When my husband and I moved into our house it had been empty for several years, and we had a scorpion problem. We treated inside and out with a recommended nonspecific pesticide that was expected to last about three months. When it began to wear off, we no longer had a scorpion problem; we had a cricket problem, and a big one. Crickets reproduce much faster than scorpions (and everything else that eats them), and this experience was an excellent demonstration of what happens when you wipe out the good bugs with the bad ones.
Insect infestations are rarely a problem in nature unless a pest spreads into territory where there are no natural predators to keep it in check. We recreate this situation any time we nonselectively kill the insects that live in our yards. Instead of getting better, the situation often gets worse when pest insects reproduce quickly before their predators are able to catch up.
Even though scorpions still creep me out, I’ve learned that they’re one of the many beneficial bugs that help with pest control. Beneficial critters come in all kinds of shapes and sizes (insects, arachnids, animals, and even bacteria), and most of them are far less creepy than the scorpion. They help us pollinate flowers and eat the insects that we’d rather not have around.
Giving up broad, nonspecific pesticides and encouraging (or even introducing) beneficial animals or insects is part of an Integrated Pest Management (IPM) approach to gardening. Rather than trying to eliminate pests, the goal of IPM is to mitigate them with the help of their natural predators, a hard spray of water from the hose (to help reduce large populations), and maybe some insecticidal soap when something gets out of hand.
For example, one great IPM approach to dealing with pests is to attract more hummingbirds by incorporating some of their favorite flowering plants into your garden. After enjoying some nectar, they’re likely to stick around for some aphids, flies, leafhoppers, weevils, small beetles, mosquitos, and gnats. They also really love spiders, and use spider webs to build their nests, so you definitely need some eight-leggers around if you want hummingbirds to nest nearby.
The more I learn about who eats or uses what in my garden, the more I understand that there’s a lot more to the world of beneficial critters than the well-known insect predators like ladybugs and praying mantises (though there’s no doubt that these are fantastic insects to have around).
If you want to be pleasantly surprised by the staggering variety of biological controls you’ve probably never heard of, and how they can benefit your garden, take a few minutes to look through an ARBICO Organics catalog or visit their website. This Baja Arizona company (ARBICO stands for Arizona Biological Control) has been providing organic solutions to customers all over the world for more than 30 years through its mail-order system. The company operates a 10-acre facility in Catalina, where some of its beneficial insects are raised, and it has a small retail store in Oro Valley that is packed with cool organic products and helpful staff.
Terri Towne has worked at ARBICO’s retail location for 20 years; she says that one of their all-time top sellers is a microscopic worm-like creature called a nematode. This tiny organism is really good at parasitizing insects that live out part of their developmental stages in the soil, but it doesn’t limit its diet to strictly soil-borne pests. ARBICO’s spring catalog lists 66 individual pesky insects that are controlled by just three species of nematode.
I was expecting their top-seller to be adorable ladybugs. But Towne said that the top-selling products at ARBICO are actually wasps. ARBICO calls them Fly Eliminators, and they’re much smaller than the wasps that most of us are more familiar with. Fly Eliminators are only about 1/8-inch long; they don’t sting animals or people; and they don’t harm our plants. The female wasps spend their time burrowing anywhere that flies might lay eggs, seeking out developing flies in their pupal stages. When the wasp locates an unlucky fly pupa, she injects it with her eggs, and it soon becomes the first meal for the Fly Eliminator’s offspring, stopping flies before they ever hatch into annoying adults. The whole process may sound a bit disturbing, but for me it’s not nearly as scary as sprinkling poison around my chickens, which peck at every single thing they see.
Of course, the well-known predator insects can be purchased, too, and ladybugs are a popular choice. These little workhorses eat 50 to 60 aphids daily in the larval stage, and 5,000 aphids as adults. They also eat a variety of other pests such as beetle larvae, thrips, whitefly, and mites.
Timing is important when introducing ladybugs or other beneficial insects into the garden. Releasing them at the wrong time of day or the wrong time of year might result in their immediate departure for cooler temperatures at higher elevations. In addition, it’s sometimes necessary to release more than one batch, or to keep a continuous schedule of applications.
If you’re not into buying your garden friends, you can always invite wild critters to volunteer their services by leaving some of their favorite insects alone, and by planting some of the things that they might need for supplemental pollen, nectar, or shelter.
Using an IPM approach also means that some of what we’re growing gets shared with some bugs from time to time. A few caterpillars won’t do much harm to an established citrus tree, and you get some butterflies in exchange. And in my opinion, butterflies are a whole lot more fun than poison.
By this time of year, there are way fewer holes being dug in the low-elevation gardens of Baja Arizona. Many of us are already spending way more time harvesting and watering than planting new veggies. Still, there are a few things you can get in the ground if you’re quick about it!
Sweet potatoes are the only thing that can be planted across all elevations this time of year. Lower elevations have until around mid-June, but those above 3,000 feet have just a short window of time to plant them around mid-May.
Those above 1,000 feet can plant okra, soy beans, and summer squash. If you’re above 2,000 feet you can add cantaloupe, cucumber, eggplant, muskmelon, pepper plants, pumpkin, and watermelon to everything above.
As we move into the higher elevations of Baja Arizona, our options open up even more. If you live around 3,000 feet or higher, you can plant everything previously mentioned as well as bush beans, lima beans, pole beans, beets, broccoli, celery, collard greens, sweet corn, mustard, parsnip, potatoes, radish, salsify, winter squash, and tomatoes.
Cabbage, rutabaga, endive, kohlrabi, cauliflower, and spinach can also be planted at the highest elevations of Baja Arizona, above 4,500 feet. ✜
Amy Belk is a garden writer and photographer, a certified arborist, and a certified nursery professional who has been learning from her garden for 15 years. She and her husband homestead on a little piece of the desert in the heart of Tucson.