Thursday, 16 October 2008

Don't Kill That Bug!

Hello, Marc from GardenDesk here.

In my organic vegetable garden I sometimes have to tolerate minor pest infestations. The only insect control I employ is hand-picking and destroying the problem insect. Many people reach for an insect killing spray at the first sign of bugs on their plants.

That is the wrong approach. Never mind what that does to the environment and your health, poisons don't discriminate. When a gardener applies an insecticide, there are actually "good bugs" in the garden that are killed along with the problem insects. If you are new to the idea of beneficial insects, let me explain. If you saw the bug in the picture on one of your tomatoes, would you want to destroy it?

You shouldn't. That is a Spined Soldier Bug and he is a soldier in the gardener's army. The Soldier is beneficial because it eats armyworms, beetles and cabbage loopers. The Soldier Beetle is so beneficial that there was a big article in Organic Gardening Magazine about how to trap them in the wild for the purpose of releasing them in your garden. Read the article HERE.

Here is a picture of another insect you might find in an organic vegetable garden:

Surely that ugly thing needs to be killed, you might be thinking. There is more in this picture than meets the eye. This insect is a very destructive Tomato Hornworm, but look closer. What about the little white cocoons attached to it? These are Braconid wasp cocoons. Braconid Wasps are parasitic. They live in the Hornworm (which is actually a caterpillar) as larvae, and then make cocoons on the outside to pupate. The adult wasps emerge, kill the caterpillar and fly off to find more caterpillars to destroy.

See, who needs chemical insecticides to control caterpillars?

To further illustrate this cycle, my daughter actually kept a hornworm in a jar and fed it tomato leaves. We got to witness the tiny wasps emerge and kill the hornworm. here is a picture montage lifted from one of my older posts about this:

We emptied the whole jar back out in the garden. I counted over 300 cocoons on this hornworm! If only half of them find a new caterpillar to invade, I soon won't have any caterpillar problems at all. No need for chemicals - nature can take care of things if we let it.

There are even smaller parasitic wasps out there. GardensAlive! is a store that sells organic and natural fertilizers and pesticides. They sell Trichogramma wasps for you to introduce into your garden to do a similar thing that my Braconids are doing. The Trichogramma wasps are almost microscopic!

These are just a few examples of beneficial insects. Depending on where you live, you will encounter different ones. When you find an insect in your garden, you should do some local research to determine if it is good or bad. If there is plant damage near by, don't assume that the creature you found is the culprit. It might be there to feed on the actual pest!

Other beneficial insects that I have discovered in my garden are ladybugs, lacewings, mantids and bees.

The bottom line is this: If you spray insecticide at all, you won't have any beneficial insects to help you. When the pest insects come back, they will inflict even more damage because of the absence of beneficials.

Gardeners and farmers who use chemicals force themselves into a never-ending cycle. They continue to have to spend money to temporarily solve their pest problems in an unsafe and harmful way. I think nature's way is better. Sometimes I may have to wait on the beneficials, hand pick pest bugs, and even lose a few crops, but I like watching nature work. It keeps gardening a fascinating endeavor instead of a divide and conquer campaign. Knowing that I'm participating with nature instead of destroying it makes makes me feel good.

Keep Growing!-Marc


dND said...

Have you had to deal with woolly aphid on lemon trees? My lemon tree is covered with them, I've tried hand picking but there are so many little ones I really feel that I'm on a loosing battle.

Lalycairn said...

Interesting. I had these bugs in my garden this year, and looked them up and thought they were squash bugs link is here:

any ideas?

They look almost exactly like a spined soldier bug? link is here:

jacqui jones said...

i do hope im brave enough to hand pick the bugs off !!

Felicity said...

Thanks Marc! Being very new to produce gardening, I'm not sure what is good and what isn't when it comes to bugs! I also prefer NOT to use any chemicals on my own food (if I wanted chemicals, I'd go to the stupormarket), so any advice you can offer on organic ways to treat common problems would be extremely appreciated - or even what common problems look like!

Tammie said...

this was so helpful...i had these in my tomatoes this past year and wasnt aware they were beneficial.

Jendodd said...

That's what those are!!! I had one hanging out on the leaf of my cherry tree for weeks and I've never seen one before!

Lisa said...

I never knew about the soldier bug before. We saw a lot of them in my tiny garden this year and the kids loved to watch them as they have such nice markings on them. We just never knew what they were. Now i can tell the kids the name of their "cool bug" :)

Bovey Belle said...

We have Shield Bugs here in the UK, which are very similar to your soldier bug.

This summer I read about our butterfly population being decimated by an invader who uses the caterpillar (especially those of the Tortoiseshell butterfly, once very common) as a host for its eggs. However, I found a Large White ("Cabbage White") caterpillar infested in the same way, so perhaps these invaders have a good side too. Even so, Tortoiseshell butterflies have been practically wiped out and they used to be so common . . .

Nadege said...

But how do you protect the tomato plant? In 2 days, these caterpillars destroyed my few tomato plants.

Notes From The Frugal Trenches said...

Really great post! I'm so much more anxious about the unnatural world then the natural world :)

Marc and Renee said...

There is a lot to learn about insect pests and beneficial insects. I suggest you pay extra close attention to what is going on in your yard and garden and try to identify the insects you find as quickly as possible. Some times you will have to use something to save your plants. I usually don't, but if you decide you need a spray, look for an "organic" method first.

dnd - I am not lucky enough to grow lemon trees but I have apple, peach and pear trees. Fruit trees are the hardest things to grow organically for me. As for aphids, ladybugs or ladybird beetles eat them, but if you have a large infestation, you probably can't wait for the beetles to help. I've heard of people spraying a mild dish soap solution on them. That is pretty safe. I was able to control my aphid problem by controlling my ant problem. The ants were actually putting the aphids on my young apple trees in order to eat the aphids "honeydew". Pretty fascinating.

lalycairn - your picture is indeed a spined soldier bug. Squash bugs are similar but they are more elongated and softer shelled.

bovey belle - shield bugs huh? It might be a different common name for the same bug. Since this blog has readers from many parts of the world, I guess we should use the Latin names when talking about insects. Next time I will look those up. As for the butterfly caterpillars - predatory insects don't care if WE like their host insects or not, they are just using them for survival. I guess you can't call them beneficial unless they are destroying an insect you DON'T like.

nadege - Hornworms will destroy a tomato plant it short order. You do need to destroy them when you find them. The ones that we found with cocoons on them were removed from the garden and put in a jar until the wasps emerged. We then put them back in the garden. If you find a hornworm without the cocoons, you should kill it right away.

Everyone else - thanks for the kind words. Together we can learn more about beneficial insects and other organic gardening techniques.

Dan B. said...

I know that these Bugs are helpful, but at my house there is an infestation of them. I mean you cannot walk through the grass without stepping on them,you cannot leave clothes outside to air dry without them getting into it. They have even infested my house ( I am literally squashing them as I wright this). Is there any way to get rid of them, or at least get their population down?

R.H.R. said...

Thank u soooo much for posting this info. Skin is still crawling from finding them on our organic tomato plants. i didnt kill them because i couldnt figure out if the white things were for our garden or against us. I truly appreciate the info and will now allow nature to continue its beautiful, if skin crawling, work!