pest control

Beneficial Garden Insects: Flower Flies

31 July, 2018 by amygwh Leave a Comment

While I’ve been walking outside our little town in Italy, missing my vegetable garden, I have paid attention to the local plants. On good days, I see a lot of flowers and pollinator-insects. At first, I thought the pollinators were all bees. Then, I looked closer. Many of them are actually flower flies, a different group of beneficial garden insects.

Flower flies, which are beneficial garden insects, look like bees but without the sting. — Flower flies are beneficial garden insects.

What are flower flies?

Flower flies really are flies, but a lot of them look like bees. It is possible that looking like a bee prevents some predators from eating them. I don’t know if that mimicry really works, though. We used to have a dog that ate carpenter bees when she could catch them. The stinging inside her mouth didn’t seem to stop her from catching and eating more.

Flower flies do not sting or bite, but they do eat nectar and/or pollen as adults. As they visit flowers to gather food, they pollinate the flowers. Flower fly babies (larvae) eat aphids and other small insects. These are definitely beneficial garden insects!

Organic gardens, in particular, rely on pollinators and predators in the garden to increase harvests and reduce pest problems. We can wait for our helpful predators (like flower flies, wasps and ladybugs) to eat the aphids, no spraying required!

Flower flies are also known as syrphid flies and as hover flies.

How can I tell which is a flower fly and which is a bee?

With only a brief glance, it is not easy to tell bees and flower flies apart. If you have the fortitude (and lack of bee-allergies) that allows you to look a little longer, you might see the difference.

Check the antennae

Flower flies have short, straight, stubby antennae. The antennae may be so short that they are hard to see. Bees have longer antennae, and their antennae are more likely to bend.

Check the wings

All flies have only two wings (one pair), and you can easily see them. One wing is on each side of the body.

Bees have fours wings (two pairs). The larger front pair of wings is easy to see, but the hind-wings can be hidden below the front pair. You might not be able to see that there are four wings.

Check the eyes

Eyes of flower flies are larger, and more on the front of their heads. Bee eyes are shifted a little to the sides of their heads.

Check the back legs

Flies do not collect pollen in clumps on their back legs. Some kinds of bees, especially our native, solitary bees, also do not collect and carry pollen on their back legs.

However, bumble bees and honeybees often store clumps of pollen on their back legs, to carry back to their colonies. If you see a bee-like insect that has pads of orange, or red, or yellow on its back legs, that is a good sign that the insect is some kind of bumble bee or a honeybee.

How can I attract flower flies to my garden?

University of California has published an easy-to-use table of plants that attract flower flies (see page 16). The table is deep within a document that is not super-easy to read, and not all the plants will grow well in the Southeastern US, but many will.

Here is a short list of plants that are known to attract and/or support flower flies to your organic garden, that I know will grow in the Southeastern US:

buckwheat, coriander/cilantro, thyme, Italian oregano, sweet alyssum, fennel, tansy, white-flowered yarrow

Summer Squash in the Southern Garden

11 June, 2018 by amygwh 1 Comment

One of my most-favorite lines ever in a UGA Extension publication is about summer squashes. The line is in a table that lists recommended varieties for each type of crop. It says, for which varieties of summer squashes (including zucchini) to plant in the garden, “all are good and easy to grow.”

This line still makes me laugh. In a way, it matches my experience. In early summer the plants look great and produce plenty of flowers and small squashes. Unfortunately, it could also read “all are finicky and frustrating to grow”, since many summer-squash plants seem to drop into wilted piles of yellowing leaves in mid-summer, long before we have eaten too much squash. When I first started gardening in Georgia, I was lucky to get five or six good-sized squashes from a plant before it keeled over.

Southern Vs. Northern Experiences with Summer Squash

I am not the only Southern gardener to be troubled by a too-small squash harvest or plants that die too soon. However, Northern gardeners do not seem to have this problem. The complaint I hear from Northern gardeners is quite the opposite – they have mountainous harvests of zucchini and yellow squashes that keep coming all summer long.

Really, the complaint is one that doubles as a brag – their squashes are so very productive that, when the harvests begin, it is risky to leave your car windows open. The risk is that gardeners who have a superabundance of squash are likely to drop a large bag of squashes into the car as “a gift”.

Legend has it that over-squashed gardeners also will fill a bag with squashes, hang the bag on the doorknob of an unsuspecting neighbor’s home, ring the doorbell, and run. By the end of August, people are totally tired of squashes, especially zucchini.

I have never had so much summer squash and zucchini that I was not happy to find another one in the garden. Happily, as I have gained experience and understanding of what is going on in the garden, my plants survive longer and the harvests are larger. I have found that it is possible to have plenty of summer squash in the Southern garden, with a little planning.

Problems with Summer Squash in the Southern Garden

Squash Vine Borers

These are the cause of much anguish in the squash patch. The borers are larvae (caterpillars) of a day-flying moth that lays its eggs on stems of our squash plants. When the eggs hatch, the babies bore into stem, where they eat the soft part of the inside of the stem. The borers seem to not eat the toughest fibers, because one sign that borers have caused your squash plants to wilt is that the stem looks frayed. You may also see some frass (caterpillar poo), a golden-orange-brown, granular-looking mush, around or in the damaged section of stem.

What to do? If the plant is already a wilted mass of yellowing leaves, it may be too late to save the plant. If, though, you look at the lower part of a squash stem, see little holes in the stem and maybe a little frass nearby, but the plant looks otherwise healthy, it is not too late!

Step 1:

Locate the sharpest blade on your pocket knife and use it to make a long slit in one side of the squash stem. The slit should run lengthwise on the stem; it should start below where the damage seems to be and extend above the damaged area. Use the tip of the knife blade to pry the slit open, so you can look inside and find the squash vine borers. Use the knife tip to remove (or kill, depending on your philosophical stance on garden pests) the borers from the stem. You might find just one, but you might find a half dozen or more.

Step 2:

Saturate the inside of the stem with a product that contains Bt for caterpillars (Thuricide is the brand I have been using – bought a few years ago and still works), and spray up the length of the stem on the outside, too. If any borers are still alive inside the stem, the Bt for caterpillars (organic approved) should reverse that status fairly soon. If your Bt is powder form instead of liquid, do your best to fill the stem with the powder, and then liberally apply it along the outside of the stem.

Any Bt applied on the outside of the stem will wash away in the next rain or watering-event, so you might want to re-apply it a few times.

Step 3:

Mound up garden soil over the damaged section of stem. If you are feeling very industrious, you can try wrapping the damaged section with aluminum foil, but I find that just piling up some good soil over the damaged stem protects it from invasion by other pests. Also, squashes sometimes will send out new roots along buried sections of stem.

Step 4:

Consider the health-status of your plant. Summer squash in the Southern garden should be lush, with huge, dark green leaves. In my garden, the largest, fastest-growing squash plants survive squash vine borer damage much better than less-lush plants. If your plants are on the puny-side, side-dress with some organic fertilizer or a shovel-full of compost or composted manure.

Squash Bugs

Squash bugs look a lot like stink bugs as adults. As youngsters, they are called nymphs, and they move around in groups. The nymphs do not look at all like the adults, but if you see groups of insects scuttling around on your squash plants, they probably are squash bug nymphs.

Squash bug eggs on a leaf of summer squash in the Southern garden — Squash bug eggs on a leaf. PHOTO/Amygwh

These feed on the squash plants – leaves and fruits – and they can cause a lot of damage. An even bigger problem is that they can carry a squash disease called Cucurbit Yellow Vine, which can definitely kill your plants.

The adults and nymphs can be removed by knocking them into a tub of soapy water. It is a good idea, though, to check your plants for squash bug eggs.

You can use a piece of clear packing tape or a piece of duct tape to remove the eggs from your plants. Just press the sticky side of the tape to the collection of shiny eggs, remove the tape, fold it over, and smash the eggs inside the tape. Simple!

Removing all the eggs will help keep the population of adults and nymphs to a much lower level, which will limit the amount of damage they can do to your plants and reduce the risk of Cucurbit Yellow Vine.

Mildews

Summer squash in the Southern garden also is attacked by mildew diseases, both downy mildew and powdery mildew. If your plants die earlier in the summer, then these will not be a problem, because the mildews usually appear after mid-summer.

Downy mildew arrives at a slightly different time each summer in upper parts of the South. It can’t survive our winters, but it comes up from Florida where it survives just fine. If the petioles (leaf stems) are still standing up on your plants, but the leaves look brown and droopy, then downy mildew is a likely cause. There is no effective spray or treatment for downy mildew, but preventive care can help.

Leaf diseases like downy mildew (and powdery mildew) need leaf wetness to infect the leaves and grow. Keeping the leaves dry as much as possible, by careful watering, can delay infection. Increasing air-flow around the leaves, so they dry faster after a rain, also helps. Remove weeds as much as possible, and allow plenty of space between plants.

Also, healthy, well-grown plants get less disease than puny plants. Just like for squash vine borers, consider whether you might need to side-dress your plants with fertilizer or compost to improve their condition.

Powdery mildew becomes a big problem in warm, humid conditions. Since that pretty much describes several months of weather across the entire Southeast, it is a safe bet that powdery mildew will find your plants eventually.

Treating Mildews in Organic Gardens

For both downy and powdery mildews, the bacterial product Serenade, which is organic-approved, can slow down the rate of infection. It should be applied to plants every 7-10 days, before any sign of infection is seen. If you see signs of disease on your plants (mottled or brown spots on leaves, for example), it is too late to get much benefit from using the product.

In a couple of Cobb County community gardens, the use of Serenade has helped extend the “squash season” for local gardeners. If your squash patch has suffered from mildew attack in past years, you might consider trying the spray, but do not wait much longer to start. By July, infection may already have begun.

Another option is to spray with homemade products of either compost tea (one gallon of well-aged compost in a five gallon bucket filled with water, soaked for three days, then strained to use in a spray bottle) or a baking-soda spray, both of which can slow down an infection. Neither of these has been shown to work as well as Serenade (which works less well than chemical fungicides), but some gardeners like to try the DIY route first.

If you are a DIY gardener, this is the recipe for baking-soda spray recipe from one of my Rodale gardening books:

Dissolve 1 teaspoon of baking soda in a quart of warm water, with up to a teaspoon of dish soap or insecticidal soap added. Spray the leaves, including the undersides.

For both compost tea and the baking soda solution, apply to plants much more frequently than the Serenade.

Hoping for Plenty of Summer Squash from the Southern Garden

Summer squashes seem to be an essential vegetable in the South. They are the base of many favorite “church casseroles” – dishes that fill the tables at summertime potluck suppers and appear at your door in hard times. I don’t remember seeing squash-casseroles when I was growing up in Oklahoma, but I certainly have seen (and enjoyed) many since moving to Georgia. In the South, the squash harvest is important.

The garden/farm where Joe and I used to volunteer got around squash-plant losses by planting MANY squash plants over several weeks. Even when some plants died, more remained and produced squash. If the squash harvest didn’t look abundant enough, we just planted more.

In home gardens, this approach is not really feasible. Hence, the long blog post about upcoming problems with summer squash in the Southern garden.

Best wishes for a squash-filled summer!

-Amy

Striped Caterpillars in the Garden, Eating the Dill

12 May, 2018 by amygwh Leave a Comment

Several weeks ago, while I was working in the garden, a battered, tattered black swallowtail butterfly flitted into my dill patch. While she was there she laid some eggs. Eventually, some of those eggs hatched, and then there were caterpillars in the garden, eating the dill.

They ate and ate. After awhile, some of the caterpillars disappeared. I assume other wildlife, such as birds, ate them. The last time I saw them, a few days ago, there were three left, fat and striped and still eating the dill.

Caterpillars in the garden are not always a problem. This one will be a black swallowtail butterfly. — PHOTO/Amygwh

They have all gone now, which means I can finally harvest the dill. The plan is to dehydrate most of it, for use this winter. I am thinking of using it on fish, in particular. It is also good in spanakopita, but I don’t eat cheese like I used to, even feta, so that recipe is no longer “in the rotation”.

What to do about caterpillars in the garden?

Even if these striped caterpillars were more voracious eaters, gnawing my dill plants down to little nubs, I probably would just make a note to plant a lot more next year. Accepting some insect-damage is part of the organic gardening way.

In addition, the world has been losing pollinators over at least the past couple of decades, probably longer. Even though butterflies are not our most effective pollinators, removing these with either an organic pesticide or a mechanical method like smashing would not be good for the future of food in the world.

Luckily, the caterpillars have left plenty of dill for us humans.

When other caterpillars in the garden eat so much that a plant is nearly bare of leaves, then control measures may be desired. As usual, the first would be to keep the adults, the butterflies, away from the plants completely. Draping small-meshed netting or a spun row cover on a support structure over the plants can keep adult fliers away (see post about cabbage butterflies and moths).

What else do these caterpillars eat?

These caterpillars are sometimes called parsley worms, because they eat many plants that are in the parsley family. If you guessed that one of those plants is parsley, you are right! Fennel and carrots are other garden plants in the same family, as is dill.

University of Florida has published a fact sheet about the Eastern black swallowtail butterfly, its lifecycle and ecology. The fact sheet includes a list of other plants these caterpillars will eat. Some are native plants, like mock bishop weed and water hemlock. Some are not native across the entire U.S., but have been introduced. One that many people will recognize is Queen Ann’s lace.

Where did the caterpillars go?

Surprisingly, Joe and I found a chrysalis way across the yard, in a flower bed, on Thursday. I almost never find these, so this one made my day.

Chrysalis of black swallowtail butterfly from 10May2018, in Georgia. PHOTO/Amygwh

The chrysalis is on a leaf of a hardy amaryllis, given to me by my mother-in-law many years ago.

Which beautiful pollinators are in your garden?

Ladybugs in the Garden – Which Ones Are They?

6 May, 2018 by amygwh Leave a Comment

My garden has been full of insect activity recently. There are lovely, tiny, metallic flies, some shiny black wasps, also tiny, and a few bees. I have also seen several ladybugs in the garden, plus some ladybug babies (larvae) and pupae (where larvae transform into adults).

Ladybugs are voracious eaters of aphids in the garden. Adult, larva, and pupa forms are very different in appearance. — Ladybug adults and larvae are voracious eaters of aphids. PHOTO/Amygwh

Which Species of Ladybug is in My Garden?

I am always happy to see ladybugs in the garden. They eat a lot of aphids. The adult ladybugs eat aphids, and the larval ladybugs eat aphids. For an organic gardener, this is a win-win combination!

Many of us would much rather rely on predators like ladybugs than use even organic-approved sprays.

When I decided to find out which ladybug is most common in my garden, I took a lot of pictures and then searched online.

My ladybugs mostly have about 16 spots on their backs, so it was easy to eliminate “two-spotted ladybug” from the list of possibilities.

Even better, university-based websites agreed that the black “M” shaped marking behind its head was a defining feature. It means my ladybugs are Asian multicolored ladybugs. At least, the adults are.

Apparently, this is a ladybug that tries to overwinter inside buildings; in winter it is considered a pest. In summertime, though, in gardens and farms, it is a big help in removing aphids from crops.

This University of Kentucky page includes pictures of several kinds of ladybugs. Maybe the ladybugs in your garden will be native, and not imports like mine!

Why Are Ladybugs in the Garden, in Georgia, from Asia?

Apparently, various people brought these ladybugs to the U.S. on purpose, to help control pests like aphids and soft scale insects. According the University of Florida and the USDA, these ladybugs were released here many times in the past. The first time may have been a hundred years ago! The multicolored ladybug finally established permanent populations in the U.S. in the late 1980s to early 1990s.

Plenty of Work for Ladybugs in the Garden

My kale, especially, has been hit hard by aphids. Luckily, we have already eaten quite a lot of the kale ourselves. The current plan is to harvest the rest of the kale, wash it very well, and eat it soon. Any we don’t use on tonight’s pizza will get stashed in the fridge to use tomorrow.

Meanwhile, I have seen aphids on the milkweed — planted for the butterflies — and a few on leaves of the iris. Aphids also can be pesky in the fall; they are not just pests for the spring. My garden will probably feed a lot of ladybugs for many weeks to come.

Organic Pest Control: Mexican Bean Beetles

29 April, 2018 by amygwh Leave a Comment

Mexican Bean Beetles can strip all the green tissue off bean plants surprisingly quickly. If your organic garden is attacked by these pests pretty much every year, odds are high that you will see them again this summer.

Mexican bean beetles have stripped green tissue from most of leaves in this bean patch. PHOTO/Amygwh

How can you recognize these pests? The adults look a lot like ladybugs, only more orange or yellow. Their babies (aka “larvae”) are bright yellow, and look a bit like stubby, spiky caterpillars. (See the picture collage lower in this post.) The damage to the leaves, which become very brown as the beetles and their babies eat the green plant tissue, is the clue most gardeners notice first.

Having some strategies in place, before the bean beetles arrive, can help organic gardeners to harvest plenty of beans in spite of the coming pests.

Strategies for controlling (or minimizing) an attack by Mexican bean beetles have some overlap with those for some other pests, such as aphids or the caterpillars of cabbage moths and cabbage butterflies.

Using Barriers to Keep Mexican Bean Beetles Off the Plants

For caterpillars like cabbage worms and loopers (babies of the cabbage moths and butterflies), we can use netting over our plants to keep the adult flyers away. If the adults can’t reach the plants to lay eggs on them, then we won’t have caterpillars on the plants.

For Mexican bean beetles, we can adapt this strategy by using a floating row cover instead of netting over the bean plants. The non-woven construction of the fabric means there are no holes for insects to sneak though. The row cover is lightweight and can be draped right over the plants, but it seems kinder to the beans to secure it over a support structure. The bean patch needs to be weed-free before the area is covered. Beans, in general, are self-pollinating; most varieties will make beans even when bees and other pollinators can’t visit the flowers.

Waiting for Parasites and Predators

There is a parasitic wasp that lays eggs inside the larvae of the bean beetles, just like there is a parasitic wasp that lays its eggs inside aphids. Sadly, the bean-wasp doesn’t seem to hang out in my yard, even though my garden gets attacked by Mexican bean beetles nearly every summer. Arbico Organics sells “mummies” (Mexican bean beetle larvae that contain wasp eggs/babies) as a bean-beetle-control for use on farms, but this is a very expensive option. It also is not really practical for home gardeners. Many of us are not growing even the minimum 70 square feet of beans per mummy recommended to make this work. It is nice, though, to know that there are insects working on behalf of farmers and gardeners to control these pests.

Spined soldier bugs and assassin bugs eat Mexican bean beetles, too. Some of these could already be present in your organic garden, but probably not enough. Certainly, there are not enough of these helpful predators in my own garden.

Stages of Mexican bean beetle infestation on bush beans, with a suggestion to alter timing of planting to harvest plenty of beans in spite of the beetles.

Insect-eating birds also can help reduce the population of bean beetles in the organic garden. In my bean patch, wrens move through the patch, hidden from my view below the canopy of leaves. All I can see is movement of the tops of the plants, until the wrens spring into flight after eating. It is great to know that these garden helpers are in action.

However, the birds seem to leave a lot of beetles uneaten. Maybe Mexican bean beetles are not very tasty.

Using Pest Control Products

In general, organic spray-type options for insect pests are not very effective, and options for beetles are worse. Spraying the undersides of the bean leaves with insecticidal soap (not an easy feat!) may kill the youngest larvae.

If you are desperate, try a product that includes Neem. Neither version of insecticidal soaps will have much effect on the adults, though.

You may have better luck than me at applying a spray to the undersides of leaves. If so, then insecticidal soap could slow down an infestation in your garden. Personally, I do not use a spray option.

For me, hand-smashing the larvae and eggs seems to slow down an escalating infestation about as effectively as using insecticidal soaps. So does knocking adults into a tub of soapy water, where they will drown. In other words, none of these options is super-effective.

Adjusting Your Planting Dates

This is the strategy that has given me the most abundant harvests. This strategy requires that gardeners plant their bush beans early — right around the estimated last-frost-date for their yard. This strategy allows gardeners to begin harvesting beans as soon as possible.

Mexican bean beetles don’t typically become abundant until sometime in the first half of July in my garden, and my estimated last frost is around mid-April. Planting near this date, when it can still be very cool, lets me bring beans to the kitchen beginning at the end of May, through all of June, and into early July, before bean beetles destroy the crop.

When the Mexican bean beetles have shifted from just feeding on leaves to also feeding on the beans, it is time (or past time!) to remove the crop completely from the garden. Be sure to clear it all away. Plant something else in this spot.

In 2-3 weeks, in another part of the garden, you can then plant a second crop of bush beans. In my garden, this second crop is untroubled by Mexican bean beetles. It does, eventually, get bean leaf rollers, but those do a lot less damage to the bean plants and they never eat the beans.

Fire Ants in the Garden – Part 2

23 October, 2017 by amygwh Leave a Comment

How well do organic methods of getting rid of fire ants work? Like other organic pest control methods, the options available are variably successful, and most need to be repeated to get really good results.

University of Florida has posted that the boiling water method has a 20-60% success rate. Repeat applications improve success, but there is a reminder that boiling hot water kills nearby plants, too, and will need to be used with caution.

University of Texas Extension personnel have done some preliminary research on homeowner options for getting rid of fire ants. They compared a chemical control, a DIY recipe for a mound drench that contains orange oil (d-Limonene), a sesame-oil based product (organic), and a drench of just plain water — not boiling.

It is not super-surprising that the chemical control worked best, but the the DIY orange-oil recipe worked pretty well, too. The sesame-oil based product worked to a much lesser extent, but definitely showed some control action when compared to the plain water treatment.

The success of the organic products is good news for organic gardeners.

If you want to try the University of Texas orange oil recipe for organic fire ant control, here it is:

1.5 fl oz Medina® Orange Oil and 3 fl oz Dawn® Soap/ gal water per mound.

In addition to working pretty well, using the orange oil recipe did not kill nearby plants. That is something that gardeners all will be glad to hear!

Would you like to know what doesn’t work, according to the University of Florida? Grits, club soda, soap, wood ashes, and shoveling mounds together.

Fire Ants in the Garden – Organic Control

18 October, 2017 by amygwh Leave a Comment

No gardener wants to encounter fire ants in the garden, but sometimes we find that they have moved in, unwanted. Getting rid of these pain-inflicting invaders can take some persistence, but options for organic control do exist. Knowing a little about the biology of these ants can help a gardener plan a successful counter-attack.

Flattened fire ant mound with deer hoof print in the middle. — Flattened fire ant “mound” shows deer hoof print. PHOTO/Amygwh

Fire ants do not tolerate freezing weather very well. If you treat a fire ant mound in fall, even if the whole mound isn’t dead within a few weeks, enough workers can be killed that the rest of the colony doesn’t survive the winter.

In spring and fall, too, most of the ants in a colony will be closer to the surface, so that a mound drench type of product has a good chance of reaching all of them.

In other words, both fall and spring are when organic controls are more likely to work well. Killing off smaller colonies in fall will also reduce the number of new colonies next spring, when mated queens that survived the winter will fly off to start new colonies.

The very first control to try, though, doesn’t use any products at all. On a cool day after a rain (when more ants are nearer the surface), pour a few gallons of boiling water on the mound, starting by circling the mound a foot or so away and then pouring the rest right on the mound. If this doesn’t kill the whole colony, move on to “Plan B”, a purchased mound-drench or a bait. (NOTE: Boiling hot water can burn people when accidentally spilled, and it will also kill plants near the mound it is being poured on. Please handle boiling water carefully, and do not use it near trees, shrubs, perennials, bulbs, or other desired plants.)

Another option is called “bucketing”. You gather up a few buckets, dust the inside with talcum powder or corn starch (to keep the ants in), and on a cool morning dig quickly into the mound, dumping shovels full of dirt into your buckets. Dig deep enough to find the bottom of the mound. Add a generous squirt of dish soap to each bucket, and add water to drown the ants. This works on small mounds, but not on old, deep colonies.

Organic-approved products for killing fire ants typically contain either d-Limonene (from orange oil) or a spinosad compound (from special bacteria) as their active ingredients.

One organic produce that contains d-Limonene, to be used as a drench, is Orange Guard Fire Ant Control. The d-Limonene products have worked pretty well in our area community gardens.

An organic product for fire ant control that uses spinosad as the active ingredient is Captain Jack’s Dead Bug Brew by Bonide. Instructions for using it as a mound drench are pretty far down the label, but they are there.

Whatever product you choose, be sure to follow package directions carefully.

Remember to NOT disturb a mound in any way before using a product on or around the mound. If the ants are disturbed, they go into “defense mode”; a whole lot of ants will boil up out of the mound where they can’t be reached by a drench.

Fire ants are not easy to eradicate, and new colonies will continue to move in from surrounding areas if they can, even when old colonies are killed off. It is their way.

However, gardeners can be persistent, too. Knowing the best times to work on the mounds for best effect helps keep our gardens fire-ant free.

Insects in the Garden – Predatory Wasps

15 September, 2017 by amygwh 2 Comments

This is the season for wasps in the garden. Most of these wasps are not aggressive and will not sting people if they are not provoked, which is good news. The other good news is that some of the wasps you see are providing pest-control services in your organic garden.

Larvae of the Blue Winged Digger Wasp eat beetle grubs. If you have a problem with Japanese beetles, for instance, tearing up your flowers and making lace out of the leaves of your favorite plants, then this wasp is your friend.

According to Penn State Extension, the adult female tunnels underground searching for beetle grubs, and when she finds one, she stings it, hauls it deeper underground, and then lays an egg on it. When the egg hatches, the baby wasp eats the grub.

Okay, so it’s a little gruesome, but this natural control for Japanese beetles requires no action on your part other than just letting the wasps do their good work.

Potter wasp on sedum flowers in the garden — Potter Wasp on sedum flowers. PHOTO/Amy W

The other helper-wasp that I’ve seen this week is the Potter Wasp. Similar to mud daubers, the adult female will build a little “clay pot” in which to lay an egg. Eileen Linton of the Master Gardeners of Galveston County explains that the wasp will hunt for caterpillars to sting and tuck inside the pot, and the baby wasp (larva), when it hatches, will dine on the caterpillars.

Like the Blue Winged Digger wasp, the adult Potter Wasps sip nectar from flowers, and as they fly from flower to flower in the garden, they act as pollinators. This is another way that both of these wasps are garden helpers.

I am kind of hoping that the Potter Wasps I’ve seen are not feeding my Monarch Butterfly caterpillars to their babies, but my garden is home to many other caterpillars, and some trees in the neighborhood have nests full of fall webworms. There are plenty of other caterpillars to feed baby wasps than the Monarchs!

Have you seen these helpers in your garden?

Control Cabbage Moths and Butterflies with Netting

5 September, 2017 by amygwh 1 Comment

Many of the crops grown most successfully in fall are in the cabbage family. One funny thing I’ve learned as a gardener is that even the insects know that the collards, mustards, and radishes are more pungent than other crops in the group. The cabbage moths and cabbage white butterflies are less likely to lay eggs on them than on the milder members of the family: cabbages, pak choy, broccoli, and cauliflower.

Those milder flavored plants are going to need some protection. The moths and butterflies are not really the problem; it is their babies, the caterpillars, that eat huge holes in the leaves and leave slimy droppings (“frass”) all over the plants. The resultant mess is very unappetizing.

protect fall veggies from egg-laying moths and butterflies — fall veggies under netting

In gardens that are managed organically, you can use a product that contains Bt for caterpillars to take care of the problem, but the easier option is to cover the plants with some kind of mesh, netting, or row cover. This will keep the flying adults away from the plants. If the moths and butterflies can’t reach the plants to lay eggs, then the caterpillar problem will never occur!

The netting needs to be draped over a support system that is high enough that the net is held away from the plants, even as they grow larger. In the picture in this blog post, bird netting that I use in spring over my strawberry bed is draped over supports to protect some small kale and pak choy plants.

August-planted beans in flower. — Becky’s Aunt Joanie Beans, planted in early August.

It might not be the most lovely thing in a front-yard vegetable garden, but the support and netting will only be there for a couple of months. By the end of November, the plants won’t need the protection. The moths and butterflies will be gone, or close to gone, for the year.

Elsewhere in the garden, my patch of heirloom beans, my friend Becky’s Aunt Joanie Beans, is full of flowers. I even see a few tiny beans! So far, all is well.

Bean Leaf Rollers Return

21 August, 2017 by amygwh Leave a Comment

If the leaves of your late-planted beans are looking a little odd around the edges – with bits snipped and folded over – fear not!

Even though there is probably a caterpillar under each little snip-and-fold, they will not (usually!) do too much damage.

These caterpillars are the larvae (babies) of a Long Tailed Skipper butterfly, which is a Georgia native.

The snipped leaf-edges you can see in the pictures are in my garden right now. I pulled back one of the folded-over pieces to show you the caterpillar inside. When the little guy gets bigger, his head will be bright red. This is one more feature, besides the odd damage on the leaves, that makes this caterpillar easy to identify.

These come every year to my late-planted beans. The first year I saw them in abundance, though, was 2012. I made a little video, with the help of my younger son, to tell gardeners about them.

You can see it, too: