Trail-following behavior in the German cockroach (Dictyoptera: Blattellidae)

The trail-following behavior of the German cockroach, Blattella germanica (L.), was evaluated by comparing the distance between cockroach movement paths and preapplied "trails" of fecal extract. For each cockroach group tested (adult males, females, gravid females, and late instars), the mean perpendicular distance of the cockroach from the trail was significantly less than the distance from a control trail. The results indicated that the German cockroaches did exhibit trail-following behavior. Trail- following accuracy varied among the cockroach groups. The mean distance from the fecal trail ranged from 18.45 to 110.05 cm with adult males < or = adult females < or = late instars < gravid females. Very dilute fecal extract could still induce trail-following behavior in adult male cockroaches. A 5.6% concentration of fecal extract in methanol was able to induce trail-following behavior in 50% of the cockroaches. Although German cockroaches have demonstrated trail-following behavior, fecal trails are still not thought to be actively deposited. Rather, the passive distribution of fecal material within the home range results in the accumulation of trails along frequently traveled routes (i.e., between resources and the cockroach harborage).     

Comparison of several traps for catching German cockroaches (Dictyoptera: Blattellidae) under laboratory conditions

German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae), catch by five types of traps and modifications of each, were tested under controlled laboratory conditions. Cockroach catch differed significantly among traps. Lo-line trap caught the greatest number of cockroaches in the test arena for each size class (23% small nymphs, 39% of gravid females, and 60% of other size classes in the experimental arena). Jar traps caught the least number of cockroaches in the test arena for each size class (range, 7-23% of each size class trapped). Modifications of traps also altered catch of cockroaches. Food bait tablets increased catch significantly; however, increases were small (<10%). Size of traps did not affect catch; whole traps or half traps caught the same number of cockroaches. Jar traps were much less effective than sticky traps, catching only half the number of cockroaches as sticky traps. A thin layer of petrolatum was a more effective barrier in jar traps to cockroach escape than powdered Olancha clay. Traps with petrolatum caught about twice as many cockroaches as traps with clay. Trapping of any of six life stages was not significantly affected by catch of any of the other stages. Rather, trap catch of each life stage was dependent on the number of that life stage available in the experimental arenas. In conclusion, of the traps tested, the Lo-line trap was the most sensitive for measuring cockroach catch, whereas the Detector trap (one third of trap) was the most economical trap (greatest sensitivity for lowest cost).     

Laboratory and field performance of an imidacloprid gel bait against German cockroaches (Dictyoptera: Blattellidae)

An experimental 2.15% imidacloprid gel bait containing approximately 44% water was evaluated in laboratory and field studies against the German cockroach, Blattella germanica (L). In continuous exposure tests, toxicity and presumably bait consumption varied with cockroach stage, deprivation of competitive food, and temperature. The LT50 values for cockroaches provided with competitive food ranged from approximately 0.9 h for adult females to 190 h for small nymphs. The LT50s for cockroaches not provided competitive food ranged from approximately 1.7 h for adult females to approximately 31 h for adult males. The LT50s decreased exponentially with temperature between 10 and 30 degrees C. Even though the bait was significantly more repellent (approximately 38%) than an untreated control (approximately 14%) when tested in Ebeling choice boxes, performance index values were positive and increased to nearly 100 (indicating high mortality and low repellency) after 14 d. When applied at 15-45 g per kitchen, the bait significantly reduced German cockroach trap catch in infested homes during a 4-wk period. There was a approximately 50% reduction after 1 wk and approximately 80% reduction 4 wk after treatment.     

Evaluation of attractants for monitoring populations of the German cockroach (Dictyoptera: Blattellidae)

Lures that are used to attract German cockroaches, Blattella germanica (L.), to traps were compared in olfactometer assays in the laboratory and in trapping experiments in cockroach-infested homes and a swine farm. In olfactometer assays, AgriSense GP-2 was the most attractive lure, followed by peanut butter, and distiller's grain. Other lures, including Trapper tablet; Victor pheromone, a crude fecal extract that ostensibly contains B. germanica aggregation pheromone; and Victor food lure elicited upwind orientation from <50% of the test insects. Peanut butter and distiller's grain were equally attractive in trapping experiments in swine production barns and they captured significantly more cockroaches than the GP-2 tablet or the Victor pheromone lure; the commercial lures failed to attract significantly more cockroaches than the unbaited control traps. When tested against blank controls, cockroaches preferred to rest in shelters that contained the aggregation pheromone-based lure (Victor), but this lure was the least attractive to cockroaches in olfactometer assays. These results do not support claims that commercial crude fecal extracts attract cockroaches to traps, and they highlight a need for developing more attractive lures for detection of cockroaches and for monitoring populations.     

Cost and efficacy comparison of integrated pest management strategies with monthly spray insecticide applications for German cockroach (Dictyoptera: Blattellidae) control in public housing

The long-term costs and efficacy of two treatment methodologies for German cockroach, Blattella germanica (L.), control were compared in the public housing environment. The "traditional" treatment for German cockroaches consisted of monthly baseboard and crack and crevice treatment (TBCC) by using spray and dust formulation insecticides. The integrated pest management treatment (IPM) involved initial vacuuming of apartments followed by monthly or quarterly applications of baits and insect growth regulator (IGR) devices. Cockroach populations in the IPM treatment were also monitored with sticky traps. Technician time and the amount of product applied were used to measure cost in both treatments. Twenty-four hour sticky trap catch was used as an indicator of treatment efficacy. The cost of the IPM treatment was found to be significantly greater than the traditional treatment, particularly at the initiation of the test. In the first month (clean-out), the average cost per apartment unit was dollar 14.60, whereas the average cost of a TBCC unit was dollar 2.75. In the second month of treatment, the average cost of IPM was still significantly greater than the TBCC cost. However, after month 4 the cost of the two treatments was no longer significantly different because many of the IPM apartments were moved to a quarterly treatment schedule. To evaluate the long-term costs of the two treatments over the entire year, technician time and product quantities were averaged over all units treated within the 12-mo test period (total 600 U per treatment). The average per unit cost of the IPM treatment was (dollar 4.06). The average IPM cost was significantly greater than that of the TBCC treatment at dollar 1.50 per unit. Although the TBCC was significantly less expensive than the IPM treatment, it was also less effective. Trap catch data indicated that the TBCC treatment had little, if any, effect on the cockroach populations over the course of the year. Cockroach populations in the TBCC treatment remained steady for the first 5 mo of the test and then had a threefold increase during the summer. Cockroach populations in the IPM treatment were significantly reduced from an average of 24.7 cockroaches per unit before treatment to an average 3.9 cockroaches per unit in month 4. The suppressed cockroach populations (< 5 per unit) in the IPM treatment remained constant for the remaining 8 mo of the test.     

Comparative study of integrated pest management and baiting for German cockroach management in public housing

This study assessed the cost and effectiveness of a building-wide cockroach integrated pest management (IPM) program compared with bait alone treatment in public housing. In total, 12 buildings (66 apartments) were treated and monitored for cockroach infestations over 7 mo. The buildings were divided into two groups: bait treatment and IPM. Apartments in the bait alone group were treated with Maxforce FC Select (0.01% fipronil) during the first 12 wk and Maxforce Roach Killer Bait Gel (2.15% hydramethylnon) from 16 wk when necessary. For the IPM group, cockroaches were flushed and vacuumed at the beginning of the study; sticky traps were placed in all apartments to monitor and reduce cockroach numbers; educational materials were delivered to the residents; and Maxforce FC Select and Maxforce Roach Killer Bait Gel were applied to kill cockroaches. Two seminars were presented to the manger, and Community Service Program staff of the Gary Housing Authority to help gain tenant cooperation in the program. Effects of the treatments were monitored using sticky traps (six per apartment) at 2, 4, 8, 12, 16, and 29 wk after treatment. More treatments were applied during each monitoring visit when necessary. Those apartments with high levels of infestations (> or =12 cockroaches in six traps) before treatment were used to compare the IPM and bait only treatments. IPM resulted in significantly greater trap catch reduction than the bait treatment. The IPM (n=12) and bait only treatment (n=11) resulted in 100.0 and 94.6%, respectively, reduction in trap catch after 16 wk. At 29 wk, only one apartment in the IPM group had a high level (>12 cockroaches) of cockroach infestation. In contrast, five apartments in the bait treatment group had high level infestations at 29 wk based on overnight trapping counts; thus, IPM is a more sustainable method of population reduction. Sanitation levels in the IPM group significantly improved at 29 wk (n=11) compared with that at the beginning of the study. The sanitation levels in the bait treatment group remained similar throughout the experiment (n=9). The cumulative cost of IPM was significantly higher than that of the bait treatment. The median costs per apartment during 29 wk were 64.8 dollars and 35.0 dollars for the IPM and bait treatment, respectively. The median amount of bait used per apartment in the IPM and bait treatment was 45.0 and 50.0 g, respectively. The cost of the IPM group for the 29 wk service was similar to that of the bait treatment group. We expect that IPM will provide better control at similar cost compared with bait treatment beyond 29 wk.     

Residual activity and population effects of noviflumuron for German cockroach (Dictyoptera: Blattellidae) control

A benzoylphenyl urea insect growth regulator with the common name noviflumuron was evaluated for efficacy and residual activity on the German cockroach, Blattella germanica (L.). In laboratory studies evaluating residual activity, 0.05% noviflumuron suspension concentrate produced 100% nymphal mortality 120 d after application to steel and masonite substrates. Residual activity of noviflumuron was more variable on painted plywood substrates compared with stainless steel and masonite. In bioassay arenas, population reductions caused by noviflumuron were significantly greater than Archer and the untreated populations. After 16 wk, populations exposed to 0.05, 0.1, and 0.2% noviflumuron were reduced by 51.9 +/- 19.8, 62.2 +/- 6.5, and 62.6 +/- 18.4%, respectively. Control cockroach populations and populations exposed to 1.3% pyriproxyfen at labeled rate (Archer, 0.61 g/m2) increased by 1286.3 +/- 125.1 and 937.2 +/- 137.1%, respectively, at the end of 16 wk. A field study in multifamily housing complexes showed noviflumuron (0.2 and 0.5%) to provide 73.3 +/- 8.0 and 90.6 +/- 3.6% trap catch reduction at 4 wk posttreatment, respectively. There were no significant differences in the performance of noviflumuron, Maxforce FC Roach Bait Stations (0.05% [AI] fipronil), and Avert dust bait (0.05% [AI] abamectin B1). Noviflumuron shows excellent potential for use in cockroach management programs.     

Cost-effectiveness of integrated pest management compared with insecticidal spraying against the German cockroach in apartment buildings

This study assessed the cost and effectiveness of an integrated pest management (IPM) program using hydramethylnon gel baits compared with conventional spraying for controlling the German cockroach, Blattella germanica (L.) (Blattodea: Blattellidae), in two residential buildings in Yasuj, Iran. The IPM approach was based on educational programs using pamphlets, posters and lectures, sanitation using vacuuming and application of hydramethylnon gel baits. Conventional approach used cypermethrin (10% EC) on baseboard and cracks-and-crevices. Sticky traps were used as tools for monitoring cockroach population densities. The IPM approach reduced (943%) the rate of insecticide application compared to the conventional spray. Cockroach populations in the IPM treatment were significantly reduced from an average of 12.2 ± 3.01 cockroaches per unit before treatment to zero cockroach per unit by week four and thereafter. Cockroach populations in the conventional spray treatment were reduced from an average of 11.5 ± 4.43 cockroaches per unit before treatment to an average of 3.4 ± 0.99 cockroach per unit after 11 weeks of post treatment. The IPM treatment improved 100% of infested units compared to 78% for spray treatment to obtain a clean level of infestation (< 1cockroach per trap per unit). The results suggest that the intervention by IPM using hydramethylnon gel baits significantly reduced cockroach infestation compared to cypermethrin spray throughout the 11 weeks of post-treatment period. However, within the study period, the IPM system involving gel baits, educational program and sanitation was 363.2% more expensive than the conventional method.     

Logistic models describing effects of temperature and humidity on residual effectiveness of chlorpyrifos and cyfluthrin formulations against German cockroaches (Dictyoptera: Blattellidae).

Multifactored logistic models were developed for chlorpyrifos and cyfluthrin formulations based on mortality data from laboratory studies with the German cockroach, Blattella germanica (L.). Insecticides were applied to stainless steel surfaces and aged at three different temperatures (23, 30, and 37 degrees C) and two levels of relative humidity (40 and 70%). After the insecticides dried, the treated panels were placed opposite plywood panels to simulate a crack and crevice application. At appropriate aging times, treated panels were removed from environmental chambers for bioassay. The combined effects of high temperature, high humidity, and aging of residues caused the greatest decline in cockroach mortality for chlorpyrifos. Increasing temperature and aging of residues resulted in decreased cockroach mortality for cyfluthrin formulations; however, mortality was greater than 87% for all formulations through 84 d. Information from this study can be incorporated into integrated pest management programs for German cockroaches.     

Toxicity of abamectin to cockroaches (Dictyoptera: Blattellidae, Blattidae).

Abamectin was fed to German cockroaches, Blattella germanica (L.), in non-choice tests. LT50s and LC50s were estimated by probit analysis. The LT50s for the German cockroach ranged from 4.4 to 1.7 d for males, from 9.0 to 2.4 d for females, and from 4.4 to 1.6 d for nymphs for bait concentrations of abamectin between 0.0025 and 0.0500%. The LC50s of abamectin were 0.0110 and 0.0040% from males, 0.0240 and 0.0090% for females, and 0.0200 and 0.0080% for nymphs at 3 and 6 d, respectively. The LT50 values of 0.0550% abamectin bait were 3.4, 3.4, 2.4, 7.5, 2.9, and 4.5 d for Periplaneta americana (L.), P. fuliginosa (Serville), P. brunnea Burmeister, P. australasiae (F.), Blatta orientalis L., and Supella longipalpa (Serville). Although the bait was effective against various cockroach species, time to death for the larger species was longer than for the German cockroach. In preference tests in which male German cockroaches were allowed to feed on rat chow or abamectin bait, all died within 5 d of exposure to abamectin bait. Abamectin bait consumption was not significantly lower than that of untreated rat chow. Arena tests with 0.0550% abamectin bait resulted in 31-75% mortality of German cockroaches after 9 d, with most control being achieved by treating harborages with the bait. The hydramethylnon standard resulted in 65% mortality after 9 d.     

Novel extraction of German cockroach (Dictyoptera: Blattellidae) fecal pellets enhances efficacy of spray formulation insecticides

Methanol extracts of German cockroach, Blattella germanica (L.), fecal pellets have limited use as pheromone attractants in the urban environment because of their unpleasant color and odor. To eliminate these characteristics, a novel aqueous extract of German cockroach feces was formulated. Fetal material was extracted with methylene chloride and mixed with water. The aqueous phase of the extract was colorless and relatively odorless compared with methanol fecal extracts. Aqueous extract was bioassayed and compared with methanol extracts for aggregation activity. The efficacy of chlorpyrifos and boric acid formulations was tested with and without the addition of fecal extracts. In tests with chlorpyrifos, the addition of the aqueous extract produced significantly greater mortality in young nymphs than either chlorpyrifos alone or chlorpyrifos + methanol extract. There were no differences in mortality between the 2 extract + boric acid treatments during the test period, and both enhanced mortality.     

Laboratory and field performance of consumer bait products for German cockroach (Dictyoptera: Blattellidae) control.

Bait formulations containing boric acid, chlorpyrifos, or hydramethylnon were evaluated in field and laboratory experiments against the German cockroach, Blattella germanica (L.). In continuous exposure tests, chlorpyrifos formulations produced 100% mortality in less than 24 h, boric acid formulations had LT50's of approximately 5.5 d, and hydramethylnon had an LT50 of 0.86 d. LT50's estimated in Ebeling choice boxes were 1.6 to 10.8 times greater than those from continuous exposure tests for chlorpyrifos formulations and 2.5 times greater for the hydramethylnon formulation. The same LT50's were produced by choice box and continuous exposure tests for boric acid formulations. Relative repellency, measured as the mean percentage of live cockroaches in the light side of the choice box, was greatest for chlorpyrifos formulations, followed by boric acid formulations, then hydramethylnon. A performance index (PI) that combined choice box repellency and mortality data indicated that hydramethylnon (Combat) had the greatest potential for field effectiveness. Only hydramethylnon significantly reduced German cockroach populations in the field. Apartments treated with the IT WORKS formulation of boric acid bait had significantly greater cockroach trap catches. The PI is an accurate predictor of the field performance of toxic baits for German cockroach control.     

Laboratory and field performance of an indoxacarb bait against German cockroaches (Dictyoptera: Blattellidae)

Experimental indoxacarb powder and gel baits were evaluated in the laboratory, and a gel bait was evaluated in subsequent field studies against the German cockroach, Blattella germanica (L.). In continuous exposure tests, LT50 values were 1.90 and 1.10 d for 0.25 and 1% indoxacarb powder baits, respectively. However, 0.25% indoxacarb gel bait had an LT50 value of 0.68 d, similar to a 0.05% abamectin gel bait formulated with the same bait base. There was no difference in toxicity between fresh and 7-d-old gel bait deposits. A pyrethroid-resistant strain of German cockroaches was significantly resistant to both abamectin and indoxacarb gel baits. Gel bait contained approximately 40% water, desiccated rapidly at 25-28 degrees C and 30-45% RH, but did not rehydrate when held at 56.7% RH for 3 d. Powder indoxacarb baits contained <1% water and did not desiccate or gain water. Indoxacarb gel bait (0.25%) was relatively nonrepellent (approximately 30%) and had positive maximum performance index values (approximately 100) in Ebeling choice box experiments. In field experiments in cockroach-infested kitchens, the 0.25% indoxacarb gel bait significantly reduced visual counts of German cockroaches approximately 74% at 3 d and >95% at 14 d. Indoxacarb baits are toxic, relatively nonrepellent, and can significantly reduce German cockroach populations.     

Comparison of two bioassay methods for determining deltamethrin resistance in German cockroaches (Blattodea: Blattellidae)

Susceptibility to deltamethrin of 10 strains of the German cockroach, Blattella germanica (L.), trapped in hotel kitchens in Singapore was determined. Two resistance detection bioassay methods (topical application and World Health Organization glass jar method) were compared. Resistance ratios based on 50% knockdown, obtained by comparison with the S strain, ranged from 17.7 to 4,235 for topical application and from 2.2 to 22 for the glass jar method. A field strain, with consistently low resistance ratios (topical method = 17.7, glass jar method = 2.2), was identified as a potential field strain to be used as a baseline for comparison with other field strains. Resistance ratios for the other field strains obtained by comparison with the R5 strain ranged from 24.5 to 239 for topical application and from 1.2 to 9.8 for the glass jar method. The results of our study demonstrate that deltamethrin-resistant German cockroaches are numerous in Singapore. Comparison between the two bioassay methods showed that there was significant correlation between KD50 and KT50 values. The glass jar method is similar to field situations but topical application is sensitive enough to define the magnitude of resistance. Differences between the two detection bioassays and the factors governing the choice of bioassay in monitoring resistance in German cockroaches are discussed.     

Performance of gel and paste bait products for German cockroach (Dictyoptera: Blattellidae) control: laboratory and field studies.

Gel and paste bait formulations containing boric acid or hydramethylnon were evaluated in field and laboratory experiments with the German cockroach, Blattella germanica (L.). Bait formulations contained 14-62% water by weight and lost the most water after 1 d of desiccation. Bait age and water content did not alter the toxicity (LT50) of boric acid-based baits. Toxicity of hydramethylnon (Maxforce) bait, however, increased with bait age. In continuous exposure tests without harborage, boric acid formulations had LT50s of 8.5 and 10.1 d for Blue Diamond and IT WORKS, respectively. Maxforce bait had an LT50 of 4.2 d. LT50s determined with cardboard harborage or in Ebeling choice boxes were 1.5 to 2.2 times lower than those from continuous exposure tests without harborage. Relative repellency, measured as the mean percent of live cockroaches in the light side of the choice box, was greatest for IT WORKS (21.4%) and Maxforce (25.4%) formulations, followed by Blue Diamond (10.9%). A performance index that combined choice box repellency and mortality data indicated that Maxforce had the greatest potential for field effectiveness. Blue Diamond and Maxforce significantly reduced German cockroach populations in the field. Maxforce performed best in field trials when applied at 10 or 20 placements per apartment. Apartments treated with IT WORKS had significantly greater cockroach trap catches. Factors that may affect the predictive power of the performance index are discussed.     

Rye bread and synthetic bread odorants – effective trap bait and lure for German cockroaches

Bread‐in‐beer and bread‐in‐water are prevalent home recipe trap baits for attracting German cockroaches (GCRs), Blattella germanica (L.) (Dictyoptera: Blattellidae), which are significant urban pests. Our objectives were to (1) test the attractiveness of these baits, (2) study the underlying factors of GCR attraction, and (3) determine whether a blend of synthetic bread odorants could replace bread in a trap lure. In large‐arena laboratory experiments with laboratory‐reared GCR males, traps baited with rye bread not only captured eightfold more males than unbaited control traps but also most males released into bioassay arenas. Neither beer nor water enhanced the attractiveness of bread. Bread crust as a bait was more effective than bread crumbs. As Porapak Q headspace volatile extracts of rye bread attracted GCRs, all rye bread odorants in extracts were identified by gas chromatography‐mass spectrometry. Synthetic rye bread odorants and other known bread odorants were then assembled into a master blend. This master blend, and even partial blends lacking certain groups of organic volatiles such as aldehydes and ketones, proved very attractive to GCRs. We conclude that rye bread could be used as an effective bait in retainer traps or, laced with insecticide, as a food source in bait stations. A lure of synthetic bread odorants may eventually replace bread as bait, but the minimum number of essential odorants for that lure has yet to be determined.     

In vivo study on combined toxicity of Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) strain ESC-1 with sublethal doses of chlorpyrifos, propetamphos, and cyfluthrin against German cockroach (Dictyoptera: Blattellidae)

The effect of Metarhizium anisopliae (Metschnikoff) Sorokin strain ESC-1 alone and in combination with sublethal doses of commercial formulations of chlorpyrifos, propetamphos and cyfluthrin on mortality of CSMA strain of German cockroach, Blattella germanica (L.), was determined by conducting in vivo studies that included 3 bioassays. Spores of M. anisopliae cultured on SDAY media had germination of >90%. Based on bioassay 1, doses ranging from 0.5 to 300 ppm of chlorpyrifos and propetamphos, and 0.05 to 40 ppm of cyfluthrin were selected for bioassays 2 and 3. Cockroach mortality ranged from 5 to 20% for insecticides alone and 48 to 70% for insecticides + M. anisopliae in bioassay 2. In bioassay 3, mortality ranged from 15 to 60% for insecticides and 57.5 to 92.5% for insecticides + M. anisopliae. Percentage of cockroach mortality resulting from insecticide + M. anisopliae combinations was significantly higher than insecticide alone. Mortality was also significantly higher in certain insecticide + M. anisopliae combinations than M. anisopliae alone. There was no significant interaction between M. anisopliae and insecticides with their concentrations in bioassay 2, indicating an additive effect. But in bioassay 3, a significant interaction was observed when M. anisopliae was combined with multiple insecticide concentrations. The interaction indicated an additive effect for chlorpyrifos and cyfluthrin, and a synergistic effect for propetamphos. There were significant differences in LT50 among various treatment combinations. M. anisopliae alone or insecticide + M. anisopliae combinations did not affect body weight in treated German cockroaches.     

Using insect traps to increase weaver ant (Oecophylla longinoda) prey capture

Weaver ants (Oecophylla spp.) are managed in plantations to control insect pests and are sometimes harvested as a protein‐rich food source. In both cases, the amount of insect prey caught by the ants is imperative for returns, as more prey leads to more effective biocontrol and to a higher production of ants. Malaise‐like traps placed in trees may catch flying insects without catching ants, as ants may use pheromone trails to navigate in and out of the traps. Thus, ants may increase their prey intake if they are able to extract insects caught in traps. In a mango plantation in Tanzania, we estimated the amount of insects caught by simple traps (cost per trap = 3.9 USD), and whether Oecophylla longinoda was able to collect insects from them. On average, a trap caught 110 insects per month without catching any weaver ants. The number of insects found in traps with ant access was 25% lower than in control traps (ants excluded), showing that ants were able to gather prey from the traps. Ant activity in traps increased over time, showing that prey extraction efficiency may increase as ants customize to the traps. The prey removed from traps by ants constituted 5% of the number of prey items collected by O. longinoda under natural conditions (without traps), potentially increasing to 14% if ants learn to extract all insects. Thus, prey intake may be increased with 5–14% per 3.9 USD invested in traps. These numbers increased to 38 and 78%, respectively, when light was used to attract insects during night time. Combining ant predation with insect trapping is a new approach potentially building increased returns to ant biocontrol and to ant entomophagy.     

THE COMPARISON OF YELLOW CYLINDRICAL, FLAT AND WATER TRAPS, AND OF JOHNSON SUCTION TRAPS, FOR SAMPLING APHIDS

Different traps were compared to find the type most suitable for studying aphid vectors of plant viruses quantitatively.
A Moericke water trap caught more aphids than a flat sticky trap of equal area. A flat sticky trap (930 sq. cm.) caught half as many aphids as a cylindrical trap (945 sq. cm.), which caught about one-third as many as a water trap (1200 sq. cm.) or a Johnson suction trap (9 in. fan) when operated at between 2 and 3 ft. over bare soil.
Yellow traps caught proportionally more Tuberculoides annulatus , and in summer more Capitophorus species than a suction trap, but significantly fewer Anoecia corni, Sitobium spp. and Pemphigus bursarius. Traps with a level surface caught proportionally more Brevicoryne brassicae, Aphis fabae and Myzus persicae , but fewer Anoecia corni and Drepanosiphum plantanoides than vertical cylindical traps. Attraction by colour influences the catch on horizontal traps more than on cylindrical traps because there is less impaction by the wind.
Only suction traps indicate the number of aphids per unit volume of air and are non-selective, but they are expensive and require an electric power supply. Water traps effectively catch those aphids that are attracted to yellow, but they require frequent attention. Sticky traps catch fewer aphids than either suction or water traps, but they can be left unattended for about 2 weeks. Flat sticky traps catch aphids likely to land on a crop, and cylindrical traps show when aphids are in the air, but not if those aphids are able or wanting to land. For routine work cylindrical sticky traps have other advantages; they are cheap and do not require skilled handling, and their catches of alate Myzus persicae have been correlated with the spread of some plant viruses.     

Induction of P450 monooxygenases in the German cockroach,Blattella germanica L

The cytochrome P450 monooxygenases are an important metabolic system whose level of activity can be influenced by several dietary constituents. We examined the effects of six known P450 inducers on the levels of total cytochromes P450, cytochrome b(5), and six monooxygenase activities in adult German cockroaches. In addition, the levels of CYP6L1 and CYP9E2 mRNA were also investigated. Phenobarbital treatment resulted in increases in total cytochromes P450 and metabolism of three resorufin analogues, but not CYP6L1 nor CYP9E2 mRNA. There was no significant effect of the other five inducers on any of the monooxygenase parameters we measured. In comparison with other insects, the German cockroach seems unusually refractory to most inducing agents.