Spring has sprung and with newly expanding foliage and warmer temperatures, the familiar sights, sounds, and smells of our desire to have a pest-free landscape are everywhere. Be it treatments to our lawns to make them dark green and weed-free to the whir of backpack blowers putting out clouds of mosquito control products, we are constantly surrounded by pesticides that are being applied in an attempt to fix a problem that may be occurring around us. While the vast majority of these applications are done in a safe and highly regulated manner, it does not always mean that there are no side effects to these treatments. These products and their applications are likely to pose very little threat to humans and the other vertebrates in the landscape but that is not the case when it comes to off-target invertebrates that share our landscapes.
Most pesticides are somewhat selective in what they control or kill but it is highly likely that no matter how precise a chemical is, insects and other invertebrates posing no harm to you or the landscape can be killed. While this is not too large of a problem as populations can bounce back relatively quickly, it does leave a void in the natural cycle of the landscape which allows for opportunistic and usually damaging insect populations to boom. As non-target and beneficial insects slowly recover and fill the void, it is often too late for nature control to begin as the pest population has a head start so damage begins to appear in the landscape. This often triggers a visual cue from the plants that damage is occurring and the cycle likely begins again with the need for additional treatment, once again causing a population crash amongst beneficials and pests alike.
Once a landscape becomes locked into a treatment cycle, it can be very hard to simply stop in the middle of a growing season so it is best to begin a new approach with a new growing season. I personally find myself in the conundrum of how to keep my vegetable garden and landscape healthy with limited pests and am taking the opportunity to try a new approach this year. I have always used organic insecticides but they are quite often broad-spectrum and kill far too many off-target insects so most of them are off my list as well this year. With a majorly diminished arsenal to keep my veggies healthy and productive, it seems that the addition of beneficial insects and mites will hopefully be the answer to my pest problems. Instead of killing indiscriminately, a properly selected beneficial can be living, breathing, seek-and-destroy predators that will only affect very selective pests.
A small microclimate in my landscape warmed enough this spring to cause a major Two Spotted Spider Mite outbreak with damage spreading quickly on the affected plants. Using a jeweler’s loop, it was possible to determine the exact species of spider mite which allowed for the selection of the correct predaceous mite to eat not only the damaging adults but also their eggs. When the outbreak is under control, the predaceous mites can simply move to a different location in search of another meal or will simply die off leaving no trace on the affected plants. This pinpoint accuracy allows for very selective pest control, almost eliminating off-target control, and boosting the native populations of beneficial insects on my property.
Nearly every year there is also an outbreak of cabbage worms and whiteflies on all of my brassicas which makes warm-season kale and collards impossible in my garden. I am hoping to change that this year with the introduction of convergent Lady Beetles (Ladybugs) and Trichogramma brassicae wasps which are specific predators of cabbage worms. The Lady Beetles are voracious feeds both in their larval and adult stages, eating nearly any soft-bodied insects they can find. While they are much less selective, it is of little concern as most soft-bodied insects in your landscape and garden are pests that damage plants. The Trichogramma wasp is the opposite as they lay their eggs only on caterpillars that damage Brassicas, which then hatch and parasitize the damaging caterpillar, eating it from the inside out!
A very damaging pest that has made quite a showing in Richmond over the past two to three years is the invasive Crape Myrtle Bark Scale. This soft-bodied scale insect appears to be the first pest in our region that can overrun and kill a Crape Myrtle. While this pest can be easily killed with many conventional and organic insecticides alike, I will be watching my five Crape Myrtles carefully for any signs of infestation, and when (not if) it appears, I will be purchasing Lady Beetles or Green Lacewings to help keep the population from growing out of control. They will help me keep the trees healthy and clean while I don’t have to worry about my neighbor’s honey bees that like to feed on my Crape Myrtles.
The hardest part of adding beneficial insects to your pest control routine is that it takes more forethought and planning than simply spraying a chemical. With beneficials being so selective in what they control, it is important to know and understand what type of pest you are trying to control. It is also important to ensure that beneficials are introduced before pest populations grow too large as they cannot deal with massive outbreaks. Finally, timing is key and many beneficials must be bought locally or overnight shipped and then released the same day to prevent death during storage.
If you are looking to utilize beneficial insects this year, they can easily be purchased online from growers and I had great success with Arbico Organics out of Arizona for my predaceous mite purchase. While they worked beautifully, I do cringe at my carbon footprint for the 2000 mites purchased as they were flown from Arizona to Richmond purely for my landscape. An even better way to help your garden and greatly reduce your carbon footprint is to buy locally as several different beneficial species can be purchased at Sneed’s Nursery in Bon Air. While these beneficials are likely still overnight shipped, by purchasing in larger quantities, nurseries like Sneed’s can massively reduce the carbon per insect as compared to my individual shipment. I look forward to inviting new guests to my landscape this year, even if it is only to push out other unwanted guests. With luck and some diligence on my part, I feel that I will be able to give my garden and landscape the care it deserves without sacrificing a healthy natural cycle around my home.