The Pest Monitor

The question from the last newsletter--You get a call about small flies occurring in an account. What insect or insects might be involved in an infestation of this type and what approach will you use in dealing with a complaint of this nature?

There are several flies that might be involved in the complaint. First, consider the time of the year. If it is in early summer and people are bringing in fresh vegetables, it could well be fruit flies, family Drosphilidae (Fig. 1). Adult flies are about 3 mm long, with a yellowish body and red eyes. These flies will feed and lay eggs in fermenting fruit, and they can go from egg to adult fly in 10 to 15 days. The cycle may be completed in as short as 8 to 10 days. Temperature is the variable which will dictate the time. The warmer the temperature, up to a point, the faster the cycle. Eggs or late instar larva might be brought into the house on overripe fruit, and it will not be long before small flies are flying about in the house. Other evidence that would suggest a fruit fly infestation is the occurrence of the flies in the kitchen, at least initially. They could move into other rooms by chance, or they could move toward lights in dens or living rooms in the evening.

It is possible that a fruit fly infestation might occur at other times of the year. For example, fruit flies might come into the house on material purchased at the grocery store or at roadside stands. Infested material might be bananas, onions or potatoes, etc., especially if there are small decay spots on the produce or if the bananas are overripe. Again, the infestation would initially center around the kitchen.

If the flies are in the kitchen and there does not appear to be infested produce or fruit, don't overlook the garbage disposal, if one is present. These units might not be working properly, and the flies will move into the refuse that remains in the disposal.

Another fly to consider is the moth fly or drain fly, family Psychodidae (Fig. 2). These dark colored flies are about 2 mm long, usually very hairy and moth-like in appearance. The wings are held roof-like over the back. This fly will be found mostly in rooms with drains which may not get much use. Females will lay eggs in these drains and the larva will develop in the gelatinous material which accumulates on the sides of the drains--very rarely, if ever in the standing water in the trap.

I received a larval sample from the northern part of the state several years ago. This particular sample had come from a jail which was under contract (for pest control) and the owner had received a complaint about these larva in one of the shower units. It seems that the inmates were complaining about "sperm worms" in the shower. They turned out to be drain fly larva.

Rooms might include bathrooms or laundry rooms and maybe kitchens; however, kitchen drains usually get so much use that the flies cannot get established in this area. If it=s a commercial account, don't overlook floor drains.

Management Options. One option for both groups is to use a space spray containing pyrethrins for adult control; however, it will not be long before the phone will ring again and you will hear, "They're back." What about identification? This will give you valuable information. It will lead you to possible sources of the infestation which will give you and the client the control you are looking for and will eliminate that phone call. If the identification proves the insect to be fruit flies, then looking for and eliminating the infested material would be the control option of choice. If adults are still present, the space spray could be used to remove the existing adults. One possibility that is not covered under this scenario is that the flies are coming from the outside. They are relatively small and some might be able to pass through the mesh in window screens. If this is the case, then controls are going to be complicated and they would probably not fall under the duties of the pest control technician.

The identification could prove the specimen to be moth flies, and this will direct you to the drains. Question which drain if there is more than one? Small clear containers can be placed over the drains for 24 to 48 hours and inspected for the presence of flies. If flies are present, cleaning will be the control option of choice. Some have tried pouring various materials down drains; however, it is doubtful that this material ever penetrates the slime layer on the side of the drain. To my knowledge, there are no insecticides that are registered for drain fly larval control.

A bottle brush or other device that fits snugly into the drain can be used. That area from the sink or lavatory outlet to the top of the water in the trap should be brushed, vigorously, in order to remove the slime layer. After brushing the drain should be flushed.

A question that needs to be considered is "should the technician undertake to look for fruit fly or moth breeding areas or to clean drains?" These activities can be time consuming and can not be done as quickly as some treatments; however, these are viable pest control methods. If you choose not to undertake these control practices, give the client some options. This might include providing the client an identification and suggesting they look for infested produce or check and clean drains or hire the services of a plumber. Give the client options, don't just leave them hanging.

There are three other groups of flies that might be involved in an infestation. I will continue the fly discussion in the first newsletter for 2001. If your choices are not in this article, they might be in the next one. In lieu of this continuation, there will not be a new quiz question.

The black carpenter ant, Camponotus pennsylvanicus, is probably the most encountered member of this genus in the state, at least in the northern half. This might be doubtful as we move toward the coast. Be that as it may, as the header states, "will carpenter ants nest within structures" or are the nests located in surrounding trees and the ants forage into structures from these nest sites? There are two ways that can be used to arrive at an answer-- literature and personal observations. First the literature.

Hedges (Structure-Infesting Ants, PCT) states "Carpenter ants also readily nest in any moist or humid, hollow void. Colonies can also be found living in voids which are seemingly dry." Hedges goes on to list a number of void nesting sites. Some that may be found in structures are under attic insulation, wall voids, voids under bay windows, hollow wooden doors, under bathtubs, etc. The above statements are not associated with any particular species. Hedges further states, "If the structure has a chimney, it is important to inspect the walls on either side of the chimney for carpenter ant colonies." He makes other statements as well, such as "look for piles of sawdust."

The eighth edition of Mallis, Handbook of Pest Control (1997) references several authors who describe carpenter ants nests as occurring within structures. I will list two from the above edition of Mallis. Furniss (1944) states "when a house becomes thoroughly infested, there is little likelihood that the fact will be long unnoted by the human occupants. On warm sunny days in the spring, people become aware of carpenter ant infestations when the "swarmers" appear and congregate around windows. A faint, rustling sound in walls, floors and woodwork is another common clue to the presence of carpenter ants." Furniss work was done in Oregon. Closer to home Vail et. al. (1994) state that most interior nests of C. tortuganus are located within voids or under insulation in structures. This carpenter ant is found only in southern Florida.

Now for the personal observations. I have received "frass" (Fig. 3) from pest control professionals and from county extension agents with an accompanying statement from a client "this material appears at about this same location -- I will clean it up and it is back in four or five days." The sample will contain small bits of chewed wood, insect parts, carpenter ant bodies and in some cases small silk-like sacks. These "refuse piles" may occur on a floor, window sill or other locations. I have experienced the same thing in my home around the window in the dining room. I believe this "refuse material" is related to carpenter ants which are nesting within the structure.

One final observation. I found a carpenter ant colony (C. pennsylvanicus) in a building between layers of stacked lumber (Fig. 4). The wood was sound and evidently, the ants had been there for some time based on the amount of "frass" (Fig. 5) that was present.

Based on the above discussion, I believe that carpenter ants can and do nest within structures. This does not mean that they will not forage into structures from surrounding trees.

Carpenter ant control becomes more difficult because one must determine if the nest is in the structure or outside. If it is outside, it is probably easier to find and treat than if the nest is within the structure. Carpenter ants are most active late in the day or early evening. Inspections should coincide with this period of activity.

If a discussion dealing with pest control goes for very long, the topic of pre-treatments soon finds its way into the conversation. Pretty soon someone will say that x company is charging eight cents per square foot or six cents, etc. Or that a company is driving from somewhere in another state to do a treatment at a government facility, in let's say, Columbus. Or that a pest control professional driving a small pick-up with a 100 gallon tank arrives at a treatment site containing several thousand square feet of treatable surface. I do not know if any of these points are valid. I do know that one will hear the same things discussed, with minor variations, in just about any part of the state.

The following is a fictitious case study for discussion purposes so that we can be more or less talking about specifics:

Foundation Type: Supported Slab. The slab will rest within the foundation walls on the "L" shaped block at the top of the wall.

Horizontal Barrier: 5,000 sq. ft treated at 1 gallon/10 sq. ft, 5000 � 10 = 500 gallons.

Vertical Barrier: Applied to inside (at time of pretreat) and outside (after finished grade) of foundation wall, consider the soil adjacent to the foundation wall to be 2 ft deep, inside and outside. This application is applied at 4 gallons/10 linear feet/foot of depth. Linear feet equal 100 + 100 + 50 + 50 = 300 linear feet. 300 � 10 = 30 gal, 30 gal x 2 ft of depth x 2 treatments x 4 gallons = 480 gallons.

Hollow Block Wall: The soil under the footing was not treated, hence the blocks should be treated at 2 gallons/10 linear foot. 300 divided by 10 = 30; 30 x 2 = 60 Gallons.

Chemical Cost per Mixed Gal.	Total Gallons	Cost x Gallons Col. 1 x Col. 2	Price/Sq. Ft Col. 3 � 5000 sq. ft
$1.30	1040	$1,352.00	$0.27
$0.90	1040	$936.00	$0.19
$0.60	1040	$624.00	$0.12

The above discussion does not include any chemical for critical areas, and the only cost covered in the chart is chemical. Other expenses that should be included are labor, vehicle operation, equipment, insurance, employee wages, benefits and, of course profit, etc.

Total Volume. The total volume for this case study is 1040 gallons--800 gallons applied at the time of the pretreatment. The remaining 240 gallons (outside perimeter treatment) will be applied after final grading and landscaping. This volume might vary from state to state based on label interpretation. To quote a price, one must know foundation type and size in order to compute the total volume. All too often, one hears that one can get a price by telephone without having told the company any foundation details.

Based on my calculations of 800 gallons, the person with the 100 gallon tank would have to leave the job site 8.0 times to refill, barring an available water source on site. Most of the time a water source is not available. Consider the person who drove to Columbus from another state with a 100 gallon tank--what options does this person have, are they going to drive back home 8 times? Of course not. If this is a governmental installation and a U.S. Attorney becomes involved, it would appear that the charge would be fraud.

Cost. A number of variables may dictate the cost of a particular treatment. Newer products tend to cost more than older products. Older products that have lost their patent may cost less than the product from the original manufacturer, special sales or promotions by suppliers or manufacturer, business volume, etc. The computed values above show a range from high to low and should take into account some of the things which will cause price to vary. At the high end, the price per square foot is 27 cents and the low is 12 cents, with an intermediate value of 19 cents. All three square foot charges are higher than the often discussed prices of six to eight cents. Of course, if the chemical price is less than $60.00 a mixed hundred, the square foot charge will be less. In today's market, does this price exist?

I have heard termite pretreatment pricing discussed for some 15 to 20 years and it is always the same--some companies will charge less than other companies. We are not talking about one or two cents. Compare eight cents with any value in the included chart. There is nothing wrong with competition but why is there such a wide range in pricing? People have to pass the licensing test and some questions deal with figuring a pretreat and they pass. Companies have in-house training programs which go into termite treatments and how to figure the volumes and concentrations, and technicians pass these programs. Label directions are available which give information on pretreats, and everyone with a license can read. Some explain this difference by saying "it's just a rogue operator" or "a manager decides to cut corners." Is this true or is it more widespread? If anyone has a plausible explanation and would like to share it, I will be glad to include it in the next newsletter. One more question--could or should NPMA take more of an active role in this discussion?

As we close out 2000, I wish for each of you a joyous Holiday Season. May your Thanksgiving be a time to give Thanks as a Family and your Christmas season be Joyous.

James H. Jarratt, Ph.D.
Box 9775
Mississippi State, MS, 39762
jjarratt@entomology.msstate.edu