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We investigated bactericidal and fungicidal properties of chitosan extracted from adults and nymphs from both German cockroach, Blattella germanica (Blattodea: Blattellidae) and American cockroach, Periplaneta americana (Dictyoptera: Blattidae). The cuticle of adults and nymphs extracted from both cockroaches were dried and ground. The powders were demineralized and deproteinized followed by deacetylation using NaOH. Finally, the chitosan yields were examined for antibacterial and antifungal activities. The degree of deacetylation (DD) was different between adults and nymph stages. The antimicrobial effect of American cockroach chitosan (ACC) and German cockroach chitosan (GCC) was tested against four bacteria and four fungi. The extracted chitosans from American cockroach, Periplaneta americana and German Cockroach, Blattella germanica suppressed the growth of Gram-negative/positive bacteria except Micrococcus luteus. The growth of Aspergillus flavus and Aspergillus niger were notability inhibited by the extracted chitosans. The antimicrobial effect of the chitosan depended on the cockroach species, with chitosan of the American cockroach showing more inhibitory effect. This difference may be due to differences in the structure of chitin between the two cockroach species.

The population size, age-class structure, and movement of the American cockroach, Periplaneta americana (L.) (Dictyoptera: Blattidae), were studied in three sewers in Penang, Malaysia, from September 2008 to October 2009. Eighteen to 20 glass-jar traps (two per manhole) were deployed for a 24-h period during each sampling occasion at each sewer. Adults and nymphs were active throughout the study period, with an average monthly trap catch of 57–97 adults and 79–99 nymphs. The mean proportions of adults and nymphs at the three sewers ranged from 0.47 to 0.57. Of the 2,177 male and 2,717 female cockroaches marked and released over the three sewers, recapture rates were 29.4–45.8 and 30.8–47.0%, respectively. The proportion of marked males and females did not differ significantly from the proportion of recaptured marked males and females. However, the mean number of times a marked female was recaptured was significantly greater than that of males. Of the 783 males and 1,030 females that were marked and recaptured, 19.4 and 24.7%, respectively, had moved between manholes, and significantly more females than males moved between manholes. Of the 406 recaptured marked adults that moved between manholes, 90.4% moved a distance of 2–20 m from their initial release site; one male moved 192 m, the longest distance recorded. Trap catch on each sampling occasion was positively correlated with daily mean temperature. The number of cockroach movements between manholes also was correlated with the mean daily minimum temperature.

Exposure and sensitization to cockroach allergens is an important risk factor for allergic disease in humans. Despite a recent burgeoning of clinical and socioeconomic studies regarding environmental pervasiveness and human exposure to cockroach allergens, little is known about the basic biology of these proteins. The purpose of this study was to ascertain gene expression patterns and the tissue distribution of Blattella germanica allergen 1 (Bla g 1), a perennial indoor environmental allergen, thought to be involved in digestion in cockroaches. We also investigated the relative potential contribution of different life stages of the German cockroach to environmental Bla g 1. Enzyme-linked immunosorbent assay was used to quantify the Bla g 1 contents of feces and various anatomical tissues, and Northern blot analysis was used to elucidate tissue-specific expression of Bla g 1. Results showed that the Bla g 1 protein is most prevalent in the midgut, and the Bla g 1 gene is exclusively expressed by midgut cells. Although Bla g 1 is produced by both sexes and all life stages of the German cockroach, adult females produce and excrete significantly more Bla g 1 in their feces than males or nymphs, even when corrected for body mass or mass of voided feces. Our results show that the concentration of Bla g 1 in feces of adult females is 6- to 7- and 30-fold higher than in adult males and nymphs, respectively, probably because females process more food than other life stages of the German cockroach.

We tested the hypothesis that presence and color of shed follicles in ovarioles of smokybrown cockroaches, Periplaneta fuliginosa (Serville), were correlated with the number of oothecae deposited in the laboratory. There were no shed follicles in females not having oviposited, whereas all females that had deposited 1-4 oothecae had shed follicles or resorption bodies, and females that had deposited greater than or equal to 5 oothecae had only shed follicle cells in the base of ovarioles. Other important correlates of female age (days after adult eclosion) were abdominal fat-free, thoracic fat and fat-free masses, and leg fat mass. Oocyte length could be substituted for oocyte fat and fat-free mass because these variables were correlated with oocyte length. Crop mass and delay in dissection after oothecal deposition were not correlated to female age or number of oothecae. Mass of body fractions (fat and fat-free) increased as females deposited additional oothecae. A generalized linear model predicted that as thoracic fat mass increased the number of oocytes already deposited by a female increased. In addition, the model predicted that red follicles would be found in females having deposited 1-3 oothecae and yellow follicles were predicted to be found in females having deposited >2 oothecae.

The residual repellency of N,N-diethylphenylacetamide (DEPA) was studied against American cockroach, Periplaneta americana (L.); German cockroach, Blattella germanica (L.); and brownbanded cockroach, Supella longipalpa (F.) at various concentrations. DEPA exhibited residual repellency for 4, 3, and 2 wk against American, German, and brownbanded cockroach, respectively, at a concentration of 0.5 mg/cm2.

Nongravid female German cockroaches, Blattella germanica (L.), and females with young or old oothecae were exposed to infective stage juvenile (L3) Steinernema carpocapsae (Weiser) All strain by topical application and continuous exposure. Topically applied nematodes resulted in < or = 40% mortality 7 d after inoculation, whereas 100% of females continuously exposed to nematodes were dead within 7 d. Females carrying old oothecae had significantly lower LT50s (0.07 h) than females with young oothecae (42.71 h) and females without oothecae (38.49 h). Fully formed oothecae were not penetrated by the nematodes, even though infective juveniles were found in the vestibulum between the female genitalia and on the proximal end of the ootheca. Partially formed oothecae were infested (100%) by nematodes derived from the female. Topical application of nematodes to the proximal end, side, or keel of mature oothecae that were detached from females did not result in nematode infestation, and the nymphs emerged normally. Oothecae continuously exposed to nematodes were similarly not infested but exhibited significant mortality, probably caused by bacterial infection.

The effects of feeding several ages of adult and nymphal German cockroaches a laboratory rat chow diet containing 0.10% allopurinol were investigated. All cockroaches fed the allopurinol diet suffered increased mortality. The range of LT50 values (the time required to kill 50% of an experimental cohort) for four ages of nymphs (1-8, 16-23, 21-28, and 28-35 d old following hatch) continuously fed the allopurinol diet was 1.36 wk (4.72-6.08 wk). Regardless of sex, young adult (1-7 d old following eclosion) cockroaches fed the allopurinol diet died significantly sooner than older adults (28-35 d old following eclosion); males died significantly sooner than females. All females fed the allopurinol diet as nymphs aborted their oothecae. Although an initial ootheca were hatched from cockroaches fed the allopurinol diet as adults, all subsequent oothecae were aborted. Untreated females mated with allopurinol-fed males experienced successful reproduction, but allopurinol-fed females mated with either allopurinol- or control diet-fed males failed to reproduce. Evidence suggests that cockroaches suffer increased mortality and reproductive failure from increased levels of hypoxanthine and xanthine.

The toxicities of Raid Max Roach Bait (sulfluramid) and COMBAT Roach Control System (hydramethylnon) to susceptible and field-collected German cockroaches were examined. In all field-collected strains, a variable fraction of the population exhibited tolerance to Raid Max. In some strains, few males were killed in the first 5 d of exposure to Raid Max and some lived for up to 123 d when provided Raid Max only. Field-collected males that were given access to Raid Max for only 3 h following a 45-h starvation exhibited a 22-fold delay in mortality of 50% of the population compared with males that were continuously exposed to Raid Max. Males exposed to COMBAT for 3 h exhibited a similar pattern of mortality as males continuously exposed to this bait. Field-collected males provided COMBAT with or without rat chow exhibited identical patterns of mortality. However, males that were offered Raid Max along with rat chow exhibited significantly delayed mortality compared with males given Raid Max alone. A direct comparison of 1% hydramethylnon and sulfluramid, the active ingredients in COMBAT and Raid Max, respectively, in rat chow showed that physiological resistance to sulfluramid was involved; field-collected males consumed both baits equally on the first day, but whereas 100% of the males that were fed hydramethylnon-containing chow died within 5 d, only one of 25 males fed sulfluramid-baited rat chow died during this period, and males continued to consume large amounts of food. This suggested that, in the presence of alternate foods, the effective dose of sulfluramid was diminished, resulting in reduced mortality in males fed Raid Max. These results suggest that relatively high levels of resistance to sulfluramid are pervasive in field populations of the German cockroach. Experiments in which cockroaches were exposed to vapors of Raid Max or sulfluramid without direct contact showed that both acted as fumigants. The Raid Max bait remained lethal without direct contact for at least 170 d of continuous aeration in a fume hood. A headspace analysis revealed that sulfluramid was present in airborne collections of both technical sulfluramid and the Raid Max bait.

Third-instar German cockroach nymphs were held to maturity in continuous proximity to test surfaces treated with hydroprene and fenoxycarb, which they were unable to contact directly. Surfaces tested were unfinished plywood, fiberboard, vinyl tile (absorbent surfaces), glass, stainless steel, ceramic tile, and formica (nonabsorbent surfaces). Number of oothecae, percent egg hatch, and survival did not differ between any fenoxycarb treatment and the untreated controls, but there was significant wing twisting (76-94%) for all nonabsorbent surfaces. Number of oothecae was significantly lower and percent wing twisting was significantly higher for all hydroprene-treated surfaces with respect to the untreated controls, although survival was not affected. These effects were less pronounced for the nonabsorbent surfaces. These results indicate that hydroprene, but not fenoxycarb, has significant biological activity through volatile action when applied at current label rates. This activity is likely to have important consequences for control, especially for "crack and crevice" applications in confined spaces.

The insecticidal constituents of hexane-soluble fraction from a methanolic extract of the seeds from Myristica fragrans (Myristicaceae) against adult females of Blattella germanica (L.) (Dictyoptera: Blattellidae) were analyzed by gas chromatography and gas chromatography-mass spectrometry. The insecticidal activity of 13 Myristica seed compounds against female B. germanica was examined by using the filter-paper contact toxicity and vapor phase toxicity bioassays. Results were compared with those of the other 23 known compounds of Myristica seed and currently used insecticides: dichlorvos, deltamethrin, permethrin, and propoxur. In contact toxicity tests using female B. germanica, (IS)-(-) -beta-pinene (0.06 mg/cm2) was the most toxic insecticide, based on 24-h LD50 values. The insecticidal activity of this compound was comparable with that of permethrin (0.05 mg/cm2). (1R)-(+) -Camphor, (1S)-(-) -camphor, dipentene, (1R)-(+) -3-pinene, and (+)-alpha-terpineol (0.10-0.14 mg/cm2) were more toxic than propoxur (0.19 mg/cm2). (E)-Sabinene hydrate and propoxur were almost equitoxic. Potent insecticidal activity also was observed with (R)-(+) -citronellal, (S)-(-) -citronellal, (R)-(-) -alpha-phellandrene, (1S)-(-) -alpha-pinene, (1R)-(+) -alpha-pinene, and safrole (0.27-0.48 mg/cm2). In vapor phase toxicity tests, the compounds tested were effective in closed but not in open containers. These results indicate that the effect of these compounds was largely a result of action in the vapor phase. Myristica seed compounds described merit further study as potential insecticides or as leads for the control of cockroaches.

Computerized moving-image analysis was used to determine movement behavior of adult German cockroaches among food, water, and harborage resource sites. Adults at different stages in the female reproductive cycle (nonmated females, mated nongravid females, and gravid females) and males were examined continually for 5 d under a photoperiod of 12:12 (L:D) h. Corresponding food and water consumption rates for these adult classes were also determined. Differences were evident among the female reproductive classes and males. Mated nongravid females were the most active overall, and consumed the most resources. Nonmated females were second to the mated nongravid females in consumption and were less active. Gravid females were the most inactive, spending the greatest time in the harborage and consuming the fewest resources. Males were second to females in the mated nongravid class regarding activity, but consumed significantly fewer resources than females in both the mated nongravid and nongravid females. Implications of these findings relating to the biology of these adult classes are discussed.

Known-age cohorts of three strains of German cockroach, Blattella germanica (L.), were mass-reared by establishing one rearing container each week (so that cockroaches within a container would be of known age). An average of 330-443 females was placed in oviposition units within these rearing containers. Percentage hatch of oothecae was 77.49-84.63%, resulting in an average of 12,258-16,359 nymphs per rearing container. Development of nymphs was similar for the three strains. Survivorship of nymphs to the adult stage was 19.95-29.56%; survivorship was significantly higher for the strain most recently colonized from the field. Adult emergence occurred at 6-7 wk, and average production per container was 2,834-3,971 cockroaches.

Brown cockroaches, Periplaneta brunnea Burmeister, were exposed to increasing population densities of the entomogenous nematode, Steinernema carpocapsae (Weiser), All Strains. A total of 160 adult cockroaches were used, 40 for each of four treatments: 0, 3,000, 30,000, and 300,000 infective juveniles added to 50 cm3 of sand. Population densities of 30,000 and 300,000 infective juveniles per 50 cm3 sand were the most effective treatments, killing 55% of the P. brunnea. The highest population density of nematodes, 300,000 infective juveniles per 50 cm3 sand, killed 93% of the P. brunnea, and produced a more rapid mortality when compared with other population densities.

The sensitive developmental period of last-instar German cockroaches, Blattella germanica (L.), to topical applications (10 micrograms/microliters) of fenoxycarb and hydroprene was determined. Developmental duration of last instars treated with fenoxycarb on days 1, 3, or 6 was 9-11 d longer than the development of nymphs treated with hydroprene or acetone. In addition, fenoxycarb caused mortality in 59% of the nymphs treated on day 6. A high level of wing twisting and sterility was observed among female and male cockroaches treated with fenoxycarb or hydroprene on days 1, 3, or 6 of the last stadium. Nymphal production by adults treated with juvenoids on day 9 of the last stadium (3-4 d before eclosion) was not affected. Our findings show that the sensitive developmental period for juvenoid-induced effects in last-instar B. germanica is limited to the first half of the stadium.

Baits, dusts, and aqueous sprays were applied to sewer shafts to control American cockroaches, Periplaneta americana (L). Boric acid and hydramethylnon baits failed to provide consistent control because of problems with mold on the baits and because large populations of cockroaches depleted the bait. Bendiocarb, boric acid powder, and a powder mixture of silica gel + synergized pyrethrins provided excellent control for at least 1 mo, but cockroaches reinfested treated shafts within 3-6 mo. Treatments made in the fall when adult cockroach populations were lowest (about 26%) provided best results. Aqueous sprays of wettable powder chlorpyrifos and microencapsulated diazinon provided outstanding control for at least 9 mo. Microencapsulated and emulsifiable concentrate chlorpyrifos sprays provided greater than 94% reductions for a year.

An apparatus for evaluating vapor-induced dispersal of Blattella germanica (L.) is described. It is made of two 750-ml crystallizing dishes connected by a glass and wire mesh tube. Its use is illustrated by experiments on exposure of late instars to vapors of a propoxur in oil formulation and those of its solvent system.

Ovicidal activity was observed in four adult groups (virgin males; virgin females; newly gravid females; and inseminated, reproducing females) of the German cockroach, Blattella germanica (L.), fed the chitin synthesis inhibitors triflumuron, chlorfluazuron, hexafluron, and UC 84572 (structure not disclosed) at the LC50's and LC95's determined from fifth-stage nymphs. All compounds were active only when fed to reproducing females (including the feeding period in which the ootheca is developing). Hexafluron and triflumuron at the LC50 caused 100% inhibition of hatch in reproducing females. Chlorfluazuron and UC 84572 at the LC50 had similar ovicidal activity (45.8 and 50.0% hatch, respectively). Female German cockroaches fed the chitin synthesis inhibitors before mating and after the ootheca had protruded from the abdomen were not affected. Reproductive capabilities of males were not affected, and males did not effectively transfer the compounds to untreated females during mating.

Trapping experiments conducted in multifamily apartments indicated movement of German cockroaches, Blattella germanica (L.), between apartments was greatest in adjacent kitchens; 65% of the emigrating cockroaches came from adjoining kitchen areas. Cockroach distribution parameters indicated that all life stages were aggregated. Aggregation was most pronounced for small nymphs, followed by adults; large nymphs were the least aggregated. Iwao's regression coefficients and resultant distributions implied movement of large nymphs was greatest, followed by adults and small nymphs.

Adults and oothecae of the German cockroach, Blattella germanica (L.), were treated topically with the juvenoids fenoxycarb and hydroprene. Fenoxycarb suppressed reproduction when applied at 10 micrograms/microliters to virgin and fertilized females. Production of offspring also was reduced when males treated with 10 micrograms/microliters of fenoxycarb were mated with untreated females. Fenoxycarb (10 micrograms/microliters) also exhibited ovicidal activity, particularly when applied to 4-d-old oothecae. Ovicidal activity by fenoxycarb diminished when applied to oothecae older than 8 d. No reproductive or ovicidal effects were caused by 1 or 10 micrograms/microliters of hydroprene.

"Push-pull" is a behavior manipulation strategy in which behavior-modifying stimuli are integrated with a pest control agent. We evaluated the efficacy of an insecticide bait in combination with attractants ("pull"), repellents ("push"), or both ("push-pull") using a hydramethylnon-based bait, feces-contaminated surfaces as an attractant, and methyl neodecanamide-treated surfaces to repel cockroaches. Both adult males and first-instar German cockroaches, Blattella germanica (L.), chose shelters nearest the attractant-treated surfaces and farthest from the repellent-treated surfaces. Food consumption was highest from food nearest the preferred shelters, and mortality was highest when the insecticide bait was near the preferred shelter. These patterns were more apparent in first instars than in adults. Our results from large arena studies in the laboratory show that the push-pull strategy can be used to displace pests from resources or commodities that are to be protected, and simultaneously lure the pest to an attractant source coupled with a pest control agent. Concentrating cockroaches into a limited area should facilitate the precision-targeting of the pest population and promises to reduce insecticide use.

Sixty-two carboxamides of 1,2,3,6-tetrahydropyridine were tested as repellents for the German cockroach, Blattella germanica. The acid moieties were derived from saturated, unsaturated, chlorinated, alicyclic, and benzoic acids. Five aliphatic or alicyclic carboxamides provided 100% repellency for a minimum of 17 days. Nine others provided 10–14 days of 100% repellency. None of the aromatic carboxamides tested were effective.

A lightweight baited trap is described for use either at ground level or attached to vertical surfaces for live-trapping cockroaches where nontarget animals are common. Dry distiller's grain in small plastic condiment cups was the bait. Reliability was exceptional: in a trial of 1,500 trap-days (125 traps used over a period of 12 d), only one trap was disturbed. Cumulatively, 15 species of cockroaches have been captured with this baited trap. Trapped cockroaches (adults and nymphs) were marked, and recapture rates for the two most commonly trapped species ( Periplaneta fuliginosa (Serville) and Eurycotis floridana (Walker)) ranged from 38.5 to 75%. Mean number of trap-days between recapture (3.5 ± 0.10) indicated that the release of marked individuals at the point of capture did not result in immediate recapture and therefore did not inflate recapture rates inordinately.

The German cockroach, Blattella germanica , is an effective mechanical transmitter of Salmonella enteritidis serotype Typhimurium via feces. Groups of restrained German cockroaches from a laboratory colony free of Salmonella were fed graded doses of S. enteritidis and their feces were assayed daily. The amount and duration of Salmonella in feces is dose-related, with outputs from 8 × 101 to 2 × 107 cells/defecation over a range of 3 to 20 days. The percentage of specimens excreting S. enteritidis is also dose-related and ranges from 8% with a 102 input to 70% with an infective feeding of 107. Salmonella multiplication in the gut or feces is a rare event. The ID50, or infective dose at which 50% of the feces will contain Salmonella during the first 10 days following ingestion, is 1.6 × 107. There were no significant sex differences in excretion of Salmonella at each dose. S. enteritidis is recoverable about 10 days longer in the cockroach gut than in the feces. Persistence is primarily in the hindgut and numbers of Salmonella decline over time in living cockroaches, with no recoveries from gut or feces after a month.

A method that allows Blattella germanica to choose between candidate chemicals and untreated areas or other chemicals within the same test environment is described. Video equipment was used to collect data. A quantitative index was employed to distinguish repellent, neutral, or aggregative properties of candidate chemicals. “Cockroach-conditioned” test plates were used in control experiments.

A new laboratory method to determine the speed at which Blattella germanica cockroaches are flushed from their harborages by various insecticides is described. The advantage of this method over other procedures is that it enables test conditions such as harborage depth, height, and construction material to be varied. Insecticides tested were cyfluthrin, fenfluthrin, permethrin + pyrethrins, deltamethrin, propoxur, DDVP, and diazinon. The rapidity of the flushing-out effect of these formulated compounds was determined in relation to the depth, height, and construction material of the harborage and with respect to the developmental stage of the test insects. The best flushing effect was demonstrated by the pyrethroid fenfluthrin, followed by permethrin + pyrethrins, cyfluthrin, deltamethrin, propoxur, and diazinon. There is a positive correlation between rapidity of knock-down and flushing-out effect of an insecticide. Field test results using some of the laboratory-evaluated formulations in apartment buildings infested with Blattella germanica document the relevance of the described method to field conditions.

Six of 21 n -alkylsulfonyl derivatives of substituted or unsaturated piperidines were highly effective in repelling the German cockroach, Blattella germanica (L.), for 2 to 3 weeks.

Seven nonresistant (“normal“) strains of the German cockroach, Blattella germanica , were evaluated to determine their relative susceptibilities to chlordane, malathion, chlorpyrifos, diazinon, and propoxur. LT50 values reported were similar for all tested strains, with no strain showing resistance to any tested chemical. The reported values should be used to cross-tabulate resistances reported from laboratories where different “normal”strains of German cockroach are used.