A week or so ago we were ambushed by a surprise striped cucumber beetle infestation. One morning we were free and clear. The next afternoon I noticed a swarm of dragonflies, swooping around the garden. They were gorging on the horde of striped interlopers that were raiding our cucumber and summer squash seedlings. The dragonflies were barely making a dent in the marauding army of beetles.
There are not a lot of options for fighting cucumber beetles, aside from applying horrible nasty insecticides. (Something we obviously won’t do.) Floating row covers would have protected the seedlings, however it’s expensive and impractical to cover over 1000 feet of crops. Instead we went to war. Pinching. Plucking. Pinching some more. We sprayed the plants with a homemade hot pepper spray -staying upwind – in an effort to make the plants a little less tasty. We released a host of very hungry lady bugs intent on dining on their smaller cousins. Then we pinched some more. It was a beetle holocaust. And it took hours. (And folks wonder why organic produce is more expensive than conventional!)
It seems we’ve won the war. The beetle population has been controlled and while there was some damage, it looks like most of the plants will recover. However, it got me thinking about Integrated Pest Management system. IPM is something that all sustainable farmers should utilize; it’s an environmentally responsible approach to pest management that relies on a combination of common-sense practices. Instead of reactively spraying chemicals to kill pests, in IPM, a grower takes action to prevent infestation, observes patterns of infestation when they occur, and makes a careful decision on how to intervene (without dangerous toxins & petrochemicals) when it becomes necessary.
The principals of IPM are pretty simple.
- Acceptable Pest Levels. It’s important to recognize that a few bugs are not an infestation. Wiping out an entire population of any species in not only extremely difficult, but environmentally irresponsible. Instead, I set a threshold of non-threatening pest levels and acceptable losses.
- Preventative Measures. In any system being proactive is clearly better than being reactive. Selecting heirloom plants with disease resistance and maintaining healthy crops is a great first step. Removing diseased or infested plants and disposing of them properly reduces spreading. Appropriately rotating crops and managing potential sites where pests will overwinter reduces recurring infestations. Green walls to avoid potential contamination from less responsible neighbors, mulching and companion planting can also work well to help prevent infestation.
- Monitoring & Education. I’m not an entomologist, however I’ve learned to identify a wide variety of insects. Many organisms are innocuous, and some are even beneficial and it’s important to know which is which. It’s also important to know the lifecycle and behaviors of possible pests.
- Controls. If pest populations exceed the predetermined threshold, control becomes necessary. Mechanical control, while tedious is extremely effective. There hasn’t been a bug yet that has evolved to resist squashing! Biological control, such as encouraging or releasing beneficial insects is also a great tool. There is a wide variety of beneficial insects that can be purchased online, from familiar ladybugs and praying mantises to the lesser known lacewings and spined soldier bugs. In extreme cases, organic controls are used – like kaolin clay barrier sprays.
The cornerstone of IPM is observation and education. Knowledge is power and a simple mistake can cause potential problems. For example, the brown marmorated stink bug is a well-known agricultural pest. It feeds on a wide range of fruits and vegetables. However, the spined soldier bug is an enthusiastic predator of gypsy moth caterpillars and the larvae of very nasty beetles such as the Colorado potato beetle and the Mexican bean beetle, making it a rather useful garden insect. However, stink and soldier are extremely similar looking. I hang my head in shame knowing that in blissful ignorance I used to squish the good guys, right along with the bad!
Insects are an undeniable part of every gardener’s life. There are approximately a million identified species of insects in the world; they’re here to stay. It’s our decision how to deal with them, but having an IPM system in place can certainly make organic gardening less stressful!
