Occasional Invaders

OCCASIONAL INVADERS

I have a client with a tremendous springtail issue.  I found most of the springtails along the foundation of the customer’s house about 2-3″ down into the soil.  She has some old mulch (of course holding moisture).  But the springtails are also getting into the house, and onto the tile floor of the basement and her kitchen countertop.  From my inspections, there are no moisture problems inside and it is a very clean house!  Do you have any suggestions?

We recommend that you rake back the mulch from the foundation by about a foot to let it dry out in those areas.  You may also apply some kind of material to the rake backed areas.  Does this customer have an automatic sprinkler system that waters daily or on a regular schedule?  This could be the issue.  Dry out the area and adjust the sprinkler timer to be less frequent.

If you are also seeing springtails inside, check for plumbing leaks around sinks and drains and bath trap areas.  Springtails cannot survive without moisture sources, and they often are good indicators of a problem plumbing issue.  Dry out the area with increased ventilation, fans and dehumidifiers and address the plumbing issue.  Various dusts may also be applied in wall void areas.  When using such a product, always read and follow all labeled instructions.

We are hearing reports about the kudzu bug and are starting to get calls about it.  What is the latest news on this pest and how can we control it?

The kudzu bug (Megacoptera cribraria) is an exotic invasive insect that was first observed in the United States in late 2009.  First reports of this insect were from northeast Georgia, where pest management professionals encountered large aggregations of the bug on the sunny, south-facing sides of houses.  Its presence has been now been confirmed in Georgia, North Carolina and South Carolina.  Prior to being discovered in the United States, the species had been reported in Asia, the Indian Subcontinent and Australia.

The kudzu bug gets its common name because the invasive plant, kudzu, is one of its favorite foods.  Unfortunately, in its native range it is also considered a pest on important agricultural crops like soybean.  It is also known to feed on other crops such as beans, sweet potato, rice, wheat, citrus, potato and others.  Kudzu bugs are known to have several generations each year.  As temperatures and day length decrease, kudzu bugs seek shelter in protected areas including structures. Residential and commercial buildings located close to food sources (agricultural fields or kudzu stands) are at particular risk for invasion, since this species is an excellent flier.  Similar to boxelder bugs, multicolored Asian lady beetles and the brown marmorated stink bug, kudzu bugs will congregate on the vertical surfaces of buildings to warm themselves in the fall.  As temperatures cool they will move inside structures through cracks, crevices or other openings, to spend the cool winter months.

Treatment recommendations to manage kudzu bugs include exclusion by sealing potential entry points and screening vents and other openings.    Bugs will begin migrating from food sources (typically kudzu or soybeans) as temperatures cool, and may continue for several weeks.  Applications of appropriately labeled insecticides to surfaces where kudzu bugs may rest or into and around potential entry points may be useful. Wettable powder, microencapsulated or other longer residual formulations may offer the best results.

I found what I originally thought were gnats, but appear to be really tiny cicadas clinging to the inside of a window screen in a customer’s house.  Are they cicadas?  What are they doing inside the house?

The insects that you are encountering are called psyllids (SIL-ids) and are commonly called jumping plantlice.  These insects are typically not a pest indoors, but may have found their way in from the outside through cracks and crevices as the weather cools.  They can be a pest in ornamental plants particularly hackberry trees (Celtis occidentalis).  The hackberry psyllids (Pachypsylla celtidisvesicula and P. celtidismamma) create galls on the upper surface and underside of hackberry leaves.

Adult psyllids overwinter in protected sites such as in cracks and crevices under loose bark or behind the siding of structures.  After emerging from these sites in the spring, hackberry psyllids lay eggs on hackberry tree leaves.  As the nymphs grow and feed on the leaves, the plant defends itself by growing abnormal fleshy tissue that surrounds the growing psyillid, creating a gall.  Usually the presence of galls is not harmful to the health of a mature tree.  Adult psyllids emerge from feeding inside galls in the late summer and will congregate on the sunny sides of buildings, eventually finding their way inside cracks and crevices around windows.  Some psyllids are so small that they can even penetrate through screens with openings larger than size 18 mesh.

Psyllids are typically nothing more than a nuisance pest, and as the weather becomes colder, the infestation may resolve itself.  However if the problem occurs year after year, it might make sense to recommend that the customer have any hackberry trees on their property showing signs of infestation treated with an appropriately labeled product.  From an IPM perspective, psyllids are attracted to lights, so it makes also makes sense to address outdoor lighting to make the structure less attractive to these overwintering pests.

Since silverfish never develop wings and the immature stages look exactly like adults (only smaller) what kind of metamorphosis do they undergo?

The types of metamorphosis can be divided into two broad categories: simple and complete.  Insects like beetles, flies, moths, wasps and fleas (holometabolous insects) all exhibit complete metamorphosis, which is characterized by four distinct life stages: egg, larva, pupa and adult.  In insects with complete metamorphosis the adult and immature stages typically feed on very different kinds of food and live in different environments.

Simple metamorphosis is a little more complicated however, and can be divided into three sub-categories: incomplete, gradual and no metamorphosis.  Incomplete metamorphosis is found in insects like dragonflies, mayflies and stoneflies (hemimetabolous insects).  There are distinct life stages: egg, naiad and adult.  The adult and naiad stages feed on different foods with naiads living in aquatic environments and possess gills which they use to “breathe” underwater.  Gradual metamorphosis is a more familiar kind of simple metamorphosis because it is found in common pests like cockroaches, termites, bed bugs and stink bugs (paurometabolous insects).  Gradual metamorphosis includes three distinct life stages, adults, eggs and the juvenile forms – typically called nymphs.  Nymphal and adult stages usually feed on the same foods and will be encountered in the same kinds of environments.  The last kind of simple metamorphosis is actually no metamorphosis at all.  Silverfish and springtails (ametabolous insects) both fall into this category.  The immature stages typically look the same as adults, feed on the same foods and are encountered in the same places.  There is no major rearrangement or changes in body structure during development.  The only major differences between adults and immature stages are size and the ability to reproduce.  So, to make a long answer short, silverfish exhibit no apparent metamorphosis at all.