Diapause induction in the codling moth, Cydia pomonella: effect of prediapause temperatures

The effect of four prediapause temperatures (18, 22, 26 and 30°C) on the photoperiodic response of the codling moth, Cydia pomonella (L.), was studied under controlled conditions. The highest rates of diapause were recorded, for all day-lengths, at temperatures of 22 and 26°C while relatively lower rates of diapause were elicited at 18 and 30°C. The same trend was demonstrated by projecting the values of the critical photoperiod which induces 50% diapause (=CPhP₅₀) over the prediapause temperature. The change in diapause incidence as a function of photoperiod, at all prediapause temperatures, exhibited a response characteristic of long-day insects, i.e. high rates of diapause at short days (12–13.5 h) and a decrease in diapause incidence at long days (14–15 h). The results for temperatures 22, 26 and 30°C support the view that lower prediapause temperatures enhance diapause induction, at a give photoperiod, while higher temperatures tend to avert or diminish the process. On the other hand, the low rates of diapause obtained at 18°C contradict this view. Nevertheless, high correlation was found between the laboratory evidence and field data, indicating the adaptability of the Israeli codling moth to subtropical climate.     

Diapause induction in the codling moth, Cydia pomonella: effect of larval diet

The effect of larval diet on diapause induction in the Israeli strain of the codling moth, Cydia pomonella (L.), was studied in a field trial using intact apple fruits of two varieties: Ana (early-ripening, in the end of June) and Granny Smith (late-ripening, in October). Diapause incidence increased as fruit age (determined as days from fruit-set) progressed. These results corroborate former studies on other strains of the codling moth, where excised fruits were used.The combination of 80-day-old, fully ripe, Ana fruit treatment with the longest days of the year, yielded 38% diapause. This result demonstrates that mature fruit (inducing diapause) cannot completely override the effect of long day (averting diapause), but does confirm that larval diet modifies the photoperiodic induction of diapause in the codling moth.Deceased, October 1988     

Antennal and behavioural response of codling moth Cydia pomonella to plant volatiles

Identification of host volatile compounds attractive to codling moth Cydia pomonella, a most important insect of apple, will contribute to the development of safe control techniques. Synthetic apple volatiles in two doses were tested for antennal and behavioural activity in codling moth. Female antennae strongly responded to (Z)3‐hexenol, (Z)3‐hexenyl benzoate, (Z)3‐hexenyl hexanoate, (±)‐linalool and E,E‐α‐farnesene. Two other compounds eliciting a strong antennal response were the pear ester, ethyl (E,Z)‐2,4‐decadienoate, and its corresponding aldehyde, E,E‐2,4‐decadienal, which is a component of the larval defence secretion of the European apple sawfly. Attraction of codling moth to compounds eliciting a strong antennal response was tested in a wind tunnel. Male moths were best attracted to a blend of (E,E)‐α‐farnesene, (E)‐beta‐farnesene and ethyl (E,Z)‐2,4‐decadienoate. The aldehyde E,E‐2,4‐decadienal had an antagonistic effect when added to the above mixture.     

A model of the effect of codling moth granulosis virus on Cydia pomonella

A model was developed based on an initial ingestion phase, followed by a period of virus multiplication and host death, to describe the effects of codling moth granulosis virus (CpGV) concentration and time from initial infection on the percentage of codling moth larvae (Cydia pornonella) dying from virus infection in the laboratory. With modification, this model also described the effect of CpGV concentration on the reduction of damage to fruit by C. pomonella larvae in the field. In both cases, the effect of CpGV increased with the l/10th power of virus concentration. LT₅₀ (time to death of 50% of larvae) was inversely related to virus concentration in the laboratory. The model predicts the threshold concentration for death of larvae, as well as LD₅₀(C₅₀ and LD₉₀(C ₉₀,) for all ages of larvae. The model also predicts that if the majority of larvae entered through the sides of apple fruits, rather than through the calyx or near the stalk (as they probably did in the field), then the efficacy of CpGV in reducing fruit damage would be lowered. This effect of site of entry is especially marked at low virus concentrations.     

Activity of Bacillus thuringiensis delta-endotoxins against codling moth (Cydia pomonella L.) larvae

Solubilized protoxins of nine Cry1 and one hybrid Cry1 delta-endotoxin from Bacillus thuringiensis were tested for their activity against larvae of the codling moth (Cydia pomonella L). Cry1Da was the most toxic, followed by Cry1Ab, Cry1Ba, and Cry1Ac, while Cry1Aa, Cry1Fa, Cry1Ia, and SN19 were still less active. Cry1Ca and Cry1Cb showed no activity. In vitro trypsin activation increased activity of all eight active delta-endotoxins, and dramatically enhanced toxicity of hybrid SN19, Cry1Aa, Cry1Ac, and Cry1Fa. The differences between toxicity of proteins before and after trypsin digestion suggests that proteolytic activation in the C. pomonella digestive tract plays a critical role for the activity of Cry proteins against this insect.     

Attract and kill: a new method for control of the codling moth Cydia pomonella

The attract and kill technique has been formulated in a product under the trade name `Sirene CM®'. It consists of a viscous paste containing 0.16% codlemone to attract the male moths and 6.0% permethrin to kill them. The formulation is applied by hand twice per season using a specially developed system which can be calibrated for application of the paste to the host plant in small droplets of either 100 l or 50 l. Between 1995 and 1997, 15 trials on control of the codling moth were conducted in isolated orchards in the Lake Geneva region. In each plot, depending on tree size, two applications varying between 52 and 537 g ha^–1 of Sirene CM were made. In 14 trials, the larval attack of the codling moth on fruit was below the economic threshold of 1% and the hibernating population stayed at a low level. One single plot (0.4 ha) had to be treated with a curative spray in 1995, because the initial population was much too high. According to the reductions in trap catch and of mating frequency measured by tethered codling moth females, efficiency of the attract and kill droplets lasted 5–7 weeks, after which it decreased slowly.     

How the oligophage codling moth Cydia pomonella survives on walnut despite its secondary metabolite juglone

Besides apple, its primary host, the codling moth Cydia pomonella uses walnut as a secondary host. Abundance of toxic naphthoquinones, among which juglone prevails, does not restrain this economically important pest insect from infesting walnut, but processes underlying the suitability of this host were yet unknown. Larvae feeding on an artificial diet supplemented with juglone at naturally occurring concentrations survived to adulthood at a similarly high proportion as those in the juglone-devoid control. However, their development time was prolonged, their weight gain was reduced, and adult sex ratio was distorted. Results from the natural system with walnut and apple fruits were in line with data gained on artificial diet. Remarkably, a twofold increase of the maximal juglone content reported from the walnut husk was lethal to the larvae. Chemical analyses showed that larvae feeding on the artificial diet supplemented with juglone concentrations present in walnut contained 1,4,5-trihydroxynaphthalene and excreted it in their frass, whereas the hemolymph contained neither detectable amounts of juglone nor the product of its reduction. Hence, effective metabolism of juglone in the intestinal system of the larvae underlies their survival on host plants containing this defensive compound.     

Mating disruption of codling moth Cydia pomonella with high densities of Ecodian sex pheromone dispensers

A mating disruption approach using high densities of pheromone dispensers, has recently been proposed for controlling codling moth, Cydia pomonella (L.) (Lep., Tortricidae). Ecodian® CP dispensers, made of low‐cost biodegradable material and easy to apply, were formulated with 10 mg of codlemone and placed at a rate of 1400–2000 dispensers/ha. Seasonal dispenser performance was evaluated using different methods. The release rate of new Ecodian dispensers, measured directly by solid‐phase micro‐extraction (SPME), was significantly higher than that of the standard monitoring lure. The release rate of field‐aged dispensers decreased over time; it was comparable with that of the standard monitoring lure after 55–90 days of field exposure and significantly lower beyond. Electroantennographic (EAG) recordings showed that field‐aged dispensers strongly stimulated virgin male moths’ antennae. Dispensers elicited close‐range approaches in wind tunnel irrespective of their age. Traps baited with aged Ecodian CP dispensers captured males throughout the season. Our results demonstrate that Ecodian dispensers achieved a good level of activity and longevity over the season. Field trials carried out from 2002 to 2004 confirmed the efficacy of Ecodian CP dispensers for codling moth control, regardless of the size of the treated area. The potential of this strategy for the control of C. pomonella is discussed.     

Active regulation of respiration and circulation in pupae of the codling moth (Cydia pomonella)

Regulation of autonomic physiological functions has been investigated by means of multisensor electronic methods, including electrocardiographic recording of heartbeat, strain-gauge recording of extracardiac hemocoelic pulsations (EHPs), anemometric recording of air passage through spiracles and respirographic recording of O(2) consumption and CO(2) output. Pupae of Cydia exhibit continuous respiration without remarkable bursts of CO(2). The dorsal vessel of these pupae exhibited regular heartbeat reversals characterized by shorter intervals of faster (forward oriented or anterograde) pulsations and longer intervals of slower (backward oriented or retrograde) peristaltic waves. The periodically repeated EHPs were present during the whole pupal interecdysial period. The internal physiological mechanisms regulating the cardiac (heartbeat) and extracardiac (EHP) pulsations were completely independent for most of the pupal instar. Simultaneous multisensor analysis revealed that the anterograde heartbeat of the dorsal vessel had similar but not identical frequency with EHPs. During advanced pharate adult development, frequency of cardiac and extracardiac pulsation periods profoundly increased until almost uninterrupted pulsation activity towards adult eclosion. At this time, the cardiac and extracardiac pulsations occasionally performed in concert, which enhanced considerably the efficacy of hemolymph circulation in pharate adults with high metabolic rates. The fastest hemolymph flow through the main body cavity was always associated with EHPs and with anterograde heartbeat. Simple physical diffusion of O(2) and CO(2) through spiracles (diffusion theory of insect respiration) does not play a significant role in pupal respiration. Instead, several kinds of regulated, mechanical ventilations of the tracheal system, including EHPs are responsible for effective tracheal ventilation.     

Temporal events in the invasion of the codling moth,Cydia pomonella,by a granulosis virus: An electron microscope study

The replication cycle of the granulosis virus of Cydia pomonella, the codling moth, was studied at the cellular and tissue level. Membranelike complexes were observed forming within the remnants of the nucleolus in the cytoplasm of infected cells. Differences in cell polarity relative to the sites of virus entry assembly and budding as well as differences in the temporal aspects of replication were observed between midgut, fat body, and epidermal cells. The progressive spread of virus throughout larval tissues was studied at 24, 32, 48, 56, and 72 hr postinfection. The basal lamina seemed to be an effective barrier for the release of budded progeny virus into the hemocoel and large numbers of budded virus were produced.     

Identification of candidate chemosensory receptors in the antennal transcriptome of Tropidothorax elegans

Molecular Biology Reports - Chemosensory receptors in the dendritic membrane of olfactory cells are critical for the molecular recognition and discrimination of odorants. Tropidothorax elegans is a...     

Cold hardiness adaptations of codling moth, cydia pomonella

The cold hardiness adaptations of natural and laboratory reared populations of the codling moth, Cydia pomonella, were examined. Hemolymph, gut, and whole body supercooling points (SCPs), 24-h LT50s, polyhydroxy alcohol concentrations, hemolymph freezing points, and hemolymph melting points were determined. Nondiapausing codling moth larvae do not have appreciable levels of ice nucleators in the hemolymph or gut. Whole body supercooling points were higher than hemolymph supercooling points. For nondiapausing larvae, LT50s were significantly higher than both the whole body and the hemolymph supercooling points, indicating the presence of chill sensitivity. As the larvae left the food source and spun a cocoon, both hemolymph and whole body SCPs decreased. Diapause destined larvae had significantly lower hemolymph SCPs than nondiapausing larvae, but whole body SCPs were not significantly different from nondiapausing larvae of the same age. The LT50s of diapause destined and diapausing larvae were significantly lower than that of nondiapausing larvae. Codling moths are freezing intolerant, with LT50s close to the average whole body supercooling point in diapause destined and diapausing larvae. The overwintering, diapausing larvae effectively supercool to avoid lethal freezing by removal of ice nucleators from the gut and body without appreciable increase of antifreeze agents such as polyols or antifreeze proteins.     

Survival of mature larvae of codling moth (Cydia pomonella) on apple trees and ground

The effects of predation by carabid and staphylinid beetles and birds (blue- and great-tits) on mature larvae of the codling moth Cydia pomonella were investigated in a field experiment. The number of predatory beetles on the ground beneath eight of 16 apple trees was reduced by an insecticide spray, and tits were excluded from the trunks and lower branches of eight trees by means of Terylene netting. Beetles had no significant effect on survival of larvae on trees, but only 8% of larvae survived to adulthood on trees exposed to blue- and great-tits, whereas on trees protected from them 48% survived. Larvae were taken rapidly by the tits from the time larvae first built cocoons in summer and, by the time the majority of larvae had emerged from apples in late summer or autumn, tits had removed most from cocoons beneath flakes of bark glued to trees. Thus tits fed on larvae mainly in summer and autumn. On trees protected from tits, 8% of mature larvae were killed by fungi, of which Verticillium lecanii was most important. It was calculated that, of the larvae maturing in apples, 44% failed to build cocoons on the trees, 47% were taken by tits, then 1% were killed by fungi. Larvae failing to build cocoons on trees may build them on the ground. Of larvae in cocoons planted on or in the ground in 1975, only one (0.3%) persisted through the winter; 98.6% disappeared, and 1.1% were found dead, covered by fungi; in 1976, all larvae disappeared by December. Larvae disappeared even in the absence of predators, and are thought to have moved in response to damp ground conditions.     

Pheromone trap and population model-based control of the codling moth, Cydia pomonella L., in Romanian apple culture

Like in most parts of the world, the codling moth, Cydia pomonello (L.), is one of the most important pests in apple orchards in the Romanian Banat region. There, the control of this pest is often inadequate and the damage and economic losses are therefore enormous. This lack of control is caused by structural problems such as the absence of an advanced distribution network for phytopharmaceutical products, obsolete spraying equipment and the insufficient exchange of knowledge and expertise of those products and the pest itself between the local research facilities and the apple growers. The purpose of this research project is rather demonstrative, because a change in the Romanian pome culture's attitude is urgently needed. Pheromone trapping and the computerized population model RIMpro Cydia, which predicts important phenological events such as adult flight and egg hatch, were used to determine the optimal spray timing. These modern pest management techniques would not only minimize pressure on the environment, but also on the income of the Romanian apple grower, for whom phytopharmaceuticals are a high-priced investment. In July 2006 a comparative study between the supervised pest control program using Calypso, Runner and Reldan, all easily obtainable and commercially available insecticides in the region, and a conventional Romanian management programme was conducted. The control plot and the two test plots were all three located in a high codling moth pressure orchard in Timi?oara. In the control plot 9,44 % of the fruits were damaged by codling moth larvae. In the plot containing the trees that were treated according to the traditional Romanian management programme 5,56 % damage was recorded, while the supervised management plot showed only 1,1% damage. Additionally damage was measured in another orchard in Periam, about 60 km away from the other plots. There, an intensive control program using Reldan, Calypso, Actare, Karate and Insegar was applied and damage measured only 0.2%. While at first glance that approach seems most efficient, it has to be noticed that it used twice as much insecticide treatments as were used in the supervised control program. Furthermore, 1 % damage is suggested by most references as being the economical threshold for treatments. The results of this comparative study clearly show that supervised codling moth control proofs to be the most profitable. Starting from August the same year, all of the control programmes in Timi?oara were stopped. Therefore the second and possibly the third generation of codling moth larvae could develop freely. In the plot which was earlier sprayed according to the warnings of RIMpro Cydia and the pheromone trap this resulted in 27.5% damaged fruits during harvest in September. In the control plot damage reached 60.95%. These results highlight the necessity of the development of an efficient codling moth control program. Once that program is fine-tuned it should be presented to the local apple growers in order to give the Romanian pome culture a boost.     

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.     

Overcoming the resistance of codling moth against conventional Cydia pomonella granulovirus (CpGV-M) by a new isolate CpGV-I12

Recently, codling moth (CM, Cydia pomonella L.) populations with a significantly reduced susceptibility to C. pomonella granulovirus (CpGV) products have been observed in Germany. A novel CpGV isolate, designated CpGV-I12, is able to overcome the CpGV resistance. CpGV-I12 originated from Iran and showed superior efficacy in laboratory bioassays against a resistant CM strain (CpR), which has a 100-fold reduced susceptibility to commercially used isolate CpGV-M. Determination of the median lethal concentration (LC₅₀) indicated that CpGV-I12 is nearly as efficient in resistant CpR as CpGV-M in a susceptible CM strain (CpS). Beyond, CpGV-I12 caused superior mortality in CpS. Infection experiments showed that the resistance breaking effect can be observed in all instars of CpR. CpGV-I12 is a promising alternative control agent of CM in orchards where conventional CpGV products fail. In addition, we demonstrate in bioassays with recombinant expressed Cry1Ab that cross-resistance to CpGV and Bacillus thuringiensis products is not likely.     

Production and field evaluation of codling moth granulosis virus for control of Cydia pomonella in the United Kingdom

Codling moth granulosis virus (Cp GV) was produced in larvae of Cydia pomonella reared on artificial diet. The average yield of virus (9 × 10⁹capsules/larva) was increased by raising the larvae on diet containing methoprene, a juvenile hormone analogue. In field trials in 1978 and 1979, one or two high-volume applications of Cp GV at 7 × 10¹⁰ capsules/litre achieved reductions in numbers of mature larvae and damaged fruit that were little different from those obtained by two applications of azinphos-methyl. A field trial in 1980 showed that at concentrations of Cp GV ≥ 6 × 10⁸ capsules/litre, damaged diminished slowly with increasing virus concentration. Following virus application in 1980, Cp GV infectivity was reduced by half in 3 days, but some activity persisted at least 4–8 wk after spraying. The results indicate that codling moth GV is an effective control agent particularly in reducing numbers of larvae and the more severe forms of fruit damage.     

Hormonal regulation of pupation in the codling moth, Laspeyresia pomonella

ABSTRACT. According to the different reactions to the juvenoid Altosid®, the last larval instar (L₅) of Laspeyresia pomonella (L.) (Tortricidae) reared under 'long day' conditions (constant light) was subdivided into three sensitive phases: an additional larval instar, a larval–pupal intermediate, or a pupa. Under short day conditions, the prothoracotropic effect of juvenile hormone (JH) in L₅, which have a continuous high titre of JH during the whole instar, indicated that it is not a particular titre of JH but a rise in the titre that can induce the production of moulting hormone. Neck-ligation experiments showed that JH acts not directly on the prothoracic glands but via the head, probably via the neurosecretory system. The meaning of the JH-peak in mature L₅ reared under long days was determined either by injections with the anti-JH, precocene II, in combination with applications of Altosid, or by forcing precocene-treated larvae to a precocious moult by injecting them with ecdysterone. Precocene delayed, and JH accelerated pupation if administered 4.5 days after the L₅ -moult. JH was also found to stimulate the growth and differentiation of the imaginal discs. Moulting hormone in long-days reared insects was detected one day after the larvae had spun their cocoon, with a maximum on the second day after spinning. The hormone was also present in freshly moulted pupae. Neck-ligation of mature larvae indicated that the delay between activation of the prothoracic glands and the production of an effective amount of moulting hormone is less than one day.