Watch Out for New Garden Pests Heading This Way

Watch Out for New Garden Pests Heading This Way

Recall for a moment the sense of excitement you feel while strolling through your garden on a summer morning. You take in the colors, the scents, the daily changes as the season flows. Gardeners make observations constantly, whether consciously or subconsciously. My new dahlias are finally in bloom! The bumblebees love this bee balm. That hydrangea we fertilized looks particularly vibrant this year. You probably make observations on the less desirable aspects of gardening as well. I need to do something about the rust on our crabapples. These poor roses have terrible black spot again. The Japanese beetles are awful this year. Or the inevitable: But those were supposed to be deer resistant!

As the owner of Tips Tree Planting, a website dedicated to gardening tips and advice, I have had the opportunity to explore various landscapes and gardens. During my travels, I often come across new pests and diseases that could potentially threaten our own gardens. It is crucial for us as gardeners to stay informed about these potential threats and learn how to manage them effectively. This knowledge not only helps us combat new plant problems but also equips us with solutions for similar issues that may already plague our plants.

Learning about innocuous insects has merit too

While exploring a grove of alder saplings in the United Kingdom, I noticed pairs of glorious metallic blue beetles munching on leaves alongside clusters of tiny caterpillars. These beetles, known as the alder leaf beetles, and the caterpillars, identified as Nematus septentrionalis, a type of sawfly, are not currently pests in the United States. Although they can partially defoliate alder trees in the UK, they rarely cause severe harm to the trees. However, understanding and learning about these seemingly harmless insects can provide invaluable insights and help us make informed decisions if the need arises.

An ounce of prevention is worth a pound of cure

Watch Out for New Garden Pests Heading This Way

During my UK adventure, while heading towards the Royal Horticultural Society Garden Wisley, I came across a cautionary sign that caught my attention. The sign warned about the presence of the oak processionary moth in the area, emphasizing the potential harm it could cause to humans, animals, and oak trees. This particular moth species was accidentally introduced to the UK from mainland Europe through the movement of live plants. Its impact on human and animal health, as well as oak trees, led to the implementation of new biosecurity regulations and importation safeguards. Fortunately, we do not yet have the oak processionary moth in the U.S., but we do have the browntail moth, which has caused lung irritation and rashes in the past. This highlights the importance of prevention and stricter biosecurity measures to avoid inadvertently introducing harmful insects into our gardens.

A serious problem on the horizon

Watch Out for New Garden Pests Heading This Way
Watch Out for New Garden Pests Heading This Way

In London, I encountered a caterpillar that poses an imminent threat to the North American landscape – the box tree moth. Its devastation was evident everywhere – from citywide planting boxes to renowned gardens like Chiswick House and Fulham Palace. This pest, native to East Asia, was accidentally introduced to the UK and Europe and rapidly spread across the continent without natural enemies to control its population. In 2018, it was discovered in Ontario, and in 2021, it made its way to several states in the U.S. Import bans and eradication programs were implemented to mitigate its impact. The caterpillar feeds on all species of boxwood, leaving behind frass, silken webbing, and bare twigs. If left unchecked, it can even kill healthy boxwood plants. Learning from the management strategies employed by gardeners in the UK, such as pheromone disruption and the use of biological insecticides, will be crucial if the box tree moth becomes established in the U.S.

How to defend against new plant pests and diseases

Watch Out for New Garden Pests Heading This Way

As gardeners, we play a crucial role in combating plant pests and diseases. Early detection is key, so if you come across any bothersome pests or diseases in your garden or area, take photos and report them to your nearest Cooperative Extension Service immediately. Your actions can make a significant difference in preventing the spread of devastating plant and ecological problems. Stay informed about the latest threats in your area by signing up for email alerts from your Cooperative Extension Service or your state’s department of agriculture or environmental protection. Following these organizations on social media can also provide helpful information on plant pests and diseases.

Remember, the next time you visit a new garden, make sure to look closely, observe any pests or diseases, and learn from them. The knowledge you gain can be invaluable in maintaining the health of your own garden. If you want more gardening tips and advice, visit Tips Tree Planting for a wealth of information to help you become a successful gardener!

Matthew Borden, DPM, is a plant health consultant specializing in diagnostics and integrated management of landscape plant pests and diseases.

Photos, except where noted: courtesy of Matthew Borden