant them directly into the soil in the fall and let nature provide the stratification.

Milkweed plants are perennials, meaning once they establish themselves, they will continue to come up year after year. Mature plants have roots that grow horizontally underground. They will send up a new shoot at intervals that grow into a new milkweed plant. So you can see how quickly milkweeds can get out of hand if you’re not careful.

I’ve had milkweeds pop up in my garden from roots sent out by plants many feet away. They can be very  persistent since a piece of root as small as an inch long can grow into a new plant.

Milkweed pods are just starting to open in southern Michigan. If you want to collect seeds, now’s the time to do it. Otherwise, soon the seeds will be gone with the wind.

Let the milkweed seeds fly or you can remove the silks and store the seeds in your refrigerator crisper until spring.
Let the milkweed seeds fly or you can remove the silks and store the seeds in your refrigerator crisper until spring.

As an extra bonus, you can spray paint your empty pods with gold paint and use them in craft projects just like we used to do in elementary school.

Bob