Donald A. Rutz

Resistance to cyfluthrin and tetrachlorvinphos in the lesser mealworm, Alphitobius diaperinus, collected from the eastern United States.

Abstract The lesser mealworm, Alphitobius diaperinus (Panzer), is an important pest in poultry facilities. The toxicity of cyfluthrin and tetrachlorvinphos to five strains of the lesser mealworm was compared with the toxicity to a susceptible laboratory strain. Bioassays were carried out with both larvae and adults. For the susceptible strain, cyfluthrin and tetrachlorvinphos had similar toxicity to adults, but cyfluthrin was 5 times more toxic to larvae when compared with tetrachlorvinphos. High levels of resistance to tetrachlorvinphos in two beetle strains were detected in both larvae and adults, although these strains were heterogeneous and still contained susceptible individuals. Resistance to cyfluthrin ranged from 1.7‐ to 9.5‐fold for adults and from 0.5‐ to 29‐fold for larvae at the LC95. Overall, the patterns of resistance did not mirror the insecticide use patterns reported at these facilities. The implications of these results to management of the lesser mealworms are discussed. Copyright

Microsporidioses of Muscidifurax raptor (Hymenoptera:Pteromalidae) and other pteromalid parasitoids of muscoid flies

Abstract An undetermined microsporidium was found infecting Muscidifurax raptor, a parasitoid of muscoid flies. Housefly hosts of the parasitoid in culture were not infected. Spores were present in newly deposited parasitoid eggs and vertical transmission experiments indicated 100% efficiency of maternal transmission. An uninfected culture was established by isolating parasitoids for oviposition and discarding the progeny of infected females. Infected parasitoids took longer to complete development, lived half as long, and produced 1 8 to 1 2 as many progeny as uninfected parasitoids. Thirty-five percent of field-collected parasitoids from New York dairy farms in August of 1990 were infected, although infection increased to 100% after two generations in culture. A survey of 11 pteromalid species collected from different geographic areas indicated that microsporidioses in Muscidifurax raptor and M. zaraptor are ubiquitous. Urolepis rufipes was the only other species examined that was also infected with microsporidia.

Impact of Exposure Length and Pupal Source on Muscidifurax raptorellus and Nasonia vitripennis (Hymenoptera: Pteromalidae) Parasitism in a New York Poultry Facility

Abstract Commercially obtained Nasonia vitripennis Walker and Muscidifurax raptorellus Kogan & Legner were released weekly for 12 wk into a high-rise, caged-layer poultry house. After the release period, parasitoids were sampled using sentinel house fly (Musca domestica L.) pupae that were either laboratory-reared or field-collected as larvae and exposed for 2, 4, 7, and 14 d. Parasitoid-induced mortality was observed in 31% of laboratory colony pupae and in 26% of field-collected pupae, whereas successful parasitism rates of 48 and 51% were observed from these pupal sources, respectively. Parasitism was primarily by M. raptorellus (88%), and Muscidifurax raptor Girault & Sanders (11%), while N. vitripennis accounted for <1%. Percent female progeny ranged from 43% in M. raptorellus to 76% in N. vitripennis. Parasitoid emergence from 2-d exposed sentinel pupae was the lowest of all treatments. Parasitoid emergence from 7-d exposed sentinel pupae was the highest of all treatments. We found no differences between pupal source, suggesting that when sampling for M. raptor, M. raptorellus, and N. vitripennis, in poultry facilities, pupal source is not a confounding factor.

Parasitism Rates of Muscidifurax raptorellus and Nasonia vitripennis (Hymenoptera: Pteromalidae) After Individual and Paired Releases in New York Poultry Facilities

Abstract Commercially reared parasitoids were released into three high-rise, caged-layer poultry houses; one house received only N. vitripennis Walker, the second house received only M. raptorellus Kogan & Legner, and the third house received an equal ratio of both species. Overall, house fly parasitism by M. raptorellus was never higher than 7% in any house. Most parasitism in the M. raptorellus release house was attributed to N. vitripennis. Parasitism of house fly pupae by M. raptorellus did not significantly increase during or after the 6-wk release period in the house that received both parasitoids. However, a depression in total parasitism was not detected when releases of the two species were made in this house.

The importance of agricultural tire habitats for mosquitoes of public health importance in New York State.

ABSTRACT The presence of mosquito species breeding in agricultural “bunker tires” on dairy farms in New York state was evaluated. Twelve species of mosquitoes (Aedes vexans, Anopheles barberi, An. punctipennis, An. perplexens, Culex pipiens pipiens, Cx. restuans, Cx. salinarius, Cx. territans, Toxorhynchites rutilus septentrionalis, Ochlerotatus atropalpus, Oc. japonicus japonicus, and Oc. triseriatus) were collected from 8 New York state dairy farms in 2001 and from 17 dairy farms in 2002. All but 2 of these species have been found naturally infected with arboviruses and could be important vectors affecting human and animal health. Because of the potential public and animal health importance of the invasive species Oc. j. japonicus, active surveillance to identify breeding sites and distribution of this mosquito is essential. In 2001, Oc. j. japonicus was recovered from 5 of 8 central New York dairy farms surveyed. In 2002, Oc. j. japonicus was recovered from 4 of the same dairy farms plus an additional dairy out of 5 surveyed. This species appears to be established on dairy farms in the south, central, and eastern regions of New York state, with greatest abundance in the southeastern region. A single Oc. j. japonicus larva was collected from the northern region on the final sampling date in September 2002. Our data demonstrate that agricultural tire habitats can be productive breeding sites for arbovirus vectors. As a consequence, these habitats should not be ignored in vector control and surveillance programs.

The influence of light and moisture gradients on the attack rate of parasitoids foraging for hosts in a laboratory arena (Hymenoptera: Pteromalidae)

Microhabitat preferences of four parasitoids (Hymenoptera: Pteromalidae) of house fly pupae were measured in a two-dimensional arena containing perpendicular light and moisture gradients. Parasitism by Muscidifurax raptorand Nasonia vitripenniswas greatest in dry substrates, with the latter preferring bright illumination and the former tending to prefer dark. Urolepis rufipesselected bright illumination and moist substrates, attacking the most hosts at bright-moist and dim-moist microhabitats. Spalangia cameroniexhibited no main-effect preference for light intensity or moisture, although parasitism was highest at dim-moist, dark-wet, and dark-moist microhabitats. These results demonstrate that simple abiotic attributes, such as light intensity and substrate moisture concentration, are important in defining some dimensions of the niches of these parasitoids.

Influence of habitat and temperature on dispersal behaviour of two pteromalid parasitoids of houseflies during an inundative release at a dairy barn

ABSTRACT. 1. About 11,000 each of Muscidifurax raptor Girault and Saunders and Urolepis rufipes (Ashmead) were released weekly for 7 weeks at a commercial dairy farm in central New York state, U.S.A. Dispersal behaviour was monitored by parasitism rates of house fly, Musca domestica L., pupae placed in sentinel bags.

Prey- and Density-Mediated Dispersal in Carcinops pumilio (Coleoptera: Histeridae), a Predator of House Fly (Diptera: Muscidae) Eggs and Larvae

Abstract Carcinops pumilio (Erichson) were collected using two trapping methods: a black light pitfall trap and a mesh-bottomed trap placed on poultry manure. C. pumilio collected with black lights and subsequently starved had a significantly higher dispersal rate during days 1-3 than fully fed groups. When densities of <500 Caloglyphus berlesei (Michael) (Acarina: Acaridae) per 50 C. pumilio were provided, mite availability had a significant effect on dispersal of beetles captured with both black light traps and the mesh-bottomed trap during the day 1-3 period. Our results indicate that the availability of acceptable food sources can delay and possibly prevent dispersal by C. pumilio. Black light-captured beetles appeared to be in a state of dispersal when captured. A subset of dispersing beetles was present in groups captured with the mesh-bottomed trap.

Efficacy of chlorfenapyr (AC 303630) experimental pour-on and CyLence formulations against naturally acquired louse infestations on cattle in New York

The four chlorfenapyr formulations examined provided 100% control of both the nymphal and adult stages of naturally acquired Bovicola bovis (L.) on cattle up to 35 days after application. Treatment with 6mg chlorfenapyr per kg BW in a 0.12ml per kg BW formulation was as effective as treatment with CyLence (cyfluthrin) in controlling naturally acquired Solenopotes capillatus (Enderlein) on cattle for 35 days. Percent reduction was never greater than 90% with any chlorfenapyr application against Linognathus vituli (L.). However, percent reduction was greater than 90% with CyLence from day 21 through 35. No adverse effects were noted on cattle from any of the chlorfenapyr dosages used.

Individual and Combined Releases of Muscidifurax raptor and M. raptorellus (Hymenoptera: Pteromalidae) as a Biological Control Tactic Targeting House Flies in Dairy Calf Facilities

ABSTBACT The impact of commercially reared house fly parasitoids released into nine dairy calf coverall facilities were evaluated over 3 yr. Individual and equally mixed ratios of the pteromalid parasitoids Muscidifurax raptor Girault and Saunders and M. raptorellus Kogan and Legner were released at a rate of 500 parasitoids per calf per week for 8 wk. Prerelease, release, and postrelease parasitism was monitored using nearly 100,000 sentinel house fly, Musca domestica L., pupae during the 3 yr study. In general, very few adult parasitoids were recovered during the prerelease period and on the no-release farms during any period. However, considerable numbers of M. raptor and M. raptorellus were recovered from sentinel pupae on respective release farms. As expected, the greatest successful parasitism occurred during release periods, with a drop during postrelease periods. High successful parasitism and uneclosed pupae on M. raptorellus release farms suggests that this parasitoid was aggressive in attacking hosts with progeny production at approximately four wasps per pupa. Solitary releases of M. raptor provided sentinel mortality between 31 and 38%, whereas sentinel mortality on M. raptorellus-release farms was double, at 59–80%. Using mixed releases of the two species, overall fly mortality was slightly lower than that observed on M. raptorellus-only farms. This study documents the advantage of releasing M. raptorellus rather than M. raptor on New York dairy calf facilities, as supported by higher parasitism rates and lower costs (35–75%) for purchase of these gregarious wasps, as 75–80% fewer parasitized pupae are needed to achieve similar adult parasitoid levels.