Did you know that the cute little lady bug that flies away home to save her children in the rhyme is actually a ruthless predator. They hunt and eat aphids, mealy bugs and scale, all of which can devastate a garden if not controlled by beneficial insects like the ladybug. The thing about insects and plant diseases is, if one takes good care of most plants with sufficient water and food (compost and fertilizer) the insects and diseases will not harm them. But if insects or disease (which is often carried by insects) take over, the plant is doomed.
Just as our wilderness areas can be devastated by the lack of large predators such as wolves, the micro-environment on a plant or in a garden needs predators as well as prey. When we in the US killed off most of the large predators the deer and rabbit populations soared causing other problems. Unfortunately, insecticides do not differentiate between the good bugs and the bad bugs, the predator or the prey. Not unlike the wolves in our forests, the prey insects such as lady bugs, braconid wasps, syrphid flies, to name a few, reproduce in smaller numbers than the bad bugs, such as the aphids, cutworms, mites and mealy bugs, that reproduce at a higher rate. So after an insecticide has killed off all of the bugs in one spot in our garden, the next generation of nasty bugs has a clear shot at your tomatoes and roses while the prey insects are just barely catching up. This is called the cascade effect.
While chemical insecticides (pesticides) kill everything, there are some safer alternatives that repel insects and can keep their eggs from hatching, cutting down on damage and allowing the plant to thrive. Insecticidal soap is a good example. If one coats the leaves, including the under side with the insecticidal soap (a soapy-oily substance) will on contact, soften the eggshells of insects and soft body insects (like aphids). Another choice for a “greener” insecticide is neem oil. This also purports to do the same thing to the eggs and soft bodied insects. In my garden this year, a combination of one spraying of neem oil mixture and picking off visible bugs has thus far kept a cucumber beetle problem under control. I will give the plants another praying 10 days later. These products can be used up to the day of harvest but the usual precautions should be taken. Always wear eye and breathing protection when spraying anything.
If the fact that using insecticides is causing a cascade effect in your garden isn’t enough to stop the use of insecticides, consider the honey bee. Bees are insects, pesticides kill them too. With the neem oil and insecticidal soap bees are only affected if you spray one directly. With the problems caused by the mysterious colony collapse syndrome killing off 1000’s of bee colonies around the world, we need all of the bees we can get these days.
If you were to approach my garden now you would see, on closer inspection, that just about every plant has some insect and disease damage. I don’t mind a few bad bugs in my garden. In fact, due to the cabbage loopers (inchworms) on my hibiscus, the leaves have a special lacy look that compliments the vivid pink blooms. How would that have happened without the inchworms? Perhaps my garden isn’t perfect but it is a safe place for humans, pets and beneficial insects.