Almost every day in our amazing world, I come across an insect I have not seen before. Usually, this is followed by excitement and the snapping of multiple photos with my camera. When I first started into horticulture, years ago, I had no idea the impact insects would have on my work and career. I knew a few back then, the obvious ones like praying mantids, lightning bugs, and grasshoppers; but there are thousands that I have seen and had no idea what they are. Being asked to become a consultant was the best thing to happen, I began to broaden my horizons and learn about the insects and how they affect plants.
There are three categories for describing insects in the horticultural sense; pests, pollinators, and beneficials. Normally, beneficials would include pollinators, but for this talk I will separate them out. There are many different orders and families of insects and each has different identifying characteristics and life cycles. Some, like true bugs, start with an instar after hatching, then a molting process, and then another before becoming an adult. Caterpillars will grow as they feed and when the time is right they will form a chrysalis and turn into a moth or butterfly.
Pest insects include all insects that eat plants; these often are the caterpillars of pollinators. In home and commercial landscapes, I tend to allow a certain number of caterpillars per plants, depending on the pollinator they turn into. There are some species that only lay a few eggs at a time, and need protecting from the overuse of insecticides. Others, such as bagworms, may lay several hundred eggs at a time, causing mass damage to the plants the affect. Some pests pick only on a certain family or species of plants; while others such as bagworms, brown marmorated stinkbugs, and grasshoppers feed on a wide range of plants.
Pollinators include some pests, but are mostly considered to be bees, wasps, butterflies, moths, and flies. These insects are responsible for the pollination of flowers all across the landscape and in gardens and orchards. Some are brightly colored like Monarch butterflies or Alianthus webworm, while some are dull or only fly at night. Most folks do not realize that wasps are pollinators; I sometimes see them more than honeybees on certain flowers. Protecting pollinators is an important step in producing fruit and seeds for the next generations. Timing and overuse of insecticides are the greatest threat to our pollinators. Most people tend to worry about honeybees and Monarchs, but ALL pollinators need to be protected.
Beneficials include parasitic wasps, assassin bugs and like, and insects that eat other insects. Praying mantids are probably the most recognized beneficial, but than can be a nuisance too, willing to eat anything that wanders by them, even hummingbirds! Parasitic wasps can be the most interesting to find at work, because they are tiny and hard to see, but you can find caterpillars laid with rows of their eggs. The eggs will hatch and the wasp larvae will feed on the live caterpillar until they have consumed it. Also, many of the pests have attackers that look just like them or are just as hard to see. Mealybugs, a pest, have a beneficial called the mealybug destroyer feeding on them. Most people also don’t realize that wasps are very important to the landscape; they pollinate and will carry off caterpillars to feed their larvae.
Learning about insects can take a lifetime; explorers are still finding new ones. For a landscape consultant, it has become very rewarding experience and I hope all of you take time to see what is lurking in your garden!