Integrated Pest Management

IPM Cover Photo

Last weekend, I attended the 2014 Carolina Yard Gardening School. One of the classes I attended was on Integrated Pest Management (IPM). Today, I’m sharing with you what I learned.

INTEGRATED PEST MANAGEMENT

Integrated pest management, or IPM, is a system to prevent and/or decrease the number of garden/farm pests in order to not have a decrease in crop value. The goal is only to decrease the number of pests. It is NOT about total eradication of pests because that would upset the ecological balance of the local system. That said, part of what a gardener or farmer must accept is a bit of aesthetic damage that doesn’t hurt the actual crop. For example, a few bug-eaten lettuce leaves doesn’t mean the entire head of lettuce is lost.

IPM seeks to prevent and decrease numbers of pests in the least toxic way with long-term pest solutions that decrease dependency on chemicals. It combines techniques that rely on an understanding of pest life cycles and ecological concepts.

Before developing a pest control strategy, you must first identify the pest – its name, life cycle, the crop it prefers, etc. This is done by monitoring the pest and doing a little research. You must also determine the amount of crop injury you can live with, as this will determine the pest control strategy necessary. Also, pest management is not something done on a set schedule; it is need based. Therefore, monitoring is also very important for knowing WHEN to initiate control strategies.

There are three types of pest management:

  • Cultural – what we humans do
  • Biological – what nature does
  • Chemical

INTEGRATED PEST MANAGEMENT: CULTURAL CONTROLS

There are many ways we can assist our crops in reaching maturity without being destroyed by pests.

  • Resistance – Choose pest (and/or disease) resistant varieties.
  • Plant fertility issues – Don’t over-fertilize. Too much nitrogen increases growth but lowers the plant’s resistance because all its energy is focused on growing quickly.
  • Reflective mulches – Silver plastic mulch confuses insects, detering them from feeding and/or laying eggs on your plants. Aluminum foil collars on the bottom of squash vines (or other plants) should help discourage squash vine borers (or other insects) from laying eggs at the base of the plant. (I’ll be trying that myself this year.)
  • Exclusion – Plan your planting so your crop’s growth occurs before or after the pest’s life cycle. (Know when the pest attacks the crop and plant accordingly.)
  • Trap crops – Plant trap crops away from your desired crop. The pest may like the trap crop better and avoid your desired crop.
  • Overwintering habitats – Get rid of any areas in your yard or garden that may be an invitation for pests to overwinter in your yard. Places like wood piles, debris piles, or overgrown areas are all engraved invitations for pests.
  • Manual removal – There is always the old-fashioned pick-them-off-and-step-on-them method!

INTEGRATED PEST MANAGEMENT: BIOLOGICAL CONTROLS

Nature has many ways we can tap into to help our crops survive an onslaught of pests. First, a pest is defined as an insect or animal that causes economic or aesthetic damage to our crops. However, because these pests are still a key part of the ecological system, we don’t want to totally eradicate them. We want to work to keep them below a certain threshold.

Different areas of the country (and world) deal with different kinds of pests. For the Charleston, SC, area (and most of the southeastern U.S.), we deal with aphids, whiteflies, flea beetles, Japanese beetles, hornworms, cabbage loopers, corn earworms, diamond back moths, army worms, bean weavils, stink bugs, squash vine borers, and leaf-footed bugs, among others. That’s quite a list! (It’s the price we pay for having three major growing seasons.)

There are two main ways to utilize biological controls:

  • Pathogens – Viruses or fungi that are enemies to the pests
  • Natural enemies – Beneficial insects (lacewings, lady bugs, ground beetles, assassin bugs, hover flies, robber flies, parasitic wasps, etc.), birds, amphibians, and reptiles.

We can’t do much about pathogens, but we can assist natural enemies as follows:

  • Conservation – Do not kill natural enemies. Get to know what your area’s beneficial insects are. Some are predators that actively hunt pests, while others are parasitoids. Parasitoids are the most effective natural enemy because they lay eggs on the host (pest), and the larvae develop inside the host, preventing it from reaching maturity.
  • Augmentation of population – You can actually purchase beneficial insects to put into your garden. However, you can’t make them stay!
  • Enhancement of population – This is done by creating or enhancing the natural habitat enjoyed by beneficial insects. Plant the flowers they like, for example.

Please remember that the goal is not total eradication of the pest. What will happen with biological controls is cyclical. You will have an infestation of pests. The beneficial insects (or animals) will arrive to munch on the food source your garden is now providing. As long as the food source remains, the beneficial insects will remain. Once the pests are gone, the beneficial insects will seek other food sources. The pests will slowly return (if it’s still the season for them) as the beneficial insect population decreases. And then the cycle will begin again. This is nature at its best.

INTEGRATED PEST MANAGEMENT: CHEMICAL CONTROLS

In most people’s minds, the term “chemical controls” brings to mind hard pesticides, but “soft” or organic products are also chemical controls. In IPM, soft products are recommended when a chemical control is needed. The most common soft products are:

  • Bacillus thuringiensis or Bt — This insecticide is made from a soil-dwelling bacterium. When sprayed on crops, insects ingest the Bt, which then causes the insect to lose its appetite, starving it to death. This works well on caterpillars, for example, but don’t use it until the number of caterpillars on your crop is above the tolerable level.
  • Insecticidal soap – This is a contact control. Spraying insecticidal soap directly on an insect that breathes through its exoskeleton (like a squash bug) suffocates the insect.
  • Neem oil – Neem oil comes from an evergreen tree and works well on chewing and sucking pests. The neem oil interferes with the insect’s nervous system, causing it to not eat or reproduce. Do not spray neem oil on plants in direct sunlight; apply during early morning or late afternoon so the plant won’t burn. Also, do not use neem oil when temperatures are too hot or when the plant is stressed from too much water or drought. If needed, reapply after a week or after a good rain.
  • Spinosad – An organic pesticide that has a semi-broad spectrum of use. Use this as a last resort.
  • Pyrethrin – Natural pyrethrin is made from a chemical in chrysanthemums and has a broad spectrum of use. It is not UV light stable, so spray in late afternoon. Use this as a last resort.

When using one of the above products, be sure not to use the same active ingredient back to back, even if they are organic. If two products will thwart the same pest, use one product for the first application then use the other product during the following week’s application. Changing it up will help prevent resistance in pests.

NEVER use the following chemical controls in your garden:

  • Synthetic pyrethroids (chemical names ending in “thrin)
  • Neonicotinoids (very toxic to bees)
  • Organophosphates
  • Carbamates
  • Sevendust – kills bees in the hive

All of the above pesticides build resistance in pests and should not be used.

INTEGRATED PEST MANAGEMENT RECOMMENDATIONS

Integrated pest management recommends several means, working together, to achieve a balance in the garden while helping crops to survive pest outbreaks.

  • Scout! Know your plants and watch daily for insects (good and bad).
  • Create habitats for beneficial insects, birds, and other natural enemies. Let nature do its job.
  • Try companion planting and farmscaping.
  • Avoid broad spectrum insecticides. Use only “soft” or organic products when you must, but use them sparingly.

The best pest management is helping nature to do the work for us.

MORE 2014 CAROLINA YARD GARDENING SCHOOL ARTICLES:

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What methods do you use for pest management in your garden?

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