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Insecticide: Choosing the Right Product
When you have a plant infected with a bug, choosing the right insecticide to treat it can be as confusing as choosing a cold medicine when you feel ill with a bug! The first step in treatment is proper diagnosis of the problem. I keep a newsletter archive on my website which may help you identify the pest. Additional resources are listed at the bottom of this page and staff members at our local nurseries are very helpful in identifying pest problems and knowledgeable regarding insecticides. Once you have a diagnosis, CAREFULLY READ THE LABEL before applying insecticides. Improper dilution or inappropriate application can be very, very harmful to you and the environment around you.

Here I will briefly discuss the three most common types of synthetic insecticides, as defined by the first active ingredient on the ingredient list:
  • Pyrethroid. Trade names: Eight, Bonide, etc. Originally derived from the Pyrethrin Chrysanthemum flower, this synthetic is a broad-spectrum insecticide meaning it will kill both the good and the bad. The active ingredient will be Pyrethroid or Permethin. It is highly toxic to fish and aquatics - avoid use near your pond. Pyrethroids cause a rapid knock-down in the pest population and are generally ineffective just one week after application.
  • Carbaryl. Trade name: Sevin, and many types of lawn pesticides. Carbaryl is water soluble, and is often (but not always) sold as a "systemic" insecticide. This term means that you will water the plant with the insecticide, then the plant will move the chemical throughout it's leaves and stems and when the insects feed on the plant they are poisoned. It is a broad-spectrum insecticide which generally protects the plant for weeks or months. Although there is a low mammal toxicity, Carbaryl is highly toxic to bees and also birds.
  • Organophosphate. Trade names: Orthene, Malathion, etc. Don't be confused by the "organo-" in the first part of the name - that refers to the fact that it is derived from carbon. Probably the most commonly used, these broad-spectrum insecticides break down quickly with very little residual effects. Organophosphates are not generally toxic to mammals, birds or fish.
Next month I'll discuss some of the botanical/natural insecticides available.

If you have concerns or questions about your container gardens or irrigation system, please contact me right away.

Also, if you're considering doing some landscaping work, please call me (970-988-3808) to help you with your landscape design.

This year's newsletter series is "Insects: the Good, the Bad and the Ugly."


The Good: Ladybugs

There are more than 450 species of Ladybugs in North America; these cute little bugs have round bodies, ranging in color from orange to red, with black spots. Ladybug adults feed on other insects but when the Ladybug is in the larvae stage it is the most hungry and can consume hundreds of pests a day. The larvae are black and red crawlers, resembling little alligators, as seen in the lower photo here. Ladybugs control aphids, mealybugs, scale, spider mites, whiteflies, and the larvae of several other bugs. Ladybugs can be purchased at the nursery. Release them in late evening directly onto well-watered, pest-infested plants but be aware that Ladybugs are ‘fair-weather friends’; they don’t like it too hot or too cold and often arrive late and leave in early fall just when many pest populations are booming.

The Bad: Spider Mites
Since Spider Mites are actually spiders (Arachnids), as their name suggests, insecticide won’t work as a control and may make the problem worse. These very, very tiny (1/20”) spiders live in large groups and spin fine webbing. The top photo is a highly magnified mite; the lower photo shows their webbing. Although they live only a few days, they can suck on plant juices causing the leaves to look mottled, yellowed, and stippled, especially in hot, dry weather. Because they are so small, you won't be able to see the mites – look for the fine webbing as their calling card. Dust encourages mites so hosing the plant down with water will clean off the dust and knock off the pests. Miticides are also available and effective with little adverse effect on natural predators.  
spider mite


The Ugly: Spiders

There are 38,000 different species of spiders, of which only 200 are poisonous to humans and only 4 of these species are found in the US. Most spider fangs are too short and too weak to puncture human skin which means most spiders are harmless.  Spiders are easily identified by having 8 legs and, as most people know, are not insects but belong to the class Arachnida. All spiders are predatory and some spiders are specific to only one food source. Some spiders spin webs and wait for prey; others, like the wolf spider pictured here, hunt their prey. They control just about any kind of insect so if you don’t have Arachnophobia, spiders can be good garden helpers.  

If you're really interested in bugs, here are a few good resources:
  • "Insect." Wikipedia. Wikipedia Foundation, 27 Apr. 2013. Web. 29 Apr. 2013.
  • Walliser, Jessica. Good Bug, Bad Bug: Who's Who, What They Do, and How to Manage Them Organically: All You Need to Know about the Insects in Your Garden. Pittsburgh, PA: St. Lynn's, 2008. Print.
  • Sunset Western Garden Book. Menlo Park, CA: Lane, 1988. Print.
  • Leatherman, David, and Whitney Cranshaw. Insects and Diseases of Woody Plants of the Central Rockies. [Fort Collins, Colo.]: Colorado State University Cooperative Extension, 2000. Print.