Dirt Dobber: Spider Killer

As children we called them dirt dobbers but this insect is also known as the dirt dauber, mud dauber, dirt diver, mud wasp, and solitary wasp. 

The dirt dauber is a bluish black wasp with a very thin waist. After mating, the dirt dauber builds a nest using mud, usually from clay. Here around our house, we have several types of dirt daubers, but the one we see most often is the organ pipe dirt dauber, which builds its nest in long cylindrical tubes resembling organ pipes.

What purpose do they serve? Dirt daubers are a beneficial insect that we like to have around the garden. They are predators, and they love to eat spiders. Well, any creature that kills spiders is a friend of mine. (Sorry, I know spiders are beneficial in the garden, but I come from a long line of arachniphobics). And that is why I allow dirt dauber nests to remain in the garage.

Each species of dirt dauber has its own favorite prey. The blue dirt dauber is the main predator of the black widow spider.

Adult dirt daubers stock their nest with spiders to feed their offspring. They prefer particular types of spiders and certain sizes too. They capture the spider by stinging him, not to kill but to paralize. Rather than choosing a couple of large spiders, they cram their nest with a couple dozen small ones instead. 

Dirt daubers are not aggessive and need not be feared since they rarely sting humans. They really should not be killed, but if the nest is in an unwanted place, you can use a putty knife to scrape it away. For more information on the dirt dauber, please visit Pollinator.com.

Pests in the Garden: How to fight them without Pesticides

While our gardens are full of bad insects that bite us and eat our plants, many of the bugs in our garden are not only helpful and beneficial but responsible for much of the food we eat. Many of our valuable pollinators are on the decline due to habitat loss and overuse of pesticides by both commercial farmers and home gardeners. Since pesticides cannot tell the difference between a good bug and a bad one, it is best to not use them at all. 

Yet, insects like aphids, Japanese beetles, and squash bugs can destroy a plant quickly. And fleas, ticks, and mosquitoes? In addition to those itchy bites, they carry diseases which can be fatal. What can we do? It depends on the insect really.

Here in our garden, we use a variety of different methods for insect control. We have chickens, ducks, and guineas that roam free-range throughout the day eating every bug they see. Since introducing chickens to our garden, we have seen a significant decrease in Japanese Beetle damage. Guineas love to eat ticks, I am told. And ducks just eat every bug within reach. Since I have read that geese eat snails, I am entertaining the thought of getting a goose for my garden. (Don't tell my husband.)

Aphids will usually be taken care of by Ladybugs, if you haven't killed them all with pesticides. If you don't have a good Ladybug population, you can order them online from Gardens Alive. Be sure to follow their instructions when you release them. Its really the Ladybug larva that devours the most aphids.

If you can't wait for the Ladybugs to do their job, use the safest insecticide you can, insecticidal soap. You can purchase it ready made or make your own (1 or 2 Tablespoons of pure liquid soap like Castile, not detergent, to 1 quart of water.) Spray on the undersides of leaves and only where you see aphids.

For Japanese Beetles, mix up a cup of soapy water and add a little vegetable oil. Take it outside and as you see a Japanese Beetle, knock it into the soapy water. The oil will prevent its being able to climb out. This is a good job for your little boy, if you have one.

For many plant pests like squash bugs and tomato hornworms, the best method of control is to simply pick them off by hand. Since I don't like to touch bugs and caterpillars, I use my pruners to knock them off. You can then mash them, or if you have chickens, knock the bug on the ground for them to fight over. It's been years since I've seen a grasshopper in the garden here. Our chickens used to fight over them. It was fun to watch.

For ticks and fleas, here is an excellent recipe for homemade repellent.

Gardening with Bugs

If you are a gardener, you must learn to accept bugs. In the garden, there are good bugs and bad bugs.  Bad bugs, pests in the garden, are the topic for a later discussion. There are 3 types of beneficial insects you want in your garden: predators, parasitoids, and pollinators. 

Predators such as Lady Bugs, Lacewings, and Praying Mantis eat other bugs. Parasitoids like parasitic wasps lay their eggs on other bugs or insects so their young will have something to eat when they hatch. And of course you know pollinators like bees, butterflies, and moths pollinate flowers so we can have fruits and vegetables to eat.

As a gardener, you will understand the importance of attracting pollinators into the garden. Just like birds and butterflies, insects need 3 things for survival: food, water, and a place to lay eggs.

Very important - do not use pesticides. Pesticides don't know the difference between a good bug and a bad bug, and you do not want to kill off your pollinators.

Creating a garden for the bugs is very simple. Brightly colored flowers will attract all types of beneficial insects to your garden. Choose a spot in full sun near your vegetable garden or fruit trees and amend the soil with compost. You can purchase annuals like cosmos, zinnia, marigolds, and vinca from your garden center or grow your own plants from seed.  Sunflowers are available in both annual and perennial plants. Native plants work best. Variety is important. A wide range of colors and flower types will in turn attract a wide variety of beneficial insects. For a printable list of native plants suitable for your own planting zone, click here.

Beneficial Insects in the Garden

When many people see an insect, the first impulse is to kill it. But not all insects are pests, and many are actually beneficial insects, meaning they do good things like eating harmful insects and pollinating flowers. When we use pesticides to control insect pests, we also kill the good bugs. You probably already know that Ladybugs or Lady Beetles are beneficial insects, feeding on aphids, scales, and mealybugs. But did you know that the larvae of ladybugs look like tiny little alligators and eat even more pests than their parents?

Lacewings are fragile-looking insects with delicate, lacy green or brown wings, large eyes, and very long antennae. Their larvae feed on aphids, scales, mealybugs, whiteflies, and young caterpillars.

The Praying Mantis shows no favoritism and will eat almost any insect (yes, they will eat the good bugs too and will even eat each other!) 

Parasitic Wasps are usually too small for you to see, but you might spot signs of their presence. If you find a crispy-looking brown, inflated aphid attached to a leaf, it was probably the victim of a parasitic wasp that laid its eggs in the aphid so its offspring would have something to eat when they hatched. You might also see caterpillars, cabbage loopers, or hornworms carrying around cocoons of developing wasps. Parasitic Wasps lay their eggs on the back of soft caterpillars so their young will have a convenient food source upon hatching. (Yuck!) 

It's almost time to see the Tomato Hornworm eating up the leaves and even the green tomatoes on our tomato plants. The best control is to pick them off and destroy them, but if you see one with loads of small white things that look like clusters of rice, just leave it alone--the white things are eggs of the Parasitic Wasp! 

Tomato Hornworm with Eggs of the Parasitic Wasp

Grandaddy Spiders, or you might call them Daddy Longlegs, eat aphids, mites, and other garden pests. (No photo this time, because spider photos give me the creeps.)

These are just a few of the many beneficial insects in our gardens. Beneficial insects can be purchased from mail-order sources, but you can attract them into your garden without purchasing them. The best way to attract these beneficial insects into your garden is to just plant more flowers and herbs!