Rick Minzenmayer

Drain Flies

September 28, 2017 by

Chris Sansone, Rick Minzenmayer and Bastiaan M. Drees*
*Extension entomologist and Extension agent—entomology (pecans), The Texas A&M University System.

Adult Drain Fly

Small flies in the home can be a common problem. Scientifically, the word “fly” refers to insects in the order Diptera, which typically have only one pair of wings. Instead of a second pair of wings these insects have threadlike, knobbed structures called halteres. The Diptera have complete metamorphosis (egg, larva, pupa and adult) and the larvae of many groups of flies are commonly called maggots.

Small flies that can infest homes include drain flies, fruit flies, fungus gnats, mosquitoes and midges. They can all enter from outdoors, but fruit flies, fungus gnats and drain flies can reproduce indoors and survive there indefinitely. The first step in controlling an infestation is to determine which of these pests is the problem.

Fruit flies are usually yellowish with clear or lightly banded wings. They are most often found around fruit and vegetable peelings, rotting fruits and other similar foods. Eliminating the food sources usually controls these flies. Fungus gnats usually have dark wings and are not fuzzy in appearance. Fungus gnat larvae feed on decaying plants or fungi and usually develop in the potting media of houseplants. The easiest way to control them is to let the houseplant soils dry out between waterings because the larvae do not survive in dry conditions.

Drain flies are also called moth flies because of their fuzzy appearance. They are dark gray to black and found near sinks and tubs. This fly belongs to the family Psychodidae.

Biology and Habits

Adult drain flies are small (1/6 to 1/5 inch long), dark, and densely covered with hairs. They hold their large wings roof-like over the
body when at rest, giving them a moth-like appearance. They are weak fliers and fly only a few feet at a time. They are most active in the evening.

Both mated and non-mated females lay eggs. Egg masses contain 30 to 100 eggs, which hatch in less than 48 hours into small (3/8 inch), legless larvae that are pale in the middle and darker on the ends.

Drain fly larvae and pupae live in the thin film found in drains and septic tank field lines and on filter stones. The larvae feed on fungi,
bacteria, algae and other microorganisms found in the liquid or slime layers that develop around debris in drains, sewage treatment beds and standing water. When food is scarce, they can become cannibalistic. Larvae can survive temperature extremes and habitats low in oxygen. The larval stage lasts 8 to 24 days and the pupal stage 1 to 2 days.

Adults live only 3 to 4 days without food, but can survive for 1 to 3 weeks if nectar or other liquid carbohydrate foods are available.

Drain fly life cycle

Control

Drain fly larvae are actually beneficial because they break down organic waste into water soluble compounds. Adult flies, however, are a
nuisance. They cannot bite, but they may become so numerous indoors that they congregate at windows and around light fixtures, showers, bathtubs, sinks and floor drains.

The key to solving a drain fly problem is to find and eliminate the source—that is, the areas where excess moisture and organic debris have built up.

Outdoors, these areas may include:

damaged or faulty septic lines;
areas where rainwater tends to pool or where air conditioning condensate lines
drain, particularly if the area is shaded;
areas where algae or mold grows on the soil or foundation; and
beneath air conditioning units on the roofs of commercial buildings or where units
adjoin a building.

Infestations also may originate in a neighbor’s yard or in nearby shallow pools or sewage treatment facilities, particularly those upwind from the home. If so, contact the people responsible for infested areas.

Indoors, infestations may occur in:

toilets (particularly if they are not used frequently);
sink and bathtub/shower drains;
floor drains in commercial buildings and basements;
condensate lines for icemakers; and
loose ceramic floor tiles where water may collect.

If there are lots of adult flies inside a drain the drain is probably a breeding site. To check for breeding sites, place a length of tape across drains (or cracks in the floor) without totally covering the opening. (If the opening is totally covered, there will be no air flow and flies will not emerge.) Check the tape periodically. If you see flies stuck to the tape, you have found a source of infestation.

Manual Cleaning

The most effective way to correct (or prevent) drain fly problems is to clean toilets, drainpipes and traps to eliminate any gelatinous, rotting, organic matter. This eliminates the larval food source. Clean pipes and traps with a stiff, longhandled brush. After a thorough scrubbing, flush the lines with boiling water to remove any material left behind. There is no benefit to treating drains with chlorine bleach or ammonia.

Chemical Drain Cleaners

There are bacterial drain treatments that biodegrade organic matter. Follow the label directions carefully for best results.

Many common drain and toilet bowl cleaners are effective. If you have a septic system, read product labels carefully to make sure a product is compatible with the system.

Caustic drain cleaners also can be used, although they may not be as effective as other cleaning methods. IMPORTANT: NEVER rinse
a drain with bleach after using a caustic drain cleaner. Mixing these two chemicals in the drain line may produce chlorine gas, which
is extremely hazardous to anyone who inhales it.

Insecticides

Once the fly breeding areas are cleaned, the use of insecticides should not be necessary. However, if quick control is needed until breeding areas can be cleaned, insecticides are useful.

The only product labeled for use in drains is Gentrol®. Its active ingredient, hydroprene, acts as an insect growth regulator on the larvae. This product does not control the adult flies. Aerosol sprays containing pyrethrins (or other “flying insect” sprays) will temporarily control adult drain flies indoors, but they are not a real solution to the problem. If the drain flies are coming from outside, applying any common residual spray for flies around the outsides of windows will give temporary relief until the source of the infestation can be found and eliminated. Always read the label and follow directions and safety precautions.

Photos by Bastiaan M. Drees, Extension Entomologist, The Texas A&M University System

Armyworms in Texas Pastures and Lawns

September 27, 2017 by

Chris Sansone, Rick Minzenmayer and John Jackman

Armyworm outbreaks are difficult to predict but infestations seem to occur in portions of the state every year especially after rains in the early fall. Common species of armyworms present in Texas include: the fall armyworm, Spodoptera frugiperda; the yellowstriped armyworm, Spodoptera ornithogalli; the beet armyworm, Spodoptera exigua; and the armyworm, Pseudaletia unipuncta . The fall armyworm is usually the species that causes the most problems in pastures, small grains and turfgrass.

BIOLOGY AND HABITS

All armyworms have four life stages: egg, larva, pupa and adult. Eggs are very small, white, laid in clusters of 50 or more and are covered with grayish, fuzzy scales from the body of the female moth. The eggs are seldom seen in grasses and are usually laid at the base of host plants. Lush plant growth is preferred by the adults for egg laying. Larvae (caterpillars) are very small when they emerge from the egg. Larvae will feed for 2-3 weeks and can be 26-37 mm (1-1.5 inches) long with various color patterns depending on the species. The larvae have five instars (stages when molting occurs) and sometimes hide in debris on the soil surface in the middle of the day. When full grown, larvae enter the soil and form the pupal stage. Adult moths emerge from pupae. Moths mate and lay eggs, thus starting the life cycle over again.

Several generations (a generation is the development from egg to adult stage) occur each year and typically take about 28 days to complete. Generation time can be extended if cooler temperatures occur and can last up to several months. Armyworms in the spring and summer occur in more distinct groups than later in the season. Fall populations of larvae often blend together several generations and may appear to be continually occurring. Some detail on the species mentioned follow.

Fall Armyworm – The fall armyworm overwinters in the pupal stage in the southern regions of Texas. The adult is a moth that migrates northward as temperatures increase in the spring. The adult moth has a wingspan of 32-40 mm (about 1.5 in.). The hind wings are silver-white; the front wings are dark gray, mottled with lighter and darker splotches. Each front wing has a noticeable whitish spot near the extreme tip on the males. Larval color can vary from light tan to shades of green. The head is brown or black with a prominent white line between the eyes which forms an inverted “Y.” The fall armyworm has four large spots on the upper surface of the last segment of its body. Along the middle of the larva’s back is a wide, yellowish-gray band with a dark, black stripe just below the yellowish-gray band.

Yellowstriped Armyworm – The yellowstriped armyworm moth has dark forewings with white and brown markings, and white hind wings. The wingspan ranges from 32 to 38 mm. The larva has a brownish head and bright yellow stripes near the top of the sides of the body and a pair of black, triangular spots running the length of the body.

Beet Armyworm – Adult beet armyworm moths have wingspans of 25 to 32 mm, with forewings that are mottled gray or brown with a pale spot near the center of each wing. The hind wings are a uniform gray or white. The larva is usually green but color can vary, with dark lateral bands running the length of the body. The larva has a single, dark spot behind the head and directly above the second pair of true legs (located directly behind the head). Beet armyworms tend to be more of a problem in hot, dry conditions and are usually a significant pest in vegetables and other broadleaf plants (such as cotton).

Armyworm – The adult moths are grayish tan, with small salmon or orange-pink dots on the forewings. The armyworm larva has a dark band running lengthwise along the middle of the back with a pale stripe just below the dark band. Fall armyworm has the reverse coloration. Armyworm caterpillars have a net-like or “honeycomb” pattern in their eyes and a dark band at the top of each proleg (unjointed legs near the back of the body). Armyworm larvae lack the inverted “Y” and four black spots on the last segment which are characteristic of the fall armyworm.

PEST STATUS AND CONTROL

When feeding, larvae strip foliage and then move to the next available food. High populations appear to march side by side to the new food. Thus, the name armyworms is derived.

Armyworms attack many different kinds of plants. When food is scarce, they will move to plants that are not normally attacked. Thus, armyworms can be found on nearly any plant as they migrate in search of edible foliage. Plants attacked by armyworms include: bermudagrass, fescue, grain and forage sorghum, corn, small grains, sweet potato, beans, turnip, clover, spinach, cucumber, potatoes, tomatoes, cotton and cabbage.

Damage consists of defoliation. The small larvae will chew the green layer from the leaves, creating a “window pane” effect. The first three instars cause very little feeding damage while the last two instars consume 85% of the total foliage consumed.

Control-Although armyworm outbreaks are memorable when they occur, in reality, the outbreaks are usually small in scope. Weather and natural enemies usually act together to keep populations under control.

Parasites such as wasps and flies are very effective against armyworms. Predators, such as ground beetles, are also effective in limiting outbreaks. Birds, skunks and rodents also consume large numbers of larvae and pupae. Diseases such as insect viruses and fungi can also be important.

However, conditions can occur that favor armyworms. High egg survival of fall armyworms is favored by above average rains in August and September. Beet armyworm outbreaks are likely in hot, dry conditions or when multiple applications of insecticides reduce natural enemies. Because armyworm moths are strong fliers, outbreaks can also occur when storms move the moths and allow them to escape natural enemies.

Armyworms should be controlled when they occur in large numbers or plant damage is becoming excessive.
The fall armyworm outbreaks usually occur late in the summer and early fall. Preventive treatments normally are not justified because attacks are sporadic and egg mortality is usually high. A variety of natural enemies keep fall armyworm larvae down to moderate numbers. Early detection of larvae is the best management tool and is achieved by frequent, thorough inspection of plants. Outbreaks seem to occur shortly after a rain or supplemental irrigation.

Fall armyworms feed any time of the day or night, but are most active early in the morning or late in the evening. Susceptible fields or lawns should be scouted by counting the number of armyworms in a square foot area in 8 different sites. Divide the total worm count by 8 to find the average number of armyworms per square foot. Be sure to take samples in the interior of the field because this pest is often heaviest near the field margins. Sometimes, only the field margins require treatment.

The threshold level ranges from two to three larvae per square foot for seedling wheat. For older plants, three to four larvae and obvious foliage loss justify control measures. Thresholds in improved pastures and lawns vary with conditions but treatment should be considered when counts average three or more worms per square foot.

Insecticide choices vary with the crop but the following (with product names and grazing restrictions in parentheses) are labeled for use in pastures include carbaryl (Sevin®) (14 days), malathion (0 days), methomyl (Lannate®) (7 days), methyl parathion (Penncap®-M) (15 days) and various biologicals such as Dipel®(0 days). Insecticide labeled in lawns and turf include halofenozide (Mach® 2), bifenthrin (Talstar®), cyfluthrin (Tempo®, Bayer Advanced®), carbaryl (Sevin®) permethrin (multiple brands) and spinosad (Conserve® and others).

FOR MORE INFORMATION

For more information about armyworms refer to Extension publications B-1220, Managing Insect and Mite Pests of Texas Sorghum; B-1251, Managing Insect and Mite Pests of Small Grains; B-1401, Integrated Pest Management Guide for Texas Forage Crops; and E-5, 6 and 7 Managing Insect and Mite Pests of Cotton.

ACKNOWLEDGMENTS

The authors wish to thank Drs. Allen Knutson, Mike Merchant, Mark Muegge and Carl Patrick for their assistance in reviewing this publication.

Predaceous Ground Beetles, Caterpillar Hunters and Bombardier Beetles

June 24, 2004 by

Rick Minzenmayer, Extension Agent-IPM
Chris Sansone, Extension Entomologist
Texas Cooperative Extension

Predaceous ground beetles can be a nuisance when numerous. They are attracted to lights and can sometimes be found by the hundreds around lights in the morning. The large numbers can also be a problem because the beetles defend themselves by emitting an odor.

Ground beetles are part of the order Coleoptera. This is the largest order of insects with over a quarter of a million species
described throughout the world — about 30,000 species in the United States. Most beetles have two pairs of wings (elytra). The
front pair is usually thickened and hard and meet in a straight line down the back when the wings are at rest. The back pair are membranous and folded beneath the front pair. All beetles have chewing mouthparts and undergo complete metamorphosis
(egg, larva, pupa and adult).

Caterpillar hunter, Calasoma scrutator(Fabricius) (Coleoptera: Carabidae

Predaceous ground beetles belong to the family Carabidae. This is the second largest family of beetles, with more than 2,500 species in North America. Most members of this family are considered beneficial, feeding on other insects in both the larval and
adult stages. A few species feed on seeds and organic litter, but only rarely does the feeding produce economic damage.

The different common names refer to the family’s habits. Because ground beetles are effective predators of caterpillars, the name “caterpillar hunter” is used frequently. The name “caterpillar hunter” usually applies to the genus Calosoma, a brightly colored ground beetle. Some species are called “bombardier beetles” because they emit what appears to be smoke from the rear of the abdomen. The “smoke” is actually a glandular fluid that vaporizes when it hits air; the fluid can irritate the skin. The ground beetles also emit an odor to stop their enemies, including people.

Biology and Habits

A ground beetle, Pasimachus sp. (Coleoptera: Carabidae).

Most ground beetles are black or dark red, although some species are metallic blue, brown or green. Most species have a thorax (middle body section) that is narrower than the abdomen. The adults have long legs, are fast runners, can fly and are attracted to
lights at night.

As their name implies, most ground beetles dwell on the ground. However, some species will climb bushes or trees to feed on caterpillars, and some species feed on snails and slugs. Ground beetles can consume their body weight in food each day. Both adults and larvae feed on ground dwelling insect larvae and pupae.

The life cycle (egg to adult) of ground beetles requires a year. Winter is spent in the larva or adult stage. The female lays eggs singly on the soil surface, and the egg hatches into an elongated larva.

Beetle larva

The larva has three pairs of well-developed legs and, unlike other beetle larva, run quickly. The full grown larva of larger species can be 3/8 to 1 3/4 inches long, slightly flattened, cream to brown colored and slightly tapered at each end. The head bears sickle-shaped jaws (mandibles). The larva develops through several stages (instars) before pupating in earthen cells. The adult emerges from the earthen cells to mate and disperse. An adult can live for two to three years. Little is known about most ground beetles since most of their
activity is at night.

Pest Status and Control

Ground beetles are unique in that they can be both beneficial insects or nuisance pests. In fields or gardens, they feed on caterpillars and other insects and are considered beneficial. However, when numbers are abundant and they start moving to lighted buildings and entering houses, they become nuisance pests.

Ground beetles are occasionally attracted to lighted homes and buildings in large numbers. This usually occurs when environmental
conditions are good and there has been an abundance of insect food the previous year. When winter moisture is plentiful and temperatures are mild, overwintering larvae (immatures) and adults survive in higher numbers. If food (caterpillars and other
insects) is plentiful in the spring, overwintered stages have food to eat and to multiply. Once a food source is used up, the beetles will
move to look for other food sources. It is this movement around and into buildings that occasionally causes problems.

Ground beetles can also become a nuisance because of the odor they emit for defense. This odorous substance can be objectionable
or cause a burning sensation on human skin when the beetles are handled or when large numbers of dead beetles accumulate.
Consequently, beetles should not be handled.

Prevention

No control is encouraged because the beetles are considered beneficial. When populations are large enough for them to be a nuisance,
however, the best form of control is preventing them from entering buildings.

Remove objects where beetles can hide such as leaf piles, old boards, rotting logs, stone piles, firewood piles, etc.
around house entrances.
Caulk and screen entryways into the home.
Since many beetles are attracted to lights, subdue the lighting around windows and doors by using less attractive
(to beetles) yellow or sodium vapor light bulbs. Avoid excessive lighting directly upon the house during the
spring when beetles are abundant.
Indoor lights should not shine directly out of door or window openings.
Colored walls that do not reflect light are preferable to glossy white.
Small numbers of live beetles found indoors can be easily collected by broom and dustpan and relocated outside
far from the house since these predators may be beneficial by helping to control other pests.
Collect dead and dying beetles with a vacuum cleaner and proper attachments

Insecticides

If preventative measures fail and the problem remains severe, insecticides can be used outdoors as a last resort. It can be helpful to
apply perimeter (barrier) sprays of pyrethroids (i.e., permethrin, cyfluthrin and others) to the house foundation, doorways, window sills
and soil or vegetation, 2 feet up and 6 to 10 feet out, as directed on the label.

Before using any insecticide, always read the label and follow directions and safety precautions. It is much better to use preventative
practices than insecticides. Avoid chemical control if possible because these insects are considered beneficial and help control many
different insect pests.

Photo Credits:
Bastiaan M. Drees and Tim Trimble
Texas Cooperative Extension
The Texas A&M University System