New species of Nearctic oak gall wasps (Hymenoptera: Cynipidae, Cynipini).

Twenty nine new species of cynipid oak gall wasps from the Nearctic region (America north of Mexico) are described: Andricus archboldi Melika Abrahamson, sp. nov., A. catalinensis Melika, Nicholls Stone, sp. nov., A. chapmanii Melika Abrahamson, sp. nov., A. chiricahuensis Melika, Nicholls Stone, sp. nov., A. coconinoensis Melika, Nicholls Stone, sp. nov., A. columbiensis Melika, Nicholls Stone, sp. nov., A. cooki Melika, Nicholls Stone, sp. nov., A. fitzpatricki Melika Abrahamson, sp. nov., A. highlandensis Melika, Nicholls Stone, sp. nov., A. mellificus Nicholls, Stone Melika, sp. nov., A. menkei Melika Abrahamson, sp. nov., A. mogollonensis Melika, Nicholls Stone, sp. nov., A. nichollsi Melika Stone, sp. nov., A. schickae Nicholls, Melika Stone, sp. nov., A. torreyaensis Melika Abrahamson, sp. nov., A. williami Melika, Nicholls Stone, sp. nov., Antron lovellae Melika, Nicholls Stone, sp. nov., A.tomkursari Melika, Nicholls Stone, sp. nov., Dryocosmus archboldi Melika Abrahamson, sp. nov., Loxaulus virginianae Melika Buss, sp. nov., Neuroterus alexandrae Nicholls Melika, sp. nov., N. aliceae Melika, Nicholls Stone, sp. nov., N. bussae Melika Nicholls, sp. nov., N. oblongifoliae Nicholls, Stone Melika, sp. nov., N. quaili Melika, Nicholls Stone, sp. nov., N. rosieae Melika, Nicholls Stone, sp. nov., N. stonei Melika Nicholls, sp. nov., Zapatella abrahamsoni Melika, sp. nov., Z. brooksvillei Melika Abrahamson, sp. nov.. Alternate asexual and sexual generations are described for four species, Andricus archboldi Melika Abrahamson, sp. nov., A. fitzpatricki Melika Abrahamson, sp. nov., A. schickae Nicholls, Melika Stone, sp. nov., Neuroterus aliceae Melika, Nicholls Stone, sp. nov.. Descriptions, diagnoses, plus information on biology and host associations are given for all new species. All taxa are supported by morphological data; matching of generations is established using DNA sequence data. We also demonstrate that Neuroterus niger var. alimas Kinsey should be considered as a nomen dubium.

Behavioral responses of pest mole crickets, Neoscapteriscus spp. (Orthoptera: Gryllotalpidae), to selected insecticides.

BACKGROUND: Mole crickets (Neoscapteriscus spp.) consume turfgrasses and pasture grasses and uproot plants by their tunneling, which is detrimental to turf aesthetics and decreases forage quantity and quality. Insecticides are frequently used to prevent damage. In typical field trials, damage symptoms, not percent mortality or achieved level of control, are used to assess treatment efficacy. Here, however, laboratory tests assessed the direct effect of key insecticides on Neoscapteriscus mole cricket behavior. RESULTS: Mole crickets, Neoscapteriscus spp., were able to detect and avoid areas treated with fipronil [formulated product (FP)] and imidacloprid (FP). They tunneled less in sand treated with fipronil and avoided sand treated with fipronil and imidacloprid if given a choice. Mole crickets escaped areas treated with acephate, bifenthrin and fipronil. Bifenthrin and acephate caused increased tunneling during the first 90 min of observation. Fipronil and imidacloprid significantly reduced overall tunneling on treated areas. CONCLUSION: Tested insecticides elicited two types of behavioral changes in Neoscapteriscus mole crickets: increased locomotory activity and tunneling [acephate (organophosphate) and bifenthrin (pyrethroid)] and reduced spatial movement [fipronil (phenylpyrazole) and imidacloprid (neonicotinoid)]. These behavioral responses resulted mainly from contact chemoreception and inherent neurotoxicity of the chemicals on Neoscapteriscus mole crickets. © 2017 Society of Chemical Industry.

Impacts of Antibiotic and Bacteriophage Treatments on the Gut-Symbiont-Associated Blissus insularis (Hemiptera: Blissidae).

The Southern chinch bug, Blissus insularis, possesses specialized midgut crypts that harbor dense populations of the exocellular symbiont Burkholderia. Oral administration of antibiotics suppressed the gut symbionts in B. insularis and negatively impacted insect host fitness, as reflected by retarded development, smaller body size, and higher susceptibility to an insecticide, bifenthrin. Considering that the antibiotics probably had non-lethal but toxic effects on host fitness, attempts were conducted to reduce gut symbionts using bacteriophage treatment. Soil-lytic phages active against the cultures of specific Burkholderia ribotypes were successfully isolated using a soil enrichment protocol. Characterization of the BiBurk16MC_R phage determined its specificity to the Bi16MC_R_vitro ribotype and placed it within the family Podoviridae. Oral administration of phages to fifth-instar B. insularis, inoculated with Bi16MC_R_vitro as neonates had no deleterious effects on host fitness. However, the ingested phages failed to impact the crypt-associated Burkholderia. The observed inactivity of the phage was likely due to the blockage of the connection between the anterior and posterior midgut regions. These findings suggest that the initial colonization by Burkholderia programs the ontogeny of the midgut, providing a sheltered residence protected from microbial antagonists.

Environmental Transmission of the Gut Symbiont Burkholderia to Phloem-Feeding Blissus insularis.

The plant-phloem-feeding Blissus insularis possesses specialized midgut crypts, which harbor a dense population of the exocellular bacterial symbiont Burkholderia. Most individual B. insularis harbor a single Burkholderia ribotype in their midgut crypts; however, a diverse Burkholderia community exists within a host population. To understand the mechanism underlying the consistent occurrence of various Burkholderia in B. insularis and their specific association, we investigated potential gut symbiont transmission routes. PCR amplification detected a low titer of Burkholderia in adult reproductive tracts; however, fluorescence in situ hybridization assays failed to produce detectable signals in these tracts. Furthermore, no Burkholderia-specific PCR signals were detected in eggs and neonates, suggesting that it is unlikely that B. insularis prenatally transmits gut symbionts via ovarioles. In rearing experiments, most nymphs reared on St. Augustinegrass treated with cultured Burkholderia harbored the cultured Burkholderia strains. Burkholderia was detected in the untreated host grass of B. insularis, and most nymphs reared on untreated grass harbored a Burkholderia ribotype that was closely related to a plant-associated Burkholderia strain. These findings revealed that B. insularis neonates acquired Burkholderia primarily from the environment (i.e., plants and soils), even though the possibility of acquisition via egg surface cannot be excluded. In addition, our study explains how the diverse Burkholderia symbiont community in B. insularis populations can be maintained.

Culturing and Characterization of Gut Symbiont Burkholderia spp. from the Southern Chinch Bug, Blissus insularis (Hemiptera: Blissidae).

UNLABELLED: The phloem-feeding Southern chinch bug, Blissus insularis, harbors a high density of the exocellular bacterial symbiont Burkholderia in the lumen of specialized midgut crypts. Here we developed an organ culture method that initially involved incubating the B. insularis crypts in osmotically balanced insect cell culture medium. This approach enabled the crypt-inhabiting Burkholderia spp. to make a transition to an in vitro environment and to be subsequently cultured in standard bacteriological media. Examinations using ribotyping and BOX-PCR fingerprinting techniques demonstrated that most in vitro-produced bacterial cultures were identical to their crypt-inhabiting Burkholderia counterparts. Genomic and physiological analyses of gut-symbiotic Burkholderia spp. that were isolated individually from two separate B. insularis laboratory colonies revealed that the majority of individual insects harbored a single Burkholderia ribotype in their midgut crypts, resulting in a diverse Burkholderia community within each colony. The diversity was also exhibited by the phenotypic and genotypic characteristics of these Burkholderia cultures. Access to cultures of crypt-inhabiting bacteria provides an opportunity to investigate the interaction between symbiotic Burkholderia spp. and the B. insularis host. Furthermore, the culturing method provides an alternative strategy for establishing in vitro cultures of other fastidious insect-associated bacterial symbionts. IMPORTANCE: An organ culture method was developed to establish in vitro cultures of a fastidious Burkholderia symbiont associated with the midgut crypts of the Southern chinch bug, Blissus insularis The identities of the resulting cultures were confirmed using the genomic and physiological features of Burkholderia cultures isolated from B. insularis crypts, showing that host insects maintained the diversity of Burkholderia spp. over multiple generations. The availability of characterized gut-symbiotic Burkholderia cultures provides a resource for genetic manipulation of these bacteria and for examination of the mechanisms underlying insect-bacterium symbiosis.

Zoysiagrass genotype responses to Sphenophorus venatus vestitus (Coleoptera: Curculionidae).

The hunting billbug, Sphenophorus venatus vestitus Chittenden, is a pest that damages stems, rhizomes, and roots of zoysiagrass through a combination of adult and larval feeding. Management of this pest is difficult because it has multiple, overlapping generations in the southern United States, and symptoms of infestations are often misdiagnosed and inappropriately treated as drought stress or disease. Experiments were conducted in a greenhouse where 18 zoysiagrass cultivars were potted and infested with S. v. vestitus adults to examine the response of zoysiagrass genotypes to S. v. vestitus feeding damage. Results showed that zoysiagrass species and cultivars differed in susceptibility to S. v. vestitus, indicating that variable tolerance may exist in these turfgrasses for improvement through breeding. In general, Zoysia japonica Steudel was more susceptible to S. v. vestitus feeding damage and supported more S. v. vestitus than Zoysia matrella (L.) Merrill. Among the Z. japonica cultivars,'Belair' and'Zenith' had less desirable agronomic traits and incurred greater feeding damage than other cultivars more tolerant to billbug damage. With Z. matrella, 'Diamond' and 'Pristine Flora' displayed superior agronomic traits and had the least feeding damage and lowest infestations of billbug immatures and were therefore considered the most tolerant or resistant Z. matrella cultivars tested. Results indicate that stem diameter may be an important factor for adult feeding and oviposition site selection, which might explain the different responses between Zoysia spp. to S. v. vestitus damage.

Life history, natural enemies, and management of Disholcaspis quercusvirens (Hymenoptera: Cynipidae) on live oak trees.

Live oak (Quercus virginiana Mill.) trees are hosts to a complex of gall making arthropods. However, the bullet galls produced by the asexual generation of the cynipid Disholcaspis quercuscirens (Ashmead) can esthetically and physically damage nursery and street trees, and thus reduce tree value. We sought to describe the unknown sexual generation of D. quercusvirens, describe the development of galls from both generations, record adult cynipid and parasitoid activity periods, and evaluate the efficacy of several insecticides to suppress the gall makers and prevent additional gall formation. The oviposition period for asexual females occurred from late November to January in both years of the caging study. Eggs laid into dormant buds resulted in small bud galls in which the sexual generation developed for 4-5 mo. Sexual adults emerged and laid eggs in young elongating shoots in April. Bullet galls began protruding from branches in June, and asexual wasps emerged 5-7 mo later. Cynipids that emerged from the bullet (asexual generation) and bud (sexual generation) galls were genetically identical. Both generations were heavily parasitized. Targeting asexual females with an early December treatment of bifenthrin or acephate significantly reduced the number of bud galls, but control did not extend to the next generation of bullet galls, possibly because of reinvasion from neighboring infested trees.

Thermal requirements and development of Herpetogramma phaeopteralis (Lepidoptera: Crambidae: Spilomelinae).

ABSTRACT The tropical sod webworm, Herpetogramma phaeopteralis Guenée is a major turfgrass pest in the southeastern United States. We evaluated larval development on five artificial diets and at six temperatures (15, 20, 25, 30, 32.5, 35 +/- 1 degree C) on St. Augustinegrass (Stenotaphrum secundatum (Walter) Kuntze). Only larvae fed St. Augustinegrass and soy-wheat germ diets completed their lifecycles. None of the artificial diets tested (corn-based, soy-wheat germ, corn cob-wheat germ, corn cob-soy flour, or pinto bean) were suitable for rearing this species, because of high mortality and slower developmental time. Total developmental time (oviposition to adult) on S. secundatum significantly decreased from 47.8 d at 20 degrees C to 21.1 d at 30 degrees C, and then increased to 32.6 d at 32.5 degrees C. Tropical sod webworm failed to complete larval development at 15 and 35 degrees C. The relationship between temperature and developmental rate was described using linear (common and polynomial) and nonlinear models (Briere-1, Briere-2, and Lactin-2). The estimated lower temperature thresholds using a linear model for eggs, first, second, third, fourth, fifth, and sixth instars, prepupa, pupa, and total development were 10.1, 6.9, 12.3, 10.5, 15.3, 13.9, 9.1, 13.1, 12.0, and 13.1 degrees C, and the thermal constant of these stages were 62.9, 66.2, 38.2, 40.3, 24.9, 32.3, 51.9, 106.4, 109.9, and 370.4 degree-days, respectively. The Briere-1 model provided the best fit with estimated lower, upper, and optimum thresholds for total development of 14.9, 34.3, and 29.4 degrees C, respectively. The developmental requirements of H. phaeopteralis can be used to help predict the distribution and seasonal phenology of this pest.

Metatranscriptomics and pyrosequencing facilitate discovery of potential viral natural enemies of the invasive Caribbean crazy ant, Nylanderia pubens.

BACKGROUND: Nylanderia pubens (Forel) is an invasive ant species that in recent years has developed into a serious nuisance problem in the Caribbean and United States. A rapidly expanding range, explosive localized population growth, and control difficulties have elevated this ant to pest status. Professional entomologists and the pest control industry in the United States are urgently trying to understand its biology and develop effective control methods. Currently, no known biological-based control agents are available for use in controlling N. pubens. METHODOLOGY AND PRINCIPAL FINDINGS: Metagenomics and pyrosequencing techniques were employed to examine the transcriptome of field-collected N. pubens colonies in an effort to identify virus infections with potential to serve as control agents against this pest ant. Pyrosequencing (454-platform) of a non-normalized N. pubens expression library generated 1,306,177 raw sequence reads comprising 450 Mbp. Assembly resulted in generation of 59,017 non-redundant sequences, including 27,348 contigs and 31,669 singlets. BLAST analysis of these non-redundant sequences identified 51 of potential viral origin. Additional analyses winnowed this list of potential viruses to three that appear to replicate in N. pubens. CONCLUSIONS: Pyrosequencing the transcriptome of field-collected samples of N. pubens has identified at least three sequences that are likely of viral origin and, in which, N. pubens serves as host. In addition, the N. pubens transcriptome provides a genetic resource for the scientific community which is especially important at this early stage of developing a knowledgebase for this new pest.

Non-enzymatic hydrolysis of RNA in workers of the ant Nylanderia pubens.

During preparation of total RNA from Nylanderia pubens (Forel) (Hymenoptera: Formicidae) workers for use in expression library construction, severe RNA degradation consistently occurred. This degradation was masked by spectrophotometric analysis but clearly evident by microfluidic-based assay. Although not specifically identified, the degrading entity was endogenous and localized to the abdomen (terminal abdominal segments) of adult ants. RNA degradation was not observed in preparations of larvae, non-melanized pupae, or eggs. Various RNase and protease inhibitors had no protective effect. However, the metal chelating agent ethylenediaminetetraacetic acid prevented RNA degradation and provides insight into the occurrence.

A synchronous rearing method for Blissus insularis (Hemiptera: Blissidae).

The southern chinch bug, Blissus insularis Barber (Hemiptera: Blissidae), is the most destructive insect pest of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze. Management of B. insularis has depended on frequent insecticide applications, which has resulted in populations becoming resistant to several insecticide classes. To facilitate developing a resistance management program for this pest, it is necessary to develop methods to rear insects of known age, generation, and pesticide exposure history. Synchronized rearing methods were developed after testing five different laboratory methods. The use of glass jars and a combined diet of fresh corn, Zea mays L., cob and St. Augustinegrass proved to be best for producing B. insularis of known age and generation. Body size was consistent over nine generations of rearing. Production of a high proportion of brachypterous B. insularis (the nondispersal adult form) also suggests that populations were not stressed during laboratory rearing. This work presents the first successful synchronized rearing method for B. insularis.

Billbug (Coleoptera: Curculionidae) species composition, abundance, seasonal activity, and developmental time in Florida.

Billbugs (Coleoptera: Curculionidae: Sphenophorus spp.) are common pests whose damage is often misdiagnosed on turfgrass in the United States. Consequently, Florida turfgrass managers have been struggling to satisfactorily control billbug outbreaks. Thus, we sought to determine the species complex, abundance, seasonality, and fecundity of key Sphenophorus spp. from field collections, and quantify duration of developmental and daily activity periods through greenhouse rearing tests. From January 2006 to December 2007, > 18,000 adults of 10 different Sphenophorus spp. were collected from four linear pitfall traps on each of two golf courses in north central and two courses in southern Florida. Sphenophorus venatus vestitus Chittenden was the most abundant species, making up > 94% of all specimens collected from three of the four golf courses (80.9% of all specimens collected). Adults were active and mature eggs were present in female ovaries nearly every week of the year. Adults were nocturnal. S. v. vestitus development from egg to adult can occur in 8-9 wk on 'Tifway' bermudagrass [Cynodon dactylon (L.) Pers.] or 'Empire' zoysiagrass (Zoysia japonica Steud.), with up to six overlapping generations per year, depending on environmental conditions. Thus, any time of year could be suitable to target either adults or larvae, and a repeated application may be needed to manage subsequently emerged larvae or eclosed adults.

Seasonal phenology and management of Tomarus subtropicus (Coleoptera: Scarabaeidae) in St. Augustinegrass.

The grub Tomarus subtropicus Blatchley (Coleoptera: Scarabaeidae) is one of the most destructive pests of turfgrass and sugarcane (Saccharum spp.) in southern Florida, but its life cycle has only been described in sugarcane production. Preventive insecticides applied against T. subtropicus in turfgrass when adult activity and oviposition were expected in sugarcane have necessitated subsequent curative treatments. Thus, the seasonal activity of T. subtropicus was monitored using UV blacklight traps and by sampling soil in infested St. Augustinegrass lawns in Cape Coral and Punta Gorda, FL, during 2005-2006. Several preventive and curative insecticides and entomopathogenic nematode species were evaluated in laboratory, greenhouse and field tests. T. subtropicus is univoltine in both sugarcane and St. Augustinegrass, but adult flight peaked approximately 1 mo later in St. Augustinegrass than in sugarcane. Halofenozide, clothianidin, and imidacloprid were effective preventive control products, and carbaryl and trichlorfon were satisfactory curative insecticides. The nematodes Steinernema scarabei (Stock & Koppenhöfer), S. glaseri (Steiner), and Heterorhabditis bacteriophora (Poinar) were most effective against T. subtropicus grubs, and second instars were more susceptible compared with third instars. Improved knowledge of the biology and effectiveness of different management options for T. subtropicus will help minimize excessive pesticide use, especially in coastal areas of Florida.

Integration of insect parasitic nematodes (Rhabditida steinernematidae) with insecticides for control of pest mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus spp.).

To develop a successful integrated pest management program for pest mole crickets (Orthoptera: Gryllotalpidae: Scapteriscus spp.), it is important to ascertain the compatibility of infective juveniles of insect parasitic nematodes and chemical insecticides. Aqueous solutions of five pesticides (acephate, bifenthrin, deltamethrin, fipronil, and imidacloprid) used in turfgrass to control mole crickets were tested for compatibility with Steinernema scapterisci Nguyen & Smart (Rhabditida: Steinernematidae) in the laboratory. Survival of S. scapterisci was >95% in solutions of acephate, bifenthrin, and imidacloprid. Infectivity of S. scapterisci in adult Scapteriscus vicinus Scudder was >60% in acephate and bifenthrin; however, infectivity was <40% in imidacloprid. The entomopathogenic nematode was compatible with most insecticides tested without significantly reduced survival or infectivity.