Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Conotrachelus nenuphar
(plum curculio)



Conotrachelus nenuphar (plum curculio)


  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Conotrachelus nenuphar
  • Preferred Common Name
  • plum curculio
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Uniramia
  •         Class: Insecta
  • Summary of Invasiveness
  • The plum curculio, C. nenuphar, is native to North America and restricted to east of the Rocky Mountains. Although it feeds on several wild host plants and several species of cultivated pome and stone fruit,...

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TitleC. nenuphar: adult
CopyrightCharles Vincent/Agriculture & Agri-Food, Canada
C. nenuphar: adultCharles Vincent/Agriculture & Agri-Food, Canada


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Preferred Scientific Name

  • Conotrachelus nenuphar (Herbst)

Preferred Common Name

  • plum curculio

Other Scientific Names

  • Curculio nenuphar Herbst

International Common Names

  • English: American plum weevil; curculio, plum; peach curculio
  • French: charançon de la prune

Local Common Names

  • Germany: Ruessler, Nordamerikanischer Pflaumen-

EPPO code

  • CONHNE (Conotrachelus nenuphar)

Summary of Invasiveness

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The plum curculio, C. nenuphar, is native to North America and restricted to east of the Rocky Mountains. Although it feeds on several wild host plants and several species of cultivated pome and stone fruit, C. nenuphar has not extended its geographical range over the years. Given its life-cycle (larvae complete their development and diapause in the soil), it is not likely to be a global invasive species. It can be considered as a local invader, as it will invade any new orchard plant (apple: Malus; plum: Prunus; peach: Prunus) and thereby become a serious pest of these agricultural habitats.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Uniramia
  •                 Class: Insecta
  •                     Order: Coleoptera
  •                         Family: Curculionidae
  •                             Genus: Conotrachelus
  •                                 Species: Conotrachelus nenuphar


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White, oval, about 0.35 x 0.6 mm, laid in the fruit.


White, curved, legless with a brown head, 6-9 mm long when mature.


White, 4.5-7 mm long. Found in an earthen cell.


A brownish-grey weevil about 5 mm long with four humps on the elytra (Lienk, 1980).


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C. nenuphar is restricted to North America (EPPO, 2003). The National Agricultural Pest Information System (NAPIS) publishes information on the distribution of C. nenuphar at:

See CABI/EPPO (1998).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

North America

CanadaRestricted distributionGarland and Campbell, 1990; CABI/EPPO, 2002; EPPO, 2014
-British ColumbiaAbsent, invalid recordCABI/EPPO, 2002; EPPO, 2014
-ManitobaPresentCABI/EPPO, 2002; EPPO, 2014
-New BrunswickPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-Newfoundland and LabradorPresentCABI/EPPO, 2002; EPPO, 2014
-Nova ScotiaPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-OntarioPresentHagley et al., 1977; CABI/EPPO, 2002; EPPO, 2014
-Prince Edward IslandPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-QuebecPresentLe Blanc et al., 1981; Lafleur and Hill, 1987; Racette et al., 1990; CABI/EPPO, 2002; EPPO, 2014
USARestricted distributionCABI/EPPO, 2002; EPPO, 2014
-AlabamaPresentCABI/EPPO, 2002; EPPO, 2014
-ArkansasPresentCABI/EPPO, 2002; EPPO, 2014
-ColoradoPresentQuaintance and Jenne, 1912; CABI/EPPO, 2002; EPPO, 2014
-ConnecticutPresentMaier, 1990; CABI/EPPO, 2002; EPPO, 2014
-DelawarePresentCABI/EPPO, 2002; EPPO, 2014
-FloridaPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-GeorgiaPresentYonce et al., 1995; CABI/EPPO, 2002; EPPO, 2014
-IllinoisPresentCABI/EPPO, 2002; EPPO, 2014
-IndianaPresentCABI/EPPO, 2002; EPPO, 2014
-IowaPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-KansasPresentCABI/EPPO, 2002; EPPO, 2014
-KentuckyPresentCABI/EPPO, 2002; EPPO, 2014
-LouisianaPresentCABI/EPPO, 2002; EPPO, 2014
-MainePresentLathrop, 1949; CABI/EPPO, 2002; EPPO, 2014
-MarylandPresentCABI/EPPO, 2002; EPPO, 2014
-MassachusettsPresentMaier, 1990; CABI/EPPO, 2002; EPPO, 2014
-MichiganPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-MinnesotaPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-MississippiPresentCABI/EPPO, 2002; EPPO, 2014
-MissouriPresentChapman, 1938; CABI/EPPO, 2002; EPPO, 2014
-MontanaPresentCABI/EPPO, 2002; EPPO, 2014
-NebraskaPresentCABI/EPPO, 2002; EPPO, 2014
-New HampshirePresentCABI/EPPO, 2002; EPPO, 2014
-New JerseyPresentCABI/EPPO, 2002; EPPO, 2014
-New YorkPresentMaier, 1990; Reissig et al., 1998; CABI/EPPO, 2002; EPPO, 2014
-North CarolinaPresentMcGiffen and Meyer, 1986; CABI/EPPO, 2002; EPPO, 2014
-North DakotaPresentCABI/EPPO, 2002; EPPO, 2014
-OhioPresentCABI/EPPO, 2002; EPPO, 2014
-OklahomaPresentCABI/EPPO, 2002; EPPO, 2014
-PennsylvaniaPresentCABI/EPPO, 2002; EPPO, 2014
-Rhode IslandPresentMaier, 1990; CABI/EPPO, 2002; EPPO, 2014
-South CarolinaPresentCABI/EPPO, 2002; EPPO, 2014
-South DakotaPresentCABI/EPPO, 2002; EPPO, 2014
-TennesseePresentCABI/EPPO, 2002; EPPO, 2014
-TexasPresentCABI/EPPO, 2002; EPPO, 2014
-UtahPresentAlston and Stark, 2000; CABI/EPPO, 2002; EPPO, 2014
-VermontPresentCABI/EPPO, 2002; EPPO, 2014
-VirginiaPresentCABI/EPPO, 2002; EPPO, 2014
-West VirginiaPresentCABI/EPPO, 2002; EPPO, 2014
-WisconsinPresentCABI/EPPO, 2002; EPPO, 2014


NetherlandsAbsent, confirmed by surveyNPPO of the Netherlands, 2013; EPPO, 2014

Risk of Introduction

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C. nenuphar is unlikely to be transported as larvae in fruits, except in cherries; contamination of packing by adults is more likely. Although adults could also be transported with dormant nursery stock, this is unlikely.

As no biocontrol agents can effectively control the pest in commercial orchards (van Driesche et al., 1987), broad-spectrum insecticides (adulticides) remain the primary controls in a commercial context.

Habitat List

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Terrestrial – ManagedCultivated / agricultural land Principal habitat Harmful (pest or invasive)
Terrestrial ‑ Natural / Semi-naturalNatural forests Principal habitat

Hosts/Species Affected

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Peaches, apricots and nectarines are the preferred hosts of C. nenuphar but apples are also widely affected. Apples are less damaged in areas adjacent to peach orchards than in areas where peaches are little grown. Pears are often scarred and deformed by the feeding and egg punctures of C. nenuphar but the larvae fail to develop in them (Armstrong, 1958). There are varietal differences in the susceptibility of apples, with eggs being destroyed and larval establishment being prevented by fruit growth in some varieties (Paradis, 1957). The larvae have also been found developing inside leaf curl galls and pockets in plum fruits, caused by the fungus Taphrina communis. The black excrescences of Dibotryon morbosum [Apiosporina morbosa] also provide satisfactory food for the larvae (EPPO, 1979). For further information on the hosts of C. nenuphar, see Maier (1990) and Yonce et al. (1995).

With mark and release experiments, Leskey and Wright (2007) established that the order of preference of the host range for C. nenuphar as (in decreasing order of preference): Japanese plum (Prunus salicina), European plum (Prunus domestica), peach (Prunus persica), sweet cherry (Prunus avium), tart cherry (Prunus cerasus), apricot (Prunus armeniaca), apple (Malus domestica) and pear (Pyrus communis).

Growth Stages

Top of page Flowering stage, Fruiting stage, Vegetative growing stage


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On apple, C. nenuphar can cause two types of damage. In spring, females oviposit in young fruit, marking them with characteristic half-moon shaped scars; and in spring and summer, the adults puncture the fruit causing round (2-3 mm diameter), feeding scars.

The appearance of plum curculio damage is highly variable and, of all fruit damage rated by IPM specialists, damage caused by plum curculio had the lowest average agreement level (71.8%) (Vincent and Hanley, 1997). Internal damage to the fruit is caused by larval feeding and exit holes. Most infested fruits drop prematurely in June, though cherries rot on the trees. Adult feeding may also cause marginal damage to leaves and blossoms.

List of Symptoms/Signs

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SignLife StagesType
Fruit / external feeding
Fruit / internal feeding
Fruit / obvious exit hole
Fruit / premature drop

Biology and Ecology

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C. nenuphar overwinters as adults in plant debris, preferably under maple leaves (Lafleur et al., 1987). The pest is univoltine in the northern part of its range (north of Virginia, USA) and at least partially multivoltine in southern areas. Spring emergence times vary with geographical location.

In Quebec, Canada, the overwintered adults appear in May, about 11 days before full bloom in apple, reaching a peak from 6 days before full bloom to 10 days after petal fall (Paradis, 1957). In south-western Quebec, adults emerged when apple trees of cv. McIntosh were in the 'green tip stage' in late April (Paradis, 1956). Emergence may take 3-4 weeks (Lafleur and Hill, 1987).

In Ontario, Canada, emergence begins at end of April and is almost (90%) complete by early June. Emergence continues until late June or early July (Armstrong, 1958).

In Texas, USA, emergence occurs in late March to early May (King and Morris, 1957). After emergence the weevils may remain on the surface of the soil for some time before appearing on the trees, where they feed on the new shoots and blossom until the fruit becomes available (Smith and Flessel, 1968; Chouinard et al., 1994).

In spring, the adults invade orchards from the surrounding woodland (Lafleur et al., 1987). In Quebec, the adult population peaks somewhere between the tight cluster stage and 10 days after petal fall in early June (Paradis, 1956). The highest distance covered by the adults, mainly by walking, was recorded from the tight cluster stage until June drop in late June (Lafleur and Hill, 1987).

In Ontario, oviposition begins in late May and continues until early August. The timing of oviposition varies with climate. In insectary experiments, some overwintered adults lived for 17 months and a few went through a second winter to 22 months (Armstrong, 1958).

In New York, USA, Reissig et al. (1998) estimated that 60% of total fruit damage by oviposition was accomplished when 230 day-degrees C above 10°C had accumulated after petal fall (on average, mid-June).

The eggs are laid in a cavity that the female bites into the epidermis of the fruit. The skin of the fruit is cut into a distinctive crescent-shaped slit which partially surrounds the egg. The eggs and young larvae are sensitive to pressure and other unfavourable effects of fruit growth. The destruction of eggs by crushing may account for varietal differences in the susceptibility of apples to attack by C. nenuphar. The gum exuding from egg-laying scars on half-grown plums can kill the larvae. More than one larva can develop in a single fruit. The abundance of fruit has a significant influence on the population of C. nenuphar and a poor crop may lead to a marked decrease in the population size. The larvae feed in the fruit, which usually drops prematurely. The time spent in the fruit varies from 15 (Armstrong, 1958) to 18 days (Paradis, 1956). When fully fed, the larvae leave the fruit and pupate in cells in the soil. The time spent in the soil depends on temperature and humidity but varies from 3 weeks to more than 5 weeks, the longer periods generally occurring more in the northern part of its range.

The summer generation of adults emerge over a long period from July to October in Ontario, Canada, and Maine, USA (Lathrop, 1949), with a peak of emergence in September. In Georgia, USA, approximately one-half to three-quarters of the adults lay eggs in the same year giving a partial second generation (Snapp, 1940). The adults leave the trees and search for overwintering sites in September. In caged experiments in Ontario, 93% of adults overwintered at the soil surface under leaves and other debris, 4% were found in the top inch of the soil and the remainder overwintered deeper in the soil (Armstrong, 1958). In Virginia, USA, weevils were found hibernating up to 15 cm deep in loose soil and in clay at an average depth of 6 cm.

For further information on the biology and ecology of C. nenuphar, see Quaintance and Jenne (1912), Chapman (1938), Snapp (1940), Smith and Flessel (1968), Racette et al. (1992) and Vincent et al. (1999). Holloway (1977) and Le Blanc (1982) have reviewed the literature on C. nenuphar.


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Df - Continental climate, wet all year Preferred Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Anaphes conotracheli Parasite Eggs
Bacillus thuringiensis entomocidus Pathogen Adults
Bacillus thuringiensis subtoxicus Pathogen Adults
Beauveria bassiana Pathogen Larvae
Bracon mellitor Parasite Larvae
Bufo americanus Predator Adults
Cholomyia inaequipes Parasite Larvae
Chrysopa Predator Larvae
Dorymyrmex bureni Predator Larvae
Metarhizium anisopliae Pathogen
Myophasia aeneae Parasite Larvae
Nealiolus curculionis Parasite Larvae
Nealiolus rufus Parasite Larvae
Solenopsis invicta Predator Larvae
Steinernema carpocapsae Parasite
Tersilochus conotracheli Parasite Larvae

Notes on Natural Enemies

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Nealiolus curculionis is the most common larval parasite of C. nenuphar in the Niagara Peninsula, Ontario, Canada (Armstrong, 1958).

Impact Summary

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Cultural/amenity Negative
Economic/livelihood Positive
Environment (generally) Negative
Human health Negative


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Next to the codling moth (Cydia pomonella), C. nenuphar is regarded as the most serious pest of pome and stone fruit in eastern North America (Prokopy and Croft, 1994). For example, in Quebec, up to 85% of harvested apples may be damaged by C. nenuphar in unsprayed orchards (Vincent and Bostanian, 1988; Vincent and Roy, 1992). Plum curculio populations return to levels of economic importance 1 to 3 years after cessation of pesticide spraying (Glass and Lienk, 1971; Hall, 1974; Hagley et al., 1977).

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Has a broad native range
  • Abundant in its native range
  • Tolerant of shade
  • Highly mobile locally
Impact outcomes
  • Negatively impacts agriculture
Impact mechanisms
  • Pest and disease transmission
  • Herbivory/grazing/browsing

Similarities to Other Species/Conditions

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The apple weevil, Anthonomus quadrigibbus is similar to C. nenuphar and is restricted to North America (Chouinard et al., 2000; Agnello et al., 2006). Anthonomus pomorum (Toepfer et al., 1999) is also similar but is restricted to Europe.


Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Field Monitoring

The best method of monitoring C. nenuphar in commercial orchards is to carefully examine thousands of small fruits looking for fresh egg-laying scars (Hoyt et al., 1983; Le Blanc et al., 1984). In commercial orchards in Quebec, Canada, Vincent et al. (1997) successfully used a threshold of 1% damaged fruit, with careful monitoring of fruit three times a week, to manage localized, peripheral treatments following full-block treatment at petal fall.

There have been several studies aimed at improving the timing of insecticide treatments by trapping adults (for example, Le Blanc et al., 1981; Tedders and Wood, 1994; Prokopy et al., 1998, 1999a, b). The principle behind the pyramid trap (Tedders and Wood, 1994), which has the silhouette of a small tree, is the tendency of C. nenuphar to move towards tree silhouettes in the spring (Lafleur and Hill, 1987). Other trap models proposed include clear plexiglass panels (Dixon et al., 1999), conical boll weevil traps (Prokopy and Wright, 1998), sticky (Yonce et al., 1995) and non-sticky apples (Racette, 1988), plastic funnels (LeBlanc et al., 1981), screen traps (Mulder et al., 1997), pitfall traps (Yonce et al., 1995), cylinder traps (Prokopy et al., 2000) and branch-mimicking traps (Leskey and Prokopy, 2002). There is an abundance of literature that documents the effects of various factors explaining trap performance, such as visual cues (Leskey, 2006), proximity of host trees (Leskey and Wright, 2004a, b), architecture (Lafleur et al., 2007) and material (Lamothe et al., 2008). Trapping has indicated that immigration in orchards of Massachusetts, USA can last for 51 to 85 days (Piñero and Prokopy, 2006). So far, none of these models has shown sufficient attractiveness or reliability to replace the visual examination of fruitlets as the recommended monitoring technique for the protection of commercial orchards.


Adult plum curculios are attracted to salicycl-aldehyde early in the season and gallic acid later in the season (Snapp and Swingle, 1929a). Extracts of peach have also been tested (Snapp and Swingle, 1929b).

Over the past 20 years, attractants have been tested for several curculionid species (Hardee et al., 1971; Hedin et al., 1979; Booth et al., 1983). Hardee et al. (1971) found that plant extracts significantly increased the attractiveness of the boll weevil pheromone and Dickens (1989) found that certain green leaf volatiles (Visser et al., 1979) were also attractive to the boll weevil.

Early attempts to identify potential attractants for adult plum curculios in stored apples and aluminium carbonate (Prokopy et al., 1995; Prokopy and Leskey, 1997), fresh apple juice and synthetic apple blossom fragrance (Le Blanc, 1982) have been unsuccessful. Butkewich and Prokopy (1993) found that because odours of host fruit were significantly less attractive at 4 and 8 cm than at 2 cm from plum curculios, fruit odor-based traps are unlikely to be useful in commercial orchards.

Eller and Bartelt (1996) isolated and subsequently synthesized an aggregation pheromone from male plum curculios: (+)-(1R,2S)-Methyl-2-(1-methylethenyl) cyclobutaneacetic acid. This compound, grandisoïc acid, is attractive to both sexes.

Placing live adults as baits in Tedder's pyramid traps has been unsuccessful, possibly because of repulsive distress signals emitted by the curculios (Prokopy and Leskey, 1997). However, lures impregnated with a racemic mixture of grandisoïc acid have been reported by Johnson et al. (1997) to significantly increase the number of plum curculios trapped in Tedder's pyramid traps. Chouinard et al. (unpublished data) demonstrated an increase in attractiveness when the lure was used in conjunction with small amounts of green leaf volatiles; high amounts showed a repulsive effect. Leskey et al. (1997) reported the attractiveness of a chemically uncharacterized host odour produced by apples at petal fall, and of water extracts of small apples and apple twigs. Plum curculio adults are known to be strongly attracted to host plum volatiles (Lesley and Prokopy, 2001; Leskey and Wright, 2007). Plant odours and pheromonal combination have been tested (Piñero and Prokopy, 2003) but none of the results are amenable to commercial use.

Behavioural Exploitation

Observations of the behaviour of adults, both in the field and in cages, has led to the design of better IPM programmes for C. nenuphar. Using Zn65 as a marker, it was shown that most adults move from orchards to the surrounding woodland in autumn (Lafleur et al., 1987). After overwintering, the returning plum curculios gradually invade apple orchards between pink and petal fall (Lafleur and Hill, 1987) after spending several days on the ground under the perimeter rows of trees (Racette et al., 1990; Chouinard et al., 1993, 1994). From full bloom to 9 days after fruit set, adults were found to be active mainly during the night (Racette et al., 1991). In field cages, adults (labelled with Zn65) showed a similar diel periodicity when foraging on dwarf apple trees and, because adults are most active in the trees between 20:00 and 00:00 h, insecticide treatments are likely to be most effective if applied in the early part of the night (Chouinard et al., 1992a).

There have been several attempts to relate adult activity to ambient temperature to optimize the timing of insecticide treatments (reviewed by Racette et al., 1992). In all of these studies, the relationship between meteorological factors and adult activity was established a posteriori. A notable exception is in the study by Lamothe et al. (2008), where adults were studied under meteorological conditions set a priori. The conclusions are that adult captures are higher: at night; during warmer periods (20 and 25ºC); when wind velocity is low; during or shortly after rainfall; and that photoperiod is a factor having an important predictive value for plum curculio captures. Two approaches have been investigated: the development of a trap to evaluate adult populations and relate population levels to risks (Prokopy and Wright, 1998), and the development of day-degree models to predict the appearance of damage in the orchards (Reissig et al., 1998). So far, both methods have not been used as the sole method to manage plum curculio populations. A model predicting nocturnal activity of the plum curculio on a hourly basis has also been recently developed and is currently under validation (Chouinard et al., 2002). A model used as a decision aid to time insecticide treatments against summer adults of the bivoltine strain has been implemented in peach orchards of southeastern USA (Lan et al., 2004).

Biological Control

Several natural enemies have been recovered from C. nenuphar but none are able to provide an effective alternative to chemical insecticides in commercial orchards (van Driesche et al., 1987; Racette et al., 1992).

Entomogenous nematodes
Several species of nematodes tested as larvicides were ineffective (Tedders et al., 1982). In the laboratory, 95.1% larval mortality was caused at a concentration of 400 Steinernema carpocapsae nematodes per larvae (Olthof and Hagley, 1993). There was no significant increase in larval mortality from 200 to 400 nematodes per larvae. At these concentrations, 73.4% larval mortality was achieved in natural sods. Nematode treatments affected larvae of the apple sawfly, Hoplocampa testudinea (Vincent and Bélair, 1992). Nematode treatments applied to the soil did not prevent damage to apples, but lowered populations of both pests for the subsequent growing season.

To prevent damage to fruit, the effectiveness of repeated applications of S. carpocapsae to the foliage or aerial parts of apple trees was tested (Bélair et al., 1998). In a caged environment, localized applications of nematodes at the base of tree trunks significantly reduced adult populations maintained there (82-100% mortality vs 0-18% in the control). The virulence and reproductive potential of Heterorhabditis bacteriophora (Hb strain), Heterorhabditis marelatus (Point Reyes strains), Heterorhabditis megidis (UK211 strain), Steinernema riobrave (355 strain), S. carpocapsae (All strains) and Steinernema feltiae (SN strain) has been tested by Shapiro-Ilan et al. (2002). S. carpocapsae and S. riobrave appeared to have the most potential for controlling adults, whereas S. feltiae and S. riobrave had the best potential for larval control. Shapiro-Ilan et al. (2004) carried out field studies to test if S. feltiae and S. riobrave control C. nenuphar larvae in the soil. S. riobrave was the only treatment that caused a significant reduction in weevil emergence.

Chemical Control

The strategy of treating 20 m-wide peripheral zones of apple orchards (when needed) in spring is based on the finding that plum curculio damage is frequently more abundant at this time in peripheral zones (Le Blanc et al., 1984) and that during the tight cluster stage most plum curculio adults move only 1-4 m per day when returning to the orchards from their overwintering sites in adjacent woodlots (Lafleur and Hill, 1987). During this 5-20 day re-invasion period, petal fall was selected as the most appropriate time for this peripheral zone treatment.

Using this approach in an experimental orchard, fruit damage at harvest was reduced from 57 to 2.4% (Chouinard et al., 1992b), while reducing the amount of insecticide used by 70%, and the plum curculio adult population by 83%. The approach has been validated in commercial orchards (Vincent et al., 1997). Plum curculio damage at harvest varied from 0.0 to 0.7% and from 0.0 to 0.8% fruit in plots receiving peripheral sprays (experimental) and  full-plot sprays (reference), respectively; and most damaged apples (95%) were found in peripheral zones. Total insect damage on fruit at harvest varied from 1.3 to 3.8% in experimental plots, and from 0.4 to 5.0% in reference plots.

Physical Control

The life-cycle of C. nenuphar can be interrupted by laying a barrier underneath the canopy of apple trees so that the larvae cannot pupate in the soil (Benoit et al., 2006). However, such a method cannot prevent damage to the fruit in the year of production. To achieve control, it must be deployed over several consecutive years. The deployment of such a barrier also exerts an entomocidal effect on the apple sawfly, H. testudinea, and herbicidal effects on a number of weeds.


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Alston DG; Stark AV, 2000. Plum curculio biology and distribution in Utah. Plum curculio biology and distribution in Utah. Logan, USA: Utah State University.

Armstrong T, 1958. Life-history and ecology of the plum curculio, Conotrachelus nenuphar (Herbst.) (Coleoptera: Curculionidae), in the Niagara Peninsula, Ontario. Canadian Entomologist, 90(1):8-17.

Bélair G; Vincent C; Chouinard G, 1998. Foliar sprays with Steinernema carpocapsae against early-season apple pests. Journal of Nematology, 30(4, supplement):599-606.

Benoit DL; Vincent C; Chouinard G, 2006. Management of weeds, apple sawfly (Hoplocampa testudinea Klug) and plum curcuclio (Conotrachelus nenuphar Herbst) with cellulose sheeting. Crop Protection, 25(4):331-337.

Blanc JPR le; Hill SB; Paradis RO, 1984. Oviposition in scout-apples by plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), and its relationship to subsequent damage. Environmental Entomology, 13(1):286-291

Booth DC; Phillips TW; Clpsson A; Silverstein RM; Lanier GN; West JR, 1983. Aggregation pheromone components of two species of Pissodes weevils (Coleoptera: Curculionidae): isolation, identification, and field activity. Journal of Chemical Ecology, 9(1):1-12

Butkewich SL; Prokopy RJ, 1993. The effect of short-range host odor stimuli on host fruit finding and feeding behavior of plum curculio adults (Coleoptera: Curculionidae). Journal of Chemical Ecology, 19(4):825-835

Butkewich SL; Prokopy RJ, 1997. Attraction of adult plum curculios (Coleoptera: Curculionidae) to host-tree odor and visual stimuli in the field. Journal of Entomological Science, 32(1):1-6; 18 ref.

CABI/EPPO, 1998. Distribution maps of quarantine pests for Europe (edited by Smith IM, Charles LMF). Wallingford, UK: CAB International, xviii + 768 pp.

CABI/EPPO, 2002. Conotrachelus nenuphar. Distribution Maps of Plant Pests, No. 47. Wallingford, UK: CAB International.

Chapman PJ, 1938. The plum curculio as an apple pest. New York State Agricultural Experiment Station Bulletin 684, 1-75.

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