Spring is the season for invasive pests to begin their reproductive cycles. You will begin to see their presence and impacts through the summer and into the fall.  Some very destructive species have entered our ecosystem in recent years causing severe damage to Maryland native and non-native trees, some of which you should monitor.  

History of Invasive Species Impacting Trees 

Invasive insect species in Maryland typically originate from other continents, arriving through global trade and travel. These insects, such as the emerald ash borer from Asia and the gypsy moth from Europe, are often introduced accidentally via shipping containers, wooden pallets, or imported plants. Once established, these species undergo rapid population cycles, often lacking natural predators in their new environments, which allows them to proliferate unchecked. Their life cycles are often synchronized with the growing seasons of their host trees, maximizing their impact on native forests. 

The adaptability of invasive insect species exacerbates their threat to native trees in Maryland. These insects can quickly adjust to local climates and exploit ecological niches that native species cannot fill. For instance, the emerald ash borer has evolved to target and kill ash trees efficiently, leading to widespread tree mortality. The loss of these native trees disrupts local ecosystems, reducing biodiversity and altering habitat structures. Invasive insects also increase the vulnerability of forests to other stressors, such as disease and climate change, by weakening tree health and resilience. 

Native Predators Respond to Invasive Species 

In recent years, some native predator species in Maryland have shown remarkable adaptability in preying on invasive insect species. For instance, woodpeckers have significantly increased their consumption of emerald ash borers, a destructive pest to ash trees. Native parasitoid wasps, such as those in the genus Atanycolus, have also expanded their host range to include invasive insects like the emerald ash borer. These adaptations are crucial in naturally controlling invasive populations, helping to mitigate their impact on native tree species and the broader ecosystem. 

Monitoring & Combating Invasive Tree Species 

Monitoring and combating invasive insect species in Maryland involves a combination of proactive surveillance and responsive management strategies. Regular monitoring includes surveys and trapping to detect early infestations of invasive species such as the emerald ash borer and the Asian longhorned beetle. Using tools like pheromone traps and visual inspections, forestry professionals and volunteers can identify the presence and spread of these insects. Public reporting systems also play a crucial role, encouraging citizens to report sightings of suspicious insects or damage to trees, facilitating early intervention efforts. 

Combating these invasive insects requires integrated pest management strategies that combine biological, chemical, and cultural controls. Biological control involves introducing natural predators or parasites that specifically target invasive species without harming native ecosystems. Chemical controls, such as insecticides, can be effective but need to be used judiciously to avoid collateral damage to non-target species and the environment. Additionally, cultural practices like removing and destroying infested trees, implementing quarantines, and promoting the planting of resistant tree species help mitigate the spread and impact of invasive insects.  

9 Common Invasive Insects Affecting Maryland Trees 

  1. Spotted Lanternfly. Noted for their red and white wings, these recently introduced pests feed on plant saps from orchard trees and others.  
  1. Euonymus leaf notcher. Non-native moth that consumes the leaves of euonymus and bittersweet pants in its caterpillar stage. 
  1. Viburnum leaf beetle. These pests lay eggs on the underside of vibernum twigs and after hatching feed on their leaves. 
  1. Emerald ash borer (EAB). A serious threat to Maryland ash trees, these insects have spread nationally, and are known to kill a mature ash tree within three years. 
  1. Sirex woodwasp. This pest is a serious threat to pine species and the timber industry in general. It has no known natural predators in our territory. 
  1. Japanese cedar longhorn beetle. These beetles attack arborvitae, false cypress, Leyland cypress, eastern redcedar, junipers, fires and pines. Their impact is shown as dead branches from the main stem and can be mistaken for winter dieback. Inspect the main stem for bore holes to indicate if the tree is infested by this beetle. 
  1. Kudzu bug.  You may not have seen this one yet, as it’s impact is currently seen only on the eastern shore and southern Maryland. It’s known to feed on invasive kudzu, soybean and legumes. 
  1. Brown marmorated stink bug.  One of the most frustrating pests for homeowners on wood and rural areas, this insect feeds on just about everything, including fruit trees, shade trees, and landscape ornamentals.  
  1. Asian Longhorn Beetle (ALB). This is another huge threat to deciduous hardwood trees including most maples, birches, alders, elms, poplars, horsechestnuts, sycamores and willows. You can spot their circular bore in the trunk of infested trees. 

An immensely valuable tool, the University of Maryland Extension offer educational resources and guidance on how residents can practically deal with these types of issues. You can also report instances of these insects on their site. 

Call Manor Tree Service to Deal with Trees Damaged by Invasive Species

If you are concerned about the health and viability of any trees on your property, give us a call and we’d be happy to take a look at it and provide recommendations for treating, managing or removing the tree. Contact us here!