Creating a wildlife haven one plant at a time

Sunday, September 28, 2014

Finding Caterpillars of the Moth Variety

I am often asked to talk on butterfly gardening because people love having them flutter around their garden. Moths often take a back seat to butterflies since most of them fly at night and lets be honest they have a  reputation as being a pest. This is unfortunate because they produce some of the most spectacular caterpillars and they are an important factor in a diverse garden habitat not only as pollinators but also as a food source.

The cooler, autumn temperatures mean that we are spending significantly more time in the garden and it is an excellent time to go exploring. In the past two weeks our boys have found several extraordinary species of moths in their larval stage.

white flannel moth caterpillar on redbud
white flannel moth caterpillar on redbud tree

We identified this one as the white flannel moth caterpillar (Norape ovina). It probably doesn't feel much like flannel and we're not about to touch it since it is a stinging caterpillar. It would be quite painful if you brushed against those clumps of short hairs covering its side and back and long hairs extruding from its body.

My son found one caterpillar munching away at the edge of a redbud leaf. Of course we spent several minutes looking for more and found at least seven on the underside of the leaves. These distinctively patterened black, yellow and orange caterpillars are pretty easy to spot once you start looking. Interestingly this colorful caterpillar will become a very ordinary white moth. According to my go to caterpillar book "Caterpillars of Eastern North America" by David L. Wagner, these caterpillars are found on black locust, elm, hackberry, redbud, greenbriar and other woody plants. 

While we were inspecting the redbud we found another fuzzy caterpillar, the American dagger moth (Acronicta americana). This is another one you don't want to touch since it can cause an irritation on your skin. We've found these in our garden before but never on the redbud tree.

American Dagger Moth
American Dagger Moth on Redbud
This is a fairly large sized caterpillar which is covered in fuzzy yellow or white hairs with distinctive black tufts. These caterpillars feed on a variety of host plants which include woodland trees: alders, maples, oaks, redbuds, poplar, elm, chestnut, birch, box elder, and willow. They are usually found on the underside of the leaves in the fall. They overwinter in their cocoons and emerge as brown moths the following summer. An important reason not to clean up all the leaf litter in your garden.!

Pawpaw sphinx caterpillar
Pawpaw Sphinx caterpillar on Holly 'Winter Gold'

A surprising find was this hornworm caterpillar on the holly 'Winter Gold'. I believe this to be the Pawpaw sphinx (Dolba hyloeus). It will host on blueberries, hollies, pawpaw, inkberry and sweetfern. As you can see this caterpillar is covered with cocoons of pupating braconid wasp so it won't be alive for long. It is our garden habitat at work.

Based on posts on Facebook and talking to fellow Master Gardeners the saddleback caterpillars (Acharia stimulea) are having a boom year. We found several on our coral honeysuckle plant. They are generalist so they feed on a variety of garden plants including aster, blueberry, buttonbush, maple, oak apple, cabbage and citrus.

Saddleback caterpillar
Saddleback caterpillar on coral honeysuckle
There is no denying this alien looking caterpillar is a cool find but it is most often associated with its effect on humans if we rub up against one. It will cause painfully stinging and a rash. What I find so fascinating is how such colorful caterpillars turn into such plain looking moths.

Saddleback caterpillar

I often wonder when we find new species of insects in our garden if they were always there but our eyes hadn't been trained to find them yet or if they found our garden due to our habitat restoration efforts. Either way, they are a reassuring sign. I encourage everyone to get out in your garden or local park and check the underside of leaves and see what you find. Happy exploring!

Tuesday, September 23, 2014

The Year of the Fritillaries

I've notice over the past few years that each year one species of butterfly seems to have a banner year in my garden. I'm not sure why because all the elements are here for each stage of a number of butterfly species to thrive. Basically it isn't for lack of food. Perhaps it is the change in weather, perhaps an increase in predators, or perhaps they just naturally have boom years in their populations.

In 2012 we had tons of black swallowtail butterflies. I recorded 20 black swallowtail caterpillars on one bronze fennel plant in the spring of that year and we continued to host them on the fennel and parsley plants from spring to fall (you can see photos here). This year the fennel, parsley and golden alexander have been barren. Last year we saw record numbers of Eastern Tiger Swallowtail butterflies. They were everywhere! They host on the tulip popular trees which grow in abundance on our property as well as black cherry.

This year was slow getting started, I suspect due to our cold, wet winter but once it started the fritillaries dominated the garden. We have masses of orange butterflies fluttering all over the garden and it is a beautiful site!

gulf fritillary on passiflora vine

We have two species of fritillaries here in North Georgia, the gulf fritillary and the variegated fritillary. Both host on passiflora vine (aka maypop) and the variegated will also host on violas. We have masses of passionvine growing around the garden. It has happily self seeded in various locations. It makes a great ground cover but is even more stunning as a climbing vine. Check out the fruit, which thanks to the busy carpenter bees, make this happen.

passiflora fruit

There are hundreds of caterpillars munching away at the leaves. Sometimes the caterpillars even find it necessary to crawl over the blooms when they get in the way.

two instars of gulf fritillary caterpillars
two instars of gulf fritillary caterpillars on passion vine

variegated fritillary caterpillar on passiflora bloom
variegated fritillary caterpillar on passion vine bloom

The vines are a bustle of activity all day long. Bees, butterflies and all varieties of pollinators are visiting the blooms, caterpillars crawl from one leaf to the next, sometimes it is a race to see who gets there first;

two gulf fritillary caterpillars
two gulf fritillary caterpillars crawling tandem

three instars of fritillary caterpillars
three instar stages of fritillary caterpillars

Our house seems to be one of their favorite places to go to form their chrysalis. It looks a bit like Christmas with the caterpillars and chrysalises hanging from the brick, the door and window frames and patio.

gulf fritillary caterpillar in "J" begining to form chrysalis
gulf fritillary caterpillar hanging in "J" 
variegated fritilllary chrysalis
variegated fritillary chrysalis
Can you believe with all these chrysalis I have yet to witness on of these butterflies emerging? But based on the number of butterflies fluttering around they are having a banner year.

gulf fritillary butterflies mating
gulf fritillary butterflies mating
Have you experienced a similar fluctuation in your butterfly populations? We all know about the perils of the Monarch butterflies. We haven't seen any in our garden since fall of 2012 despite all the milkweed we've planted. I like to document the butterfly activity in our garden as it helps me analyze the habitat and be a better observer. I ask myself are there certain times of year where we are lacking nectar sources? Are there enough host plants? Are there enough overwintering sites available (leaf litter, bark, wood, etc.)? Are there new or an increase in predators? Fall is the best time of year to address these issues and I know I will be doing some more plant shopping over the next few weeks. I'm sure the butterflies will be even happier next year!

Monday, September 1, 2014

Controlling a Squash Beetle Invasion

This August we were away for more than three weeks leaving the garden to mostly fend for itself. This is only possible because I companion plant, rotate our crops each year, have good soil management and mostly importantly a wonderful husband who diligently kept the garden hydrated during the heat of the summer. But even with the best practices in place it seems that while the gardener is away the insects will play.

Our watermelon vines were invaded by a lady beetle look alike, known as the squash beetle (Epilachna borealis). This beetle is a native to Eastern North America and is larger than your typical beneficial lady beetle.

adult squash beetle on cucurbit with larvae on underside of leaf

Unlike most lady beetles which are a gardener's friend, since they eat loads of aphids and scale insects which feed on our fruits, vegetables and flowers, the squash beetle attacks the leaves of cucurbits which include squash, pumpkins, cucumbers, gourds, watermelons and cantaloupes; sucking on the tasty juices.

Southern Meadows

The squash beetle has an odd behavior of circling the leaf area that it feeds on. A study at the University of Delaware found that this feeding method preserves the leaf tissue's suitability for feeding because it reduces the influx of chemical defenses from the injured plant (source: Purdue University Extension). This typically creates a skeletonized appearance on the upper side of the leaves.

The larvae are yellow, alien looking creatures found mostly on the underside of the leaves. Aren't they creeping looking things?

Southern Meadows

According to the University of Purdue Extension the best time to control these insects is at noon since the beetles are easiest to find. They can be hand picked and placed in a container of soap and water. Be sure to check the underside of the leaves for eggs and larvae. I usually remove the entire leaf if their are eggs present or you can try to scrape them off.

The photo above shows old eggs but it will give you an idea of what to look for. They are very similar to the beneficial lady beetle eggs (yellow, bullet-shaped) but if you find them on cucurbits your probably safe in assuming they are from the squash beetle.

If you are not inclined to remove them by hand you can make a homemade spray of liquefied ingredients: garlic clove, small onion, fresh or powdered hot pepper (habanero, jalapeno or cayenne).  Add this to a quart of water and let steep for an hour. Strain off the solids and then add a drop of dish soap to your liquid solution. Spray this mixture onto the lady beetles (adults and larvae) that are on your cucurbits. If your not one to make your own spray Neem Oil is an option.

At the end of the growing season be sure to dispose of all the plant residue so you won't have any overwintering beetles in your soil. Rotating crops is a good practice to keep diseases and insects in check too but diligently attending a garden to catch the signs early is the best way to go!