Comparison of mating disruption with pesticides for management of oriental fruit moth (Lepidoptera: Tortricidae) in North Carolina apple orchards

The efficacy of mating disruption by using Isomate-M 100 pheromone dispensers and two formulations of microencapsulated sprayable pheromone for management of oriental fruit moth, Grapholita molesta (Busck), was compared with conventional insecticides in large plot studies in Henderson County, North Carolina, in 2000 and 2001. In addition, experiments were conducted in small and large plots to test the response of oriental fruit moth males to different application rates of sprayable pheromone. Pheromone trap catches were significantly reduced in mating disruption blocks compared with conventional and abandoned orchards. Pheromone traps placed in the upper canopy captured significantly more moths than traps placed in the lower canopy across all treatments, and lures loaded with 100 microg of pheromone caught more moths than traps with 300 microg, but the difference between doses was statistically significant at only one location in 2001. Isomate-M 100 provided excellent trap shutdown and was significantly more effective than sprayable pheromone formulations. Fruit damage by oriental fruit moth larvae was very low (< or = 1%) in mating disruption blocks and was generally lower than in conventional and nonmanaged blocks. Based on male moth response to pheromone traps in small plots, there was little difference among doses of sprayable pheromone, ranging from 12.4 to 49.1 g (AI)/ha, but efficacy declined at 2.4 g (AI)/ha. With the exception of one orchard, there was no significant difference between 12.4 and 37.1 g (AI)/ha under low and high oriental fruit moth population pressure in large plot studies. Mating disruption proved to be an alternative to organophosphate insecticides for managing oriental fruit moth populations in North Carolina apple orchards.     

Sprayable microencapsulated sex pheromone formulation for mating disruption of oriental fruit moth (Lepidoptera: Tortricidae) in Australian peach and pear orchards

Areawide mating disruption treatments have been effective in controlling infestation of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), in Australian pome and stone fruit orchards. Although successful, the areawide mating disruption program has been an expensive approach by using hand-applied Isomate dispensers. Sprayable microencapsulated (MEC) pheromone formulations that can be applied with standard spray equipment could substantially reduce the cost of application. Field trials conducted during two consecutive seasons (2002-2004) demonstrated that monthly applications of MEC-OFM phase V (3M Canada, London, Ontario, Canada) at a rate of 125 ml/ha (37.1 g [AI]/ha) in replicated 2-ha blocks of both peaches and pears reduced oriental fruit moth shoot tip and fruit damage as effectively as a single application of Isomate OFM Rosso hand-applied dispensers (500 dispensers per ha) and as or more effectively than standard broad-spectrum insecticide sprays. Fruit protection was achieved despite high oriental fruit moth population densities in both crops as measured by moth catches in terpinyl acetate food and pheromone traps. Similar numbers of oriental fruit moths were captured among all treatments in food traps but captures of males in pheromone traps were disrupted (96-99%) in pheromone-treated blocks relative to controls. The results of this study suggest that microencapsulated formulations of pheromone could be effectively used in areawide mating disruption programs for oriental fruit moth in Australia as a cost-saving alternative to reservoir-style dispensers requiring labor-intensive hand application.     

Potential for outbreaks of leafrollers (Lepidoptera: Tortricidae) in California apple orchards using mating disruption for codling moth suppression

Two species of leafrollers, Argyrotaenia citrana (Fernald) and Pandemis pyrusana Kearfott, represent serious obstacles to the implementation of mating disruption for control of codling moth in coastal California apple orchards. Larval and adult densities of A. citrana and P. pyrusana and subsequent fruit damage were compared under different codling moth control treatments. Leafroller larval counts and levels of fruit damage were significantly higher in most plots that were untreated or treated only with codling moth pheromone. Leafroller fruit damage levels in these plots were commonly between 10 and 15% at harvest. As summer larval counts were good predictors of fruit damage levels, larval sampling could be a useful tool for predicting leafroller outbreaks. Use of pheromone trapping for A. citrana to detect localized outbreaks within an orchard was not useful and failed to correlate with larval numbers, whereas adult monitoring for P. pyrusana appears more promising. Efforts to implement a codling moth mating-disruption program in California must include changes in strategies for monitoring and controlling leafroller species.     

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.     

Oriental fruit moth (Lepidoptera: Tortricidae) phenology and management with methoxyfenozide in North Carolina apples

The phenology of oriental fruit moth, Grapholita molesta (Busck), on apple (Malus spp.) in North Carolina was studied using pheromone traps and egg sampling in abandoned and commercial orchards in 2000 and 2001, with subsequent development of an oviposition degree-day model and management studies in relation to codling moth, Cydia pomonella (L.), phenology. Oriental fruit moth eggs were found in greater numbers on leaves early and on fruit later in the growing season, on the top versus the bottom of the leaf surface, and on the calyx area versus the side or stem end of the fruit. A degree-day (DD) model to predict oriental fruit moth oviposition was developed based on temperature accumulations from peak moth trap capture of the first (overwintering) generation, by using 7.2 and 32.2 degrees C as the temperature limits. The model predicted four ovipositing generations of oriental fruit moth with the second beginning 507 DD after peak moth catch. Using predictions of the oriental fruit moth and codling moth degree-day oviposition models, an experiment was conducted to determine the level of second generation oriental fruit moth control with methoxyfenozide applied under different scenarios for first generation codling moth. Methoxyfenozide was equally effective in managing codling moth and oriental fruit moth for all treatment timings.     

Efficacy and mode of action of female‐equivalent dispensers of pheromone for mating disruption of codling moth

1 We evaluated the efficacy and mode of action of commercially available female‐equivalent dispensers of pheromone for mating disruption of codling moth Cydia pomonella (L.) (Lepidoptera Tortricidae). 2 Scentry fibres, but not Hercon flakes, were consistently as or more effective than Isomate C Plus dispensers when applied by hand at 50 dispensers per tree. 3 Individual Scentry fibres were slightly more attractive to male codling moth than Hercon flakes. 4 Efficacy of aerially applied Scentry fibres was equivalent to that of Isomate dispensers in disrupting male codling moth in 4‐ha commercial apple plots. 5 Initial deposition and retention of aerially applied fibres were inefficient with approximately 44% formulation loss at application, poor rainfastness and a gradual loss of dispensers from tree canopies after application. 6 Male codling moths were captured in traps baited with lures containing 0.1 mg of pheromone and mated with tethered virgin females that were surrounded by eight fibres placed 30 cm away or 16 fibres placed 45 cm away in untreated plots and plots treated with a background of 50 Isomate dispensers per hectare. 7 A plausible explanation for mating disruption of codling moth by female‐equivalent dispensers is competitive attraction without associated habituation and thus improving the effectiveness of these technologies will depend on maximizing the attractiveness of individual dispensers as well as the application density of dispensers per area of crop.     

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.     

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.     

Potential of high‐density pheromone‐releasing microtraps for control of codling moth Cydia pomonella and obliquebanded leafroller Choristoneura rosaceana

Recent large‐cage studies with codling moth Cydia pomonella (L.) reveal that the removal of moths from an apple orchard using pheromone‐releasing traps is more effective at reducing capture in a central monitoring trap than is a mating disruption protocol without kill/capture. The present study uses open orchard 0.2‐ha plots comparing a high‐density trapping scenario with mating disruption to confirm those results. Two tortricid moth pests of tree fruit are studied: codling moth and obliquebanded leafroller Choristoneura rosaceana (Harris). Codling moth treatments include Isomate CM FLEX (ShinEtsu Ltd, Japan), nonsticky traps baited with Trécé CM lures (Trécé, Inc., Adair, Oklahoma), and sticky traps baited with Trécé CM lures, all at equal application rates of 500 dispensers ha^?1, as well as a no pheromone control. These microtraps are of a novel design, small and easy to apply, and potentially inexpensive to produce. Mating disruption using Isomate CM FLEX and nonsticky traps reduces codling moth capture in standard monitoring traps by 58% and 71%, respectively. The attract‐and‐remove treatment with sticky traps reduces capture by 92%. Obliquebanded leafroller treatments include Isomate OBLR/PLR Plus and Pherocon IIB microtraps baited with Trécé OBLR lures, both applied at 500 dispensers ha^?1, as well as a no pheromone control. Mating disruption reduces capture in monitoring traps by 69%. The attract‐and‐remove treatment reduces capture by 85%. Both studies suggest that an attract‐and‐remove approach has the potential to provide superior control of moth populations compared with that achieved by mating disruption operating by competitive attraction.     

Higher densities of distributed pheromone sources provide disruption of codling moth (Lepidoptera: Tortricidae) superior to that of lower densities of clumped sources

Field experiments quantified the effect of synthetic pheromone release-site density and distribution on 1) orientational disruption of male codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae), to pheromone-baited traps; and 2) fruit injury. A clustering test varied pheromone release-site density from 0 to 1,000 Isomate-C Plus dispensers per ha while maintaining the total number of dispensers at 1,000. Percentage of orientational disruption of pheromone-baited traps increased significantly as a function of increasing density of release sites. Fruit injury decreased as the density of release sites increased and was lowest in plots treated with Isomate-C Plus dispensers distributed as 1,000 point sources per ha. We also manipulated point source density of 0.1-ml paraffin-wax drops containing 5% codlemone [(E,E)-8,10-dodecadien-1-ol], and thus the total amount of pheromone deployed per hectare. The percentage of disruption of traps baited with either 1.0- or 0.1-mg codlemone lures increased with increasing density of wax drops deployed. Both trapping and field observations confirmed that wax drops were attractive to male codling moths, suggesting that disruption was mediated by competitive attraction. Development of dispensers that can be mechanically applied at high densities has potential to improve the efficacy and economics of codling moth disruption at high population densities.     

用性信息素诱捕法防治梨小食心虫的研究

用性信息素诱捕法防治梨小食心虫Grapholitha molesta(Busck)的试验于1978—1980年在辽宁省绥中县的梨园中进行。1978、1979和1980三年的诱捕防治面积分别为2、100和780公顷。在田间试验中每公顷使用10—15个梨小食心虫性信息素水碗诱捕器。在对照区,每年8月至9月喷2次杀虫剂防治梨小食心虫,在诱捕区不喷这两次药。 试验是成功的。1978、1979和1980年,诱捕区梨小食心虫的虫果率分别为1.4—4.4％、0.4—2.0％和0—1.2％,而化学防治对照区分别为7.6—8.6％、3.3％和0.3—2.7％。诱捕区梨小卵的寄生率为32.6—75.9％;在化学防治对照区只有10—26.6％。诱捕区的防治费用比化学防治区节省78—89％。     

Mechanized applicator for large-scale field deployment of paraffin-wax dispensers of pheromone for mating disruption in tree fruit

A tractor-mounted mechanized applicator was developed for large-scale deployment of paraffin-wax dispensers of pheromone for mating disruption of oriental fruit moth, Grapholita molesta (Busck). The wax formulation was mostly water and emulsified paraffin wax containing 5% (by weight) pheromone [93:6:1 blend of (Z)-8-dodecen-1-yl-acetate:(E)-8-dodecen-1-yl-acetate: (Z)-8-dodecen-1-ol]. Ten milliliters of wax was applied per tree as approximately 160 deposits (0.04 ml of wax per drop). An average of 23 min was required to treat 1 ha of crop. Disruption efficacy of mechanically applied wax was measured relative to an untreated control in replicated 0.4-ha blocks within a recently abandoned apple orchard. From 6 May to 27 June, 100% disruption of tethered virgin females and 97% inhibition of pheromone traps was achieved for 52 d with two applications of wax. However, during mid- to late summer (July-August), this level of efficacy was maintained for only approximately 1 wk after each of two applications. Higher temperatures later in the season may have accounted for abbreviated efficacy of the applied small drops. Mechanically applied paraffin-wax technology may increase adoption of mating disruption given that a higher level of efficacy was achieved despite deploying less active ingredient per hectare relative to that used with reservoir dispensers. The savings in labor by not requiring hand application of reservoir dispensers could be directed toward cost of machinery. However, the short duration of efficacy obtained with the current wax formulation and mechanical applicator is judged uneconomical given the eight or more applications that would have been required for high-performance disruption over the full season. Larger drops with lower surface area-to-volume ratios are expected to prolong pheromone release for extended efficacy and desirable overall economics.     

Comparison of delayed female mating on reproductive biology of codling moth and obliquebanded leafroller

Delay of mating was examined as a possible mechanism for population decreases associated with mating disruption for codling moth, Cydia pomonella L., and obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). We examined the effect of delaying female mating 0, 2, 4, or 6 d while holding male age constant on life table parameters of both species. We found that increasing delays in mating were accompanied by two responses: (1) an increase in the percentage of sterile pairs and (2) a reduction in net reproductive rate and population growth unrelated to sterility. On a percentage basis, obliquebanded leafroller population growth was more strongly affected than codling moth. However, the net fertility rate of obliquebanded leafroller was nearly eight-fold higher than that of codling moth, so that obliquebanded leafroller females that experienced a 4-d delay in mating had nearly the same reproductive rate as codling moth females that experienced no delay. Leslie matrix simulations using life tables with field-based adult longevity estimates showed that codling moth females experiencing >2-d delay in mating resulted in decreases in population density or extinction within two generations. In contrast, obliquebanded leafroller females delayed <6 d showed rapid population growth that decreased as female age at mating increased; only the 6-d delay treatment resulted in decreased population levels. Our results indicate that obliquebanded leafroller females must on average experience a much longer delay in mating to significantly reduce population growth compared with codling moth females, suggesting that delay of mating likely plays a greater role in codling moth mating disruption than for obliquebanded leafroller.     

Behavioral observations of codling moth, Cydia pomonella, in orchards permeated with synthetic pheromone

Mating disruption of codling moth, Cydia pomonella, was studied in apple orchards treated with the main pheromone compound codlemone, (E,E)-8,10-dodecadienol, and a blend of codlemone and codlemone acetate, (E,E)-8,10-dodecadienyl acetate, a strong pheromone antagonist. Codlemone alone and the pheromone/antagonist-blend had a similar effect on the behavior of males emerging into air-permeated orchards. Male flights within tree canopy and upwind orientation along tree rows were strongly enhanced by both formulations, compared to untreated plots. However, the codlemone/codlemone acetate-blend increased the rate of cross-wind and downwind flights within the orchard, compared to codlemone alone. The major difference between these two formulations was that males from nearby, untreated orchards were attracted towards orchards treated with codlemone, but not towards treatments with codlemone/codlemone acetate. Additional tests were done with an equilibrium blend of codlemone and its geometric isomers. Aerial pheromone concentrations in the orchards were recorded by the field electroantennogram technique. Decreasing pheromone concentrations towards the upper part of the tree canopy, together with the stimulation of male flight activity by synthetic pheromone explains failures to control codling moth at high population densities with current dispenser formulations.     

Comparative activity of baculoviruses against the codling moth Cydia pomonella and three other tortricid pests of tree fruit

The granulovirus of Cydia pomonella (L.) (CpGV) offers potential for selective control of codling moth. Two major limitations of CpGV are its narrow host range and lack of persistence in the orchard agroecosystem. The nucleopolyhedroviruses of the alfalfa looper Autographa californica (Speyer) (AcMNPV) and those of the celery looper Anagrapha falcifera (Kirby) (AfMNPV) have broad host ranges. Comparative assays of CpGV, AcMNPV, and AfMNPV against codling moth neonate larvae revealed a 54-93-fold greater susceptibility of codling moth to the granulovirus than to the two nucleopolyhedroviruses based on the LC(50) values for each virus. The LC(50)s for CpGV, AfMNPV, and AcMNPV were 32.7 capsules/mm(2), 1.77 x 10(3) occlusion bodies (OBs)/mm(2), and 3.05 x 10(3)OBs/mm(2), respectively. The LT(50) determined for AfMNPV using an approximate LC(95) of the virus against neonate larvae was 3.6 days. Histological examination of tissues in moribund codling moth larvae that had been treated with AfMNPV revealed the presence of nonoccluded and unenveloped virus rods in midgut tissue. Neither OBs nor signs of infection were detected in other tissues. The activity of AfMNPV was also evaluated in three other tortricid apple pests (obliquebanded leafroller, Choristoneura rosaceana (Harris); Pandemis leafroller, Pandemis pyrusana Kearfott; and the oriental fruit moth, Grapholitha molesta (Busck)). Codling and Oriental fruit moths were significantly more susceptible to AfMNPV than were the two leafroller species.     

Comparison of pheromone application rates, point source densities, and dispensing methods for mating disruption of tufted apple bud moth (Lepidoptera: Tortricidae)

Small-plot (approximately 0.1 ha) studies were used to evaluate different pheromone dispensing systems, application rates, and point-source densities for mating disruption of the tufted apple bud moth, Platynota idaeusalis (Walker). Using polyvinyl chloride spirals impregnated with tufted apple bud moth pheromone (1:1 ratio of E11-tetradecenyl alcohol/E11-tetradecenyl acetate), pheromone rates of > or = 1,482 spirals per hectare (74.1 g pheromone per hectare) were superior to a rate of 988 spirals per hectare (49.4 g pheromone per hectare) in decreasing male response to pheromone traps in 1995, whereas no differences were detected among rates of 988, 1,482 and 1,975 spirals per hectare in 1996. Within a range of 370-988 pheromone dispensers per hectare, point source densities were equally effective in suppressing male response to pheromone traps. Pheromone-impregnated paraffin disks were equally effective at inhibiting male response to pheromone traps compared with polyvinyl chloride spirals. However, a paraffin emulsion formulation of pheromone applied with a hand-held grease gun provided longer residual communication disruption effects than polyvinyl chloride spirals. Dilution of paraffin emulsion pheromone formulations in water for application with a backpack sprayer and airblast sprayer rendered them ineffective in reducing male response to pheromone traps. The releases of pheromone from polyvinyl chloride spirals and paraffin disks aged in the field were described by a linear and negative logarithmic curve, respectively, indicating that dispenser life time should be longer for spirals. The ratio of acetate to alcohol components of pheromone released from spirals increased over time, whereas the release ratio remained more constant for paraffin disks. This suggests that the disruption efficacy of spirals may be prematurely reduced because of imbalance of the released components.     

Field evaluations of concentrated spray applications of microencapsulated sex pheromone for codling moth (Lepidoptera: Tortricidae)

The application of a microencapsulated (MEC) sex pheromone formulation (Checkmate CM-F) for codling moth, Cydia pomonella (L.), in low volume, concentrated sprays was evaluated in a series of small plot and grower trials in apple, Malus domestica Borkhausen, and pear, Pyrus communis L. Preliminary tests found that MEC sprays applied at 172-207 kilopascals in 12-23 liters/ha deposited the highest density of microcapsules per leaf. The addition of a latex sicker did not increase the deposition of microcapsules. Small plot tests in 2004 compared the effectiveness of two low-volume sprayers against a standard high-volume spray (926 liters/ha) applied at 1,379 kilopascals. Moth catches and fruit injury were significantly lower in plots treated with the low-volume sprays compared with plots treated with the standard sprayer. These results suggest that concentrating the MEC formulation increases the deposition of microcapsules and improves its effectiveness. Larger trials were conducted with a low-volume sprayer in 4-ha plots within commercial apple (2005-2006) and pear orchards (2005) paired with similar plots treated with hand-applied pheromone dispensers. Levels of fruit injury were not significantly different between pheromone treatments in any of the three tests. Moth catches, however, were significantly higher in the MEC- versus the dispenser-treated apple plots in 2005. No difference was found in the fruit injury levels in MEC-treated apple orchards in 2005 caused by irrigation method, but moth catches were significantly higher in overhead versus undertree orchards. The advantages and current limitations of using MEC sex pheromone sprays to supplement current grower's management strategies for codling moth is discussed.     

Male oriental fruit moth response to a combined pheromone-based attracticide formulation targeting both oriental fruit moth and codling moth (Lepidoptera: Tortricidae)

Combined attracticide formulations targeting Oriental fruit moth, Grapholita molesta (Busck), and codling moth, Cydia pomonella (L.), were tested in a field trapping experiment. Capture of male codling moths in traps baited with the combined formulation was reduced compared with traps baited with the codling moth formulation alone, whereas capture of male Oriental fruit moth was increased compared with traps baited with the Oriental fruit moth formulation alone. Subsequent wind tunnel experiments showed that a single locus of the mixed attracticide formulation or close parallel presentation of the two formulations enhanced source contact by male Oriental fruit moths but did not influence earlier behaviors. However, the two formulations presented in a serial arrangement to Oriental fruit moth males in the wind tunnel resulted in enhanced lock-on, upwind flight, and source contact behaviors. In addition, male Oriental fruit moths remained on mixed pheromone droplets of the paste matrix longer than on droplets of the Oriental fruit moth formulation alone. The increased time spent on the mixed droplet was correlated with a more rapid poisoning and a greater proportion of poisoned males compared with males exposed to the Oriental fruit moth attracticide alone. These results demonstrate that a combined attracticide formulation will have different effects on each of the targeted species. It is anticipated that, due to decreased attractiveness, a combined formulation would be less effective against the codling moth. However, a mixed formulation, due to increased attractiveness and toxicity, could be more effective against the Oriental fruit moth under field conditions.     

Dual pheromone dispenser for combined control of codling moth Cydia pomonella L. and oriental fruit moth Grapholita molesta (Busck) (Lep., Tortricidae) in pears

Codling moth (CM) and oriental fruit moth (OFM) are very important orchard pests worldwide, and particularly in Victoria, Australia, where both species damage pome fruit. Individually CM and OFM have been controlled successfully by pheromone‐mediated mating disruption, but treatment of pome fruit with full registered rates of two individual hand‐applied dispensers for CM and OFM could be uneconomical for growers. Field trials conducted over three seasons in plots sprayed with insecticides consistently demonstrated that dual Isomate C/OFM TT dispensers, designed to disrupt both CM and OFM, were as effective as Isomate CTT and Isomate OFM Rosso dispensers applied individually in pears for control of CM and OFM respectively. The dual‐ and individual‐species dispensers reduced moth catches and fruit damage to a similar degree. The results suggest that combined control of CM and OFM in pears by applying dual Isomate C/OFM TT dispensers at the full‐recommended rate of 500 dispensers per hectare will be more economical than use of individual species dispensers, because the price and application cost of dual dispenser is about half that for individual dispensers.     

Characterisation of Cydia pomonella granulovirus from codling moths in a laboratory colony and in orchards of British Columbia*

Sequence analyses indicate that a granulovirus isolated from a laboratory colony of codling moth in British Columbia, Canada is identical or very similar to the Mexican isolate of Cydia pomonella granulovirus (CpGV-M). In addition to codling moth, the vims was found to cause mortality of secondary leafroller pests of North American orchards, including the fruit tree leafroller and the obliquebanded leafroller. A survey in apple growing regions of British Columbia indicates that 23% of the wild population of codling moth larvae carry CpGV.