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

The amazing salvia flower

You can find some really amazing things in the garden if you know where to look. For example, look closely at a salvia flower and you will see something unique.

Like most flowers, salvia produces nectar to lure pollinators such as wild bees, honeybees and others. And as usual the pollinators end up carrying pollen it picked up from the first flower to the next flower it visits thereby pollinating the second flower and others after that. Usually nectar collection is pretty straight forward, the bee simply visits the flower and sucks out the nectar and moves on to the next flower.

In the case of salvia however, something marvelous happens. The flower has a tiny structure that blocks access to the nectar. Instead if simply inserting its tongue and sucking out the nectar, the pollinator has to physically push itself deeper into the flower past the blockage in order to get to the nectar. That tiny gate that is hindering the bee is connected to the flower’s stamens by way of a pivot point like a see-saw. At the other end of the see-saw are a pair of stamens. At the very end of each stamens is a pollen sac.

When the pollinator pushes against the blocking structure, it causes the stamens to pivot downward. As the stamen moves down and touches the pollinator’s back, pollen is released from the pollen sacs onto the insect. The pollen sticks to that spot on the insect and once it is done gathering nectar, it moves on to other salvia flowers carrying the pollen with it.

To see the stamens move, use a pencil to mimic the pushing action of a bee inside the flower.

All salvias have this astonishing mechanism in their flowers. Different species of salvia have slightly different lengths,sizes and shape of stamens. Some scientists believe that the different lengths of stamen by species minimizes hybridization ie. the pollination of two different species with one another. One type of salvia may deposit its pollen toward the rear of the insect while another may deposit at the front thereby reducing the mixing of pollen.

We’re nearing the end of the growing season but there are still some salvias blooming.

Bob

 

Sneezeweed is blooming

We were sitting out on the porch earlier this week enjoying that summery weather.  One flower caught my eye, it was fresh and bright among the others that were either gone or fading fast. It was one we forgot that we had planted this spring — it was sneezeweed.

Sneezeweed, also referred to as Helenium  by many gardeners, is not as elegant as some other flowers but it provides a nice splash of color this time of year.

This plant is native to our area and in the wild, it is normally found in damp spots. Our flower garden is high and dry with very sandy soil and a southern exposure. Since we water that garden whenever it needs it, the sneezeweed seems to have adapted nicely. Often, when gardeners grow sneezeweed  in rich garden soils it grows tall but the stems will be weak causing the plants to fall over. That means more work for the gardener: staking and tying the plants. Cutting the plants back during June encourages branching and keeps the plants shorter avoiding the need to stake them later in the season. Ours are about three feet tall and were never cut back yet the stems are strong enough to keep the plants upright. That’s probably due to the growing conditions in our garden.

The full flower heads measure about one and a half inches across. Later the ray flowers drop off leaving behind the round disc flowers.

Helenium belongs to the compositae family of plants and like most of the plants in this group, they have composite flowers. What most people (other than botanists) call its flower is actually two different types of flowers combined into a single display. The outer ring of petal-like things are the “ray florets” or flowers. The center ball-shaped structure is a cluster of other tiny flowers called the “disc florets”. Daisies, sunflowers and dandelions all have similar flower structures.  If you watch bees visit these flowers, you can see them collecting nectar from each little floret.

Sneezeweed is a perennial and will continue to come up every spring for several years. Horticulturists and plant breeders have developed many varieties with different colors and growth habit. They are more civilized than their wild cousins but still retain the basic Helenium characteristics.

Bob

Dogbane in prairie area


When I was aroud ten years old, back when all kids were free-range, I spotted spotted a plant during my wanderings that impressed me so much that I’m intrigued by it to this day. I didn’t know what it was called at the time. It wasn’t until later, when I was in college, that I found out it was called dogbane.

What caught my eye way back then, were the long, thin seed pods. They were hanging from the plant in two’s, connected to each other at the top. What looked weird to me was the fact they weren’t  attached like two green beans. They appeared to be one pod that grew into two parts, separating at the top. I’d never seen anything like that before in my young life.

Distinctive dogbane seed pods.

I’m not sure if dogbane was ever that hard to find but I have noticed however, in the past twenty years, more and more dogbane growing all over our area. That’s probably due to more people leaving space for wild plants to grow for butteries, pollinators and other wildlife

A few years back someone brought me a part of the plant that they had collected asking what the plant was. Recognizing it immediately, I said without hesitating “that’s dogbane”. They looked at me like I was BS-ing them, like I made the name up. I could tell they didn’t believe me when they took their plant and just walked away. The next day they told me they had done research on their own and discovered that indeed the was a plant called dogbane and that yes, their plant really was dogbane.

There’s a spot on my property that I cultivated as a vegetable garden for a few years. I decided it wasn’t a good garden spot so I let it go back wild. Lots of different plants moved in including a single dogbane. That one plant has since expanded into a fairly dense stand. Right now the stand is turning a beautiful gold color.

On farms, dogbane can develop into a fairly serious weed. Since it reproduces by seed and by underground rhizomes is can form stands that out-compete field crops. In most cases farmers keep it under control by herbicides or crop rotation.

Bob

 

 

 

 

 

Tar spot on maple trees

In many cases, diagnosing plant problems requires an in-person look at the plant in question. Too many disorders look similar when all you have is a photo to go by.

Earlier this week someone sent me a photo asking about spots on a valuable tree they have in their front lawn. That was an easy one. I took one quick look at the photo and knew right away what it was. Their maple tree was infected with a fungal disease called “tar spot”. It’s quite easy to identify because in this case the name is very descriptive, the leaves really do look like they’re covered with spots of tar.

Tell-tale symptoms of tar spot.

Even though it looks pretty bad, tar spot is relatively harmless even in a heavily infected  situation. There’s no good way of preventing the disease. Some years are worse than others for tar spot and some varieties seem to be disposed to having more dramatic symptoms than others.

The spores from the disease over winters in fallen leaves so you wound think that raking them up and disposing of them would help the situation. Unfortunately the fungal spores can travel for miles in the air and can land on your tree and take hold.

When a tree has a severe case of tar spot, it can lose many of its leaves causing the tree raking season tobegin earlier than normal.

One bright spot is: since tar spot is species specific, it will not spread to other types of trees such as oaks.

Bob

Grape ripening

According to my records, my grapes are about ten days ahead of last year at this date. Every growing season is different and any particular year doesn’t necessarily line up with seasonal average growing conditions.

Ten days is a long time when it comes to grapes. I covered the grapes with netting last week to keep the birds from robbing the grapevines. If I had followed the calendar and waited until last year’s date to cover them, the birds would have eaten them all by now.

I have a trick that I use to determine when to put on the netting. I have a vine of early grapes that ripen about a week earlier than my main crop. When the birds start eating the grapes from that vine, I know it’s time to get the netting on my main crop. It’s a quick and easy way for me to keep track of grape development since I have so many other things going on than just grapes. Serious grape growers have more sophisticated ways o monitoring their grapes but this method works for me.

Color is not the best indicator of ripeness.

How did my grapes get so far ahead from last year? Plants need a certain amount of heat during the growing season to grow and develop. Scientist have developed a thing called “growing degree days” to help farmers predict when crops reach a particular stage of development. I looked the the growing degree days for our area to see if how much warmer the growing season was, thinking that might account for the early timing of my grapes. The record shows that there are fewer growing degrees this year than last! How could that be?

Some time earlier during the growing season, we had a warm stretch of weather that pushed the grapes into further along in their development than they normally would be. That means the grapes would be that much further along. Raw degree days won’t tell us very much about plant development for specific crops. Plant scientists have come up with methods to apply that data that are unique to each individual crop. Had I been following those scientific parameters, I would have known even before the birds when the grape would be ready to cover.

Bob

Sunflowers cause problems in garden

Plants have developed an number of different survival techniques that can give them advantages over other plants competing for the same growing space. For example, some plants have roots that produce chemicals that inhibit the growth of other nearby plants of other species. It’s a process known as allelopathy.

Black walnut trees are probably the most recognized allelopathic plants. Homeowners find that it’s impossible to grow many kinds of plants in the root zone of a black walnut tree. Although they work differently than black walnuts, many farm crops such as alfalfa, buckwheat, winter rye and others are alleopathic plants.

Sunflowers provide a wonderful backdrop in the garden as they tower over a space making them a favorite of many gardeners. What gardeners might not know is sunflowers are also alleopathic plants. Because they have the ability to suppress the growth of weeds, sunflowers and other plants are the subject of on-going research to develop organic herbicides for use in sustainable agriculture. Unfortunately, along with weeds, many kinds of garden plants are affected by sunflowers as well.

Tomatoes struggle to grow under sunflowers.

Until you know which of your plants can tolerate growing near sunflowers, the best thing is to grow them in a separate bed away from other garden plants.

Bob

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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

 

Tomato disease score

This is the time of the season when tomato plants start showing signs of disease infections, usually as different shapes and colors of spots depending on which particular disease has infected the plant.

Last week I took an informal survey of several varieties of tomatoes to see how each variety is holding up under early disease pressure. My MO was to look for leaf spots on the plants. I made no attempt to identify which disease was causing  what spots. Then I ranked them on a scale of zero to ten depending how bad the plants looked. Zero meaning no spots were visible, ten meaning severe symptoms. No plants were bad enough to score what I imagined to be ten.

I didn’t count how many leaves were infected; or measure how many square centimeters were discolored; or brix levels of leaves; or levels of ethylene gas; or any other scientific criteria. Heck, I didn’t even alphabetize the list of varieties. I ignored any cultural differences such as mulch, staked or caged plants, planting history, etc. .Over half were heirloom varieties, some of those looked quite good compared to the modern ones.

I surveyed about fifteen gardens in two different locations about 20 miles apart. I made a point to look at them all the same day because twenty four or even twelve hours could mean the difference between no spots and spots. Here’s a chart of what I came up with:

Tomato variety Plant score
Brandywine 3-6
Belarus 0-1
Cherokee 1
Juliet 0-1
Sheboygan 0
Pruden’s Purple 0
Granny Crantrell 1-2
Super Sweet 3
Belstar 3
Pink Honey Drip 3
Roma 4-6
Yellow Cherry 5
Large Red Cherry 6
Early Girl 3-5
Rainbow Blend 3
Roma Type 7
Beefsteak type 6-7
Brandywine Pink 6
Moon Glow 3-4
San Marzano 3
Bobby’s Girl 0
Chadwick Cherry 0-1
Unknown varieties 5-6

Pruden’s Purple, by far looked the best it has no spots and  very vigorous leaves. Chadwick Cherry came in a close second. There were a few different beefsteak-type tomatoes that were not specifically tagged by variety but all of them had more advanced disease progression.

Keep in mind this is only a snapshot of conditions for one day. That could all change later on as the plants begin to get stressed by fruit production.

Bob

 

 

Striped cucumber beetles causing problems

A couple of gardeners I know asked me why their cucumbers didn’t come up this year. Others have mentioned that their beans didn’t come up either. Was there something wrong with the seeds this year?

After inspecting a few gardens, it became apparent to me what was going on. In each case, there was a heavy infestation of striped cucumber beetles. They are voracious feeders and are always on the lookout for their preferred food, cucumber vines and related plants such as melons and other vine crops.

In those gardens, the beetles ate every plant they could find that tasted like a cucumber. The sprouts just emerging from the soil were particularly vulnerable which is why it appeared that the cucumbers didn’t come up — they ate every last bit of the tiny cucumber sprouts before the gardener knew what happened. And larger, young transplanted cucumber plants were well on their way of disappearing down the gullets of the beetles. When the vine crops were all gone, they moved over to the bean sprouts and ate those down to the ground. Even older bean plants had lots of holes in their leaves from the beetles.

Striped cucumber beetle.
Striped cucumber beetle.

Striped cucumber beetles are about a quarter of an inch long. They have bright yellow bodies with distinct black stripes running the length of their wings.

This was just the first wave of cucumber beetles, we can expect one or two more generations of beetles to show up later this season.  This generation of beetles will lay its eggs at the base of the plants in the garden. Later they will hatch, feed on plant roots for a while then pupate and emerge as adults later in the season. The next generation of beetles will feed on the underside of the leaves and even chew gouges in the fruits.

Even more important, cucumber beetles carry and will spread bacterial wilt, a serious disease of vine crops. Infected plants wilt and never recover. There is no cure for bacterial wilt once it infects a plant. It’s very disheartening to see your cucumber vines grow and begin to flower only to lose them to wilt. So it’s a good idea take care of cucumber beetles as soon as you find them. Hand picking doesn’t work because they can get away too fast. Instead, apply an insecticide labeled for cucumber beetles, most garden insecticides are effective against them.

Bob