Toxicity and residual activity of methoxyfenozide and tebufenozide to codling moth (Lepidoptera: Tortricidae) and oriental fruit moth (Lepidoptera: Tortricidae)

A series of studies were conducted to examine the residual activity and toxicity of the ecdysone agonists tebufenozide and methoxyfenozide to codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), in North Carolina apple systems. Methoxyfenozide exhibited greater activity than tebufenozide against codling moth eggs in dose-response bioassays, with a 4.5- and 5.3-fold lower LC50 value to eggs laid on fruit treated before or after oviposition, respectively. Oriental fruit moth eggs were 57- and 12-fold less sensitive to methoxyfenozide than were codling moth eggs on fruit treated before and after oviposition, respectively. Methoxyfenozide was effective in reducing larval entries of both codling moth and oriental fruit moth in field residual activity bioassays, exhibiting activity for at least 28 d after application. Residue breakdown on fruit was approximately 80% at 28 d after treatment for both methoxyfenozide and tebufenozide, with the most rapid residue decline (60%) occurring during the first 14 d after application. Two applications of methoxyfenozide applied at 14-d intervals provided better canopy coverage and higher residue levels than one application. Spray volume (683 versus 2,057 liters/ha) did not affect the efficacy of methoxyfenozide. Leaf and fruit expansion during the season was measured to determine potential plant-growth dilution effects on residual activity. There was very little increase in leaf area after mid May, but increase in fruit surface area over the season was described by a second order polynomial regression. Implications for codling moth and oriental fruit moth management programs are discussed.     

Influence of canopy aspect and height on codling moth (Lepidoptera: Tortricidae) larval infestation in apple, and relationship between infestation and fruit size

Monitoring systems based on traps with female attractants are expected to enhance forecasting of insect population size and damage. The optimal placement of such traps should match the small-scale distribution of ovipositing females. In the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), fruit infestation takes place in proximity to the oviposition site. We characterized the within-tree distribution of codling moth infestations and the size of uninfested fruit based on a survey of 40,000 apples (Malus spp.) from trees belonging to 160 different apple genotypes and growing in two different environments. Each tree was subdivided into 12 sectors, considering canopy aspect (north, east, south, and west) and canopy height (bottom, middle, and top). This study revealed that fruit infestation by the first but not by the second generation of larvae correlated significantly with canopy aspect. Similarly, fruit size differed significantly between the north- and the south-facing tree side for the period of infestation by the first but not by the second larval generation. Significantly lower fruit infestation was observed on the north- compared with the south- or east-facing tree side for the first generation. A significant influence of canopy height on larval infestation was observed in three of eight assessments, in which the middle height level showed the highest infestations. Significant differences in within-tree distribution of codling moth infestation suggest that oviposition preference is guided by nonrandom factors including microclimate, fruit phenology, and wind direction. These cultivar-independent findings should be considered in future monitoring systems that focus on female codling moth.     

Phenology of Lacanobia subjuncta (Lepidoptera: Noctuidae) in Washington and Oregon apple orchards

The phenology of Lacanobia subjuncta (Grote & Robinson) (Lepidoptera: Noctuidae) was investigated in 30 apple orchards in central Washington state and northeastern Oregon from 1998 to 2001 (57 total orchard-yr). Adult captures in pheromone-baited traps were fit to a Weibull distribution to model emergence of the first and second generations. Initial capture of first generation adults was observed at 216.2 +/- 2.6 degree-days (DD) (mean +/- SEM) from 1 March by using a base temperature of 6.7 degrees C. The model predicted that flight was 5 and 95% complete by 240 and 700 degree-days (DD), respectively. Monitoring of oviposition and hatch was used to establish a protandry plus preoviposition degree-day requirement of 160.0 +/- 7.7 DD, as well as to provide data to describe the entire hatch period. Egg hatch was 5 and 95% complete by 395 and 630 DD, respectively. The start of the second flight was observed at 1217.1 +/- 8.3 DD by using an upper threshold for development of 32 degrees C and a horizontal cutoff. The model indicated that the second flight was 5 and 95% complete by 1220 and 1690 DD, respectively. Second generation hatch was 5 and 95% complete by 1440 and 1740 DD, respectively. A discussion of the potential uses of these detailed phenology data in optimizing management strategies is presented.     

Seasonal and cultivar-associated variation in oviposition preference of Oriental fruit moth (Lepidoptera: Tortricidae) adults and feeding behavior of neonate larvae in apples

The Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has become a pest of tree fruits since its introduction to the United States in the early twentieth century. Oriental fruit moth has historically been a major pest problem in peach production, and outbreaks in commercial apple (Malus spp.) orchards in the eastern United States were rare until the late 1990s. Recent outbreaks in Mid-Atlantic apple orchards have lead researchers to investigate host-associated effects on oriental fruit moth biology, behavior, and population dynamics. Studies were designed to assess cultivar level effects in apples on oviposition and larval feeding behavior of oriental fruit moth. In a mixed cultivar apple orchard, total oriental fruit moth oviposition and oviposition site preferences varied between cultivars. These preferences also varied over time, when sampling was repeated at various times of the growing season. Although most adult female oriental fruit moth preferentially oviposited in the calyx and stem areas of apple fruit, noticeable numbers of eggs also were laid on the sides of fruit, contradicting some previous reports. Oriental fruit moth females exhibited a strong ovipositional preference for fruit that were previously damaged by oriental fruit moth or codling moth, Cydia ponmonella (L.). The majority of newly hatched oriental fruit moth larvae were observed to spend <24 h on the surface of apple fruit before entry, and this behavior was observed on several apple cultivars. Neonate larvae exhibited a preference for entering fruit at either the stem or calyx ends, regardless of their initial site of placement. Our findings underscore the importance of adequate spray coverage and accurate timing of insecticide applications targeting oriental fruit moth.     

Adjusting the phenology model of codling moth (lepidoptera: tortricidae) in Washington State apple orchards

Studies were conducted with codling moth, Cydia pomonella L., to fit cumulative curves for the occurrence of injured fruits and male moth catches in sex pheromone-baited traps as a function of accumulated degree-days after the start of moth flight. Twelve data sets were collected from seven apple, Malus domestica Bordhausen, orchards in Washington State from 2003 to 2006. Cumulative data were grouped across years for orchards either treated with sex pheromone dispensers or untreated and fit to logistic equations for both the first and second generation. No significant differences were found for the cumulative curves of moth flight or egg hatch between pheromone-treated and untreated orchards; thus, these data were combined. These new logistic models for moth flight and egg hatch were compared with a widely used distributed-delay model originally developed in Michigan. The cumulative flight curves for the logistic and distributed-delay models were statistically different (slopes) for the first but not the second generation. Cumulative egg hatch in the logistic model was significantly different from the distributed-delay model (intercepts and slopes) for both generations. Most strikingly, the timing of 50% egg hatch during the first generation was delayed 100 DD in the logistic model. The potential impact of this change in the characterization of codling moth's phenology on the effectiveness of insecticide programs targeting eggs and newly eclosed larvae was examined. Possible explanations for this significant difference between the models are discussed.     

江苏无锡梨小食心虫发生动态及性诱剂防治

利用性诱剂调查江苏无锡地区三个水蜜桃Prunus persica种植区梨小食心虫Gtapholitha molesta成虫的年发生动态,并比较不同时间挂放诱芯的诱集效果。结果表明,在无锡地区,梨小食心虫年发生5代,部分发育较快的五代幼虫在越冬前发育为成虫,但因无法找到合适的产卵场所而成为无效虫口。越冬代成虫和一代成虫发生较为整齐,可以使用性诱剂集中诱杀,但从二代成虫开始,发生呈现多个高峰,田间世代重叠明显。对梨小食心虫的性诱剂防治试验表明,在无锡地区,需高密度放置诱芯并2周更换1次诱芯方能达到防治效果。     

Life stage toxicity and residual activity of insecticides to codling moth and oriental fruit moth (Lepidoptera: Tortricidae)

The codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), are two key pests of apple (Malus domestica Borkh.) in North Carolina. Growers extensively relied on organophosphate insecticides, primarily azinphosmethyl, for > 40 yr to manage these pests. Because of organophosphate resistance development and regulatory actions, growers are transitioning to management programs that use new, reduced-risk, and OP-replacement insecticides. This study evaluated the toxicity of a diversity of replacement insecticides to eggs, larvae, and adults, as well as an assessment of their residual activity, to codling moth and oriental fruit moth. Laboratory-susceptible strains of both species were used for all bioassays. Fresh field-harvested apples were used as a media for assessing the ovicidal activity of insecticides. For larval studies, insecticides were topically applied to the surface of lima bean-based diet, onto which neonates were placed. Toxicity was based on two measures of mortality; 5-d mortality and development to adult stage. Ovicidal bioassays showed that oriental fruit moth eggs were generally more tolerant than codling moth eggs to insecticides, with novaluron, acetamiprid, and azinphoshmethyl having the highest levels of toxicity to eggs of both species. In contrast, codling moth larvae generally were more tolerant than oriental fruit moth to most insecticides. Methoxyfenozide and pyriproxyfen were the only insecticides with lower LC50 values against codling moth than oriental fruit moth neonates. Moreover, a number of insecticides, particularly the IGRs methoxyfenozide and novaluron, the anthranilic diamide chlorantriliprole, and the spinosyn spinetoram, provided equal or longer residual activity against codling moth compared with azinphosmethyl in field studies. Results are discussed in relation to their use in devising field use patterns of insecticides and for insecticide resistance monitoring programs.     

Is biofix necessary for predicting codling moth (Lepidoptera: Tortricidae) emergence in Washington State apple orchards?

The heat-driven phenology model used for initiating codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), management in Washington state was examined to determine the need for using the capture of the first moth as a method of synchronizing the model and phenology of field populations (= biofix). We examined trap catch data taken at 1-2-d intervals from two research orchards; one data set encompassed a 28-yr period and the other data set a 4-yr period. We also examined consultant-collected data taken at 7-10-d intervals from 15 sites (N = 81), mostly between 2001 and 2005. At the two research sites, we found the mean biofix occurred at 96 degree-days (DD) (DD Celsius by using 10 degrees C lower threshold and 31.1 degrees C horizontal upper threshold) after 1 January (SD = 14.4; min. = 68, max = 122). After correcting for longer sampling intervals in the consultant data set, the biofix at the nonresearch sites occurred at 97 DD (N = 50, SD = 14.4; min. = 74, max = 120), nearly identical to that at the research sites. We also examined the performance of the codling moth model at predicting moth flight and egg hatch using a biofix and by just accumulating heat units from 1 January. The model performance was similar in both generations regardless of whether a biofix was used. The elimination of biofix simplifies management and eliminates mistakes associated with poor trap catch, particularly in low-pressure situations where mating disruption reduces trap efficiency.     

Walnut development affects chemical composition and codling moth performance

1 We investigated for early and late blooming walnut cultivars in California whether variation in nut phenology resulted in differences in nutritional quality and whether this, in turn, affected the performance of the codling moth, Cydia pomonella (L.), and the extent of nut damage. 2 Mid‐season, during the period of nut growth, nuts from the early cultivars were larger than those from the late cultivars and had higher nitrogen content in both husk and kernel tissue, while kernel phenolic content was significantly lower. No major differences were observed later in the season after nuts from all cultivars had reached their final size. 3 Throughout the season establishment of neonate larvae was highest on nuts from the early cultivars but this was only significantly so at the beginning of the third codling moth generation. During the second codling moth generation (mid season) relative growth rates of third‐instar larvae were significantly higher on early than on late cultivars. Nut damage in the field was also significantly greater on early than on late cultivars during generation 2, while no significant differences were observed during generation 3. 4 The data suggest that the variation in codling moth damage among walnut cultivars is related to bloom phenology due to the influence of nut phenology on larval performance.     

Confirmation and efficacy tests against codling moth and oriental fruit moth in apples using combination heat and controlled atmosphere treatments

Codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), are serious pests of apples (Malus spp.) grown in the United States and other countries. In countries where these species are not found, there are strict quarantine restrictions in place to prevent their accidental introduction. The treatment used in this study consisted of hot, forced, moist air with a linear heating rate of 12 degrees C/h to a final chamber temperature of 46 degrees C under a 1% oxygen and 15% carbon dioxide environment. We found that the fourth instar of both species was the most tolerant to the treatment, with equal tolerance between the species. Efficacy tests against the fourth instar of both oriental fruit moth and codling moth by using a commercial controlled atmosphere temperature treatment system chamber resulted in > 5,000 individuals of each species being controlled using the combination treatment. Confirmation tests against codling moth resulted in mortality of > 30,000 fourth instars. These treatments may be used to meet quarantine restrictions for organic apples where fumigation with methyl bromide is not desirable.     

Sprayable microencapsulated sex pheromone formulations for mating disruption of four tortricid species: effects of application height, rate, frequency, and sticker adjuvant

Several application parameters of microencapsulated (MEC) sex pheromone formulations were manipulated to determine their impact on efficacy of disruption for codling moth, Cydia pomonella (L.); oriental fruit moth, Grapholita molesta (Busck); obliquebanded leafroller, Choristoneura rosaceana (Harris); and redbanded leafroller, Argyrotaenia velutinana (Walker). Depending on the experiment, the formulations evaluated were those formerly manufactured by 3M Canada (London, ON, Canada) or those that are currently available from Suterra LLC (Bend, OR). The efficacy of MEC formulations applied by air-blast sprayer evenly throughout the entire canopy of 2-3-m-tall apple (Malus spp.) trees was equivalent to treatments in which targeted applications of MECs were made to the lower or upper 1.5 m of the canopy (at equivalent overall rates) for oriental fruit moth and both leafroller species. The realized distribution of deposited microcapsules within the tree canopy corresponded well with the intended heights of application within the canopy. The additional coapplication of the pine resin sticker Nu-Film 17 increased efficacy but not longevity of MEC formulations for oriental fruit moth; this adjuvant had no added effects for codling moth or leafroller formulations. Increasing the rate of active ingredient (AI) per hectare by 20-30-fold (range 2.5-75.0 g/ha) did not improve the disruption efficacy of MECs for codling moth or either leafroller species when both low and high rates were applied at equivalent frequencies per season. A low-rate, high-frequency (nine applications per season) application protocol was compared with a standard protocol in which two to three applications were made per season, once before each moth generation for each species. The low-rate, high-frequency protocol resulted in equivalent or better disruption efficacy for each moth species, despite using two-fold less total AI per hectare per season with the former treatment. The low-rate, frequent-application protocol should make the use of MEC formulations of synthetic pheromone more economical and perhaps more effective.     

Egg adhesion of the codling moth Cydia pomonella L. (Lepidoptera,Tortricidae) to various substrates: II. Fruit surfaces of different apple cultivars

In the late growing season of apples, most eggs of the codling moth, Cydia pomonella L. (Lepidoptera, Tortricidae), of the second and third generations are deposited directly on fruits. The apple fruit surface is densely covered by three-dimensional micro- and nanoprojections, the epicuticular wax crystals, emerging from an underlying wax film. These epicuticular waxes render the apple fruit surface hydrophobic, which could affect the attachment of insect legs and eggs to it. A better survival of the codling moth offspring is expected to be ensured by the selection of suitable oviposition sites by females, as well as by a proper adhesion of deposited eggs to these sites. In this study, we investigated egg adhesion of the codling moth to the fruit surface of different cultivars of the domestic apple, Malus domestica Borkh., by measuring the pull-off force required to detach eggs from fruits. Since surface characteristics may influence insect egg adhesion, the information about morphological and physicochemical properties of the fruit surface is crucial for understanding oviposition site selection by females. In the present study, surface morphology, wettability, and free surface energy of the apple cultivars ‘Boskoop’, ‘Elstar’, ‘Golden Delicious’, ‘Jonica’, and ‘Topaz’ were analyzed. Eggs adhered tightly to the fruit surface of all apple cultivars tested: pull-off forces averaged 63.9 mN. These forces are four- to tenfold stronger than those previously measured on adaxial and abaxial leaf surfaces of the identical apple cultivars. The mechanisms used by the moth to fix its eggs on the waxy surface of apple fruits, and the influence of fruit surface properties on egg glue adhesion are discussed. Furthermore, the results are debated in the context of the oviposition site selection by females, and its role in offspring survival of the second and third generations of the codling moth.     

Phenology simulation model of Scotinophara lurida (Hemiptera: Pentatomidae)

A phenology simulation model was developed for Scotinophara lurida (Burmeister). The components for the model were a degree-day immigration flight model of overwintered adults, temperature-dependent developmental models of each stage, survival rates of each stage, and an adult oviposition model. A degree-day model for immigration flight of overwintered adults was developed with blacklight trap catch data by a Weibull function. Laboratory experiments using seven constant temperature regimens were conducted to determine the effect of temperature on the development of immature stages. Developmental rates of each immature stage fit well to a linear model. Distribution of developmental time for each immature stage was successfully modeled against physiological age by a Weibull function. To determine the temperature effect on longevity, fecundity, and survival of female adults, laboratory and greenhouse experiments were conducted. The adult developmental rate (1/median longevity) was described by a linear model. The oviposition model was developed incorporating the three components of average total fecundity, cumulative oviposition rate function, and survival rate function. The simulation model predicted the time of peak occurrences of life stages of S. lurida well.     

Temperature thresholds and degree-day model for Marmara gulosa (Lepidoptera: Gracillariidae)

The developmental thresholds for Marmara gulosa Guillén & Davis (Lepidoptera: Gracillariidae) were investigated in the laboratory by using 17, 21, 25, 29, and 33 degrees C. The lowest mortality occurred in cohorts exposed to 25 and 29 degrees C. Other temperatures caused >10% mortality primarily in egg and first and second instar sap-feeding larvae. Linear regression analysis approximated the lower developmental threshold at 12.2 degrees C. High mortality and slow developmental rate at 33 degrees C indicate the upper developmental threshold is near this temperature. The degree-day (DD) model indicated that a generation requires an accumulation of 322 DD for development from egg to adult emergence. Average daily temperatures in the San Joaquin Valley could produce up to seven generations of M. gulosa per year. Field studies documented two, five, and three overlapping generations of M. gulosa in walnuts (Juglans regia L.; Juglandaceae), pummelos (Citrus maxima (Burm.) Merr.; Rutaceae), and oranges (Citrus sinensis (L.) Osbeck; Rutaceae), for a total of seven observed peelminer generations. Degree-day units between generations averaged 375 DD for larvae infesting walnut twigs; however, availability of green wood probably affected timing of infestations. Degree-day units between larval generations averaged 322 for pummelos and 309 for oranges, confirming the laboratory estimation. First infestation of citrus occurred in June in pummelo fruit and August in orange fruit when fruit neared 60 mm in diameter. Fruit size and degree-day units could be used as management tools to more precisely time insecticide treatments to target the egg stage and prevent rind damage to citrus. Degree-day units also could be used to more precisely time natural enemy releases to target larval instars that are preferred for oviposition.     

Monitoring populations of saddled prominent (Lepidoptera: Notodontidae) with pheromone-baited traps

Field trials with three types of pheromone traps were performed in eight northern hardwood stands in northern New York state to develop a population-monitoring tool for the saddled prominent, Heterocampa guttivitta (Walker) (Lepidoptera: Notodontidae). Lure specificity and the relationship between pheromone trap catch and subsequent egg density were examined. A study of moth emergence in relation to temperature was designed to determine whether moth activity throughout the flight season can be predicted using a growing degree-day (DD) model. Pherocon 1C wing traps were significantly more effective than the green Unitrap bucket style. Catch was not affected by position when traps were > or =20 m from an opening (road), and lures were specific to saddled prominent. Lure specificity was examined using green Multipher bucket traps, which effectively attracted and held moths. In the first year of the study, number of viable eggs per 10 leaf clusters was significantly correlated (r2 = 0.59) with average moth catch/trap in pheromone-baited Pherocon traps. When differences in stand density (basal area) and relative abundance of sugar maple (percentage of total stems per hectare), the principle host, were accounted for, the multiple regression model also was significant and r2 = 0. 83. Neither model, however, was significant the second year. Using a base temperature of 5.5 degrees C and on-site temperature data, the peak of moth flight occurred at 316 +/- 8 DD and end of flight occurred at 533 +/- 9 DD.     

Modeling the interaction of physiological time, seasonal weather patterns, and delayed mating on population dynamics of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae)

The effect of delaying female mating on population growth in codling moth (Cydia pomonella (L.)) was found to act on a physiological time (degree-day) basis and was predictable using a simple quadratic equation. When combined with previous work on degree-day based mortality, we were able to evaluate how the magnitude of population reduction and survival varied between sites, years, and generations at locations in California, Michigan, Pennsylvania and Washington states. In general, reductions in population growth associated with females mating 1–3 days after emergence were greater in warmer areas and during warmer times of the year. In any given year and location, the temperature profiles during peak flight were crucial in determining the population reductions, but over an 11-year period, the average seasonal temperature profile was more important. During the overwintering generation, conditions were relatively mild in all locations and only minor differences were observed in population growth rates between locations. Populations experiencing 1–3 days delay in female mating were reduced 8, 19 and 32 % compared to populations experiencing no delay, respectively. During the first summer generation, population reductions doubled compared to those seen in the overwintering generation. During the second summer flight, reductions in population growth rate at the three cooler locations decreased, while they increased in the warmer California location. Overall, the results show delayed mating can help understand how population growth is related to environmental conditions experienced naturally by insect populations and will help guide studies of the mechanisms of mating disruption, a technique used for pest suppression in agricultural and forest systems.     

Host status of fresh prunes by potential quarantine pests in laboratory tests and evaluation of packinghouse culls.

The status of fresh prunes, Prunus domestica L., as a host for codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae); peach twig borer, Anarsia lineatella Zeller (Lepidoptera: Gelechiidae); omnivorous leafroller, Platynota stultana Walshingham (Lepidoptera: Tortricidae); oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae); navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae); and walnut husk fly, Rhagoletis completa Cresson (Diptera: Tephritidae), was investigated in laboratory tests and by examination of packinghouse culls. In laboratory no-choice tests, the mean number of adults reared per fruit was 0.01 for codling moth, 0.08 for omnivorous leafroller, 0 for oriental fruit moth, and 1.6 for navel orangeworm. In choice tests the mean number of adults reared per apple or fresh prune was for codling moth, 0.78 and 0.02 (significantly different); for omnivorous leafroller, 0.05 and 0.02; and for oriental fruit moth, 2.07 and 0 (significantly different), respectively. Walnut husk fly oviposited in fresh prunes in no-choice tests but pupae did not develop from the fruit. In choice tests, walnut husk fly did not oviposit in fresh prunes when caged with its normal host, green walnuts, in which large numbers of pupae developed. Inspection of packinghouse culls for immature insects showed that fresh prunes with possible larval feeding sites in the form of frass or fruit gum extrusions were lighter in weight, significantly less firm, similar in color, and had significantly higher soluble solids than noninfested fruit. Based on packinghouse cull samples, 1 fresh prune per 133 harvested fruit would be expected to show possible insect damage. Eleven peach twig borer larvae were found in fresh prune cull samples (213.9 kg) removed from a 16,744.5-kg harvest. The calculated level of infestation was 1 infested fruit per 8,501.8 fruit harvested or per 21.7 cartons of medium-sized packed fruit. Based on our results, the risk of infestation of fresh prunes by the insects in this study would be minimal in fruit exported from the San Joaquin Valley of California.     

Control of Cydia pomonella L. and Cydia molesta (Busck) (Lepidoptera Tortricidae) in pome-fruit orchards with Ecodian sex pheromone dispensers

A mating disruption approach using high densities of pheromone dispensers, has been recently proposed for codling moth, Cydia pomonella (L.), and oriental fruit moth, Cydia molesta (Busck.), (Lepidoptera Tortricidae), control. Ecodian Star dispensers, made of low-cost biodegradable material and easy to apply, were formulated with 10 mg of codlemone (E8,E10-12OH) and 10 mg of grapamone (Z8-12OH) and placed at a rate of 1,400-2,000 dispensers/ha. The pheromone release rates from new and field aged dispensers were evaluated by hexane extraction of the residual attractant (indirectly) and gas-chromatographic analysis. The release rate of field-aged dispensers decreased over time with a good linearity; they released a significant amount of synthetic sex pheromones over the entire season. Dispensers elicited close-range approaches of codling moth males in wind tunnel irrespective of their age. Field trials carried out from 2003 to 2004 confirmed the efficacy of Ecodian Star dispensers for codling moth and oriental fruit moth control, regardless the size of the treated area. Our results demonstrate that Ecodian dispensers achieved a good level of activity and longevity over the season. The potential of this strategy for the control of the moths is discussed.     

Particle films for suppression of the codling moth (Lepidoptera: Tortricidae) in apple and pear orchards

Studies were conducted in 1997 and 1998 to evaluate the effects of three particle film formulations consisting of kaolin and adjuvants on neonate larvae, ovipositing adult females, and eggs of the codling moth, Cydia pomonella (L.). Neonate larval walking speed, fruit discovery rate, and fruit penetration rate on apple host plants coated with particle films were significantly lower than on host plants without particle films in laboratory assays. Females oviposited less on host plants covered with a particle film residue than on untreated plants in laboratory choice and no-choice tests. Hatch rate of codling moth neonate larvae was unaffected by particle films sprayed on host plants either before or after oviposition. Fruit infestation rates were significantly reduced on particle film-treated trees compared with untreated trees for both first- and second-generation codling moth in field trials in both apple and pear orchards. Particle films appear to be a promising supplemental control approach for codling moth in orchards where moth density is high, and may represent a stand-alone method where moth densities are lower.     

Stage‐specific probabilistic phenology model of Cydia pomonella (Lepidoptera: Tortricidae) using laboratory maximum likelihood parameter estimates

In this study, a probabilistic degree‐day phenology model has been developed for the codling moth, Cydia pomonella, and calibrated using data from laboratory growth studies. The model is further used to predict the succession and overlapping of certain biological events of C. pomonella in probabilistic‐physiological time scale in northern Greece fruit orchards. The model satisfactorily predicts the stage‐specific pest population dynamics, including egg laying and hatching, the occurrence of larvae and pupae stages and the emergence of adults. According to the model projections for the adult flights, there is a very high probability, p = 0.999, of observing adults of the first flight generation until 333 degree‐days (DD), but a very low probability of finding adults of the second flight generation. Moreover, at 575 DD, the probability of finding an individual to lay eggs is p = 0.15. However, there is nearly the same probability of egg hatch, p = 0.36, and larval completion p = 0.313, while at the same time, the probability of pupal completion is very low, p = 0.001. The above model predictions were validated using field data for the adult stage emergence as well as for the percentage of larval damage providing satisfactory results considering that larval emergence prediction was close to actual fruit damage observed in field. This information is very important considering that IPM programs rely on the use of biorational compounds, such as IGRs and bio‐toxins which are stage selective and often have a shorter residual activity than the preceding broad‐spectrum insecticides.