Tired of pests in the garden? A flexible, general use insecticide may initially seem to be an appealing solution to our garden woes. Neonicotinoids, a specific type of insecticide, can be used to control a broad range of pests over all parts of a plant (Goulson, 2013; Jeschke et al., 2011; Oliver et al., 2010). But do the risks of using these chemicals outweigh the rewards? We break down when general systemic insecticides are used, their environmental impacts and alternative, direct pest management strategies that reduce ecological harm, so you can have a pest-free garden without harming the helpful critters that live there.
Do you know what beneficial organisms are visiting your garden’s flowers? What beauties may be bathing in the dew of your lawn? Neonicotinoids do not kill a specific pest, rather, the chemical kills all invertebrates. Indiscriminate use of neonicotinoids can therefore remove a host of beneficial organisms from your garden while you try to rid yourself of a single pest.
Insects are the most sensitive animal group to neonicotinoids. However, chronic exposure to a pesticide inevitability leads to increasing resistance in pest species, producing stronger, hardier pest species. Beneficial insects are unable to so quickly adapt, and neonicotinoid use will lead to their decline. This matter is especially crucial for our pollinators, including both managed honeybees and wild pollinators that rely on treated crops and flowers. Even relatively low doses of neonicotinoids sprayed on plant foliage can translocate to pollen and nectar, reducing learning, foraging ability and homing ability in bees, and ultimately impacting the success of a colony (Goulson, 2013; Yang et al. 2008; Han et al. 2010; Mommaerts et al. 2010; Henry et al. 2012).
Loss of biodiversity threatens our ecosystem services, or, more blatantly, our food production system and landscapes. All pesticides will be harmful to non-target organisms to some degree, but we must balance the cost and benefit between us, pollination services and soil health. To sustainably manage biodiversity and ensure long-term ecological health of landscapes, gardeners should rely on biological and cultural methods of pest mitigation and use chemicals knowledgably and with discretion. In some cases, the responsible use of neonicotinoids has been an indispensable tool to save ecosystems, as is the case of hemlock wooly adelgid plague on southeastern hemlock forests
To responsibly manage your garden, start by identifying your pest, then research control methods and read your labels. Is that garden pest of yours really a big deal, or can you sacrifice a few leaves? Identification of a pest allows a targeted mitigation approach based on the specific lifecycle. Internet forums or bugguide.net are great places to get a quick ID of a potential pest. Try increasing airflow, changing your watering regime, picking off the pest or accepting that your plant is not right for its location. If chemicals are needed, read your labels. Look up the active ingredient and learn how it works, what it affects, when to apply and how to apply it (Goulson, 2013; Metcalf and Luckmann, 1994). When in doubt, please contact your local extension agent for help. The critters in your garden, and our ecosystems, will thank you.
Literature cited
Goulson, D. (2013) Review: An overview of the environmental risks posed by neonicotinoid insecticides. Journal of Applied Ecology, 50(4), 977-987.
Han, P., Niu, C.Y., Lei, C.L., Cui, J.J. & Desneux, N. (2010) Quantification of toxins in a Cry1Ac+CpTI cotton cultivar and its potential effects on the honey bee Apis mellifera L. Ecotoxicology, 19, 1612– 1619.
This summary article was created by Rachel Smith, April 2021, SBG Graduate Student and UGA Department of Horticulture.