Pests and Diseases: A Quick Look at Beneficial Insects

They’re the reason that I don’t spray pesticides at my house and strongly encourage others to do the same. The beneficial insects. There are so many of them that we need to preserve so that THEY can do the hard work for us. There will always be more bad bugs than good bugs. If we go in and remove the good bugs from the equation, the bad bug population can explode and then you end up on a never ending roller coaster of insecticides. Instead, we should accept that it’s OK to have some bad bugs and let Ma Nature do her thing. If she needs some help, we can step in and use mechanical means (hand picking), cultural controls (planting the right plant in the right place to begin with) and/or organic insecticides (like horticultural oil or horticultural soap). If all else fails, add another dose of compost!

Now that we’ve skimmed the surface as to why we should encourage beneficial insects, let’s look at a mile high view of them.

beneficial insects
Green Lacewing. They grow to about 1″ long but it’s not the adults that are the real predators. It’s their larvae that are known as aphid lions. Photo courtesy of www.fcps.edu

 

beneficial insects
Aphid lion. Look at the mandibles on the far right hand side of the picture. I’m glad that I’m not an aphid! Photo courtesy of www.uky.edu

 

beneficial insects
Do you know that this is a ladybug larva? Many people don’t as they don’t resemble their grown up counterparts at all. Photo courtesy of www.uky.edu

 

beneficial insects
Braconid wasp. Not the “normal” wasp that you think of, there are many parasitic wasps that lay their eggs in the bad bugs and result in killing the pest. Photo courtesy of www.forestryimages.com

 

 

beneficial insects
Braconid wasp pupae that have taken over a tomato hornworm. Nature can be gruesome! Photo courtesy of www.ces.ncsu.edu

 

beneficial insects
Praying Mantis. When I was younger, these would really freak me out…I’m not sure why. But now I see them as insect harvesting machines. Be on the lookout for their cocoons in the late summer and early fall. Photo courtesy of www.marchbiological.com

 

beneficial insects
Praying Mantis cocoons. If you see them in the garden, leave them intact so that you’ll have lots of babies next year. Photo courtesy of www.bugs.org 

 

We’ve just scratched the surface on all of the beneficial insects that we should strive to protect. Which ones are regular visitors to your garden? Leave me a comment below or e-mail me. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list (upper right hand corner of this page), become a fan on Facebook and follow me on Twitter. Happy gardening!

 

 

Organic Gardening vs. Conventional Gardening

 

Sorry that I didn’t post yesterday…my son had a birthday party to go to and we didn’t make it home until late. I thought that I would make it up by posting today instead.

I’ve been thinking quite a bit about organic gardening versus the conventional way of using chemical fertilizers and pesticides. My personal philosophy revolves around working with the natural cycles that Ma Nature has laid down well before my existence on this planet. I am an environmentalist with a little e, not an Environmentalist with a big E. To me, the difference between the two is that the big E folks tend to treat the earth almost like a religion. I prefer to put my belief system in God and his Son Jesus Christ. If you’re thinking that perhaps I’ve gone off on a tangent, you’re right…the more you get to know me, the more you’ll understand that’s a tendency of mine. My environmental stance is that we should leave the world a better place than we found it for our children and grandchildren. That means that we shouldn’t carelessly apply fertilizers and chemicals without realizing their repercussions.

Many gardeners will apply nitrogen based fertilizer in the spring and then wonder why they have aphids literally sucking the life out of their plants. Or they’ll treat their plants with imidacloprid and then wonder why they have an explosion of spider mites. The answer to both of these problems is that there is an imbalance. In the fertilizer example, the plants are growing at such a fast rate that they invite aphids to take them over. Aphids love fresh new succulent growth and by applying high nitrogen fertilizer, you have pushed the plants past their normal level of growth which triggers the aphid infestation. With the imidacloprid, you have successfully killed off the insects (six legs) that were troublesome but you have opened Pandora’s box for spider mites (eight legs) because there are no longer any natural predators to keep the mite population in check.

What would have happened if you wouldn’t have put down any more nitrogen in the spring? Unless you have very poor soil, the plants would have flushed out from their winter dormancy and probably done very well. If there was a nutritional deficiency, there’s a magic soil amendment that would have taken care of it…COMPOST! If we as gardeners would focus more on feeding the soil instead of feeding the plants, our results would be amazing. But instead, we see that the plant looks a little yellow so we put down fertilizer on everything. Or worse, we fertilize every spring because that’s what we’ve always done. Another thing that we could do instead of fertilizing is take a soil sample and determine the pH of the soil. Many nutrients, including iron, are unavailable at certain pHs and that can make your plants look chlorotic.

What would have happened if you didn’t apply imidacloprid to your willow oaks to treat for scale? If you noticed the problem before the temperatures were above 80 degrees, you could have applied dormant horticultural oil which would have smothered the scale. One of the attractive features of imidacloprid is that it has residual activity since it is taken up by the tree into the phloem. If an insect feeds on it after the chemical has been applied, then the insect is also consuming the insecticide. But on the flip side of things, can you see the problem that this presents? All of the predatory insects are also killed and as a result, you have an explosion of spider mites that you now have to contend with.

Now I have to admit, I spray glyposhate based products such as RoundUp or RazorPro to deal with weeds and I’ll use MiracleGro on plants that are showing nitrogen deficiencies. But I only do these things after I have determined that the real problem isn’t something else that is manifesting itself as a deficiency. And I’ll add compost to the soil to try to fix the real problem…soil fertility. Again, it’s not a plant fertility problem, it’s a soil fertility problem.

I’ve been learning a lot about permaculture lately and Jack Spirko from The Survival Podcast has been my primary source of education. For those of you who don’t know, it’s a daily podcast that he produces on a wide array of topics from gardening to food storage to prepping. The founder of permaculture, Bill Mollison has described permaculture as “a philosophy of working with, rather than against nature; of protracted and thoughtful observation rather than protracted and thoughtless labor; and of looking at plants and animals in all their functions, rather than treating any area as a single project system”. I think that’s a pretty accurate description of how we should see any gardening that we do. Whether you enjoy vegetable gardening, woody plants, herbaceous perennials or annuals, we need to see the system as a whole, instead of just its parts. By doing this, we can ensure that our children and grandchildren are left with a planet that can sustain them and many generations to come.

I’d love to hear how you’ve incorporated organic gardening principles into your landscapes. Or perhaps you haven’t and can’t see a reason to start doing so…I love a good debate and I’d love to hear your thoughts. Leave them in the comment section below or e-mail me at stacey@midatlanticgardening.com. Happy gardening!

December 10, 2011Permalink 2 Comments