A case study of a pheromone-based attract-and-kill management strategy for codling moth, Cydia pomonella (L.), was conducted to examine key insect behavioral factors mitigating the possible effectiveness of this strategy. Last Call CM is a newly registered attracticide product that combines the primary component of codling moth sex pheromone with the insecticide permethrin. Studies of competition between pheromone point sources within caged trees showed individual attracticide droplets were significantly more attractive to male moths than calling females. In commercial orchard blocks, marked male moths were recaptured after visiting attracticide droplets applied at rates of 50, 100, and 200 droplets/ha, although no marked moths were recaptured in plots with 500 droplets/ha. This experiment also revealed no significant differences among 0, 50, 100, and 200 droplets/ha in suppressing total catch in female-baited traps, nor were total numbers of females attracting at least one male reduced significantly. In plots with 500 droplets/ha applied, male moth catch was suppressed significantly compared with catches in untreated control plots, and the number of females attracting at least one male was reduced significantly as well. Experiments investigating sublethal physiological effects of attracticide exposure upon mating competency of male codling moths demonstrated male leg autotomy at 1, 24, 48, and 72 h after exposure. Male codling moth at 1, 24, 48, and 72 h after exposure placed near calling virgin females exhibited significant behavioral differences from sham-treated males in courtship and mating. These results clarify some of the possible mechanisms, and strengths and weaknesses of this attract-and-kill management strategy for codling moth.

The white pine weevil’s [Pissodes strobi (Peck)] choice of bark tissue for ovarian maturation feeding was determined. In addition, the thicknesses of primary cortex tissue were determined to ascertain if primary cortex thickness was positively correlated with the selection of oviposition sites. White pine weevils engaged in ovarian-maturation feeding and oviposition, referred to in this article as reproductively active female weevils, preferentially feed on primary cortex tissues of Sitka spruce, Picea sitchensis (Bongard) Carriere, and interior spruce (a complex of white spruce [Picea glauca (Moench) Voss] and Englemann spruce [P. englemannii Parry]) leaders. On these leaders they feed mostly and oviposit almost exclusively in sterigmata ridges where the thickest primary cortex occurs. Branches of open-grown trees have insufficient primary cortex thickness; they are not normally used for oviposition and are used poorly by caged reproductively active female weevils. Reproductively active female weevils do not normally oviposit on the main stem below the leader where the primary cortex is thinner, but will do so when they do not have access to the leader or when caged on lower inter-nodes. This weevil attacked branches and the main stem below the leader in Picea chihuaiana (Martinez) and P. mexicana [=P. engelmannii Parry variety mexicana (Martinez)] trees in locations where the thickness of the primary cortex is greater than in other species studied. Only primary cortex thickness increases with tree height in Sitka and interior spruces. The female white pine weevil’s preferential feeding upon this tissue in the spring can account for their movement from ground level to tree tops.

A novel, binary δ-endotoxin from Bacillus thuringiensis Berliner (Bt) strain PS149B1 has been identified, and the two genes that code for the peptides that make up the binary insecticidal crystal protein (bICP) have been inserted into maize plants, Zea mays L. Transformed maize plants that express the proteins are resistant to western corn rootworm, Diabrotica virgifera virgifera LeConte, a major pest of maize. A laboratory study was conducted to better understand the degradation of the bICP in soil. Insect bioassays using southern corn rootworm, Diabrotica undecimpunctata howardi Barber, were used to track degradation. A first-order kinetic model using a truncated data set predicts a half-life of <4 d, indicating a rapid rate of decay in soil. The degradation pattern for the complete data set exhibits systematic departures from a first-order kinetic model. A novel 3-parameter degradation model was developed and validated with 23 additional degradation data sets representing both Bt proteins and synthetic organic molecules. This new model often fits degradation patterns better than a first-order model and a 3-parameter, biexponential (biphasic) model. The new model also retains an additional degree of freedom in the analyses compared with the biexponential model, making it especially useful when modeling small data sets. The time until 50% dissipation of the bICP was estimated at <2 d based on this new model.

Effects of feeding by Tetranychus urticae Koch and Eotetranychus carpini borealis (Ewing) on red raspberry physiology was investigated under greenhouse conditions. Measurements of chlorophyll fluorescence and chlorophyll contents were made from infested leaves and the most recently expanded and uninfested leaves of infested plants. Measurements were compared with those taken from similar leaves of the control plants. After 24 h of feeding, uninfested leaves of T. urticae infested plants showed lower maximum fluorescence (F_m) and higher initial fluorescence (F_o) than these of E. carpini borealis infested plants. After 2 wk, no significant difference was found for these parameters while significant increase of maximum fluorescence (F_m) and variable fluorescence (Fv) was detected for infested leaves. Half rise time (t1/2) was significantly reduced for these leaves. When compared with control, Fv/F_m, Fo, and chlorophyll contents of infested leaves were not affected by spider mite feeding following 2 wk of feeding. The results of this study indicate that cellular injury occurs before appearance of damage and that the primary site of injury for spider mite feeding may be the plastoquinone pool (QA), which plays major role in electron transport during photosynthesis. Comparisons of injury caused by the two spider mite species are made and potential implications of spider mite injury to red raspberry plants are discussed in relation to field conditions.

Survival and development time from egg to adult emergence of the diamondback moth, Plutella xylostella (L.), were determined at 19 constant and 14 alternating temperature regimes from 4 to 40°C. Plutella xylostella developed successfully from egg to adult emergence at constant temperatures from 8 to 32°C. At temperatures from 4 to 6°C or from 34 to 40°C, partial or complete development of individual stages or instars was possible, with third and fourth instars having the widest temperature limits. The insect developed successfully from egg to adult emergence under alternating regimes including temperatures as low as 4°C or as high as 38°C. The degree-day model, the logistic equation, and the Wang model were used to describe the relationships between temperature and development rate at both constant and alternating temperatures. The degree-day model described the relationships well from 10 to 30°C. The logistic equation and the Wang model fit the data well at temperatures <32°C, but only the Wang model described the decline in development rate at temperatures >32°C. Under alternating regimes, all three models gave good simulations of development in the mid-temperature range, but only the logistic equation gave close simulations in the low temperature range, and none gave close or consistent simulations in the high temperature range. The distribution of development time was described satisfactorily by a Weibull function. These rate and time distribution functions provide tools for simulating population development of P. xylostella over a wide range of temperature conditions.

Predation on lepidopteran eggs in soybean and corn and the temporal partitioning of predation among the predator species were examined in soybean Glycine max (L.) and sweet corn Zea mays (L.). The complex of predators feeding on lepidopteran eggs [Helicoverpa zea (Boddie)] and the key predators discovered in this study were different in each crop. The dominant predator in each crop was consistent from year to year but the secondary predators varied in importance. Nabids were the dominant predator group in soybean contributing 51 and 50% of the observed predation events in 1993 and 1994, respectively. The coccinellid, Coleomegilla maculata (DeGeer), was the dominant predator in corn contributing 43.9 and 46.3% of the observed predation events in 1993 and 1994, respectively. Other predators causing ≥10% of the observed predation events included Geocoris punctipes Say and the Phalangiidae in soybean, and the nabids, Orius insidiosus Say and Lygus lineolaris (Palisot de Beauvois) in sweet corn. All predators observed feeding exhibited taxa specific diel patterns of predation. C. maculata, O. insidiosus and G. punctipes were primarily day active, with 75, 85.7, and 100% of observed predation events occurring during daylight hours, respectively. Nabids were primarily nocturnal with 84.2% of predation events happening at night. Phalangiids, Clubiona abbotii Koch, Lygus lineolaris, and the elaterids were only observed preying upon H. zea eggs nocturnally. Because the dominant predators and their diel activity varied between crops, the period of peak egg predation did also. Egg predation was usually higher during the day in corn and at night in soybean. Crop, date, and time of day all affected intensity of predation on H. zea eggs. Predation in both crops increased through the beginning of August and then declined on the last sampling date. Predation was usually higher in corn than in soybean (three of four sample dates). However, when anthesis was occurring in corn plots, predation rates in soybean and corn were similar. Apparently the availability of sweet corn pollen as an alternative food source for C. maculata caused a reduction in egg predation.

Reintroduction of fire and thinning have been suggested as the main practices to regain forest health in northern Arizona ponderosa pine (Pinus ponderosa Dougl. ex Lawson) forests. Criteria for assessing the impact of such management practices in the forest are based on benchmark reconstructed conditions resembling pre-European forest stand structure and on the enhancement of tree vigor. A range of forest conditions currently exists including stands that have been unmanaged, thinned only, thinned plus prescribed burned and burned by wildfire. A surrogate taxon was used to assess forest condition under criteria of maintaining habitat for native species operating at the soil level. We assessed changes occurring in ground beetle assemblages at the stand scale as related to changes that had occurred in forest stands previously treated with the above treatments. A pitfall-trapping scheme was deployed during the summer months of 1998, 1999, and 2000. A total of 4,452 specimens was caught representing 15 genera and 20 species of ground beetles. We found that species diversity increased as the level of disturbance increased. The indicator species assemblage found on the wildfire treatment was represented by species in the genera Amara and Harpalus that are characteristic of dry-open habitats. Unmanaged stands generally had the lowest diversity and the assemblage was dominated by the species Synuchus dubius (Leconte). The thinned only stands did not significantly vary from unmanaged stands in species assemblage. Cyclotrachelus constrictus (Say) was indicative of the thinning plus broadcast burned stands. Stands that were thinned plus burned were richer than both unmanaged and thinned only stands without a shift toward an open-area dominant assemblage as occurred in the stands burned by wildfire.

We used multiple regression modeling to investigate the numerical response by the predatory insects Hippodamia convergens Guérin-Méneville, H. parenthesis (Say), and C. septempunctata L. (Coleoptera: Coccinellidae), Chrysoperla plorabunda (Fitch) (Neuroptera: Chrysopidae), and Nabis americoferus Carayon (Hemiptera: Nabidae) to aphids during 5 yr in three geographically separated alfalfa fields in eastern South Dakota. Regression models for abundance of adults of all species were significant. Regression models for immature H. convergens, H. parenthesis, and C. septempunctata were significant, but regression models for immature C. plorabunda and N. americoferus were not significant. Regression parameters differed among the three fields for most predator species, indicating that the numerical response was dependent on geographical location. To obtain insight into why the numerical response by predators differed among fields we determined how the abundance of predators in alfalfa fields was influenced by the landscape surrounding a field and the vegetation in it. Variables describing the complexity of the landscape surrounding alfalfa fields and the plant community in the fields entered into regression models for predator abundance and explained a greater proportion of the variance in predator abundance than aphid abundance did. We conclude that the structure of the landscape matrix plays an important role in determining the abundance of aphid predators in alfalfa fields, as does the plant community in a field. These effects can sometimes overshadow the direct numerical response by predators to aphids.

Tomicus piniperda (L.), a Eurasian scolytid first discovered in North America in 1992, is established in at least 12 north central and northeastern states and the Canadian provinces of Ontario and Quebec. The expanding range of T. piniperda, its ability to develop and shoot-feed in most North American pine species, and its relatively early spring activity have generated questions about its potential interactions with native competitors and natural enemies. Our objectives were to compare phenology of T. piniperda with native phloem-feeding insects and to evaluate phenological synchrony between T. piniperda and native predators in red pine forest stands. We monitored adult beetle activity using baited funnel traps and observations of insect activity on freshly cut red pine logs in four to eight stands in southwestern and northern lower Michigan during two field seasons. Logs were periodically returned to the laboratory and individually caged. Phloem-feeders, predators and parasitoids emerging from logs were identified. Tomicus piniperda was collected only in southwestern stands and was consistently the first scolytid collected in funnel traps. Ten native phloem-feeding species were collected in funnel traps or reared from logs; at least two native species were actively colonizing logs concommitently with T. piniperda in early spring. We observed adults of the predatory clerid Thanasimus dubius (F.) actively moving on logs and preying on T. piniperda adults and other scolytids early in spring, roughly 3–4 wk before this species was first collected in funnel traps. Other native scolytid predators including Cucujus clavipes F. and three staphylinids were also active early in spring. Results suggests that T. piniperda is likely to encounter interspecific competitors and natural enemies in North America, but further research will be needed to demonstrate how these interactions affect T. piniperda population dynamics.

We studied the spatial and temporal distribution of third-instar Musca domestica L. in three high-rise poultry facilities in central Pennsylvania, and investigated its relation to manure moisture. Autocorrelograms, a geostatistical index, revealed pronounced spatial autocorrelation in M. domestica, with ranges of spatial structure from 13 to 117 m. Under normal field conditions, we observed a nonlinear functional relationship between manure moisture and larval abundance, and empirically derived an optimal manure moisture range of 74–78%. The abundance of third instars was significantly positively correlated with manure moisture at the same location in space and time for approximately half of the sampling intervals. However, moisture measurements were generally spatially random at scales ≥4 m, and thus do little to explain the spatial structure of M. domestica. Also, we rarely observed significant correlation between moisture and larval abundance over discrete temporal lags ≥7 d. However, atypical field conditions, resulting in moisture measurements that were abnormally high or low, were observed to dictate larval population dynamics over time by rendering manure habitats unfavorable for natural enemy establishment or to fly propagation, respectively.

Immature insects that develop within plant structures entirely of their parent’s choosing are dependent on those parents to select suitable hosts. Weevils that develop within tree fruits are an obvious example of this situation. We examined oviposition choice by the black walnut curculio, Conotrachelus retentus (Say), in a walnut plantation setting for 10 yr, focusing on the effects of cluster size on oviposition. The percentage of nut clusters with curculio oviposition did not differ significantly among cluster sizes, although the percentage of individual nuts destroyed was significantly lower in single nuts compared with two-nut clusters. Our data support the hypothesis that the curculio behaves as though the nut cluster was the ecological unit for oviposition, as do other weevils such as the pecan weevil.

The failure of crop rotation to protect corn from larval western corn rootworm, Diabrotica virgifera virgifera LeConte, injury has become common in regions of Illinois and Indiana, and is apparently spreading east into Ohio and Michigan. The extensive use of a corn-soybean rotation is considered to have selected a variant of the western corn rootworm that has expanded its ovipositional range to include soybean fields. Laboratory and field observations suggest that suspected variant western corn rootworm adults have a greater acceptance for soybean foliage as an adult feeding site than that of wild type adults. We attempted to identify variant western corn rootworm populations based on their propensity to feed on soybean foliage and what factors influence the consumption of soybean foliage. Feeding on soybean and corn leaves was quantified in laboratory feeding assays. There was no significant difference in amount of soybean leaf area eaten by western corn rootworm from Illinois versus those from Nebraska or Michigan, both regions were rotation failures have not been reported. To identify what factors influence western corn rootworm feeding on soybean, we first demonstrated that western corn rootworm feeding on corn foliage was influenced by corn phenology. Corn phenology also influenced the consumption of soybean leaves; more soybean leaf area was consumed in the presence reproductive stage corn leaves than younger, vegetative stage corn leaves. A phenology effect was observed also with corn silks; soybean consumption was reduced in the presence of corn silks compared with leaves. Given that western corn rootworm acceptance for soybean increases in the presence of older corn, we propose an explanation for western corn rootworm oviposition in soybeans based on corn phenology.

Our understanding of foraging and space use in Reticulitermes species is limited because their subterranean colonies are not associated with distinct physical nest structures and the colony affinity of workers cannot be readily identified with behavioral assays. Recently, we found that in Reticulitermes flavipes (Kollar) colonies from Massachusetts, the average colony inbreeding coefficient, measured with five polymorphic allozymes, was significantly greater than zero for non-Mendelian colonies with worker genotypes corresponding with the offspring of multiple inbreeding secondary reproductives rather than male and female primary reproductives. Foraging groups of termites with positive inbreeding coefficients suggest that workers feeding at fallen trees and branches frequently originate from different reproductive centers. The positive inbreeding coefficients appear to result from foraging traffic and not from inbreeding among secondary reproductives. A positive correlation between colony inbreeding coefficients and colony foraging range for non-Mendelian colonies suggested that the number of separate reproductive centers and/or the allele frequency contrasts between reproductives from separate centers increased with the expansion of a colony’s foraging area. It is unlikely that an increase in the subdivision of breeding groups in a single reproductive center would closely coincide with an increase in foraging range. However, the extent of mixing between workers from neighboring colonies could have increased with foraging range expansion, especially given the apparent lack of nestmate discrimination in R. flavipes. Nevertheless, foragers from neighboring colonies have high genetic contrasts, and therefore appear to maintain distinct foraging areas.

We found that variation in temperature and humidity significantly affected mortality rates and population dynamics of the spittlebug Deois flavopicta Stål by monitoring cohorts of diapausing eggs and nymphs for three generations. Cohorts of quiescent eggs, when exposed to increasing periods of high moisture (free water), produced higher proportions of eggs resuming embryonic development in laboratory experiments. The accumulated number of eggs resuming development as a function of days of exposure to moist conditions was modeled using a β distribution. Periods of drought and high temperatures after the beginning of postdiapause development increased embryonic and nymphal mortality. Mortality was modeled with a linear function, and in combination with the development model allowed the simulation of varying mortality rates in the newly emerged nymphal population. Comparisons with field data demonstrated a close fit to the observed and expected proportion of nymphs hatching daily. By accurately simulating natural mortality, hatching distribution and population dynamics, the model promises to be useful for managing the spittlebug in the field.

Improvements in the way Bemisia argentifolii Bellows & Perring is managed have led to reduced whitefly populations in the southwest United States. However, the potential of the silverleaf whitefly to develop new biotypes, as well as its apparently increasing role in virus transmission, makes it a persistent threat in many parts of the world. Characteristics such as biotype formation and vector competency are at least partially explained by the host range of B. argentifolii. Consequently, a better understanding of the factors that play a role in the host acceptance process and subsequent development of this pest could lead to novel control strategies. Here we used a newly developed artificial feeding system that consists of a polycarbonate chamber, equipped with a Teflon membrane, and filled with a sterilized artificial diet, to determine how biotic and abiotic factors influenced egg hatch, crawler establishment, and development of B. argentifolii. Egg age significantly influenced hatch rates, and to a lesser extent survival and development of nymphs reared on the artificial diet. Five- to six-day-old eggs had higher hatch rates, and nymphs survived longer and developed faster than nymphs from younger or older eggs. There were negative associations between the number of eggs placed on the membranes and both hatch rate and establishment of crawlers. Eggs oviposited on and then subsequently removed from plants held under long-day conditions (14:10 [L:D] h) or high light intensity (≈36,000 lux) had higher hatch rates than eggs oviposited under short-day conditions (10:14 [L:D] h) or low light intensity (≈11,000 lux). Long-day conditions during oviposition also significantly enhanced survival of nymphs through day 20 and developmental rate for day 6 counts. Light intensity, at least for the range tested here, did not significantly affect development or survival of whitefly nymphs.

We determined the effect of enhanced dietary nitrogen on the ovarian maturation of female primary and neotenic reproductives of the termite Zootermopsis angusticollis Hagen. Supplementing the wood diet of newly paired reproductives with a 0.05% uric acid solution resulted in both primaries and neotenics gaining less body mass. This may have occurred because the increased nitrogen content of their food allowed reproductives to consume less wood to meet their dietary needs, thereby reducing the mass of their gut contents. An abundance of exogenous nitrogen may have also stimulated females to excrete excess uric acid rather than store it, further reducing mass gain. Nitrogen supplementation resulted in significant increases in ovariole number and fecundity for neotenic females but not primary females. These results suggest that although enhancing dietary nitrogen may release newly molted neotenics from nutritional limitations on their fecundity, dietary enhancement with 0.05% uric acid does not significantly effect the reproductive development of recently dealated primaries. Possible reasons for each reproductive form’s response to enhanced dietary nitrogen are discussed.

We investigated the effect of plot-based and unrestricted (plot-less) sampling on an inventory of a megadiverse taxon, spiders, in an Afrotropical forest for the purpose of species richness estimates. We also investigated the efficiency of human-based sampling methods and the effect of allocation of sampling effort to different sampling methods to cover as many microhabitats as possible. In the 10-d sampling period in the montane forest of the Uzungwa Scarp Forest Reserve in Tanzania, eight collectors sampled spiders for 350 h and 800 pitfall “trap-days.” Two hundred hours of sampling were restricted to a 1-ha plot and 150 h of sampling took place outside the plot. The sampling team included both experienced and inexperienced collectors using five different hand collecting methods during day and night sampling periods. Sampling yielded 9,096 adult spiders representing 170 species in total. Number of species and adult spiders per sample and overall species composition depended mainly on the sampling methods used and time of day. Whether the sampling took place within or at random outside the plot did not affect species composition or number of species per sample. Collector experience did affect the number of species collected per hour and thereby overall species composition of the sample but was less important than sampling methods used and time of day.

Dicyphus hesperus Knight has good potential as a biological control agent for greenhouse pests in greenhouse tomato crops. The spatial distribution of D. hesperus was studied and a sampling plan was developed to monitor this species in greenhouse-grown tomatoes. Adults and nymphs are distributed in a more aggregated pattern among plants than within plants. The strong, significant relationship between the mean population density and the proportion of occupied sample units (leaves or plants) makes it possible to use a binomial or presence-absence sampling approach. Presence-absence sampling is an efficient method for crop management purposes because less time is needed to process the samples compared with a method where all insects are counted. At high densities, considering a sample unit to be occupied only when there are more than a determined number of individuals reduces considerably the optimum sample size required.

The ecology and control for the little-understood, blueberry bud-infesting gall midge Dasineura oxycoccana (Johnson) was studied to help reduce an estimated 20–80% blueberry crop loss due to this insect in the southern United States. Principal natural enemies were eulophid wasps, 85% of which were Aprostocetus (Perkins). Overall parasitism rate was 7% in the field, at times peaking around 34%. A 75% decline in the abundance of larval D. oxycoccana coincided with parasitoid activity between April to September. Larval Toxomerus geminatus (Say) Metz (Syrphidae) were early-season predators of immature D. oxycoccana. Prey handling took 3–10 min, with each predator eating approximately seven gall midge larvae in a 16-h period. Prebloom applications of malathion would be effective larvicides against D. oxycoccana, inducing 94% mortality in 24 h. A microbial-based alternative to malathion, spinosad, induced average mortality of 46% in 24 h. Spinosad was as effective as phosmet (50% mortality in 24 h) for D. oxycoccana control. Patterns of host plant resistance to D. oxycoccana were not obvious among 26 cultivars, accessions and species of Vaccinium. Additionally, the use of a dormancy-breaking compound, hydrogen cyanamide, could also have a deleterious side-effect: boosting gall midge populations and spurring 50% greater infestation of D. oxycoccana larvae in rabbiteye blueberry buds.

A field study was conducted to calculate the functional lower developmental threshold and cumulative required degree-days for first emergence of adult Apthona nigriscutis Foudras, a classical biological control agent of the exotic weed leafy spurge Euphorbia esula L. The study was conducted in Wyoming, Montana, and Minnesota from 1991 through 1999 and made use of the computer program, CALFUN (version 2.0), to estimate the thresholds and required degree-days. Five different methods were used to calculate degree-days, and two kinds of estimates (mean and median) were made for functional lower developmental threshold and required degree-days. In all, 10 phenology models were developed. When we tested these for their accuracy in predicting adult A. nigriscutis first emergence, those that used the historical or sine wave methods for calculating degree-days, and those that used median functional lower developmental thresholds and required degree-days, provided the best predictions. Based on these findings, we suggest using the median functional lower developmental threshold from the historical (−2.56°C) or sine wave (0.14°C) methods to calculate degree-days. Then, when cumulative degree-days approach 1,189.2°C (historical method) or 898.5°C (sine wave method), the onset of adult A. nigriscutis emergence should be imminent. A computer program was written for use by spurge managers so they can easily determine when first emergence of adult A. nigriscutis is likely to begin.

Catolaccus hunteri Crawford is an external parasitoid of cryptic Coleoptera, particularly of Bruchidae and Curculionidae in flowerbuds, small fruits, and seeds. It is the most common parasitoid of the pepper weevil, Anthonomus eugenii Cano, in the United States, Mexico, and elsewhere, and was introduced from Guatemala to Hawaii for control of this pest. Studies were conducted to assess effects of temperature and host on life history parameters of C. hunteri as a step toward eventual mass rearing and inoculative release for pepper weevil control. Oviposition, postovipostion period and adult longevity were shorter at 30°C than at 20 or 25°C. Mean number of eggs oviposited per female was greater at the lower temperatures than at the highest temperature. Duration of all development stages was shorter at 30°C than at 20 and 25°C. Developmental period of C. hunteri was longer and adult longevity was shorter on boll weevil, Anthonomus grandis Boheman, than any other host. Female wasps laid most eggs on the cowpea weevil, Callosobruchus maculatus (F.), larvae. Transferring of C. hunteri reared on C. maculatus to pepper weevil or boll weevil caused a reduction in the mean number of eggs/female. Age-specific life tables and age-specific fecundity for C. hunteri were analyzed using three constant temperature regimes and five sources of host. These tables were used to calculate the innate capacity of natural increase (r_m), the finite rate of increase (λ), the mean generation time (T), the net reproduction rate (R_o), and the gross rate of reproduction. The results indicate that C. hunteri populations are capable of increasing in all of the environmental conditions tested in the current study. The optimum temperature for population increase for C. hunteri is 25°C. With respect to host suitability, greater numbers of C. hunteri female progeny were produced when this parasitoid was reared constantly and invariably on C. maculatus larvae than on any other host.

Field studies were conducted in 1996 and 1997 to determine the most suitable release sites in cotton for inundatively released encapsulated Trichogramma exiguum Pinto & Platner. Atypical applications of a plant growth regulator, mepiquat chloride (Pix), were used to manipulate cotton plant size and canopy closure to produce a range of plant sizes that might be present in North Carolina when Trichogramma releases for suppression of third-generation (F₃) heliothines were made. Pix treatments had a significant effect on canopy closure, which significantly influenced the number of hours soil surface temperatures between rows were ≥35°C. The mean daily number of hours temperatures were ≥35°C was greatest on the soil surface between rows, followed by in the canopy, then soil surface within rows. A significant correlation between the number of hours preimaginal Trichogramma were exposed to temperatures ≥35°C and Trichogramma emergence was found in 1997. Consequently, suitability of the soil surface as a release site for Trichogramma capsules depended significantly on the level of canopy closure, location of capsules relative to the center of rows, and length of time capsules remained in the field before parasitoid emergence. Our results indicate that these factors should be considered when implementing augmentative releases of Trichogramma wasps in cotton.

Cotesia rubecula (Marshall) was first released in New Zealand for control of Pieris rapae (L.) in December 1993. It has since been released in nine regions and is established in eight of these, from Northland to Southland (35° 15′ S to 46° 10′ S). Natural geographic spread of C. rubecula has averaged ≈2 km/yr in the Pukekohe area in South Auckland. Death rates due to parasitism ranged from 48 to 97% of host larvae at selected study sites, but were lower at most commercial sites. Three paired comparisons of sites with and without C. rubecula showed that the parasitoid reduced the survival of P. rapae larvae and limited the density of fifth instars. Although C. rubecula reduced parasitism by Cotesia glomerata (L.) in sites where they were both present, total parasitism of P. rapae was increased at these sites. Some hyperparasitism of C. rubecula by Tetrastichus galactopus was observed, but it does not appear to be limiting establishment of C. rubecula.

Tachinaephagus zealandicus Ashmead is a gregarious endoparasitoid that attacks third instars of muscoid flies in the Southern Hemisphere. The purpose of the current study was to evaluate the influence of six constant temperatures (16, 18, 20, 22, 25, and 27°C) on development time, the influence of emergence order on longevity, and the effects of temperature and food treatment on longevity. Emergence success was greatest at 22°C for both males and females; significantly fewer (24.1–30.4%) parasitoids emerged at 16 and 25°C compared with 22°C. Development time ranged from 24.0 to 56.9 d for both sexes. No emergence was observed at 27°C. Early-emerging parasitoids had greater longevity than parasitoids that emerged later from the same cohorts. The longevity of females given honey and water decreased with increasing temperature, and those reared at 16°C lived about three times longer than those kept at 27°C. Females given honey and water had similar longevities at 16–20°C, and females that were given only water lived for only 4.8–7.6 d at all temperatures. Females lived significantly longer overall than males at all temperatures except 16°C, but differences due to sex were small compared with the effects of temperature and nutrition. Further investigations will be necessary to determine the climatic zones in which T. zealandicus is most likely to be an effective biological control agent of muscoid flies.

The infectivity of four species of entomopathogenic nematodes, Steinernema carpocapsae (Weiser) [Breton strain], Steinernema riobrave Cabanillas, Poinar & Raulston [Weslaco strain], Heterorhabditis bacteriophora Poinar [HP88 strain], and Heterorhabditis indica Poinar, Karunakar & David [Coimbatore strain] was examined in the laboratory against two subterranean termites: Reticulitermes flavipes (Kollar) and Coptotermes formosanus Shiraki. In petri dish tests, they were all effective against C. formosanus at ≥400 nematodes per termite. Steinernema riobrave had no detectable effect against R. flavipes even at a rate of 2,000 nematodes per termite. The virulence of the nematodes for R. flavipes was H. indica > H. bacteriophora > S. carpocapsae > S. riobrave. The virulence of the nematodes for C. formosanus was H. indica and H. bacteriophora > S. carpocapsae and S. riobrave at α = 0.10 level. The LD₅₀ of H. indica against R. flavipes in petri dishes and in containers with vermiculite/sand medium were 296 (95% FL: 231–353) and 264 (95% FL: 176–344) nematodes per termite, respectively. The LD₅₀ of H. bacteriophora against R. flavipes in petri dishes was 494 (95% FL: 357–625) nematodes per termite. Heterorhabditis indica repelled termites at high concentrations in sand and vermiculite medium. The length of repellency varied with the nematode concentration. Nematodes were able to reproduce from R. flavipes and C. formosanus. The possibility of using nematodes to control termites is discussed.

The parasitoid guild attacking preimaginal Tortricidae on shrubs and small trees in broadleaf/podocarp forests was studied at six sites in the central North Island. Connectance and quantitative webs were used to interpret the complexities of host parasitoid interactions at a community level and identify competition between native parasitoids and the introduced species Trigonospila brevifacies (Hardy). Trigonospila brevifacies is numerically dominant in the tortricid parasitoid guild. Its host range overlaps with 12 native and one introduced parasitoid species, and it parasitizes more species of Tortricidae than other parasitoids at the North Island forest sites surveyed. Quantification of the parasitoid load on native Lepidoptera indicated that T. brevifacies parasitism comprised between 15.6 and 79.5% of the parasitoid load per species. Only the introduced Australian canefruit pest Eutorna phaulocosma Meyrick (Lepidoptera: Oecophoridae) received a higher proportion of parasitism from T. brevifacies than any of the native Lepidoptera. The number of parasitoid species attacking each preimaginal host stage (except for pupae) of native Lepidoptera was relatively constant. The only pupal parasitoid recorded was the introduced ichneumonid Xanthopimpla rhopaloceros Krieger (Hymenoptera: Ichneumonidae). All native parasitoid species were less abundant than T. brevifacies.

Laboratory experiments were conducted to determine the influence of two tomato (Lycopersicum esculentum Miller) varieties (‘Trust’ and ‘Floridade’) on the biology of two whitefly species, Bemisia argentifolii Bellows & Perring and Trialeurodes vaporariorum (Westwood), and the interactions of host plant and whiteflies on the biology and parasitization of two parasitoid species, Eretmocerus eremicus Rose & Zolnerowich (native) and Eretmocerus mundus Mercet (exotic). Natural mortality, developmental time, and fecundity of B. argentifolii were not significantly different from those of T. vaporariorum on either tomato variety. The two species of Eretmocerus responded differently to the whitefly hosts. Eretmocerus mundus developed significantly faster, produced more progeny, and had greater parasitism and rate of emergence in B. argentifolii than in T. vaporariorum. Eretmocerus eremicus performed similarly on both whitefly species except that its females deposited more eggs in B. argentifolii than in T. vaporariorum nymphs. Females of both parasitoid species emerging from T. vaporariorum were significantly larger than those emerged from B. argentifolii. Tomato variety had no significant effect on the two parasitoid species. Eretmocerus eremicus attack both whiteflies efficiently and it can be used as a single species for whitefly management.

Nothing was known about the life cycle of Pseudacteon cultellatus Borgmeier. Because this species seems to be a promising candidate for biological control of fire ants, we studied several aspects of its development. We measured selected life history traits of the fire ant parasitoid Pseudacteon cultellatus as a function of (1) host species (Solenopsis invicta Buren versus Solenopsis richteri Forel), (2) temperature (22 versus 25°C), and (3) size distributions of available host ants (homogeneous small versus mixed sizes of workers). We found that larval, pupal, and total developmental periods of this phorid fly were between 12 and 18% longer on S. richteri than on S. invicta, and 11–19% longer at 22 than at 25°C. Although larval developmental times did not differ as a function of sizes of host offered, average time of development in the pupal stage was extended by 12% in the case of host size mixtures which included workers larger than the phorid’s preferred host size in comparison to homogeneously small ants. P. cultellatus exhibited a strong preference for small ants, especially when using S. invicta workers as hosts. We did not find a relationship between size of host and sex of emerging flies as previously documented for some other Pseudacteon species. P. culltelatus seems to be a promising species for controlling S. invicta as it develops faster in this smaller host, and because it prefers to attack small ants and does not need larger hosts to produce female flies. Thus, this P. cultellatus can attack the majority of ants in a colony without the risk of producing a male-biased sex ratio.

Four species of pteromalid parasitoids [Muscidifurax raptor Girault & Sanders, Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia gemina Boucek, and the chalcidid Dirhinus himalayanus (Masi)] were evaluated for their ability to locate house fly pupae at various depths in poultry manure (41% moisture), fly rearing medium (43% moisture), and sandy soil (4% moisture) from a dairy farm. Searching activity in manure was largely confined to the surface (M. raptor, D. himalayanus, and S. gemina) or to depths of up to 2 cm below the surface (S. endius, S. cameroni). S. cameroni was the most effective species at locating buried pupae in manure. All of the species searched over a wider range of habitat depths in fly rearing medium, although M. raptor and S. gemina tended to concentrate their searching activity relatively close to the surface of the substrate. Host attacks by these species at 6 cm were 30–40% lower than on the surface of the medium. S. endius searched uniformly at all depths in rearing medium and S. cameroni had highest rates of host attacks 1–2 cm below the surface of this substrate. The parasitoids displayed considerable fidelity to their search patterns regardless of whether or not they were given a choice of habitat depths in which they could find pupae. None of the parasitoids were effective at attacking fly pupae that were buried in sandy soil at any depth. The results suggest that fly larvae that pupate in the sandy soils typical of Florida’s coastal plains are relatively impervious to attack by pupal parasitoids.

Development, survivorship, longevity, and reproduction of Lysiphlebia mirzai Shuja-Uddin, a parasitoid of Toxoptera citricida (Kirkaldy), was studied at constant temperatures in the laboratory. Larval development ranged from 8.3 d at 32°C to 20.3 d at 10°C, and pupal development ranged from 3.7 d at 30°C to 15.4 d at 10°C. No adults emerged from mummies at 32°C. Duration of larval development was longer than pupal development. The respective low developmental temperatures and degree-days (DD) were estimated at 3.7°C and 142.7 DD for larval stage, 4.8°C and 94.2 DD for pupal stage, and 6.2°C and 181.2 DD for combined immature stage. The respective optimal temperatures of 30.3, 33.3, and 31.1°C for larval, pupal, and combined immature development were determined from a nonlinear biophysical model. The pupal survivorship was relatively constant within 10–20°C (90–84.5%). The average number of eggs laid per female in the initial 24-h period varied from 106.3 at 25°C to 41.8 at 32°C. The average longevity of L. mirzai adults decreased linearly with increasing temperature. At high (37 and 40°C) and low (5°C) temperature, the average pupal survivorship decreased as treatment time increased. Adult parasitoids failed to emerge from the mummies at 40°C after a 4-h treatment. In addition, the mean longevity of adult parasitoids was enhanced when they were fed with honey and water. The optimal constant temperature range for L. mirzai population growth was 15–25°C. This parasitoid may be more effective in control of brown citrus aphid in cooler months than in summer months.