By Geoff Wilson MSc, PAg, Provincial Specialist – Apiculture, Prince Albert
Very few things in life are free, however, the agricultural industry has millions of free workers in the form of insects that help producers daily. Protecting and promoting beneficial insects can provide great rewards for the farm, including increased yields and returns.
Many crops benefit from pollination. While some producers rent bees (e.g. hybrid canola production, alfalfa seed, fruit production, pumpkins, cucumber) most of the value from pollination is provided by bees and other insects for free.
One example of a crop that benefits from both rented and free pollination is canola.
- Every hybrid canola seed planted in Saskatchewan is the result of insect pollination, making bees an essential part of the canola industry. Without bees, the current way of producing hybrid canola would not exist.
- Although canola in a production field can produce a crop without pollination, pollinators have been shown to increase yields by up to 20 per cent. This free pollination service has a great potential to increase yields for producers.
Beneficial insects (e.g., lace wings, lady bugs, parasitoid wasps, beetles) help reduce damage to crops by feeding on pests. When pest pressures are below thresholds, it is often these beneficial insects that are keeping them under control. If the insect pressures are above economic thresholds, treatment becomes necessary, however, when pressures are below the thresholds, treatments may do more harm than good by killing the beneficial insects.
How to Promote and Protect Beneficial Insects:
When pest numbers exceed the economic thresholds, treatment is needed to protect the crop. However, there are always options to reduce the impact on your beneficial insect populations.
- Use economic thresholds for treatment decisions. If the insect pressures are too low to cause economic damage, or the cost of the insecticide application is more than the return from the application, do not spray.
- When the decision to apply an insecticide has been made, choose one that will work for your pest problem, but also a product that has lower toxicity to bees and beneficial insects.
- Apply insecticides between 8:00 p.m. and 8:00 a.m. The activity of pollinators greatly decreases during this time period and by spraying while the pollinators are out of the field, there is less risk to damaging the beneficial insects.
- Always apply the pesticide according to the label. Label directions are meant to improve effectiveness while mitigating risks. One of the risks mitigated is environmental health, including protection of beneficial insects.
Another simple, hands on method available to promote beneficial insects is to improve the habitat. Approaches include:
- Leave non-tilled areas as nesting sites and as a source of food. Field borders, ditches and old homesteads are key sites for many of these insects.
- Use practices that reduce drift when applying pesticides. Applying the product only where needed may allow flowers to grow which provides forage for pollinators when the field may not be in bloom, and reduces the chances unintentionally spraying the nesting sites or bee hives.