Lady beetle release, Johnny's Research Trialing Greenhouse, Albion, Maine
" …Stephen Buchmann and Gary Nabhan wrote that, of the world's 94 major crop plants, 18 percent are pollinated by the wind, 80 percent by insects (92 percent of these by bees), and about 2 percent by birds. "
What Good Are Bugs , by Gilbert Waldbauer
When most growers think about insects, they are trying to figure out how to get rid of them. Insects, however, are an extremely diverse group — while some devour crops, others actually make farming easier. By turning our flowers into fruit ( pollinators ), attacking crop pests ( natural enemies ), and providing other ecosystem services , they help to make farms more profitable and sustainable.
The precise roles and relationships of many of these beneficial insects are still poorly understood by many farmers. By learning how to attract and support populations of beneficials, your work as a grower can be more successful. Let's take a closer look at how some of these insects benefit growers. Then we will outline the basic steps for successfully establishing long-term flowering "set-asides" to help support them.
Parasitoid wasp vs. tobacco and tomato hornworms
The parasitoid braconid wasp, Cotesia congregates, injects its eggs into the living body of both tobacco and tomato hornworms. The eggs hatch, and the wasp larvae consume the bodily fluids of the hornworm, eventually emerging through the pest, pupating, and leaving the caterpillar to its death.
Parasitoid wasp vs. common asparagus beetle
Anyone who grows asparagus is familiar with the common asparagus beetle. The grayish larvae, covered in their own excrement (the technical term for which is frass ) munch on ferns, rendering spears unmarketable and decreasing the plants' ability to photosynthesize and store energy. Like a band of warriors, parasitoid wasps can kill the majority of common asparagus beetles by parasitizing their eggs — in some cases up to 71% of them! This beneficial wasp not only lays its eggs inside of the pests' eggs, it also consumes eggs as an adult.
Hover flies, lady beetles & banker plants vs. aphids
The unchecked growth of aphid populations quickly reduces the marketability of crops. This sap-sucking pest can even transmit plant diseases. Healthy populations of beneficial insects help farmers keep these pests in check.
Lady beetle larvae , for example, consume 100–400 aphids during their development (around 23 aphids per day). As adults they continue to consume aphids at a lesser rate, and moderate population explosions by laying eggs in areas where aphid populations are increasing.
A host of other natural enemies play major roles in aphid control, including lacewings, ground beetles, and hover flies to name a few. The predatory larvae of brightly colored hover flies (also known as flower flies or syrphids), consume legions of aphids to fuel their growth into winged, nectar-feeding adults.
Another method of aphid control is to establish populations of certain aphid species that do not feed on the particular crops you're trying to protect, yet still provide food for natural enemies. Here at Johnny's Selected Seeds, we use banker plants to support these non-pest aphids, thereby maintaining healthy populations of aphid predators in the greenhouse.
Live releases of lady beetles, lacewings, and parasitoid wasps — all supported by flower plantings and strategic placement of banker plants — are all essential components of integrated pest management here at Johnny's Selected Seeds.
Ground beetles vs. weeds & pests
Ground beetles are another often unheralded farm worker. These cosmopolitan beetles in the family Carabidae consume weed seeds, in some cases decreasing weed pressure in the following year by 80–90%! Farmers can actively encourage the beetles' consumption of weed seeds by making appropriate management decisions. For example, recently shed weed seeds can be allowed to sit on the soil surface, where they are most vulnerable to predation, instead of tilling them in. Ground beetles are also opportunistic predators of many pests, including aphids, cutworms, armyworms, cucumber beetles, and more.
— The Forgotten Pollinators , by Stephen L Buchmann & Gary Paul Nabhan (2012)
Fat and fuzzy bumblebee queens can be seen early in the spring, looking for prime nesting sites to start a colony. Each queen's worker bees will visit flowers throughout the season, turning blueberry, raspberry, apple blossoms, and more into tasty, high-value fruit.
Crop pollination is often one of the major input costs of pollinator-dependant growers. Some farmers annually rent or purchase managed pollinators for crop pollination. Commercially available pollination options include honeybee hives, cardboard boxes of bumblebees, and small tubes of solitary orchard and alfalfa leafcutter bees. Pollinator-dependant greenhouse, high tunnel, and hoophouse growers commonly purchase commercial bumblebee colonies to enhance both the size and number of fruit produced.
Wild, unmanaged bees and other pollinators have been doing this work unbidden for millennia. In fact, in most crops throughout the world, wild bees contribute more to pollination than honeybees, providing a necessary, but free service to growers.These are only a small fraction of the beneficial insects hard at work managing pests, protecting the integrity of your crops, and turning flowers into marketable fruit in fields, gardens, hoophouses, and greenhouses.
One such strategy is the installation of permanent or semipermanent set-asides of flowering plants for pollinators, sometimes called "insectaries."
The best flower mixtures for this purpose contain both annual and perennial wildflowers, and provide pollen, nectar, and habitat for beneficial insects year-round. Once established, they fill the entire season with bloom so that at any given part of the year, beneficial insects can choose between two or three simultaneously blooming flowers.
Hover flies, parasitoid wasps, lacewings, predatory wasps, and a large number of other beneficials all require nectar as adults. Research has shown that flower-rich plantings not only attract these beneficial insects to your farm, but can actually increase their local populations, help to manage pest populations, and increase crop yields through improved crop pollination and pest control.
To help growers to take advantage of beneficial insects, Johnny's offers a selection of flower , herb , and farm seed varieties known to Attract Beneficial Insects . Included are several different mixtures of annual and perennial flowering plants that are designed to support natural enemy and pollinator populations.
- Beneficial Insect Attractant Mix . This seed mix contains flowers that are especially attractive to both natural enemies, such as sweet alyssum, cilantro, false Queen Anne's lace, fennel, and dill, and those more heavily used by pollinators, such as coreopsis, clover, bergamot and blazing star. This mix offers growers a broad approach to beneficial insect management, providing food for a large swath of both natural enemies and pollinators throughout the season.
- Bee Feed Mix . This seed mix targets pollinators by providing a season-long abundance of a variety of flowers that are especially attractive to bees. This type of flower mixture is especially useful when planted adjacent to crops that rely on, or benefit from pollination. Examples of such crops include orchards, small fruits, berries, tomatoes, squash, pumpkins, cucumbers, and melons.
Flower mixes are easy to establish, provided the grower follows some general guidelines. The steps outlined below are adapted from a University of Maine Cooperative Extension Fact Sheet coauthored by Eric Venturini, the Education Coordinator here at Johnny's.
The first step to successful establishment of small-seeded flower mixes is the control of weeds, especially weed seeds. A properly prepared seed bed sown to a perennial mixture of flowering plants can continue to provide beneficial insects with forage for 5–10 years only if weed pressure is minimized. In fact, if weeds are not controlled prior to planting, they can and will out-compete the slow-growing perennial flowers within the first year.
Methods that growers can use to drastically reduce the weed seed bank include stale-seed bedding, flame-weeding, soil solarization, topsoil removal, a combination of cover-cropping and stale-seed bedding, or if necessary, judicious repeat applications of herbicides. Even two or three cycles of stale-seed bedding in the spring prior to sowing a flower mix can greatly reduce weed competition and help to increase the longevity of the planting. See our article on Weed Management Basics to learn more.
Flowering mixes require very little fertility input. In wildflower plantings, the addition of fertilizers can actually cause more harm than good, by providing weeds with the materials that they need for growth without benefiting the sown species. We do suggest testing the pH of your soil to determine whether the addition of lime or sulfur is required. A pH that is between 5.5 and 7.0 should be adequate for successful flower establishment. Light shallow tillage to break up the soil structure prior to sowing seed will help increase germination and emergence.
Native seed drills, hydro-seeders, and spin seeders like the Ev-n-Spred ® are all effective tools for seeding beneficial insect flower mixes. Excepting extremely large areas, the Ev-n-Spred Seeder is a very practical option that can be easily used to seed plantings of up to several acres.
Due to the extremely small size of many of the wildflower seeds within these mixes, when broadcast-seeding, flower seed should be bulked with sand, vermiculite, or something similar to help ensure that the seed is distributed evenly throughout the planted area. After sowing, lightly rake the area with a landscaping rake.
Small-seeded annual and perennial flowers, especially wildflowers, require seed-to-soil contact to successfully germinate and establish. Compaction of the seedbed after sowing is extremely important for success. Culti-packers and lawn rollers are both very effective tools for pressing the seeds into the soil.
Once established, these mixes require very little care. During the first year, however, irrigating the stand with ¼ to 1 inch of water per week can help establish slow-growing perennials. We recommend mowing your flower mix once each year in the late fall, after the last flowers have finished blooming.
— Biodiversity Information System for Europe (BISE)
Learn more about ecosystem services from BISE