Edible Gardening

Good Bugs, Bad Bugs

Assassin Bugs on Tomato plant

Assassin Bugs on Tomato plant

A friend sent me the photo above and asked what had been attacking her tomatoes.  These pretty freaky looking bugs are appropriately called “Assassin Bugs”, and they are NOT causing the problem she is having with her tomatoes.  In fact, they don’t eat plants at all.  Assassin bugs are considered beneficial insects because they are carnivores, they eat other bugs, hopefully the ones we want to eliminate in our garden like aphids, caterpillars and Japanese beetles.  Here is a picture of a new cropthat  just hatched on my squash plants. (Yeaaa – Go get ’em, babies!)

Assassin babies on Squash

Assassin babies on Squash

Nymphs and adults are often seen stalking or laying in wait for their prey, which they inject with venom once they have caught.  Assassin bugs are common natural enemies on many plants, feeding on a wide variety of small to medium-sized insect prey including caterpillars, leafhoppers, small bugs, and aphids. (They also feed on beneficial species such as lacewings & soldier beetles.)

Assassin Bug, photo by Debbie Roos

Assassin Bug, photo by Debbie Roos

Here is a link to Debbie Roos’ photos of beneficial insects on the NCSU Small farms Website: NCSU Growing Small Farms website with Debbie Roos   Also check out her photos of many other good garden bugs , and her schedule of tours of the lovely pollinator garden in Pittsboro which is open to the public every day.

Praying Mantis function in somewhat the same manner as assassin bugs. While they are considered beneficial because they eat other bugs, they are non-discriminatory and will eat flies and spiders as well as butterflies.

Japanese beetles have shown up in my garden just this week, and they are usually with us until the end of August.  If you do not have a full-force infestation, they are easily killed by tapping them off your plant into a jar of soapy water.  A hand-held vaccum cleaner (think Dust Buster) will suck up a lot of these bad bugs too!

For larger populations, liquid Sevin (Carbaryl) spray is still the most effective for wiping out hard shelled insects such as Japanese beetles, cucumber beetles and squash bugs.  Spray only at dusk to avoid killing your bees!

Japanese beetles love roses. You can buy a Rose Food that contains a systemic insecticide and fungicide.  You apply it to the ground around your roses and it is taken up into the leaves and flowers of the plant. It will kill insects (beetles) that eat the leaves, and it won’t hurt your bees.

Squash bugs are my nemesis!  Per the NCSU Extension, “Squash bugs are the grey, shield-shaped bugs that feed on squash and pumpkin plants. If you have had problems with these insects in the past, you know that they are almost impossible to control when mature. This is because the squash bugs have a hard body that an insecticide has difficulty penetrating. Thus, spraying when the insects are small is important. We are now seeing the nymphs of the first generation. These nymphs will eventually become adults, which will lay eggs that will become the second generation. The second generation is often huge and devastating. Therefore, it is important to control as many squash bugs now as possible. Because squash bugs feed by sucking juice from the plant, only insecticides that directly contact the insect will work. General use insecticides such as permethrin, malathion, rotenone, and methoxychlor provide control if a direct application is made to young, soft-bodied squash bugs.  [Sevin is still my choice, less toxic, less odorous.]  This means that you MUST spray or dust the underside of the leaves because this is where the insects live.

Perhaps the biggest problem with Squash bugs is that they spread a fungal disease that slowly weakens and eventually kills the plant.  Squash bugs love hiding in dark places.  This year I am testing a strategy of placing an upside-down black nursery tray at the base of my squash, filpping it over early in the morning and immediately dusting the bugs with Sevin. The benefit of this is that I can kill just the bad guys!

Here is a natural spray you can use for Mildew prevention on plants such as squash, roses, tomatoes & zinnias. Mix 1 tablespoon of baking soda & 1 teaspoon of dish soap in ½ gallon of water. This works as long as you start spraying weekly before the mildew shows up.  Personally I am willing to tolerate some mildew if I son’t have to spray.  When squash gets too ugly, I simply remove it from the garden.  Tuck a few new seeds in the ground now to eventually replace tired plants.

What about ANTs?  Mostly they are annoying.  Stepping into an ant hill? Uugghh!  Fortunately, NCSU says that those tiny little reddish-brown ants known as “Fire Ants” whose painful bites cause blisters that take 3 weeks to heal, are still at the southern edge of Guilford County.  But if you happen to find a huge mound of tiny ants in the middle of your lawn, get the ant bait out fast.  If you accidentally step on a mound of fire ants they can be on you like oil spreading on water! Click here for pictures and more information: http://growingsmallfarms.ces.ncsu.edu/growingsmallfarms-fireants/

“Fire ants are omnivorous, feeding on insects, animals, and plants. Fire ants can have a devastating impact on native populations of ground-nesting insects, reptiles, birds, and mammals… ATTRA, the National Sustainable Agriculture Information Service, reports that the aggressive use of insecticides against the imported fire ant has only served to wipe out competing and predatory native ant species and increase the competitive dominance of the imported species by killing off its competition. “  With that in mind, it is important to know what you are killing!

Luckily, our big red and black NC ants are benign.  The only time I get suspicious is when I see them running up and down my okra plants.  They have a habit of “farming” aphids, meaning that they actually bring the first aphids to your okra plants where they rapidly multiply and provide the ants a constant source of “honey dew” for food.

The aphids cause your okra pods to curl and also  weaken your plant.  Ants feed on the base of developing okra blooms before the bloom buds open causing them to be disfigured or to abort.

Kill aphids with Safer insecticidal soap. Slow the ants by putting Sevin dust on the ground around your okra plants. (OK, Sevin dust floats in the air and can kill bees, so be very careful with it.)  Gently sprinkle it on the ground where the ants walk.  It should reduce the ant population or at least get them to go elsewhere.  Borax sprinkled on the ground will work too. Terro Ant Killer is very effective and the active ingredient is Boric Acid.

Bottom Line

There will always be bugs in the garden, and many are essential to the health and productivity of our plants.  The key is to take specific measures only as needed to keep nature in balance.

Remember too that healthy soil and healthy plants are your best defense against bugs & disease.  If your plants are not growing well, the first things to check are your soil pH,  the amount of organic matter in your soil, and the amount of sun and water your plants are receiving. 

Use organic fertilizers to give your plants a slow release nitrogen boost.  Good choices include Espoma’s Plant-tone, blood meal, fish emulsion, and feather meal.  Look for natural fertilizer labels that include lists of bacillus and fungi.  Feed the microbes in your soil with a solution of kelp/seaweed, humic acid, liquid bacteria and fungi, and molasses.  Any and all of it is good, and the benefits to your soil are long term.

Summer arrives tomorrow, kicked off by the Summer Solstice Festival at the Arboretum.   What better place to be than in a garden?!