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Studying the susceptibility of peach trees to Grapholita molesta (Busck) is one of the major steps in the development of pest-resistant peach varieties. This work evaluated the susceptibility of 55 genotypes of the "Prunus Rootstock Collection" ("Coleção Porta-enxerto de Prunus") of Embrapa Temperate Climate (Pelotas, Rio Grande do Sul, Brazil) to the natural infestation of G. molesta, assessed the oviposition preference of G. molesta in choice and no-choice bioassays, and estimated the biological parameters and the fertility life table on different Prunus spp. genotypes in the laboratory. Genotypes Prunus kansuensis (Rehder), I-67-52-9, and I-67-52-4 were the most susceptible to G. molesta infestation in the field (>60% of branches infested), while 'Sharpe' (Prunus angustifolia x Prunus spp.) and Prunus sellowii (Koehne) were the least infested (0% of branches infested). In choice and no-choice bioassays, G. molesta preferred to oviposit on P. kansuensis when compared with Sharpe. The Sharpe genotype also showed an antibiosis effect, resulting in negative effects on the fertility life table parameters when compared with the genotypes P. kansuensis and 'Capdeboscq.' The results found in the present study can provide information to initiate a long-term breeding program moving desired G. molesta resistance traits from the rootstock into the Prunus spp. cultivars. [ABSTRACT FROM AUTHOR]

Sensory adaptation has been measured ill the antennae of male Grapholita molesta (Busek) after 15 min of exposure to its main pheromone compound (Z)-8-dodecen-l-yl acetate (Z8-12:OAc) at the aerial concentration of 1 ng/m³ measured in orchards treated with pheromone for mating disruption. Exposing males to this aerial concentration of Z8-12:OAc for 15 rain, however, had only a small effect on their ability to orientate by flight to virgin calling females in a flight tunnel. Experiments were undertaken to determine if exposure to the main pheromoue compound in combination with the two biologically active minor compounds of this species, (E)-8-dodeeeu-l-yl acetate (E8-12:OAc) and (Z)-8-dodecen-l-ol (Z8-12:OH) would induce greater levels of sensory adaptation and have a greater effect on male sexual behavior. The exposure of male antennae to 0.5 g/m³ air of one of the three pheromone compounds induced sensory adaptation to this compound and to the other two pheromone compounds demonstrating cross adaptation. Average percentage sensory adaptation to a pheromone compound was similar after 15 min of exposure to 1 ng/m³ air of Z8-12:OAc or to 1 ng/m ³ air of a 1:hl or 93:6:1 blend of Z8-12:OAc, E8-12:OAc, and Z8-12:OH. The exposure of males to 1 ng/m³ air of Z8-12:OAc or the two ratios of Z8-12:OAc, E8-12:OAc, and Z8-12:OH for 15 rain had no effect on their ability to orientate to a virgin calling female. The implications of these results for the operative mechanisms of sex pheromone-mediated mating disruption of this species are discussed. [ABSTRACT FROM AUTHOR]

The monoterpenoid citral synergized the electroantennogram (EAG) response of male Grapholita molesta (Busck) antennae to its main pheromone compound Z8-12:OAc. The response to a 10-µg pheromone stimulus increased by 32, 45, 54, 71 and 94% with the addition of 0.1, 1, 10, 100 and 1,000/µg of citral, respectively. There was no detectable response to 0.1, 1, or 10 µg of citral; the response to 100 and 1,000/µg of citral was 31 and 79% of the response to 10/µg of Z8-12:OAc. In a flight tunnel, citral affected the mate-seeking behavior of males. There was a 66% reduction in the number of males orientating by flight to a virgin calling female when citral was emitted at 1,000 ng/min ≈1 cm downwind from a female. Pheromone and citral induced sensory adaptation in male antennae, but citral did not synergize the effect of pheromone. The exposure of antennae to 1 ng Z8-12:OAc/m³ air, 1 ng citral/m³ air, 1 ng Z8-12:OAc + 1 ng citral/m³ air, or to 1 ng Z8-12:OAc + 100 ng citral/m³ air for 15 min resulted in a similar reduction in EAG response of 47-63%. The exposure of males to these same treatments for 15 min had no effect on their ability to orientate to a virgin calling female in a flight tunnel. The potential for using citral to control G. molesta by mating disruption is discussed. [ABSTRACT FROM AUTHOR]

Sexual behavior of male moths after prolonged exposure to the 1-ng pheromone/m³ air previously measured in orchards treated with pheromone for mating disruption was examined in a flight tunnel. The exposure of Graptwlita molesta (Busck) to 1-ng (Z)-8-dodecen-1-yl acetate (Z8- 12:OAc)/m³ air for 15 min had no effect on their ability to fly upwind to a conspecific, virgin calling female. After 30 min of exposure, males exposed to a control treatment were 1.4x more likely orient to a female than males exposed to pheromone-treated air. Some G. molesta males retained the ability to orient to a female after a 3O-min exposure period when the aerial concentration of Z8-12:OAc was increased 500,00OK to 0.5 gm/m3. Prolonged exposure to Z8-12:OAc did not affect response to a synthetic pheromone lure. The time required to initiate behavioral responses to a female or a lure was not affected by pheromone exposure. Male Choristoneura rosaceana (Harris) exposed to a control treatment for 15 min were 38.5x more likely to orient to a conspecific, virgin calling female than males exposed to 1-ng (Z)-11-tetradecen-1-yl acetate (Z11-14:OAc)/m³ air for 15 min. After 30 min of exposure males were unable to fly upwind to a female. Males exposed to a control treatment for 15 min were 4.3x more likely to fly upwind to a synthetic pheromone lure than males exposed to 1-ng Z11-14:OAc/m³ air for 15 min. The time required to initiate behavioral responses to a female or a lure was not affected by exposure to pheromone. [ABSTRACT FROM AUTHOR]

Grapholita molesta (Busck) is one of the main pests of apple trees, and lives on their shoots and fruits. In southern Brazil, the insect is also found on old branches and structures similar to aerial roots, so-called burrknots. This study evaluated the development and population growth potential of G. molesta fed on burrknots, compared with apple fruit cultivar. Fuji and a corn-based artificial diet. The study was carried out in the laboratory under controlled temperature (25 ± 1°C), relative humidity (70 ± 10%), and photophase (16 h). The biological parameters of the immature and adult stages were determined, and a fertility life table was constructed. Insects fed on burrknots showed a longer duration and a lower survival for the egg-to-adult period (29.3 d and 22.5%) compared with those that fed on apples (25.1 d and 30.0%) and artificial diet (23.9 d and 54.8%). Insects reared on aerial roots had a lower pupal weight (10.0 mg) compared with those reared on either artificial diet (13.7 mg) or apple cultivar. Fuji (12.4 mg). The fecundity and longevity of males and females did not significantly differ for the three foods. Based on the fertility life table, insects reared on burrknots had the lowest net reproductive rate (Ro), intrinsic rate of population growth (rm) and finite rate of increase (λ), compared with insects reared on artificial diet and apple fruit. Burrknots support the development of the complete cycle of G. molesta, which allows populations of this pest to increase in orchards. [ABSTRACT FROM AUTHOR]

The lingonberry fruitworm, Grapholita libertina Heinrich, is a tortricid moth whose larvae infest wild lingonberry (Vaccinium vitis-idaea L. variety minus Lodd) fields in Newfoundland, Canada. This study investigated the potential for predicting G. libertina larval damage by using adult pheromone trap captures. Spatial patterns of capture were studied in relation to subsequent larval and damaged berry distributions in four wild lingonberry fields during 1998, 1999 and 2000. A model was tested that incorporated the effects of resource availability and coincident plant composition on insect distribution. In 1998 and 2000, the mean adult capture/trap correlated well with larval (R2 = 0.38–0.63) and damaged berry (R2 = 0.41–0.59) density within grids at each site. In 1999, larval and damaged berry densities were not significantly correlated to adult distributions, and were more dependant on a limited host berry distribution (R2 = 0.54 and 0.47, respectively). The results of this study suggest that correlation between adult trapping of G. libertina and subsequent larval distributions is dependant on a minimal host berry population. Other factors that may contribute variability are also discussed. [ABSTRACT FROM AUTHOR]

Six different attracticide formulations (LastCall OFM) were tested for attractiveness and toxicity to the Oriental fruit moth, Grapholita molesta (Busck). Oriental fruit moth pheromone was incorporated into the formulation at rates of 0.016, 0.16, and 1.6%, with and without the insecticide permethrin (6.0%), for a total of six different formulations. Formulations containing 0.016 and 0.16% pheromone were equally attractive to male moths, and both were significantly more attractive than formulations containing 1.6% pheromone. The presence of 6% permethrin in the formulations did not influence trap capture and there was no pheromone × insecticide interaction effect. Comparison of the most attractive formulations in a wind tunnel bioassay showed a significant effect of pheromone dose and a pheromone × insecticide interaction effect on the proportion of males that took off from the release device and contacted the attracticide droplet. There was no pheromone dose, insecticide, or pheromone × insecticide effect on the proportion of males that exhibited wing fanning, locking-on to the pheromone plume, and upwind-oriented flight behaviors in the wind tunnel. A second wind tunnel experiment revealed that a greater proportion of male Oriental fruit moths conducted all behaviors to calling virgin females compared with attracticide formulations containing 0.016 and 0.16% pheromone and 6% permethrin. Toxicity of the attracticide formulations was determined at 3 and 24 h after exposure in the laboratory and in the wind tunnel. Almost all of the males exposed to formulations in the laboratory bioassay and 66.4% of males exposed in the wind tunnel showed signs of pyrethroid poisoning by 3 h after exposure, and significant mortality was observed at 24 h after exposure. This research showed that attracticide formulations containing 0.016 and 0.16% pheromone and 6% permethrin were effective in attracting wild and laboratory-reared Oriental fruit moths and exposing them to insecticide through source contact. Further work is necessary to determine if LastCall OFM formulations are competitive with calling virgin females under field conditions and whether treatment with LastCall OFM will result in reduced mating frequency and ultimately population control. [ABSTRACT FROM AUTHOR]

We studied pupal diapause maintenance and termination in Endopiza viteana, a pest of commercially grown grapes. We observed considerable variation in diapause intensity, which ranged from 5.5 to 10 mo under natural temperatures and photoperiods. Adult males tended to emerge from diapause slightly earlier than females, suggesting that E. viteana may be protandrous. In the field, low temperatures maintained diapause in overwintering pupae, and adult emergence began at ≈148 degree-days accumulated from 1 January. Photoperiod did not influence diapause termination in E. viteana. Overall, most adults emerged in spring at roughly the same time, regardless of the date at which pupae entered diapause; however, emergence was extended over a 6-wk period. Moreover, eggs oviposited by late-emerging females may experience photoperiods that would lead to diapause in pupae. Under natural conditions, extended adult emergence may result in overlapping generations; accordingly, coordinating the timing of control tactics with peak oviposition is very difficult for this insect pest. [ABSTRACT FROM PUBLISHER]