You may think that you’re home alone at night, but some creepy, crawly bug may be trying to break in. Bugs enter through windows, cracks around doors, through chimneys and vents, or just lie in wait on the siding or stucco outside. The evidence of their invasion includes stained curtains and walls, clusters of bugs huddling together in corners of a room, their dead bodies on the floor, or fuzzy pupal cases or egg masses just outside.

The culprits may be the immatures of several insect species that wander away from their host plants and are looking for a protected area in which to pupate. They may also be adult moths or beetles who are attracted to lights at night or warm temperatures from homes in the fall. Some (e.g., gypsy moth egg masses) may even be hitchhikers on vehicles or camping gear after a family vacation or from infested houseplants (e.g., fungus gnats, whiteflies).

Here are some examples of bugs that may have day jobs as plant-feeders or natural enemies but moonlight in or around buildings at some point in their lives. As with any occasional invader, it is important to find any entry points to a building and seal or eliminate them as a first defense.

CABBAGE PALM CATERPILLAR

The cabbage palm caterpillar, Litoprosopus futilis, also called the cabbage palm worm, is the larva of an owlet moth. It typically feeds on the developing bloom spikes (inflorescences) of cabbage and Washingtonia palm trees. This may not be important to many folks but, thousands of these larvae may consume all traces of bloom, which can lead to less palmetto honey produced in Florida by honey bees. The larvae (Figure 1) may be present from April to November throughout the state, but a localized outbreak may only last less than a week. When mature, larvae (ca. 1 1/2 inches long) drop to the ground on silken threads and crawl to find protected pupation sites (e.g., buildings). Large populations of caterpillars can invade homes and damage household fabrics or stain home exteriors. When pupating, the larvae incorporate any available fabric into their cocoons, including fiberglass window screen and drywall. Adults are also attracted to lights at night and can also be a nuisance if they get inside.

It may be possible to reduce early infestations by treating the palm flowers, but if honey production is a goal, then choose products that won’t harm bees, like Bacillus thuringiensis (Bt), variety kurstaki. Although it may not be very effective, another possibility is to use a perimeter application around the home or building to stop wandering larvae. An interior application is not a good idea. Probably the best defense is getting a shop vac and vacuuming the larvae up before they can spit and stain anything.

JADERA BUG

This native insect has several other common names (Red-shouldered bug, soapberry bug, scentless plant bug, goldenrain tree bug), but typically refers to Jadera haematoloma. It concerns people because children’s clothing can be stained while they play in the yard and because the bugs wander into homes. Kids find them fascinating to hunt after, too, probably because they are so easy to see. Although most of the alarmed calls to county extension agents and pest control companies occur in the spring, the nymphs and adults are active year-round. The nymphs (Figure 2) are primarily red-colored, but adults (Figure 3) are brownish-black with red eyes, shoulders, and the border area of the abdomen. Jadera bugs are often mistaken for boxelder bugs, which are in the same insect family. Although Jadera bugs feed on several hosts, including the seeds of balloonvine and some fig trees, large populations only seem to occur on goldenrain tree.

Insecticidal control is usually not recommended for Jadera bugs because they really don’t cause any plant damage and are only a nuisance pest. If control is desired, an insecticidal soap, horticultural oil, or an insecticide aimed on the ground around the source tree, or into the tree canopy when the insects clump in the branches, may reduce their numbers. Insects can also be collected and killed in a bucket of soapy water or vacuumed up. Raking and removing the seeds before they detach from leaves may also help minimize infestations. Apparently, the goldenrain tree is listed by the Florida Exotic Plant Council as a Category II invasive species, so the Jadera bug’s feeding on seeds may help limit seed germination.

MULTICOLORED ASIAN LADY BEETLE

This common predator, Harmonia axyridis, was deliberately introduced into the U.S. from Asia as a classical biological control agent, but multiple accidental introductions also occurred. It finally became established and had spread throughout the entire U.S. and Canada by 1994. Larvae (Figure 4) are rarely encountered and are considered good natural enemies of crape myrtle aphids, mites, thrips, scales and moth eggs.

The adults (Figure 5), although also predaceous on the same arthropods as the larvae, can be pests when they migrate into homes to overwinter. They can also consume enough prey to the extent that other native natural enemies might be outcompeted and become less abundant. In Japan, this lady beetle overwinters en masse on mountainsides, but it is attracted to light-colored buildings in the U.S. The migration indoors is triggered by cold weather and lack of prey, usually from November to January in north Florida.

Thousands of beetles can enter homes, and their rustling movement can be easily heard inside. When disturbed, the adults secrete a yellow, bad-smelling substance that can stain walls and fabric, and adults can even give a little bite if held. Thus, vacuuming them up is faster and more effective at minimizing stains than sweeping. Another option is to collect them with a blacklight trap that is operated inside the home at night.

Despite this annoying habit of overwintering indoors, the multicolored Asian lady beetle is still considered a valuable biological control agent and should be conserved as best as possible.

All photos by Lyle J. Buss, UF/IFAS

Eileen Buss is assistant professor in the Entomology and Nematology Department, University of Florida, Gainesville.