TG27 - Stored Product Pest Monitoring Methods

This revision of Technical Guide 27 (TG 27), Stored-Product Pest Monitoring Methods, includes updated technical information and additional material not available when the TG was first published in 1992. The Armed Forces Pest Management Board (AFPMB) acknowledges the contributions of the following individuals to this revision:

Mr. Gary Walker, past Chair of the AFPMB Stored-products Protection Committee, served as principal author of the first edition of TG 27 published in June 1992. The following individuals also contributed to the first edition: members of the AFPMB Stored-product Protection Committee; research scientists from the USDA, ARS, Grain Marketing Research and Production Center, Manhattan, Kansas; Dr. Wendell Burkholder, USDA, Stored-products Insect Unit, Madison, WI; and members of the AFPMB. The following individuals contributed to this current revision: LCDR Eric Hoffman, Chair Quarantine/Stored Commodities Protection Committee, Capt Mary Ann Haberman, Vice Chair Quarantine/Stored Products Protection Committee, LTC William Sames, Dr. Herb Bolton, Dr. Mike Mullen, Mr. Gary Walker and Mr. Shannon Sked. AFPMB greatly appreciates their technical input and editorial comments for this TG.

Disclaimer

We have used trade names in this TG to provide specific information, but do not imply endorsement of specific products named or criticism of similar products not mentioned in this TG. Our reference to trade names does not constitute a guarantee or warranty of the products by the AFPMB, the military Departments, or the Department of Defense.

Foreword

Stored-product pests continue to present an important threat to cause considerable damage to military food and clothing worldwide. The Department of Defense (DoD) must ensure that effective integrated pest management (IPM) programs are established for stored-product pests that use all appropriate surveillance and control techniques currently available. This TG provides current information on insect monitoring systems, including pheromone lures and other trapping devices, which are appropriate for use in the stored-product pest programs within the Department of Defense.

SECTION 1. INTRODUCTION

A. Purpose. The purpose of this Technical Guide (TG) is to provide current information that DoD personnel can use to establish a stored-product insect monitoring program. The main emphasis of this TG is on pheromone and food attractant traps. Other insect monitoring/detection methods are also briefly discussed.

B. Background.

1) Stored-product insects may cause significant damage and loss to stored foods, fibers such as those used to produce uniforms, tents, blankets, and animal products such as leather. DoD personnel can minimize losses if infestations are quickly identified and the appropriate management measures implemented. Methods of identifying stored-product insect infestations at DoD installations include: product inspections (receipt, warranty, cyclic and issue), walk-through (visual) inspections, customer complaints, and accidental discovery by personnel. Product and visual inspections are both labor-intensive and time-consuming activities. Product inspection is subject to "luck of the draw" in finding an actual infestation when low level infestations are involved.

2) Numerous methods for detecting stored-product insects, particularly food pests, have been investigated. The most useful technique currently available is monitoring storage facilities with insect pheromones and/or food attractants. This technique is the key component of an integrated management program of stored-product pests. Other detection/monitoring methods that are useful in specific situations or that are being researched include carbon dioxide emission, acoustics, light traps, pitfall traps, product incubation, glue boards and immunoassay.

3) The incorporation of monitoring methods into existing stored-product pest management programs can lead to early detection of low level infestations and pinpointing hidden infestations. Monitoring has several distinct advantages. Information obtained from monitoring may be used to justify a reduction in pesticide use or the need for intensified surveillance and other pest management methods. Monitoring results can also serve as an indicator of how well the integrated pest management (IPM) program components are functioning.

4) Detailed information on individual monitoring methods and insect monitoring systems can be found in journal articles, research reports, and manufacturers' literature. A selected bibliography of publications is listed in Section 4. TG 25, Devices for Electrocution of Flying Insects (DEFLIs), provides guidance on electrocution type light traps.

SECTION 2. DEFINITIONS

Food Attractant. An oil or food extract (non-nutritive products are preferred) or synthesized scent that will attract a select group of insects. In some cases the food attractant is impregnated into an artificial medium. Oil food attractants are also used as killing agents or for trapping insects.

Food Attractant Trap. A device using a food attractant to attract insects. It is used for monitoring a group of insects (e.g., stored-product insects, soil insects). Some traps are designed to retain attracted insects. They are often combined with pheromone lures in a single trap.

Incubation. Process or procedure of keeping material in a favorable (optimum) environment in order to stimulate development of organisms/life stages (eggs, larvae, spores, bacteria, etc.) that may be present.

Lure. A small rubber or plastic device impregnated with or retaining a pheromone or food attractant. Lures are designed to release materials gradually over a designated period of time, either passively or by controlled release.

Pheromone. A chemical compound produced by an organism that initiates a behavioral activity in others of the same species. Pheromones are identified and synthesized to attract target insect species.

- Aggregation pheromone. A communication chemical predominantly produced by males that attracts both sexes. Effective compounds have been synthesized for stored-product insect species with long-lived adults (e.g., Tribolium) and species that need to feed to reproduce.

- Sex attractant pheromone. A communication chemical usually produced by females to attract the opposite sex. Effective compounds have been synthesized for stored-product insect species with short-lived adults (e.g., Lasioderma) and adults that do not need to feed to reproduce.

Pheromone Trap. A device utilizing a pheromone lure that attracts and captures insects, used primarily for monitoring particular species. However, in some situations these traps can aid in the suppression of insect populations. Pheromone traps may be combined with food attractants in a single trap.

Precision Targeting. A technique developed to rapidly monitor, assess and efficiently treat insect infestations. For stored-product pests, monitoring data from pheromone or food attractant traps are analyzed by spatial analysis.

SECTION 3. DETECTION/MONITORING METHODS

A. Pheromone/Food Attractant Traps (PFAT): Pheromones have been identified for many of the stored-product insects. Some synthesized lures have been commercially developed and a variety of trap designs are available. Pheromone traps have been used for monitoring many species of stored product pests in a variety of stored food commodities. PFAT monitoring has the potential for early detection of low-level and isolated infestations of certain stored-product insects.

1) Benefits of PFAT Monitoring.

a. Provide twenty-four hour a day monitoring.

b. Target a defined area of a facility.

c. Help pinpoint the location of an infestation.

d. Can reduce the amount of pesticide used for control by targeting the specific area to be treated and indicating when applications are necessary.

e. Can reduce the amount of product loss by early detection of insect

activity.

f. Easily moved around in a warehouse. Not labor intensive.

g. Non-toxic.

h. Do not involve additional product inspection (unless an infestation is indicated).

i. Provide tools for evaluation of the current pest management program.

j. Supplement other existing surveillance programs.

k. Reduce the amount of time inspecting stored products for signs and symptoms of pests.

2) Factors to Consider When Using PFATs.

a. Some traps will collect insects other than the target species; this can be advantageous in some circumstances.

b. Collected specimens in sticky traps may be difficult to remove intact for identification.

c. Some trap designs do not work well in dusty areas.

d. Floor-placed traps may frequently be lost or damaged.

3) Trap Selection.

a. Pheromone lures have been developed for several stored-product insects (Tables 1 & 2). Currently, sex pheromone lures developed for species with short-lived adults have proven to be more effective than those baited with aggregation pheromones. Good results have been attained with the lure for the Indianmeal moth and its’ close relatives and the cigarette beetle, Lasioderma serricorne. Trogoderma sp. and lesser grain borer, Rhyzopertha dominica. Pheromone traps baited with these lures should be used in dry subsistence storage areas. In addition traps baited with aggregation pheromone should be used for the flour beetles, Tribolium sp. Beetle traps are generally also baited with food attractant to enhance capture. The oil based food attractant will also attract other pest species such as sawtoothed grain beetle, Orizaephilus surinamensis, the merchant grain beetle, O. mercator, Khapra beetle/warehouse beetle (Trogoderma spp.) Attagenus and Anthrenus. Food attractants are especially effective for long lived insects and may aid in the capture of larvae. Oil baits should not be used beyond their indicated shelf life.

(1) Oil lures oxidize and solidify over time. Collected specimens may have to be freed from the oil before they can be identified. Polymerized oils need to be dissolved using an aromatic solvent (xylene).

(2) Researchers have used sesame oil in Khapra beetle traps as a substitute for the standard oil lure. Sesame oil can be quickly dissolved with a 5% detergent solution (a non-sudsing detergent such as automatic dishwasher detergent must be used for vacuum filtration of the rinsate). This method removes most of the oil from the collected specimens.

b. Lures for different species can be combined into a single trap.

(1) Cigarette beetle, warehouse beetle, lesser grain borer and Tribolium lures can be combined, as these insects are active on the floor or at relatively low levels in the warehouse. Lures for species that are active fliers can also be combined in a single trap (e.g., wing or hanging delta trap). Some traps are designed to hold as many as four different pheromones plus a food oil attractant.

Table 1. Surveillance information for moths commonly infesting stored-products (see Figures 1 & 2).

Adult Trap Lure Lure

Moths Stage Type Type Duration Effectiveness NSN (3740-01-xxx-xxxx) Notes

Almond Moth 3-7 days W,D,SR sex ~12 weeks good 414-8117 (kit-3 traps)

(Ephestia cautella) 414-8118 (25 lures)

418-1929 (100 lures)

418-5107 (100 wing traps)

418-5110 (25 wing traps)

Angoumois Grain Moth 2-14 days W,D sex 4 weeks good Open purchase Use any wing

(Sitotroga cerealella) or diamond trap

Indian Meal Moth 7-25 days W,D,SR sex ~ 3 months good 414-8117 (kit-3 traps)

(Plodia interpunctella) 414-8118 (25 lures)

418-1929 (100 lures)

418-5107 (100 wing traps)

418-5110 (25 wing traps)

Mediterranean Flour Moth 9-14 days W,D sex ~ 3 months good 414-8117 (kit-3 traps)

(Anagasta kuehniella) 414-8118 (25 lures)

418-1929 (100 lures)

418-5107 (100 wing traps)

418-5110 (25 wing traps)

Raisin Moth 7-14 days W,D sex ~ 3 months moderate 414-8117 (kit-3 traps)

(Ephestia figulella) 414-8118 (25 lures)

418-1929 (100 lures)

418-5107 (100 wing traps)

418-5110 (25 wing traps)

Tobacco Moth 3-14 days W,D,SR sex ~ 3 months good 414-8117 (kit-3 traps)

(Ephestia elutella) 414-8118 (25 lures)

418-1929 (100 lures)

418-5107 (100 wing traps)

418-5110 (25 wing traps)

_________________________________________________________________________________________________________________________________________________

Trap Type: W = Wing; D = Diamond; SR = Short range (SP locator)

Table 2: Surveillance information for beetles commonly infesting stored-products (see Figures 1 & 3).

Adult Trap Lure Lure NSN

Beetles Stage Type Type Duration Effectiveness (3740-01-xxx-xxxx) Notes

Black Carpet Beetle 30-60 days P, D sex/food 4 to 8 weeks good Open Purchase Use with any

(Attagenus megatoma) diamond trap or

addition to Dome trap

Common Carpet Beetle 30-60 days P, D sex/food 4 to 8 weeks good Open Purchase Use with any

(Anthrenus scrophulariae) diamond trap or

addition to Dome trap

Cigarette Beetle 14-42 days P,W,D sex/food 4 weeks good 414-9397 (25 lures) Use with any wing

(Lasioderma serricorne) trap or addition to Dome trap kits

Drugstore Beetle 14-60 days P, D sex 4 weeks good Open Purchase Use with any (Stegobium paniceum) diamond trap or addition to Dome trap

kits

Flour Beetles 180-1080 days P, food/ag. 4 weeks good 414-9393 (Dome trap kit)

(Tribolium spp.) 414-8123 (25 lures)

Lesser Grain Borer 90-180 days P,W,D sex/ag. 8 weeks good 414-9399 (25 lures) Use with any wing

(Rhyzopertha dominica) trap

Merchant Grain Beetle 90-125 days P food replace as needed good 414-9395 (Dome trap kit)

(Oryzaephilus mercator)

Sawtoothed Grain Beetle 130-1100 days P,GB food replace as needed good 414-9395 (Dome trap kit) Rodent glue board

(Oryzaephilus surinamensis) also works as

monitoring tool

Warehouse Beetle 14-28 days P,W,D sex/food 4 weeks good . 414-9391 (kit)

(Trogoderma spp.) 414-8124 (25 lures) _________________________________________________________________________________________________________________________________________________________________

Trap Type: W = Wing; D = Diamond; P = Pitfall (Dome trap); GB = glueboard; sex/ag. = sex and aggregation

Figure 1. Surveillance Traps: (a) Pitfall Dome trap, (b) Glue Board, (c) Wing Trap, (d) Diamond Trap

a. Pitfall Dome Trap

b. Glue Boards

Wing Trap

c. Wing trap

d. Diamond Trap

(2) The Tribolium spp. (Red/Confused Flour Beetle) lure should not be combined with an Indianmeal moth lure due to differences in flight activity of these insects. Indianmeal moth readily flies, red flour beetle can fly short distances, and the confused flour beetle does not fly. Therefore, trap placement and subsequent capture may not provide an accurate representation of the density/distribution of each of these species.

(3) Dermestid beetles are generally small, mostly black insects and as a group may become serious pests. Outdoors, dermestids (hide beetles) feed on dead carcasses or carrion and are important "recyclers" as they break down animal matter. Indoors, dermestids (carpet/furniture beetles) may damage woolens, stored foods, stuffed animals, and household furnishings, especially if made with animal matter (hair, skin, feathers, etc.). They are also serious pests of stored commodities such as dry pet food. Trogoderma spp. is a particular group of dermestid. Within this group, Trogoderma granarium or the Khapra beetle is particularly destructive, quarantine and medically important. Facilities that monitor specifically for Khapra beetle can place Trogoderma lures in suspended traps as well as wall-mounted or floor traps. The suspended traps will attract non-Khapra Trogoderma spp. Since Khapra beetles do not fly, these specimens would not require Khapra beetle verification. This will reduce the number of beetles requiring verification. Because the Khapra beetle is a quarantinable insect, if suspected, must have its identification confirmed by an expert in Khapra beetle taxonomy. (Note: Unless a CONUS facility receives material from another region of the world, especially Northeast Africa or Southwest Asia, it is unlikely the facility would have Khapra beetle. However, any collected specimens suspected of being Khapra beetle should be positively identified).

d. There are a variety of trap designs available (Appendix B). The adhesive surface of some traps is exposed (wing type, e.g., Serrico, Thin Line and Sanitrap) and can quickly become coated with dust and dirt. For dusty areas, the pitfall, funnel or other covered trap design would be more appropriate.

4) PFAT Placement in Food Warehouses with Infestible Products.

a. Initial trap density will vary according to the species of insect and the pheromone used. For Indian meal moth, trap density should be about 1 per 25,000 cu ft. Beetle traps should be arranged in a grid pattern at intervals of 25ft or less. Infestations can be pinpointed by increasing the trap density around areas suspected of containing infested stores.

b. Traps may be placed outside the warehouse and away from the building to determine if an infestation(s) is originating from an external source. Accurate identification of the species is critical if outside monitoring is conducted.

c. To reduce the chance of attracting insects from outside the facility, traps should not be placed within 30 ft of exterior doors or open windows.

d. Traps should be placed to minimize damage to the traps from normal facility operations.

(1) Most beetle traps are designed to lie flat. However, depending upon design, some traps can be mounted on vertical structures/walls, pallet rack systems or pillars.

(2) Wing type and most funnel traps need to be suspended, which can limit their placement in warehouses. Nevertheless, they should be placed as close to dry pet food and breakfast cereal areas as possible because these products are prone to infestation by Indian meal moth. The traps can be hung from small pulleys over or near pallets, allowing them to be out of the way but still accessible. The trap height for Indian meal moth can range from 6-30 ft.

e. If highly infestible products are consolidated into a few areas, concentrate trap placement in those areas.

5) Trap Monitoring.

a. In temperate climates, PFATs should be utilized from at least April through October. In warm climates or where heated warehouses are utilized, year-round monitoring is recommended and traps or lures should be changed more frequently as they tend to lose attractiveness over a shorter period of time.

b. Pest management personnel should maintain an accurate map or listing of trap locations.

c. Traps should be checked on a weekly basis, and a log or record sheet of catches maintained. Trap and/or lure replacement and other actions should be documented for maintenance purposes or precision targeting.

d. For those traps that contain insects:

(1) Determine if target stored-product insects were collected.

(2) Record the number of each species/type collected.

(3) To prevent specimens from being recounted on sticky traps, they should be removed, marked, or the trap should be replaced.

(4) If justified (paragraph 3.A.7)), trap density should be increased in the area where activity is evident. This will help pinpoint the location of the infestation. These additional traps should be checked daily.

(5) Appropriate pest management procedures should be implemented when a stored-product infestation is located. After the insect source is eliminated, monitor the facility at the former trap density.

(6) Representative samples of collected specimens and a DD Form 1222 (Appendix D) should be sent to a military laboratory for identification (Appendix A).

(7) Traps will also collect non-target insects. It is advisable to have a verified, representative reference specimen collection available to aid in identifications or in separating target from non-target insects.

(8) The presence of large numbers of a non-stored-product insects (e.g., Phoridae, Psychodidae, Drosophilidae) in traps indicates other potential pest management problems (e.g., leaking product, dirty drains, etc.) that need to be located and eliminated.

6) Trap Maintenance.

a. Replace damaged and dirty traps as necessary. Lures from such traps should be reused if possible. Moth lures may be used up to 6 months and beetle lures 1 to 3.5 months, depending on the specific lure. Damaged or unusable lures must be destroyed and not left on or near the premises because these lures can attract insects.

b. Lures should be handled with tweezers (forceps) or rubber gloves to avoid contamination of the lure. Staples or other fastening methods that damage the surface of a lure can reduce its longevity and/or effectiveness.

c. Unused lures should be stored in a refrigerator or freezer to reduce oxidation and to maintain their shelf life of approximately 2+ years. Refer to the manufacturer’s instructions that accompanied the lures for specific product information.

d. Traps require regular monitoring and good maintenance of the bait or attractant. If neglected, traps may become the foci for infestations. The more rapid monitoring techniques used in precision targeting may eliminate the need for trap maintenance.

7) Interpretation of Trap Catch for Target Species.

a. Catch over time for the trap at each location is evaluated instead of the total catch for all traps in a warehouse or bay. The trends and patterns for collections in each trap are what is important.

b. 1-2 specimens collected in a week at scattered locations. If this situation occurs infrequently, then the catch is probably incidental. The specimens probably wandered in or came in on pallets or packaging.

c. A few (2-5) specimens collected on a regular basis in the same location. This catch probably represents a small infestation. The trap density in the area of the suspected infestation should be increased and product inspection considered. Exception: The trapping efficiency for Dermestid larvae. A catch of more than 1 larva in a week requires greater scrutiny of an area and a catch of greater than 2 should be considered a probable infestation.

d. Several (6-9) specimens collected weekly. This catch indicates that a small to moderate infestation may be present. Trap density and monitoring frequency should be increased to identify the extent of the infestation. Product inspection should be initiated.

e. Numerous (10+) specimens collected in a trap. This situation indicates that an active infestation is present and that immediate action should be taken to isolate and control the stored-product pest. Often, this results from an already infested pallet of material being brought into the warehouse. Pinpointing the source of such infestations quickly will help minimize the spread of the infestation. Product inspection is necessary. Additional traps should be placed in the area to aid in determining the extent of the infestation.

NOTE: The above numbers are to be used as guidelines. There are no "magic" or standardized numbers to correlate trap catches to actual infestation levels. Each storage facility must be evaluated individually. Generally, any deviation from a normal trend or baseline indicates a point where additional integrated pest management actions are necessary. The type of product and the species collected should also be considered when determining the severity of an infestation. Additionally, if a Khapra beetle(s) is (are) collected and verified from a CONUS facility, USDA eradication procedures must be followed.

f. Trap catches may also be used to determine the seasonality and migration of the target species at a storage facility. This information can be used in refining the pest management programs for the facility. For example, insects may migrate into the facility from surrounding areas during seasonal change (fall) or environmental modification (harvest activities). As a result, this may require additional attention by the pest manager to avoid the establishment of insect populations.

B. Glue Boards. In addition to rodent and cockroach surveillance, glue boards may be used to monitor stored-product insects (e.g., flour beetles and sawtoothed grain beetles). The traps must be deployed at a higher density than that required for PFATs when used for monitoring stored product insects. They can also be used to supplement PFAT or to target specific areas (e.g., areas surrounding an identified infested product location). There have been reports of insect repellency by some traps. This repellency varies among traps from the same manufacturer and may be due to minor variations in individual glue lots. Trap effectiveness may be increased by placing a small amount of product (i.e., pasta, dry pet food, peanut butter, etc.) on the trap.

C. Acoustics. Use of acoustics to monitor stored-product pests is still experimental and is not a practical method for use in DoD at this time. Researchers have shown it is possible to detect insect activity in certain packaged commodities at depths of 2-6 cm using highly sensitive microphones. Some problems that still need to be overcome include poor sound transmitting characteristics of some commodities, detection of the smaller species of stored-product insects, and screening out or separation of product and other background noise from insect-generated noise. Until acoustics is validated and becomes an established procedure in the food industry, the AFPMB does not recognize it as a practical method for monitoring stored-product insects at DoD installations.

D. Light Traps. Research on the effectiveness of light traps for monitoring and suppressing stored-product pest populations has involved two basic types of light traps, 1) Devices for Electrocution of Flying Insects (DEFLIs) and 2) suction traps. The limitations of light must be kept in mind. In general, light traps primarily collect flies and few stored-product pests. Although light trap data may provide some useful information, there are no direct correlations with other monitoring data. The need to keep light traps clean and maintained cannot be overemphasized. If not kept clean, these traps can become a source of infestations.