We are all critically dependent on pollinators for our food, whether we grow our own or buy it at the market. Pollinators are responsible for production of nearly 75 percent of the plants we eat. That translates to one in three bites of the food and drink we consume daily.
Take a moment to consider how radically our diets would change if we were to become primarily reliant on wind-pollinated crops such as wheat and corn. Many of our fruits and vegetables would disappear from our dinner plates. So would meat, as the animals are reliant on pollinated forages for much their diet too. We’d have no more fruit juice to drink. Would we become ever more reliant on corn syrup sweetened beverages? It’s not a food future most of us would like to envision.
Pollinator Awareness Month
June is Pollinator Awareness Month, with National Pollinator Week celebrated during the third week of June (20th – 26th, 2016). It is a good time to reflect and remind ourselves of the part we play in protecting or destroying our pollinator population. As fruit gardeners in temperate North America, we think of bees, mainly honey bees, as our primary pollinators. However, there are many more pollinators, about 200,000 species actually. Approximately 1,000 of these species are vertebrates — birds, bats, and small mammals. In tropical climates and other regions of the world, these other pollinators can play a roll in fruit production as well. The remaining 99.95 percent of the pollinator population are beneficial insects — bees, wasps, beetles, flies, butterflies, moths, and ants.
Bees as Primary Pollinators of Fruit Crops
Let’s focus on the primary fruit pollinators: bees. Although honey bees are the first to come to mind, various studies have observed that there are over 150 species of bees present in commercial orchards and berry plantings at some time during the season. About half this number, 75 different species, pollinate either stone or pome fruits. In a given season, a core group of about 30 bee species will be present during bloom and responsible for the majority of pollination that occurs in orchards and berry plantings.
Beyond the traditional honey bee hive that most of us think of, different bee species have varied nesting habits. Many, about 80 percent of the world’s species, are ground-nesters. They are the predominant species that provide pollination in stone fruit (cherry, peach, plum) orchards. At least 4 species of Bumble Bees are common pome fruit pollinators, that avail themselves of old rodent burrows for nesting.
While ground-nesting bees are generally less common in pome fruit (apple and pear) orchards, other cavity nesting bees, often found along orchard edges, in old bramble canes, or pithy stems of mullein or elderberry plants are major pollinators. The Osmia species, or Mason bee, and the various carpenter bees are all in this group. They are more frequent pollinators of pome fruit orchards, emerging from their cavities too late for stone fruit pollination. Blackberries, raspberries, and pears that have too low a sugar nectar to be strong attractants of honey bees all benefit from the work of the various later-emerging Mason bees.
Why the Bee Decline?
Why has there been a major decline in honey bee populations in the last decade? Some answers may be obvious and perhaps part of nature’s normal cycle of population peaks and valleys. Colony collapse disorder, Varroa mite infestations, and other hive diseases have certainly been at the forefront. Sequencing of the honey bee genome has shown them to possess a greatly reduced number of genes that code for detoxification enzymes, when compared to other insect genomes. It is these detoxification enzymes that make insects more resilient and resistant to diseases, viruses or chemical substances.
Possible climate change and weather patterns likely also play a part. The recent unusually harsh winters experienced in the northern United States and drought in the west and southwest make bee survival much more challenging. When certain plants that serve as nectar sources die as a result of these weather events, food source biodiversity diminishes. Water, of course, is critical for survival for all life.
General loss of habitat over time has been another contributor. As a line from a Joni Mitchell song of the 1970s says, “We paved paradise and put in a parking lot.” That leaves less habitat for ground dwelling pollinators. The advent of the manicured and highly maintained suburban lawn does likewise.
Several “environmental” groups, often using highly emotional rhetoric to spur their fundraising, have put a target on the back of our nation’s farmers and their use of crop protection pesticides without taking a look in the mirror to consider their own part in the situation. Certainly, we have undergone a major shift in pesticide use over the last century while trying to figure out how to feed an ever expanding population. As these highly vocal groups have railed against broad spectrum, environmentally persistent pesticides (and I am not saying those materials were good), they may have driven food producers and consumers to favor materials that were just as damaging or worse. Under the guise of safer, natural, or “organic” they have encouraged use of pesticides such as neem oil, pyrethroids, and spinosad that are all toxic to bees and other beneficial insects. Even the substances that beekeepers themselves applied for control of Varroa mite have been shown to have effects on reproductive capacity and longevity of honey bees.
What Gardeners Can Do to Help
It is unlikely that we can quickly and miraculously solve the complex problem of pollinator decline on a global scale. However, as individuals, we can take action toward solutions locally. As many small and disjointed pieces have created the problem, the power of many small efforts may provide the turnaround and solution. Here are some steps you as a gardener can take:
Plant for pollinators
- Diversity is important. The pollen and nectar of each plant species contribute different nutrients to the pollinators’ diets.
- Provide food sources that bloom throughout the season. This could include flowers, shrubs, and trees.
- Native or indigenous plants are most likely to provide the nourishment needed by the local pollinators. Consult these sources for some appropriate plant selections for your growing region:
- Xerces Society — Lists of regional, native species pollinator plants
- Pollinator Partnership — 32 detailed regional guides to establishing pollinators. This one is a bit trickier to find your region as it is classified using Baileys’ Ecosystem Provinces. I found northern Michigan in the The Laurentian Mixed Forest list.
Create favorable habitat
- Provide appropriate habitat. Materials such as mud or waxy leaves are often used for nest building.
- Build and place nest boxes for solitary bee species. Find how-to instructions here.
- Clean, safe water is as critical for pollinator survival as it is for our own. Fresh as well as muddy, mineral rich water can be provided in shallow containers or depressions so that pollinators can drink without drowning.
Reduce your impact
- Do your part to minimize urbanization and increase green spaces.
- Reduce your pesticide use by substituting more pollinator favorable cultural practices when possible.
- Know your pesticide. When you do choose to use one, select pollinator-safe choices.
- Use pesticides only according to label directions and apply when there will be no drift, typically early in the morning or near dark.
- Do not apply pesticides during fruit bloom. Be aware of any blooming ground cover where pollinators may be active and mow before application if necessary.
- Liquid formulations are generally safer for bees. If possible, avoid using pesticides that come in the form of dusts or wettable powders. Micro-encapsulated pesticides can be particularly dangerous as they are carried back to the hive like grains of pollen.
Educate and encourage others, especially our children
- If you would like to learn and understand more about bees, this publication, Bee Basics: An introduction to native bees, offers considerable information.