Article 4-3 Practice Prevention
Control Pests and Bring in More Good Bugs
By Sherri-Lee Mathers, Balsam Way Organics
In my last article I wrote about using beneficial insects instead of chemical pesticides and explained exactly what beneficial insects are, i.e. parasitic or predators. In this article I would like to give some more background on why and how beneficial insects fit into the overall gardening "scheme of things".
The buzzword nowadays is IPM or "Integrated Pest Management".
IPM is using all available tactics or strategies to manage pests so that an acceptable appearance and quality can be achieved economically and with the least disruption to the environment. With the goal of IPM to reduce the occurrence of plant problems and maintain insect populations and disease problems at levels where aesthetic and economic losses are tolerable. Rarely is pest eradication a goal nor is it possible. All economically and environmentally sound practices that help prevent or reduce plant injury are used.
The basic components of IPM are:
- Regular monitor and early detection.
- Proper diagnosis and identification.
- Determining the economic significance.
- Selecting management methods.
- North Carolina State University.
Note: They say to maintain insect populations and disease at levels where aesthetic and economic losses are tolerable and total pest eradication is not a goal. If you read my last article you would know why total eradication is not wanted, as you need to maintain a balance in order to feed the predator insects, for if they have nothing to eat then they will die off - and then what happens when a fresh outbreak happens with no predators for control?
Surprisingly, most of the best ways to control pests and diseases may not seem like controls at all. Organic gardeners look at their garden as an overall system that must be kept in balance so that no one pest or disease gets out of hand. Of course no one wants pests or disease in their garden. Yet at one time or another we have all had to deal with insects that eat holes in our prized flowers, favorite vegetables or fruit trees.
For some, and I am guilty of this in the past myself, we have "exterminated" the entire yard with a chemical to get rid of all those bad bugs. Little did I know that those pests that went after my garden were really only a small fraction of the total insect population around us, and I actually did much more harm than good. I managed to eradicate many of the beneficial insects that work as crop pollinators, pest predators and even plant-material decomposers. I wondered why my garden wasn't like the one that my grandmother had, with the bees buzzing around, the snakes in the grass and the ladybugs crawling around. It didn't take me too long to figure out exactly what I did, but now with many years of trying to balance, and I must admit I still don't have it 100% (I'm still working at it). I have a very busy yard, which I can enjoy watching. For a gardener it is much more exciting to watch the bees busily moving from plant to plant, especially the mason bees in the spring "swarming" the greenhouse than to be watching television (that is of course unless it is a gardening program). Long gone are the days when I was "afraid" of the bugs in the yard and wanted them gone. I now realize that they are my friends and work much harder than I do at the garden and my piece of paradise.
Insects aren't really high on most gardener's lists of favorite things, as it is much too easy to notice the bug-ravaged leaves of lettuce and ignore or take for granted the benefits of pollination and role of pest killing of the predators. Did you know that according to the USDA that 14% of all crops now are lost to insects and disease, interestingly they reported that 50-years-ago crop loss was only 7% due to insects and disease. But why has this number doubled in the past 50 years?
For three reasons:
- loss of soil fertility i.e. healthy soil creates healthy plants which are stronger and more able to fight off disease and insects;
- loss of insect habitat; and
- increased use of pesticides.
Therein lies our answer on "how to control pests". 1) Strong and healthy plants; 2) provide an insect habitat; and 3) eliminate the use of pesticides and let Mother Nature return her own balances and controls.
How does one go about providing an "insect habitat"?
Simple, provide plants that the beneficial insects like parsley, dill, fennel, marigold, mint and clovers. As well be sure that there is water available for them to get a drink.
Eliminate the use of pesticides: Here is what happens when we use pesticides: Insects that feed on plants reproduce at staggering rates and quickly surge to astronomical numbers. But the insects that prey on these pests reproduce more slowly and are generally far fewer in number. Now this is because a predators' food supply is less abundant (of course there is more foliage than bugs to eat), and it takes more energy for a predator to hunt than it does for a pest to graze on your favorite pepper plant. Therefore, there is less energy available for the predator to breed versus their prey - predaceous ladybugs don't reproduce as quickly or prolifically as its prey the aphid. Nature has always put this check in place, predators occur in much smaller numbers than their prey which makes them vulnerable to extinction when conditions are bad.
Now to compound this, there is a time lag between the breeding of prey and their predators. For instance an outbreak of aphids can reach damaging proportions in just a week or two (here is an interesting fact, aphids give birth to already pregnant young).
Ladybugs can be on the scene quickly and have the ability to decimate this aphid population, however, if there isn't enough habitat for them to shelter and breed, there will not be enough of them to take control of the outbreak of aphids.
The good news is that with an abundant food source and good conditions the ladybugs will breed, but they need time to lay and have their eggs hatch. As I mentioned in the last article the ladybug larvae are absolutely voracious eaters with no wings to fly and find a mate thus no distractions from their dining. But remember - there is that lag between egg and larvae in which the aphid numbers can build to an astounding rate. This is the stage when we as gardeners are generally guilty of interfering with nature's balance.
Most of the time this is when we have finally noticed the outbreak and try to control the aphids by spraying. This generally will give a knock back of aphids, but also a knock back of the ladybugs and especially their larvae that are more susceptible than the adults are to interference. Now the remaining ladybugs have just had their food source knocked back to almost nothing and their survival is being threatened. And of course now - we gardeners seeing any aphids whatsoever, try to take matters into our own hands again and "eliminate" them. The ladybugs survival is being threatened again - depending upon the method used, but don't forget they need to eat. The remaining ladybugs either fly off in search of "greener grazing pastures", or die off. It only takes a few rounds of this cycle to eliminate the ladybugs. Guess what - it only takes a few aphids to build up those populations and lucky them, they are now predator free and can multiply unchecked.
We have eliminated nature's safeguards and thus put our gardens and crops in jeopardy. It is imperative that we restore the natural balance in the garden, by providing insect habitats and not chemically interfering with Mother Nature. This is possible to obtain in indoor gardens as well as in our outdoor garden. How?
Practice Prevention, Control Pests and Bring in more Good Bugs
Practicing Prevention is the best thing to do that will save you both time and money and is really quite simple.
- Build up your growing medium - again, I must stress healthy plant are better able to ward off pest attack
- Grow a wide variety of plants. When you plant a large amount of a single plant it tends to draw insects like magnets. When you intermix some of the flowers in with your vegetables it confuses pests and they have trouble finding their favorite snacks. Many people tend to mix in a few marigold plants with their tomatoes; as well these provide important insect habitats.
- Plant healthy plants. Don't import problems from a garden center or nursery. An aphid-infested "bargain" is really no bargain when it spreads to the rest of your plants.
- Keep your garden area clean. Pests find hiding and breeding places beneath old leaves and stalks, so be sure to regularly remove debris.
- Be sure to change your clothing when you come from a nursery or garden centre - or someone else's garden. Believe it or not this is how many pests get transmitted - they hitchhike home with you on your clothing. As well, if you know a friend has a pest infestation, politely try to keep them out of your garden as they are carriers of pests and you could shortly have the same infestation that they have.
- If you have a greenhouse, be sure to use barriers i.e. have the windows covered with screens - this will help eliminate some of the larger insects from coming in.
- Keep your greenhouse conditions at optimum for beneficial insects. Most beneficial insects thrive in humid conditions whereas pests have a tendency to thrive in dry conditions.
- Purchase beneficials early in the season to build up populations and keep outbreaks from occurring. Every year to avoid soil pests, I introduce beneficial nematodes right at the start, when I start my seedlings. The populations grow and are moved to protect the plant each time it is transplanted.
- Use Yellow or Blue Sticky Cards to monitor the amount of pests around your plants.
Did You Know that just like sticky cards bright colorful clothing has a tendency to attract pests that you can carry back to your garden?
If you practiced prevention and still have pests some ways to control them as follows:
- Spray them with Water. Blasting spider mites and soft-bodied insects like aphids can knock them off the plant or even kill them outright. Be sure to spray the underside of the leaves.
- Handpick them. Some insects are big enough to pick off your plants like caterpillars, beetles and slugs. Squash them immediately or drop them in a bucket of soapy water. Soapy water causes the pest to sink and drown instead of crawling out when you aren't looking.
- If you have a small infestation, try a pheromone trap - this is a commercially produced trap that is coated on the inside with sex hormones and floral fragrances that will attract specific insects who then can't get out. Be aware, these work great indoors, but if you try it outdoors it may attract a bigger problem to your garden area.
- Purchase beneficials specific to a problem to outnumber and keep the pests in check. I.e. persimilus to control spider mites. Remember that you generally need to purchase more than 1 application of beneficials to get control of a situation. And be sure to provide these beneficials with a habitat in which to live and multiply. Interplanting mint, dill, parsley, and marigolds in your crop provide excellent habitat for beneficials.
- Another excellent and natural pesticide is spiders (I must admit I am still trying to get over being squeamish when I find one running away after I have disturbed it.) Provide a "spider mulch" for them to hide in, such as straw or dried grass - they will be attracted and set up house and keep other pests under control. Remember you are setting up a mulch around the plants, now allowing debris to accumulate.
- As a last resort, use insecticides or fungal sprays. Try to use the least toxic ones which will do minimal damage to the beneficial insects and other animals, the environment and of course your own safety.
After practicing prevention and control, you must outweigh the costs of using chemicals. s it really worth it to purchase $20 worth of chemicals to fight off some aphids from your flowers? To some it is, especially when there is the possibility they will move from the flowers to vegetable area - sometimes it is easier to cut back the plant or remove the plant all together. It seems drastic, but again you must weigh out the financial and environmental impact of what you are doing.
Each year when I plant, I always plant more than enough for my family, the insects and "others" in my yard. I use a 30% rule, 30% for the pests, 30% for the birds and the other warm and fuzzies in the yard (a rabbit managed to get at one area of lettuce this year and in 2 days feasted it all down, luckily I plant 3 beds of lettuce spread out around the garden and house - this way, he only got 1 bed and I still have 2 others) and then 30% for us. The remaining 10% is a bonus to whomever gets at it first!
Although many commercial growers want to optimize their dollar and get 100%, it is really unrealistic to do that without having an impact on the environment, only you can decide for yourself which is the safest way to grow.