Tree-Destroying Pest: Identification Techniques Uncovered

Tree-Destroying Pest: Identification Techniques Uncovered

In the Buckeye State, the box tree moth (BTM), a new invasive species, poses a significant menace to the health and beauty of boxwoods (Buxus spp.). This pesky critter, Cydalima perspectalis, can wreak havoc on Ohio's landscapes and nurseries, and it's essential we keep an eye out for it[1][3].

To guard against this green-and-black intruder, knowing what to look for is crucial. Here's a handy guide to help spot an infestation[2].

How to Spot a BTM Infestation

Caterpillars

These unwelcome visitors are easy to identify, with their green or greenish-yellow bodies adorned with black stripes and dots. Native Ohio pests don't strip boxwoods, so a caterpillar gnawing away at your boxwoods is a clue it's the BTM[4].

Strange Leaf Damage

As BTM caterpillars grow bigger, they munch on entire leaves but tend to leave behind the leaf edges and sometimes the midvein. This results in a quirky, curlicue appearance to the leftover tissue that eventually turns brown[3]. Nothing else replicates this peculiar damage.

Silk Webbing

While BTM caterpillars don't produce as much webby silk as other pests like webworms or tent caterpillars, you might find them on wispy clusters that hold caterpillars tightly to their boxwood host[5]. Their silk sometimes entangles feeding debris and frass, making infested boxwoods look tattered.

Beyond webbing, BTM caterpillars create pupation structures, wrapping themselves in whole leaves as well as leaf debris before spinning a loose silk cocoon to pupate[5]. These remnants linger for some time, making identification easy.

Frass (Insect Droppings)

BTM caterpillar excrement is akin to small, light-green to greenish-brown pellets. Frass may collect under infested plants or get entangled in caterpillar silk[3].

Boxwood Damage

BTM damage evolves as infestations grow. Early instar caterpillars focus on the upper or lower leaf epidermis, leaving marks that may be tough to spot[3].

To make matters trickier, BTM caterpillars hide from view by gobbling up inner foliage during the early stages. Healthy-looking boxwoods could conceal a hidden infestation[3]. However, as infestations intensify, caterpillars venture out, consuming the entire leaf and leaving behind only debris[3].

In extreme cases, a boxwood may turn from green to brown in just a few weeks. Examine damaged leaves closely to distinguish BTM damage from winter injury or fungal infections. Boxwoods with disappearing leaves aren't a sign of environmental damage or disease[3].

Adult Moths

BTM adults are diminutive moths with wingspans of 1 to 1 1/2 inches. They appear in two color morphs, with the most common having gray to grayish-brown edges on white wings. A minority might sport purple-tinged wings. A distinguishing feature is a cluster of white spots on the forewings that resemble crescent moons[6].

While BTM adults fly at night and may seem hard to spot, synthetic pheromones have been developed to detect infestations. Traps using these synthetic pheromones are an effective tool for detection[6].

Eggs

BTM eggs are laid on the underside of boxwood leaves and are initially green or greenish-yellow. As they mature, they change color[4]. Although eggs are distinctive, their small size and difficulty in spotting limit their usefulness in detection[4].

For more info on the box tree moth and how to combat it, check out the Buckeye Yard & Garden Online[7].

Enrichment Data:

• The box tree moth can defoliate entire boxwood plants if infestations are severe, weakening them and reducing their aesthetic appeal.
• Due to the moth's invasive nature and lack of native predators, it can spread rapidly and cause extensive damage in Ohio.
• As the moth's presence expands in the region, vigilance is key; BTM-affected plants may appear healthy initially but reveal hidden infestation upon closer inspection.

1. In the realm of agricultural and horticultural pursuits, understanding the characteristics of the box tree moth caterpillar is essential for identifying infestations in boxwoods.
2. While recognizing the habitat of this invasive species can help prevent damage, boxwoods damaged by the box tree moth may initially appear healthy, necessitating closer inspection for hidden infestations.
3. Pest management in home-and-garden settings necessitates knowledge of the different signs of a BTM infestation, such as caterpillars with distinctive green or greenish-yellow bodies, curlicue leaf damage, silk webbing, frass, and changes in the overall health of the boxwood plant.
4. For those interested in environmental science and preserving the beauty of their gardens, keeping a watchful eye on boxwoods and utilizing tools like synthetic pheromone traps can help manage the box tree moth infestation, potentially preventing widespread damage to Ohio's landscapes and nurseries.

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