Bruce A. Barrett

Fecundity and fertility reductions in adult leafrollers exposed to surfaces treated with the ecdysteroid agonists tebufenozide and methoxyfenozide.

The effects on the fecundity and fertility of redbanded leafroller, Argyrotaenia velutinana (Walker), and obliquebanded leafroller,Choristoneura rosaceana (Harris), exposed as adults to surfaces treated with the ecdysone agonists tebufenozide (RH‐5992) and methoxyfenozide (RH‐2485) were examined. The first part of the study consisted of recently emerged moths being exposed to treated surfaces continuously throughout their lives (including mating and oviposition). Continuous exposure to tebufenozide‐ or methoxyfenozide‐treated surfaces significantly reduced the mean number of eggs laid and the percent of eggs that hatched in both species. The second part of the study involved exposure of recently emerged virgin moths (by sex) to treated surfaces for 24 h, after which, the exposed moths were paired with a nontreated partner to mate and oviposit on nontreated surfaces. In this experiment, for A. velutinana, significant reductions in fecundity occurred only when the female was exposed to methoxyfenozide‐treated surfaces. Significant reductions in A. velutinana egg fertility occurred with both male and female exposure in the methoxyfenozide treatments and only female exposure in the tebufenozide treatments. For C. rosaceana, significant reductions in fecundity occurred with both male and female exposure in the tebufenozide and methoxyfenozide treatments. Significant reductions in C. rosaceana egg fertility occurred with both male and female exposure in the tebufenozide treatments and only with female exposure in the methoxyfenozide treatments.

Effects of methoxyfenozide-treated surfaces on the attractiveness and responsiveness of adult leafrollers

Abstract The attractiveness and responsiveness of the adult redbanded leafroller, Argyrotaenia velutinana (Walker), and obliquebanded leafroller, Choristoneura rosaceana (Harris), exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide were investigated in wind tunnel and orientation tube assays. For both species, when males were exposed to water‐treated surfaces for 48 h, and regardless of what treatment surfaces the females had been exposed to, the mean percentage recaptures of such treated males in the wind tunnel assays were always significantly greater than the recaptures of males that had been exposed to methoxyfenozide. However, exposure to surfaces treated with surfactant (Latron B‐1956) also negatively affected the responsiveness (or attractiveness) of both moth species. In the orientation tube assays, males exposed to methoxyfenozide‐treated surfaces always had significantly lower mean levels of individuals exhibiting sexual excitability, and the mean distances traveled upwind, regardless of females’ exposure. In addition, exposure to surfactant‐treated surfaces did not affect mean levels of sexual excitibility and distances traveled upwind. The two bioassays demonstrated that male A. velutinana and C. rosaceana exposed to methoxyfenozide‐treated surfaces were not as responsive to calling females (treated and non‐treated) as were the non‐treated males. Conversely, females exposed to methoxyfenozide‐treated surfaces were just as attractive to non‐treated males as water‐treated females. It appears that a males ability to respond to a calling female is more negatively affected by the ecdysone agonist than a females ability to call and attract males.

Predicting the emergence of the codling moth, Cydia pomonella (Lepidoptera: Tortricidae), on a degree-day scale in North America

BACKGROUND Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a major pest of apple, pear and walnut production in North America. Management programs are based on preventing larval entry into the fruit or nut and are typically timed by heat-driven models that are synchronized to field populations by first capture of overwintering moths in pheromone traps. Unfortunately, trap capture is affected by a range of environmental parameters as well as by the use of mating disruption, which makes detecting first flight difficult, thus complicating implementation of management programs. The present goal was to evaluate data collected from a broad range of locations across North America to see whether average first spring emergence times could be predicted. RESULTS Average emergence time on a degree-day scale from 1 January was predictable using latitude and elevation. Sites at elevations of <400 m fit a simple quadratic equation using latitude, but, when higher elevations were included, a multiple regression using elevation was required. CONCLUSIONS The present models can be used to simplify management programs for codling moth in areas where heat-driven models that require extensive trapping to synchronize with emergence are currently used.

Effects of ecdysone agonists on the expression of EcR, USP and other specific proteins in the ovaries of the codling moth (Cydia pomonella L.)

Tebufenozide and methoxyfenozide have been previously shown to significantly reduce fecundity and cause vitellogenin accumulation in hemolymph of the codling moth Cydia pomonella L. In the present study, the effects of these ecdysone agonists, tebufenozide and methoxyfenozide, on the expression of ecdysone receptor (EcR), ultraspiracle protein (USP) and other proteins in the ovaries of C. pomonella L., were investigated at both the translational and/or transcriptional levels with an aim to elucidate the mechanisms by which the fecundity was reduced. Western and Northern blot analyses revealed that the expression of a 65 kDa (p65) EcR, and 60 and 64 kDa (p60 and p64) USP proteins were enhanced by tebufenozide and methoxyfenozide at both transcriptional and translational levels. Northern blot analysis indicated that the p65 EcR protein is encoded by EcRB1 transcript and that the p60 and p64 USP bands were the products of USP-1 transcript. Immunoprecipitation assays demonstrated that both the p60 and p64 USP coprecipitated with the p65 EcR and that p64 was a dominant USP to form complex with EcR. In addition, several other specific proteins were also identified and their expressions affected by the agonists. The data suggest that the ecdysone agonists regulate, via the EcR/USP complex, the expression of these specific proteins that might eventually lead to the inhibition of fecundity in the codling moth.

Assessment of methoxyfenozide exposure on the sexual attractiveness and responsiveness of adult codling moth, Cydia pomonella L., in small orchard blocks.

BACKGROUND The sexual attractiveness of female and the responsiveness of male codling moth, Cydia pomonella L., exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide were investigated in small orchard block experiments. The main purpose of the study was to determine whether the reported sublethal effects of methoxyfenozide affecting moth behavior also occur under field conditions. RESULTS Data from the first experiment showed that in some trials untreated females were significantly more attractive to wild males than methoxyfenozide-treated females. The second experiment revealed that some released methoxyfenozide-treated males were not as responsive to calling females as untreated males, and that some untreated females were more attractive to males than methoxyfenozide-treated females. The third experiment revealed that wild males exposed to treated tree surfaces were significantly less responsive to traps than were wild males exposed to untreated trees. However, there were no significant differences in mean recaptures of released males between the untreated and treated orchard blocks. CONCLUSION Exposure of adult C. pomonella to methoxyfenozide-treated surfaces resulted in a negative impact on male responsiveness to calling females and synthetic pheromone lures. However, the level of impact on the sexual attractiveness of treated females did not appear to be as explicit.

Sublethal Exposure to Methoxyfenozide-Treated Surfaces Reduces the Attractiveness and Responsiveness in Adult Oriental Fruit Moth (Lepidoptera: Tortricidae)

Abstract The chemical communication (female attractiveness and male responsiveness) of adult oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide for 48 h were investigated in two laboratory wind tunnel assays. The recapture assay examined the ability of treated males to orient to a single cage of treated females, and the data gathered were mean percentage of males recaptured per treatment. The male sexual behavior assay examined some specific orientation behaviors (associated with sexual excitability) of treated males when they were given a choice of two competing pheromone sources (cages of treated females), and the data gathered were mean time males spent in upwind plume orientations and at source contact (female cage) per treatment. Data from the recapture assay suggests that exposure to methoxyfenozide impacts male responsiveness more than female attractiveness. In contrast, data from the sexual behavior assay strongly revealed that exposure to methoxyfenozide-treated surfaces does negatively impact both the ability of calling females to attract males and of aroused males to display sustained upwind flight behavior and time spent at the female cages.

Small plot mating disruption trials for tufted apple bud moth, Platynota idaeusalis, in Pennsylvania apple orchards

Mating disruption treatments for the tufted apple bud moth (TABM), Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component isomeric blend of E‐11‐tetradecen‐1‐ol (E11–14:OH) and E‐11‐tetradecenyl acetate (E11–14:Ac). A 50:50 ratio of these two components was used in standard monitoring septa and in mating disruption treatments released from either hollow fibers (‘fiber’) or PVC tubes (‘PVC’). Other pheromone blends tested included a 90:10 ratio of E11–14:Ac and E11–14:OH (‘EAc’) and its reverse (‘EOH’), mixture ‘EAc’ with 30% of the Z‐isomers (‘low EAc’), and a blend similar to the preceding with 2% Z9–12:Ac (‘generic’). These other blends were released from multi tube tape (‘tape’) or Shin‐Etsu type rope (‘rope’) dispensers. Seasonal dispenser release rate in mg ha−1 h−1 was ca. 30 for the ‘rope’ dispensers, 14 for ‘PVC’ and 6 for ‘fiber’. ‘EAc‐tape’ and ‘EOH‐tape’ were equally effective in reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also reduced fruit injury. ‘EAc‐rope’, ‘fiber’ and ‘PVC’ also were generally effective; whereas, the ‘low EAc’ and ‘generic’ treatments reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction in trap capture for the ‘low EAc‐rope’ and ‘genericrope’ treatments. Traps loaded with ‘fiber’ dispensers captured more male TABM than the other treatments in non‐pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone treatments. ‘EAc‐rope’ and the ‘TABM’ treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9 (10.1), respectively, for the redbanded leafroller, Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller, Choristoneura rosaceana (Harris).

Seasonal Occurrence and Soil Distribution of the Lesser Chestnut Weevil, Curculio sayi (Coleoptera: Curculionidae) in Mid-Missouri

Abstract The seasonal emergence periods from the soil of adult lesser chestnut weevil, Curculio sayi (Gyllenhal), was assessed for three years at a site in mid-Missouri using wire cone emergence traps. Two additional trap types, Circle and pyramid, were used to assess the timing of adult movement into the trees. The trap data indicated there were two distinct adult emergence periods, the first occurring in early-May and the second beginning late-August. This is in contrast to previous studies that have reported C. sayi as having only one seasonal emergence period (which occurs in the spring). Our study also examined the underground development of C. sayi. The data showed that, after leaving the chestnut, most larvae burrow to a soil depth of 7.5–15 cm where they remain for at least 19 mo, and that the weevils have an overall life cycle (egg hatch to adult emergence) of about 20–21 mo.

Fecundity, Fertility and Longevity Reductions in Adult Oriental Fruit Moth (Lepidoptera: Tortricidae) Exposed to Surfaces Treated with the Ecdysteroid Agonists Tebufenozide and Methoxyfenozide

The effects on the fecundity, fertility and longevity of oriental fruit moth, Grapholita molesta (Busck), were examined in a 2-part study that exposed adults to surfaces treated with the ecdysone agonists tebufenozide and methoxyfenozide. The first experiment revealed that when recently-emerged moths were exposed to tebufenozide- or methoxyfenozide-treated surfaces continuously throughout their lives (including mating and oviposition), mean fecundity was significantly reduced. In addition, continuous exposure to methoxyfenozide-treated surfaces significantly reduced female longevity. Exposure to surfaces treated only with a surfactant (Latron B-1956®) used in field applications of tebufenozide and methoxyfenozide also significantly impaired the mean fecundity and percent fertility of the oriental fruit moth. The second part of the study showed that when recently-emerged unmated moths were exposed to treated surfaces for 24 h, then paired with a nontreated partner of the opposite sex to mate and oviposit o...

Behavioral and Electroantennographic Responses of the Lesser Chestnut Weevil, Curculio sayi (Coleoptera: Curculionidae), to Odors Emanating from Different Chestnut Plant Tissues

Abstract The lesser chestnut weevil, Curculio sayi (Gyllenhal), is a key pest of chestnut in the eastern and central United States. Y-tube bioassays and electroantennogram (EAG) studies were conducted on adult C. sayi regarding their behavioral and EAG responses towards odors from different chestnut tissue types (leaf, catkin, bur and nut) to determine the possibility of using host-plant volatiles in monitoring this highly host-specific pest. In behavioral trials, spring emerging weevils (of both sexes) were significantly attracted to odors emanating from catkins (flowers) and burs, with males also attracted to the odors from the nut. In the late-summer, weevils (of both sexes) emerging or returning to chestnut trees were again significantly attracted to the odors from bur and catkin tissues, with females also being attracted nut tissue. Odors emanating from leaves were not attractive to either sex. The EAG trials revealed that weevil antennae responded significantly to odors from bur spikes and the inner bur tissue layer, as well as to odors from catkin and leaf tissues; however, the weevils (regardless of sex or season of collection) were not significantly responsive in EAG tests to odors from the nut tissue (site of oviposition). This study provides key initial data that strongly suggests that chestnut plant volatiles can be successfully utilized as attractants in a semiochemical-based monitoring trap for C. sayi adults.