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Oakworms are Culprits in Courthouse Tree Mystery

Mysterious disappearances have long held the public’s interest and fuelled speculation about what really happened to a particular person. Amelia Earhart and Jimmy Hoffa are two good examples of the gone-but-not-forgotten mystery subjects which inhabit popular imagination and generate headlines.

Earhart went missing over 75 years ago while flying in the Pacific, but is still the subject of searches and conjecture about her fate and whereabouts. Hoffa, a controversial labor union leader, vanished after a steak dinner with some associates and has had investigators looking for him ever since.

Novelists have used this type of storyline for countless pages of entrainment, if not literature, for many generations of readers who relish the brain teasing challenge of solving the mystery. Even Wakulla County had a vexing disappearance recently, the vanishing oak leaves on the trees around the courthouse in Crawfordville.

Young oaks on the south side of the building were stripped of their foliage, but were otherwise unharmed. Luckily, there was plenty of evidence to point to the culprits that defoliated these trees.

Local oakworms are hard at work preparing in the waning days of summer. Their numbers have built up in the favorable weather conditions of a wet summer which produced bountiful foliage to consume and support their reproductive efforts.

The guilty parties for the damage at the Wakulla County Courthouse’s trees are the Spiny Oakworms (Anisota stigma). This is one member of a moth genus which is actually a caterpillar not a worm.

The difference between worms and caterpillars is substantial, but caterpillars are often identified as worms. The tubular shape is a stage of life for a caterpillar which ultimately becomes a butterfly or moth.

The tubular shape is usually the development pinnacle of the worm’s life cycle. Most caterpillars tend to eat live vegetation while worms consume dead plants and animals accelerating their decomposition and return to the nutrient base.

Healthy small oaks usually have enough vigor to leaf-out and survive the assault carried out by the Oakworms. Larger oaks have enough leaf producing capacity to out produce the caterpillars’ collective ability to eat.

In addition to the Spiny Oakworms, there are Red-humped Oakworms and Yellow Striped Oakworms which are native to Wakulla County. As their name implies, oak leaves are the nourishment of choice.

All the oakworms are about an inch in length with bristly hairs, especially in the case of the Spiny Oakworm. Colors and body patterns are the simplest way to identify the species in this genus.

These caterpillars are rarely seen alone in a tree. They are commonly found in colonies of 50 or more, each dining on a leaf.

When threatened, they curl into a U shape and remain still. Predators are confused by the behavior and seek other meal choices.

Home owners and landscape managers sometimes seek methods for controlling these caterpillars, but nature does the best job. Caterpillar population’s will peak in late summer to early autumn with birds, bats and others feasting on the defenseless moths before they can lay eggs.

Soon cold weather will halt oakworms for the year. A disappearance, but it is not mysterious.

Contact the UF/IFAS Wakulla County Extension Office at 850-926-3931 to learn more about Oakworms in Wakulla County.

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