Miriam F. Cooperband

Trans-bergamotenes-male pheromone of the ectoparasitoid Melittobia digitata.

The first male-produced sex attractant pheromone in the parasitic Hymenoptera has been identified. The elaborate courtship behavior of Melittobia digitata, an idiobiont that parasitizes the last larval instar or the pupal stage of solitary bees and wasps, involves a series of coordinated movements of legs, wings, and antennae, initiated after the female is attracted to the blind, flightless male. We identified α- and β-trans-bergamotene as the active compounds of the male M. digitata sex attractant. Variation in the release of the sex pheromone by males and the pheromone load during aging is also described.

Male-Produced Pheromone in the European Woodwasp, Sirex noctilio

A male-produced pheromone that attracts both males and females was identified for the European woodwasp, Sirex noctilio, a serious pest of pine trees. Males displayed excitatory behaviors when placed in groups, and were attracted to the odors from males that were 2-5-d-old, but not to odors from males that were 0-1-d-old. An unsaturated short-chain alcohol, (Z)-3-decen-1-ol, was discovered in samples collected on SuperQ filters over groups of males and identified by using micro-derivatization reactions and gas chromatography coupled with mass spectrometry (GC-MS). The compound was not detected in volatile samples from females. Gas chromatography coupled electroantennographic detection (GC-EAD) of antennae from males exposed to male headspace odors produced strong antennal responses to the main peak of (Z)-3-decen-1-ol, as well as to an unknown minor component that had a similar retention time. Antennae from both males and females responded to synthetic (Z)-3-decen-1-ol. Several different synthetic candidates for the GC-EAD active minor components were selected based on GC-MS and GC-EAD responses to male headspace collections. These synthetic compounds were tested for antennal activity using GC-EAD, and those that produced strong responses were blended with the major component and tested for male attraction in the Y-tube olfactometer at different concentrations and ratios. Males tested in the Y-tube olfactometer were attracted to a synthetic blend of (Z)-3-decen-1-ol and (Z)-4-decen-1-ol at a ratio of 100:1. Whereas the addition of some suspected minor compounds reduced attraction, the addition of a third compound found in male emanations that produced strong male antennal responses, (E,E)-2,4-decadienal (at a ratio of 100:1:1), resulted in attraction of both males (Y-tube and wind tunnel) and females (wind tunnel).

Effects of Wind Speed on Aerosol Spray Penetration in Adult Mosquito Bioassay Cages

ABSTRACT Bioassay cages are commonly used to assess efficacy of insecticides against adult mosquitoes in the field. To correlate adult mortality readings to insecticidal efficacy and/or spray application parameters properly, it is important to know how the cage used in the bioassay interacts with the spray cloud containing the applied insecticide. This study compared the size of droplets, wind speed, and amount of spray material penetrating cages and outside of cages in a wind tunnel at different wind speeds. Two bioassay cages, Center for Medical, Agricultural and Veterinary Entomology (CMAVE) and Circle, were evaluated. The screen materials used on these cages reduced the size of droplets, wind speed, and amount of spray material inside the cages as compared to the spray cloud and wind velocity outside of the cages. When the wind speed in the dispersion tunnel was set at 0.6 m/sec (1.3 mph), the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.045 m/sec (0.10 mph) and 0.075 m/sec (0.17 mph), respectively. At air velocities of 2.2 m/sec (4.9 mph) in the dispersion tunnel, the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.83 m/sec (1.86 mph) and 0.71 m/sec (1.59 mph), respectively. Consequently, there was a consistent 50–70% reduction of spray material penetrating the cages compared to the spray cloud that approached the cages. These results provide a better understanding of the impact of wind speed, cage design, and construction on ultra-low-volume spray droplets.

Biology of two members of the Euwallacea fornicatus species complex (Coleoptera: Curculionidae: Scolytinae), recently invasive in the U.S.A., reared on an ambrosia beetle artificial diet

Recent molecular studies have found that the ambrosia beetle Euwallacea fornicatus Eichhoff (Coleoptera: Curculionidae: Scolytinae) is a complex of cryptic species, each carrying a different species of symbiotic fungus, in the genus Fusarium, which they farm within galleries inside woody hosts. Several of these beetle species have become invasive pests around the world for attacking and infecting healthy trees with their phytopathogenic fungal symbionts. Diet and rearing protocols were developed for two members of the E. fornicatus species complex, polyphagous shot hole borer (PSHB) and tea shot hole borer (TSHB), using sawdust from host trees, allowing collection of data on beetle biology, phenology and sex ratios. Adults developed within 22 days at 24 °C. Single PSHB or TSHB foundresses averaged 32.4 and 24.7 adult female offspring, respectively, and up to 57 and 68 female adults within 6–7 weeks. A strong predictor of the number of offspring in a colony was the number of entry holes. Average sex ratios (% male) for PSHB and TSHB, respectively, were 7.4% and 7.2%. Being haplodiploid, virgin PSHB foundresses were able to produce and mate with male offspring, then subsequently produce female offspring, confirming that they have arrhenotokous reproduction. A cold tolerance study found significant mortality rates among PSHB colonies exposed to −5° or −1 °C but not colonies exposed to 0°, 1° or 5 °C. Given Hamiltons local mate competition (LMC) theory, a number of LMC predictions were violated. PSHB sex ratios were not affected by the number of foundresses; approximately 14% of broods did not contain males; males did not usually eclose before females but eclosed around the same time (22–23 days); and PSHB males were found walking outside of their natal galleries on the trunk of a heavily infested tree in the field. Alternatives to LMC are considered, such as early forms of sociality (maternal care, cooperative brood care), local resource enhancement and kin selection.

Assessing trap and lure effectiveness for the monitoring of Sirex noctilio

Lure‐baited traps are an important tool for monitoring the spread and establishment of the Sirex woodwasp Sirex noctilio. The utility of these traps, however, is limited in areas with low wasp populations as a result of the reliance on a plant volatile (kairomone) lure in the absence of an identified pheromone. Knowledge of the optimal trap type and deployment strategy is also lacking. We tested the effectiveness of a putative pheromone in baited traps, by means of a series of field trials in South Africa, over a 3‐year period. We also examined the influence of lure type, trap type and trap height on capture success. The pheromone was found to be ineffective as an attractant under South African field conditions for both male and female wasps. Lure type, trap type and trap height were found to have little to no effect on female wasp catch. Given the moderately strong responses to the blend under wind tunnel and laboratory conditions, we suggest possible aspects of the biology and life history of S. noctilio that may influence lure effectiveness. The traditional black intercept panel traps with kairomone lure remains the best trap for S. noctilio, at least where populations are high.

Tracing the origin of a cryptic invader: phylogeography of the Euwallacea fornicatus (Coleoptera: Curculionidae: Scolytinae) species complex: E. fornicatus species complex phylogeography

The ambrosia beetle morphologically identified as Euwallacea fornicatus consists of several cryptic species that exhibit large differences in the DNA sequences of several nuclear and mitochondrial gene regions. Based on these differences, we suggest that there are at least three different species each with distinct phylogeography. Members of this cryptic species complex have invaded many areas outside their native range and cause substantial damage to both agriculture (avocado in particular) and other tree species. Three of these cryptic species have invaded the USA: two species in California and a third species in both Florida and Hawaii. Identification of their native range allows directed search for their natural enemies that may be used in biological control of these tree pests.

Attraction of Euwallacea nr. Fornicatus (Coleoptera: Curculionidae: Scolytinae) to Lures Containing Quercivorol

Summary Euwallacea nr. fornicatus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae) is an exotic ambrosia beetle that vectors fungal Fusarium spp. to avocados. Two field trials testing potential attractants to trap Euwallacea spp. were conducted in south Florida. Quercivorol + Ultra High Release Ethanol (URH) was the most powerful attractant for E. nr. fornicatus in the 2 field trials. In Florida, the populations of E. nr. fornicatus are small. The attractiveness of quercivorol lures to other Euwallacea spp. should be tested in conditions where population levels are greater as in California and Israel.

The importance of olfactory and visual cues in developing better monitoring tools for Sirex noctilio (Hymenoptera: Siricidae)

To improve the monitoring of the invasive European woodwasp, both sexes of Sirex noctilio were studied in a walk‐in wind tunnel. We evaluated three trap types: unbaited traps, traps baited with a three‐component pheromone lure and traps baited with a commercial Sirex kairomone lure and ultraviolet light. When no lure was present, the black intercept trap caught more females than the clear jar trap. The increase in pheromone concentration from 0.1 to 1 mg increased the capture of females, and not males, in the black intercept panel trap. Both of these findings suggest that the visual cues provided by the black intercept trap play an important role in attraction for females. Capture rates between unbaited clear versus black intercept traps did not differ but the addition of a ultraviolet light increased trap efficacy. Intercept traps baited with light were more attractive than the commercial kairomone lure. Both olfactory and visual cues were found to play important roles in the response of S. noctilio to traps. A black trap may enhance the capture of females, whereas the addition of ultraviolet light could enhance capture for both sexes. Integrating these different components may help in developing an improved species‐specific trap for S. noctilio.

Communication Disruption of Epiphyas postvittana (Lepidoptera: Tortricidae) By Using Two Formulations at Four Point Source Densities in Vineyards

ABSTBACT Light brown apple moth [Epiphyas postvittana (Walker) ] is now established as an economic and quarantine pest in California, and new technologies are being investigated to increase options for its management. Two new organic formulations for mating disruption, SPLAT LBAM HD-O and organic Hereon Biotie (biodegradable) were field tested at four point source densities (25, 72, 322, and 500/ha) and compared with the standard Isomate LBAM Plus(500/ha, as a positive control) and an untreated (negative) control. Assessment involved trapping using synthetic lures and virgin females. In total, 175,776 male light brown apple moths were caught to both the caged females and synthetic lures, from 10 February to 19 May 2011. The light brown apple moth catch dramatically decreased from baseline measurements after the treatments were applied, with the highest density treatments reducing catch to below 10% of the catch in the untreated controls within the first week (>90% disruption). In synthetic lure traps, the SPLAT and Biotie treatment performed similarly well over all rates (P = 0.317 for posttreatment percentage communication disruption), but SPLAT performed better at disrupting virgin female traps (P = 0.045). There was a significant increase in disruption with an increasing number of points/ha (P < 0.001). Disruption of communication was similar for all three technologies (SPLAT, Biotie and Isomate) at 500 points/ha for both types of trap (P > 0.74). Disruption of this species in vineyards is thus highly feasible.

Distribution, Pest Status and Fungal Associates of Euwallacea nr. fornicatus in Florida Avocado Groves

Members of a complex of cryptic species, that correspond morphologically to the ambrosia beetle Euwallacea fornicatus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), were recently found attacking avocado (Persea americana Mill.) in Israel and California. In early 2016, an outbreak of another member of this species complex was detected infesting approximately 1500 avocado trees in an avocado orchard at Homestead, Florida. An area-wide survey was conducted in commercial avocado groves of Miami-Dade County, Florida to determine the distribution and abundance of E. nr. fornicatus, to identify different populations of E. nr. fornicatus and their fungal associates, and to assess the extent of damage to avocado trees. Ewallacea nr. fornicatus were captured in 31 of the 33 sampled sites. A sample of 35 beetles from six different locations was identified as E. nr. fornicatus sp. #2, which is genetically distinct from the species causing damage in California and Israel. Eleven fungal associates were identified: an unknown Fusarium sp., AF-8, AF-6, Graphium euwallaceae, Acremonium sp. Acremonium morum, Acremonium masseei, Elaphocordyceps sp. and three yeast species. The unknown Fusarium isolates were the most abundant and frequently found fungus species associated with adult beetles and lesions surrounding the beetle galleries. In addition to fungal associates, three bacteria species were found associated with adult E. nr. fornicatus. Visual inspections detected significant damage in only two orchards. A large number of beetles were captured in locations with no apparent damage on the avocado trees suggesting that E. nr. fornicatus are associated with other host(s) outside the groves or with dead trees or branches inside the groves. More research is needed to determine the potential threat E. nr. fornicatus and its fungal associates pose to the avocado industry and agricultural and natural ecosystems in Florida.