Article

"Ecology and management of , nenuphar [Coleoptera :], in orchards"

G. Racette, G. Chouinard, C. Vincent et S.B. Hill Phytoprotection, vol. 73, n° 3, 1992, p. 85-100.

Pour citer cet article, utiliser l'information suivante :

URI: http://id.erudit.org/iderudit/706025ar DOI: 10.7202/706025ar Note : les règles d'écriture des références bibliographiques peuvent varier selon les différents domaines du savoir.

Ce document est protégé par la loi sur le droit d'auteur. L'utilisation des services d'Érudit (y compris la reproduction) est assujettie à sa politique d'utilisation que vous pouvez consulter à l'URI https://apropos.erudit.org/fr/usagers/politique-dutilisation/

Érudit est un consortium interuniversitaire sans but lucratif composé de l'Université de Montréal, l'Université Laval et l'Université du Québec à Montréal. Il a pour mission la promotion et la valorisation de la recherche. Érudit offre des services d'édition numérique de documents scientifiques depuis 1998. Pour communiquer avec les responsables d'Érudit : [email protected]

Document téléchargé le 13 février 2017 05:11 Ecology and management of plum curculio, Conotrachelus nénuphar [Coleoptera: Curculionidae], in apple orchards

Gaétan Racette1'3, Gérald Chouinard1'4, Charles Vincent2, and Stuart B. Hill1

Received 1991-12-27; accepted 1992-11-10

Plum curculio {Conotrachelus nénuphar) is a native pest of pome and stone fruit in eastern North America. It is a key pest of apple { pumila) orchards in Québec. In spring, adults disperse primarily from woodland overwintering sites to apple orchards. Before fruit set, the are mainly nocturnal. As fruits become available for oviposition, adults extendtheir activity to the daytime. Full grown larvae found in dropped in June (June drop) enter the soil to pupate. The summer brood émerges in August, feeds on the remaining fruit throughout the fall and then disperses to suitable overwintering sites. Little is knownofitscommunity and host plant relationships, dispersai behavior,factors influencing its mode of locomotion, choice of food sources, overwintering sites, micro-habitat sélection, orientation, and action threshold. Commercially availa­ ble biocontrol agents are not effective, and convenient and reliable monitoring techniques for the timing of sprays hâve not been developed. However, récent field and insectary studies on the behavior and activity of plum curculio adults may allow us to improve the efficiency of control stratégies. Thèse findings are presented hère, together with their implications for control of the plum curculio by modifying its habitat, and by better timing and location of sprays and other interventions. Thispaperalsoincludesbriefreviewsofbiological controls, growth regulators, and genetic controls for plum curculio. Racette, G., G. Chouinard, C Vincent, and S.B. Hill. 1992. Ecology and manage­ ment of the plum curculio, Conotrachelus nénuphar [Coleoptera: Curculioni­ dae], in apple orchards. PHYTOPROTECTION 73: 85-100. Le charançon de la prune {Conotrachelus nénuphar) est un insecte originaire de l'Amérique du Nord. Il s'attaque aux fruits à pépins et à noyaux de l'est des États- Unis et du Canada. Il est un ravageur prépondérant en vergers de pommiers {Maluspumila) au Québec. Au printemps, les adultes se déplacent de leurs sites d'hibernation, localisés principalement dans les boisés, vers les vergers. Avant la nouaison, l'activité de ces insectes est surtout nocturne, mais elle s'étend à toute la journée dès l'apparition des fruits. Les larves quittent le fruit au moment de la chute physiologique, et la pupaison s'effectue dans le sol. La nouvelle génération d'adultes apparaît en août, et se nourrit de fruits jusqu'à l'automne,

1. Department of Entomology, Macdonald Campus of McGill University, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Québec, Canada H9X 3V9 2. Station de recherches, Agriculture Canada, 430 boul. Gouin, Saint-Jean-sur-Richelieu, Québec, Canada J3B 3E6 3. Current address: Station de recherches, Agriculture Canada, 430 boul. Gouin, Saint-Jean-sur- Richelieu, Québec, Canada J3B 3E6. Contribution No. 335/92.09.02R 4. Current address: Service de phytotechnie de Saint-Hyacinthe, Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec, 3300, rue Sicotte, Saint-Hyacinthe, Québec, Canada J2S 7B8

85 puis retourne vers les sites d'hibernation. Plusieurs éléments de la bio-écologie du charançon sont méconnus, notamment les relations entre l'insecte et l'hôte, le comportement, la dispersion, le mode de déplacement, la reconnaissance des plantes hôtes et des sites d'hibernation, l'orientation, et les seuils économiques. Il n'existe actuellement aucune méthode fiable pour dépister ce charançon, et aucun moyen biologique de lutte contre ce ravageur. Cependant, des études récentes sur le comportement et l'activité du charançon de la prune en condi­ tions semi-naturelles et naturelles pourraient permettre le développement de stratégies de lutte plus efficaces. Ces travaux sont présentés ici de même qu'une revue des méthodes de lutte (chimique, biologique, génétique, mécanique et culturale) envisageables contre le charançon de la prune.

INTRODUCTION king technique, using the radioisotope 65Zn (Lafleur et al. 1985) has made possi­ Québec commercial apple {Maluspumila ble the study of the behavior of large Mill.) orchards harbor a complex entomo- numbers of adults in the field. The design fauna including9keypests, 15secondary ofimprovedactographshasenabledusto pests and 17 occasional pests (Vincent study adult activity in a field insectary and Bostanian 1988). Amongthekeypests (Racette et al. 1990). Previous behavioral is America's native plum curculio (Cono- studies relied largely on tree tapping, trachelus nénuphar Herbst), which at- rearing cages, and visual observations. tacks pome and stone fruits throughout Lafleur and Hill (1987) and Lafleur et al. most of its geographical range, often ran- (1987) described the plum curculio's king first or second in term of potential spring, fall and within-orchard pattern of économie damage if left unchecked (Hoyt dispersai. Chouinard (1991), Chouinard et et al. 1983). From 1977 to 1989, damage a/.(1992b),Owensefa/.(1982),and Racette by this insect at harvest was usually be- et al. (1990, 1991) described within-tree low 1% in Québec commercial apple or­ activity. Thèse significant contributions chards, whereas damage in unsprayed provide the basis for several new control orchards varied between 6 and 85% approaches. (Vincent and Roy 1992). Within 1-3 yr after The séminal paper by Quaintance and cessation of pesticide spraying, plum Jenne(1912) remains an invaluable sour­ curculio populations invariably return to ce of information aboutthe plum curculio's levelsof économie importance (Glass and synonymy, distribution, developmental Lienk 1971; Hagley étal. 1977; Hall 1974). stages, life history, habits, host plants, The main control tactic is to apply an natural enemies, and control measures. insecticide treatment at fruit set, or after Other key papers include Chapman's the first plum curculio oviposition scar is (1938) observations of plum curculio in observed (Prokopy 1985). New York apple orchards, and Smith and Flessel's( 1968) studies of hibernation and Progress in understanding the plum winter mortality, duration of diapause, curculio's behavior and ecology has been émergence from hibernation and time of hampered by its cryptic coloration, noc- arrivai in host trees. Paradis (1956b) and turnal behavior,thanatosis (Wigglesworth Armstrong ( 1958) hâve described the bio- 1953), apparent lack of any pheromone, logy of the plum curculio in Québec and limited visual and olfactory responses, Ontario respectively. Holloway (1977) and the associated lack of adéquate moni- provides a list of papers published be­ toring techniques. Consequently, plum tween 1911 and 1972. Le Blanc (1982) curculio has remained the least known of reviewed the literature up to 1982. the key North American fruit pest (Hoyt et al. 1983; Whalon and Croft 1984). In accordance with Roitberg and Ange- In the past décade, however, new infor­ rilli (1986) we believe that, with a better mation has accumulated concerning the knowledgeofthe behavior and ecology of ecology and behavior of the plum curcu­ the plum curculio, a réduction in the lio. The development of a reliable mar- amount of pesticides used is possible.

86 RACETTE ET AL.: PLUM CURCULIO IN APPLE ORCHARDS

Hère we review the literature on the life Spring and summer history, behavior, and ecology of this pest, The plum curculio is univoltine north of with particular référence to Québec apple Virginia and multivoltine (two and some- orchards, and discuss howthis new infor­ times a partial third génération) to the mation might be used to more effectively south (Schoene 1936). In southwestern control this . Québec apple orchards, the first adults émerge from hibernation when apples of cv. Mclntosh reach the «green tip» stage ECOLOGY AND BEHAVIOR date April), with populations peaking in the trees between mid-May (before tight Winter cluster stage) and early June (10 d after petal fall) (Paradis 1956b). Lafleur and Hill It has been claimed that adult plum curcu- (1987) observed that during that last pe- lios overwinter under leaves, grass roots, riod, the beetles moved the greatest dis­ dried grass, trash, honey suckle growth, tance per day. This high rate of movement pruning piles alongditchbanks, nearorin lasted until late June (June drop). Else- orchards, woodlots, brush land, fence where, the highest population densities rows and stone walls (Bobb 1949; Chap- hâve been recorded 1-2 wk after petal fall man 1938; Quaintance and Jenne 1912; (Chapman 1938; Cox 1951; Garman and Whitcomb 1929). Récent detailed studies Zappe 1929; Quaintance and Jenne 1912; in Québec, however, hâve failed to find Smith and Flessel 1968; Snapp 1930; beetles in most of thèse locations. Forest Whitcomb 1929). Thèse high population with a thick layer of fallen maple (Acer densities last for about 20 d and then saccharum Marsh) leaves constituted the décline rapidly, reaching their lowest le­ favorite overwintering site (Lafleur et al. vels in early August (Armstrong 1958; 1987). Thèse sites are characterized by Lafleur 1985), when most of the popula­ high relative humidity and low air move- tion has pupated in the soil. ment. Such conditions minimizethe risks of desiccation, particularly in spring Before mid-May, adult plum curculios (Garman and Zappe 1929; Smith and Fies- are inactive or walk slowly within their sel 1968). Higher winter mortality is as- overwintering sites (Lafleur and Hill 1987). sociated with orchard turf (Lafleur et al. Throughout its geographical range, 3to 4 1987), grass litter (Bobb 1949) and bare d of favorable climatic conditions, inclu- soil (Smith and Flessel 1968). Winter mor­ ding rain (Bobb 1949; Garman and Zappe tality was 85-96% in orchard turf compa- 1929; Lathrop 1949) and the reaching of red with 24-58% in thick litter in an adja­ certain température thresholds (Table 1 ), cent deciduous forest (Lafleur et al. 1987). trigger spring émergence and dispersai. McGiffen and Meyer (1986) found that However, before the tight cluster stage, high températures induced higher mor­ an increase in mean température does tality in diapausing adults; 90% of dead not elicit rapid dispersai (Lafleur and Hill collected in spring were infected 1987). Waterlossmayinhibit adult disper­ by the fungal pathogen Beauveria bassi- sai (Smith and Flessel 1968). Although ana (Balsamo) Vuillimen. Lafleur et al. spring émergence may extend over 3-4 (1987) also found plum curculios infected wk(Lafleur and Hill 1987), upto 60% of the by in spring in rear- population hâve been observed to émer­ ing boxes within a deciduous mixed for­ ge on a single day, with maies emerging est. Reproductive diapause isterminated slightly earlier than females (Smith and before the end of winter, following pro- Flessel 1968). The movement of plum longed exposure to low températures curculios from the ground into host trees (McGiffen and Meyer 1986; Smith and is a graduai process, and massive arrivai Flessel 1968). Long days are not required on apple trees on a single day has not for completion of diapause termination been observed. Smith and Flessel (1968) (McGiffen and Meyer 1986). Plum curcu­ suggested that this prolonged build-upof lios that émerge from hibernation hâve plum curculio populations in host trees low fat levels (Smith and Flessel 1968), results from a physiological adjustment and must feed on a suitable host for the required to induce dispersai after plum maturation of their ovaries (Smith and curculio émergence. McGiffen and Meyer Salkeld 1964). (1986) attributed the lag between emer-

87 Table 1. Climatic factors related to spring dispersai of the plum curculio

Factor Effect Condition Région Référence

Mean daily induces spring between 10.8-15.6 Québec Paradis 1956b température émergence Ontario Armstrong 1958 (X) induces spring 12.8-15.6 Arkansas, Georgia, Quaintance and Jenne 1912; Snapp 1930; dispersai for 3-4 d Maine, Maryland, Chapman 1938; Graham 1938; Michigan, New York, Lathrop 1949 Pennsylvania

Maximum induces spring 21.1 for 1d Massachusetts, McGiffen and Meyer 1986 Température dispersai New York (<£) 23.9 for 1 d Massachusetts Whitcomb 1929 23.9 for 2-3 d New York Chapman 1938

Soil induces spring 13.3-13.9 at 2.5 cm Québec Paradis 1956b température émergence 10 at 7.6 cm Virginia Bobb 1949 (°C)

Soil increases spring high Connecticut, Maine Lathrop 1949; Garman and Zappe 1929 humidity émergence Ontario Armstrong 1958

Atmospheric inhibits flight >17 North Carolina McGiffen and Meyer 1986 saturation inhibits spring high New York Smith and Flessel 1968 déficit (mm Hg) dispersai

Relative induces spring >50 New York Smith and Flessel 1968 humidity (%) émergence

genceandappearanceinhosttreeseither The mean speed of spring dispersai is to sampling error associated with tree characterized by a séries of peaks that tapping or to a delay in the occurence of coïncide with the phenological stages of suitable environmental conditions (tem­ apple trees (Lafleur and Hill 1987). The pérature and vapor pressure déficit) for curculios exhibitedtheirgreatest speed of flight. Theyconcludedthat once tempéra­ dispersai (4.4 m perd) between 10and 16 ture reached or exceeded the threshold June (fruit set) when 697 degree-days required for adultactivity, low vapor pres­ (above a base of 0°C) had been accumula­ sure déficits would elicit a spring disper­ ted. High speed of dispersai (3.3 m per d) sai flight. Chouinard (1991) also found was also observed atthe beginning of the that variations in total activity was related fall dispersai period (Lafleur et al. 1987). to air saturation déficit. Le Blanc (1982) Lafleur and Hill (1987) concluded that the noted the poor flying ability of plum cur­ speed of dispersai before fruit S€ît is in- culio, and Owens et al. (1982) concluded fluenced by accumulated heat units, but that plum curculio rarely . However, not by small fluctuations in température. Whitcomb (1929) stated that the plum Variations in daily activity within caged curculio was a strong flyer and, R. Blan- trees also appeared to be related to phe- chet (personal communication) intercept- nology (Chouinard 1991; Racette et al. ed 80% of dispersing plum curculios on a 1991). large screen trap, and only 20% in gutter pitfall traps, both installed in spring be­ Upon arrivai in the orchard, the adults tween a forest (overwintering site) and an may congregate in approximately equal adjacent apple orchard. Plum curculios numbers of maies and females within landed on the screen as high as 2 m above the ground cover at the base of the fruit ground level. Chouinard (1991) conclud­ trees in the orchard perimeter rows ed that dropping, crawling and flying are (Chouinard 1991; Lafleur and Hill 1987). ail important means of dispersai. Sounds produced by both sexes (Mampe

88 RACETTE ET AL.: PLUM CURCULIO IN APPLE ORCHARDS

and Neunzig 1966) are possibly the cause is also known that air movement within for thèse aggregations. The evolutionary végétation sometimes inhibits insect acti­ significance for this behavior is yet to be vity (Shaw 1982). Furthermore, access to determined. apples, their main food in the trees, may produce physiological changes in the plum In spring duringtreeinvasion,theadults curculio that reduce its susceptibility to frequently return to the ground, probably desiccation (Johnson 1969). Availability in response to changes in température of native hosts that bear fruit earlier than and humidity (Chouinard 1991; Lafleur commercial applecultivarsmayfavorany and Hill 1987; Racette et al. 1991; Smith physiological adjustment required for and Flessel 1968). A study conducted in a heightened dispersai activity. A few days southwestern Québec apple orchard re- before June drop, both within-host tree vealed that at full bloom, the beetles mo- movements and diurnal activity decreased vedlittle, butwhenmovementsoccurred, (Lafleur and Hill 1987; Racette et al. 1991). they happened in late afternoon and at night (Chouinard et al. 1992b; Racette et Plum curculio apparently moves little al. 1991). They moved into the trees dur- from tree to tree (Rings 1952; Snapp 1940; ing evening when the wind had dropped Steiner and Worthley 1941). In spring, and the humidity had increased. At petal however, some individuals hâve been fall,theywererelatively inactive intheday observed to move 146 m in 10 d and 205 and active at night, even at low tempéra­ m in 40 d (Rings 1952; Snapp 1940). A tures. At that time, Owens et al. (1982) quantitative study revealed that 42% of observed that under central Massachus- released beetles (111 of the 264 recaptu­ sets conditions, plum curculios were ac­ res) remained on the same standard ap­ tive within hosttrees during the daytime; ple trees over a 65-d period starting at but no observation was made at night. As apple bloom (Lafleur and Hill 1987). After the season progressed, they moved into their dispersai from overwintering sites, the trees for increasingly longer periods the first plum curculios to arrive at the and extended their activity period to day­ border row of apple trees were those that time (Racette et al. 1990, 1991). Rate of subsequently moved furthest within the movementwaspositivelyrelatedtomean orchard (Lafleur and Hill 1987). Early cul­ daily air température, but some activity tivars throughout the orchard and young persisted at températures as low as 1°C. fruits were also preferentially attacked. Owens et al. (1982) also observed that in Beetles hâve been recovered from trees the evening, the frequency and speed of not bearing fruit (Chapman 1938; Lafleur crawling increased with increasing tem­ and Hill 1987; Smith and Flessel 1968). pérature. Within-tree rate of movement Thèse findings support previous sugges­ was highest at fruit set when 50% of the tions that plum curculios are more active beetles were still active in the morning than was supposed (Calkins et al. 1976; (Racette et al. 1991), and at that time fe- Smith and Flessel 1968), and that most male plum curculios deposit about an trees within an orchard are subjected to equal number of eggs at night and during plum curculio exploration (Chapman the daytime (Crandall 1905; Quaintance 1938). After fruit set, dispersai activity and Jenne 1912). decreases gradually, apparently indepen- dently of population density (Lafleur and Dispersai within host trees (Racette et Hill 1987), probably as the need for food al. 1991), and withinthe orchard, probably and oviposition sites are met. Mating has occurs in response to foliage develop- been observed as plum curculios congre- ment and to the associated within-tree gate in the host trees (Smith and Salkeld decrease in air movement and increase in 1964), in apple blossoms on warm spring humidity. This is probably because plum days (Le Blanc 1982), and on the ground curculio's need for humid conditions is under the trees (Stuart B. Hill, unpub- critical at this time (Garman and Zappe lished data). Adults may copulatethreeto 1929; Smith and Flessel 1968). This is four times during the oviposition period further supported by Lafleur and Hill's ( Armstrong 1958), wh ich sta rts at f ru it set (1987) observation that the plum curculio (late May in Ontario, Armstrong 1958, or exhibited a préférence for early cultivars early June in Québec, Paradis 1956b) when with dense foliage, even before fruit set. It the fruit is as small as 6 mm in diameter

89 (GarmanandZappe1929).lnQuébec,egg appearance of thèse scars atfruit maturity laying continues intensively for 3 wk until vary among cultivars (Chapman 1938). early July (Paradis 1956b), and then dé­ Oviposition damage iseconomically more clines abruptly, with relatively few eggs importantthan feeding damage. It is diffi- beinglaiduntiltheterminationofoviposi- cult to assess the true impact of plum tion in early August (Armstrong 1958; curculio on «June drop» because this Paradis 1956b). phenomenon overlaps with natural fruit abeission. In heavy crop years, such thin- Timing of the onset of oviposition is ning protects the trees from overbearing affected by température, size and rate of (Howard 1906). Larvae eat out irregular growth of the young apples, and possibly cavities in the apple and, in extrême cas­ the physiological state of the plum curcu- es, reduce the fruit to a frass-filled shell lio (Lathrop 1949). Oviposition rate is di- (Chapman 1938). The fourth instar rectly related to température (Lathrop remains in the fallen fruit for a few days, 1949), but the daily oviposition patterns makes an exit hole, and then leaves the are apparently unaffected by température fruit to burrow into the soil to pupate fluctuation (Owens et al. 1982; Whitcomb (Quaintanceand Jenne 1912). Emergence 1929). Females lay eggs singly in young of larvae from fallen apples increases af- apples and eut a distinctive crescent- terrainfall,atwhichtimetemperaturehas shaped flap that will prevent the emerg- no effect (Lathrop 1949). At other times, ing larva from being crushed by the rapid- heat from direct exposure to the sun may ly developing apple (Armstrong 1958; resuit in larval death within the fallen Chapman 1938; Quaintance and Jenne apples. Emerged larvae move around for 1912). In Québec, Paradis (1956b) found 30 to 50 min as if searching for a suitable that females lay an average of 73 eggs. place to enter the soil. They pupate at a Damaged fruit are most abundant in tree depth of 1-8 cm (Quaintance and Jenne rows adjacent to woodlots (Chapman 1912). After 1 mo, starting in July,, a new 1938; Garman and Zappe 1929; Le Blanc génération of adults émerges, with peak et al. 1984; Quaintance and Jenne 1912). émergence occurring in August in south­ Towards the center of the orchard, plum ern Québec (Paradis 1956b). Moisture is curculio damage is usually less severe. required for plum curculios to enter, pu­ Fruit in the upper part of trees tend to be pate, and escape from the ground (Chan- attacked more thanthose in the lower part dler 1932). Adult émergence increases (Calkins étal. 1976; Le Blanc étal. 1984), after rainfall (Armstrong 1958; Neiswan- but there is no différence in level of at- der 1948; Quaintance and Jenne 1912) tack with respect to compass direction and also after a few days of high tempér­ (Le Blanc et al. 1984). atures (26-29°C) (Lathrop 1949). Develop­ ment from egg to adult takes 50 to 55 d The egg stage lasts from 3 to 12 d at (Armstrong 1958; Paradis 1956b). mean daily températures of 25 to 18°C respectively (Paradis 1956b). Larvaespend Fall 15(Armstong1958)to18d (Paradis 1956b) Newly emerged adults feed on apples, in the fruit. Pectic enzymes and cellulase, both on the trees and on the ground, by released by the larvae as they feed on the digging cavities underthe skin with their fruit (Levine and Hall 1978a, 1978b), resuit beak. The apple skin around the holes in prématurédroppingofthe infestedfruit eventually blackens. Thèse feeding cavi­ (Whitcomb 1932) before it reaches3cm in ties may harborone or more adults. When diameter (Levine and Hall 1977). This adults hâve storedsufficientfattheycease «June drop» occurs at différent times in feeding and seek suitable hibernation si­ June in the USA (Chapman 1938) and tes (Smith and Salkeld 1964). during the last week of June in southern Québec (Paradis 1956b). Larvae in apples Migration from the orchard to hiberna­ that do not fall at this time are usually tion sites occured from early September crushed by the growing fruit tissue (Para­ to the end of October (Lafleur and Hill dis 1957; Quaintance and Jenne 1912). 1984; Lafleurefa/. 1987). The farthest dis­ Apples with egg-laying and feeding scars tance covered during fall dispersai was that remain on the trees become further 142m(LafleurandHill1987).Thefirststep deformed as they mature. The size and in plum curculio dispersai may involve

90 RACETTE ET AL.: PLUM CURCULIO IN APPLE ORCHARDS

orientation towards high tree silhouettes et al. 1983; LeRoux 1961; Prokopy et al. at the edge of an adjacent woodlot, al- 1980), especially on early cultivars. Re- though the prédominant direction of mo- commendations following positive scar vement is not always oriented towards identification dépend upon previous in- thenearestwoodlotorthehighestskyline festation history and on the characteris- point (Lafleur et al. 1987). This suggests tics of the surrounding environment that other factors such as celestial eues (proximity of neglected orchards, natural (sun, moon, stars) and the magnetic field hosts, potential overwintering sites). of the earth may influence adult dispersai However, such scars are only détectable (Lafleur et al. 1987). Celestial eues for mi­ several weeks after the arrivai of plum gration (Wehner 1984), magnetic sensiti- curculio within orchards, and this may be vity (Gould 1984), and compass sensé of too late to achieve optimal control (Le orientation (Baker and Mather 1982; Blanc et al. 1984). An efficient and reliable Schmidt-Koenig 1979) hâve been repor- monitoring technique or device, and its ted as navigational eues in other insect associated économie threshold, are still species. Lafleur étal. ( 1987) consideredthat lacking. Limb jarring is not popular in wind direction is unlikely to be responsi- integrated pest management (IPM) pro- ble for the orientation of the adults. grams because it can be inaccurate, in­ convénient and can cause tree damage. The second step in dispersai, explora- Samples obtained by limb jarring can tory behavior, occurs at the edge of an varywithtimeofday,timeofyear(Racette adjacent deciduous woodlot. The adults et al. 1990) and skill of the field scout. initially moved along the forest edge and, Among the 15 monitoring déviées tested searched for an area with a thick layer of by Le Blanc (1982), Le Blanc et al. (1981), dead leaves about 3-5 m inside the woo­ and Radke (1982) none succeeded in dlot (Lafleur et al. 1987). When the subs­ catching enough adult beetles to be suffi- trate was unsuitable (e.g., thin deciduous ciently reliable for use in an IPM program. or any thickness of coniferous litter), they Inspection of Granny Smith1 apples placed returned to the orchard and hibernated in in the trees prior to fruit set for egg laying the turf beneath the apple trees (Lafleur et scars has been used to detectthe earliest al. 1987). When leaf litter approximates présence of ovipositing females in the the normal cover in undisturbed deci­ trees by Le Blanc et al. (1984). Thèse ap­ duous woods or when 1-5 cm thick of ples must be installée! in the upper crown straw is available, the plum curculio re­ level of standard trees, and careful fré­ mains between the ground and the leaf quent examination is required to detect cover (Armstrong 1958; Lafleur et al. 1987; oviposition scars. Smith and Flessel 1968; Snapp 1930). When the litter layer is thin or absent Sélection of monitoring sites should (grass, bare soil) and the adults hâve no- take into account that 1) plum curculio where else to overwinter, some penetrate attack is greater in the upper level of the as deep as 5 to 8 cm into the soil (Arm­ trees (Calkins et al. 1977; Le Blanc et al. strong 1958; Bobb 1949; Smith and Fles­ 1984), 2) early cultivars with dense foliage sel 1968). Some adults enter loose soil, attract overwintered plum curculios befo- even when the litter is thick (Lafleur et al. re fruit set (Lafleur and Hill 1987), 3) dam­ 1987). Unlike many other beetles, plum age is more severe in tree rows adjacent curculiosarenotgregariousinthefalland to woodlots, and 4) before petal fall, plum winter (Lafleur et al. 1987; Smith and curculios may occur individually and in Flessel 1968). clusters on the ground under the rows of apple trees adjacent to woodlots or other overwintering sites. Interception traps, MANAGEMENT STRATEGIES located between an overwintering site and the orchard, might prove effective in Monitoring techniques catching plum curculio duringtheirspring The présent method of monitoring adult dispersai. plum curculio in commercial orchards is limited to the examination of several Although no pheromone has been thousand apples at fruit set for évidence identified, Alm and Hall (1986a)foundthat of fresh feeding or egg laying scars (Hoyt some sensory structures of plum curculio

91 antennae are similarto known pheromo- orchards, can greatly reduce fruit damage ne receptors in other . Conse- in commercial orchards (Alm and Hall quently, chemical communication be- 1986b; Maier 1990; Prokopy et al. 1990). If tween plum curculios and détection of earlycultivarsofexoticfruitsandvarieties host plants should be investigated further of native host plants are présent they can both to elucidate mechanisms involved provide females with the food required and help in the development of an effec­ forovarian maturation and for the physio- tive plum curculio monitoring technique. logical adjustment necessary to survive harsh spring conditions priorto dispersai Cultural control measures (Smith and Flessel 1968). Maier (1990) Cultural controls encompass an array of lists 19 exotic and native fruit tree hosts of techniques that were widely used before the plum curculio in the northeastern USA. the advent of synthetic insecticides. They Habitatmanagementshouldbeperformed include habitat management, sanitation, for a distance of at least 162 m from the and apple cultivar préférence. They can border of the orchard. This was the far- contribute to reducing curculio popula­ thest distance from an orchard recorded tions and are an essential component of foranadultduringfall dispersai (Lafleur et an effective IPM program. Their impor­ al. 1987). This is similar to the 200 m tance has been stressed in Hill's (1984, habitat management zone recommended 1990a) approachtoecological pest mana­ by Prokopy et al. (1990) for second-stage gement through the redesign of agroeco- IPM programs. system and Prokopy efa/'s( 1990) second stage IPM program. Both approaches are Sanitation heavilydependentonaccesstoadetailed Recommended sanitation measures, such knowledge of the pest's behavior and as removing stone walls and stone piles biology (Chouinard et al. 1992a, b; Lafleur (Bobb 1949; Chapman 1938; Graham and Hill 1987; Lafleur et al. 1987; Racette et 1938), are unlikely to be effective in south- al. 1991). ern Québec because Lafleur et al. (1987), using labeled beetles, found no plum Habitat management curculio in eitherofthese locations. Discing New orchards should be established as deeper than 5 cm, especially under the far as possible from a forest, or isolated tree canopy, for several weeks after petal from woodlots by plants that are rejected fall has been recommended to kill pupae as overwintering sites or in which winter or expose them to unfavorable weather mortality is high (open fields with grass and natural enemies (Howard 1906; Slin- litter or bare soil, or coniferous borders). gerland and Crosby 1914; Snapp 1923, Established orchards next to forests 1931; Woodside 1935). might be protected by manipulating their borders. Modifications of the habitat to Removal of wormy fruit that hadfallen create warmer microclimates with drier onto the ground was once a common conditions might also be detrimental to control practice for plum curculio (Bethu- winter survival of plum curculio, because me 1907; Chandler 1940; Chapman 1938; of its need for conditions of high relative Howard 1906;QuaintanceandJenne 1912; humidity duringthisperiod(Garmanand Smith 1948; Snapp 1931; Snapp and Zappe 1929; Lafleur et al. 1987; Smith and Thompson 1931). The fruit was destroyed Flessel 1968), and because highertempe- by burying it (Snapp 1923, 1931; Snapp ratures hâve been found to increase mor­ and Thompson 1931), by dumping it into tality in diapausing adults (McGiffen and large bodies of water (Snapp 1923; Snapp Meyer 1986). andThompson 1931),bysubmergingitin boiling water (Snapp 1931), by burning it An alternative control tactic is to create (Snapp 1923) or by raking it into the sun an overwintering site so favorable that it (Slingerland and Crosby 1914), sothatthe attracts most of the weevils, which are larvae were killed by excessive heat then killed by application of a pesticide (Crandall 1905; Quaintance and Jenne (chemical or biological). 1912). Fallen apples can be collected with Sélective removal of wild hosts (Ame- modified golf bail picking machines, and lanchier sp., Prunus sp., and destroyed by composting them (Hill sp.), and of neglected apple trees and 1990b). Ground feeding birds (Quaintan-

92 RACETTE ET AL.: PLUM CURCULIO IN APPLE ORCHARDS

ce and Jenne 1912) and hogs (Petch 1927) Chapman 1938; Paradis 1956a; Wylie hâve also been used to destroyfallen fruit 1951 ). No accurate data are available, but in unsprayed orchards. Properly pruned Chapman (1938) estimated that jarring trees that allow the sun and wind to pene- can resuit in a 1 to 36% decrease in fruit trate into the canopy could create less damage. Jarring is time consuming, favorable conditions for both adult activi- however, and is not practical for large ty(LafleurandHill 1987; Racette efa/. 1991) orchards with standard trees. Furthermo- and larval development and activity (Slin- re, losses due to fruit falling mayoccur. In gerland and Crosby 1914). small orchards planted with dwarforsemi- dwarf rootstocks, it remains a valuable Apple cultivar préférences means of control. Racette et al. (1990) Early apple cultivars usually hâve dense found the most productive time for tap- foliage and produce flowers and fruit soo- ping apple tree branches was between ner than other cultivars. They are therefo- 06:00 and 09:00 at petal fall stage. At fruit remoresubjectedtoplumcurculioattack, set, however, the number of captures re- partly because they provide better cover mained relatively high from 09:00to 01:00. against natural enemies and adverse cli- matic conditions, and because they pro­ Chemical controls vide food at a critical period when alter­ Insecticides are still the most efficient native sources are scarce. Many studies controls for plum curculio. Since the ad- reported that the early cv. Melba, which vent of synthetic chemicals, a number of has a particularly dense foliage, harbored products hâve been used against adults, a greater number of plum curculio adults namely nerve poison insecticides and in- in spring than the cv. Mclntosh (Lafleur sect growth regulators. Insecticide résis­ and Hill 1987; Racette 1988; Whitcomb tance has not yet been reported in plum 1929). curculio. Alm and Hall ( 1986b)foundthat mostof Insecticides the crabapple cultivars that are résistant Two insecticidal sprays are usually re- to plum curculio, are also résistant to commended to control the adult plum apple scab, cedar apple rust, powdery curculio in the USA. A spray at petal fall mildew and fire blight. The cultivars Or- ideally is applied within hours of detec- miston Roy and Donald Wyman suffered ting the first oviposition scar of a plum less than 4% damaged fruit at the end of curculio. A second spray (first cover) is the plum curculio'segg-laying period. Lack applied 10 d after the latter if substantial of oviposition stimulants, and présence of rainfall had occured, and 14 d later if repellent or antibiotic chemicals may ac- conditions are relatively dry (Prokopy countforthenon-preferenceof thèse cul­ 1985). In Québec apple orchards, the first tivars. Fruit size is unlikely to be an im­ spray is applied at petal fall (between 30 portant factor in the résistance mecha- May and 10 June) and, if necessary, a nism because plum curculios can breed second spray is applied 7 to 10 d later on plants with small fruit such as blue- (between 10 and 18 June) (Anonymous berry {Vaccinium sp.) and wild plum 1991; Paradis 1956a, 1979). {Prunus sp.) (Alm and Hall 1986b). With careful monitoring of the fruit for The development of late apple cultivars oviposition scars, and knowledge of pre- with a sparse foliage, and pruning, desi- vious location andtimeof plum curculio's gned to provide non-optimal conditions attacks, effective control may be achieved for plum curculio, may be helpful in the by applying insecticidal sprays only to planning of comprehensive IPM programs. those parts of orchards that are adjacent The use of early apple cultivars and other to suitable overwintering sites. It may still early flowering alternate hosts as trap be necessary, however, to spray the enti- trees should also be considered as part of re orchard once, and apply a supplemen- integrated control programs (Hill 1990b). tary spray along the edges of the orchard, or only where jarring and fruit examina- Mechanical control measures tion indicate high plum curculio infesta- Jarring was once used as the main control tion. Recently, border row sprays hâve measure for plum curculio mostly in small been found to be effective in achieving orchards in the USA (Chandler 1940; acceptable control (e.g., < 5% fruit dam-

93 âge atharvest)ofplumcurculio m a south- lio are fed on treated apples (Freednnan et ern Québec apple orchard (Chouinard et al. 1982). Under laboratory conditions, al. 1992a). Because most plum curculios pupation, egg hatch and larval develop- are active at night, and because suscepti- ment are adversely affected by diflub- bility to pesticides increases with the ac- enzuron [1-(4-chlorophenyl)-3-(2,6- tivityofthetargetspecies(Saunders1982), difluorobenzoyl)urea)](Calkinsefa/.1977), spraying should be done in early evening but soil treatments in orchards hâve been oratnight(Chouinardefa/. 1992a; Racette inconclusive. et al. 1990). Susceptibility of plum curcu- lio to pesticides also varies with the com- Genetic control pound used (Hall 1979; Neiswander 1948), Three approaches hâve been tried in the voltinism, âge of the adults (Snapp 1951) laboratory. First, Featherson and Hays and with the time of year (Smith 1954). (1971) crossed diapausing with non-dia- pausingstrainstoincreasethe proportion The discovery that plum curculio con- of non-diapausing individuals. The latter gregates on the ground, under the peri- are less likely to survive the winter. In a 6- meter rows of trees adjacent to overwin- yr study, Smith and Flessel (1968) recor- tering sites, suggests that control might ded more than 70% mortality in a multi- be achieved by applying insecticides in voltine strain reared in the laboratory and thèse areas, and to adjacent wild hosts released in hibernation cages. The morta­ and neglected orchards (Chouinard et al. lity was 100% in 4 of the 6 yr. Secondly, 1992a). However, if the product applied is Padula and Smith (1971) and Stevenson repellent, such as lead arsenate (Quain- and Smith (1961), by crossing univoltine tance and Jenne 1912; Whitcomb 1932), and multivoltine individuals, were able to some insects may avoid treated areas cause accelerated degeneration of sper- (Gould 1991), and infestthe unprotected matozoae in the spermathecae, and redu- central zone. To kill individuals that dis­ ced oviposition and egg hatch. Thirdly, perse into orchards over several weeks the effect oftwochemosterilantalkylating (Lafleurand Hill 1987),the productshould agents (apholate and tepa) on both fecun- hâve a relatively long residual effect. dity and mortality of plum curculio hâve been tested in the laboratory (Roach and Pathogenic micro-organisms (bacteria, Buxton 1965). Reducedfecundity wasthe fungi, ) should be tested with most apparent effect when using a 10% this «border row treatment approach», because: Dtheycan persistlongerintheir (byweight) concentration. Thenumberof host's cadavers, and would allow for in- offspring produced by females were re- fested insects to act as a réservoir for duced by ca. 90% as compared to con- subséquent contamination , 2) they are trols. Among many mammalian hormo­ not known to be repellent, and 3) would nes and related compounds tested for hâve fewer négative effects on natural theirabilitytosterilizefemale plum curcu­ enemies, and probably be less detrimen- lios, colchicine was the most effective, tal to soil fauna (Lafleur et al. 1987). with no offspring being produced when it was included in the diet at a concentration Another chemical approach consists of of 0.02 % (by weight) (Hays and Cochran controlling, with organochlorine or orga- 1964). Jacklin et al. (1970) reported that 8 60 nophosphate insecticides applied to the krad of Co were enough for complète ground, the larvae as they leave the fruit sterilization of maies and females, and (Stelzer and Fluke 1958). Nowadays, this suggested that the stérile maie release approach seems promising with biologi- technique in the field was justified. Huet- cal control agents (Brossard and Hill 1990; telefa/.(1976)found,however,thatsperm Vincent and Bélair 1992). It has yet to be from the latest mating replaced that from tested for plum curculio in apple orchards. a previous mating. Thus, repeated re- leases of stérile maies would be required Insect growth regulators to maintain stérile mating in wild plum Amaytansinoid compounds (mainly curculio populations. So far, no manage­ trewiasine)from ethanol extracts of Trewia ment program has involved mass release nudiflora (Euphorbiaceae) seeds reduce of stérile individuals against the plum thenumberof progeny when plum curcu­ curculio.

94 RACETTE ET AL.: PLUM CURCULIO IN APPLE ORCHARDS

Table 2. Most important natural enemies of the plum curculio

Name Family Stage Comment Référence attacked

Parasitoids Anaphoidea conotracheli Girault Mymaridae egg widely distributed in Howard 1906; USA Quaintance and Jenne 1912; Snapp 1930 Aliolus rufus (Riley) Braconidae larva widely distributed Armstrong 1958 Aliolus curculionis Fitch Braconidae larva widely distributed Armstrong 1958 Triapsis kurtogaster Martin Braconidae larva observed in Québec Paradis 1956b only Microbracon mellitor Say Braconidae larva recorded in eastern Quaintance and Jenne 1912 USA Tersiocholus conotracheli (Riley) Ichneumonidae larva widely distributed Armstrong 1958; Quaintance and Jenne 1912 Myophasia aeneae Wiedemann larva attacks many weevils Armstrong 1958; Quaintance and Jenne 1912 Cholomyia inaequipes Bigot Muscidae larva attacks many weevils Armstrong 1958; Quaintance and Jenne 1912

Predators Chrysopa spp. Chrysopidae larva many species recorded Quaintance and Jenne 1912 Garmania bulbicola Owdms. Phytoseiidae larva recorded in New York Smith 1957 Lycosa gulosa Walckenaer Lycosidae adults recorded in Québec Lafleur ef a/. 1987 Bufo americanus americanus Holb. Bufonidae adults recorded in Québec Chouinard ef al. 1991 thrips Thripidae egg one species recorded Quaintance and Jenne 1912 ground beetles Carabidae adult gênerai insect feeders Howard 1906; Quaintance and Jenne 1912 ants Formicidae larva Howard 1906; Snapp 1930 fowls Phasianidae adult Quaintance and Jenne 1912 and larva

Pathogens Beauveria bassiana (Balsamo) adults mostly overwintering Lafleur et al. 1987; Vuillimen adults McGiffen and Meyer 1986

Bacillus thuringiensis var. adults isolated from adults Lafleur ef al. 1987 eniomocidus or subtoxicus Heimpel

Biological control ble biological control agents (Van Drie- Although a number of predators (Choui­ sche and Carey 1987) hâve been tested in nard étal. 1992a; Howard 1906; Lafleur et the field. The fungal pathogens Beauveria al. 1987; Quaintance and Jenne 1912; bassiana and Metarhlzium anisopliae Smith 1957; Snapp 1930), parasitoids (Metschnikoff) Sorokin caused high le- (Armstrong 1958; Paradis 1956a; Quain­ vels of mortality in larvae confined in pétri tance and Jenne 1912; Snapp 1930), and dishes and in cups containing soil. Under pathogens (Brossard and Hill 1990; La­ the same conditions, the Stei- fleur et al. 1987; McGiffen and Meyer 1986) nernema carpocapsae {=Neoplectana hâve been identified for plum curculio carpocapsae) Weiser was ineffective (Table 2), few of the commercially availa- (Tedders et al. 1982). Many adult plum

95 curculios infected with Bacillus thurin- 1992a). Habitat modification will proba- giensis Berliner var. subtoxicus and bly play an increasingly important rôle in Beauveria bassiana hâve been collected the long-term control of récurrent pest in thefield (Lafleur et al. 1987). Beauveria problems, including the plum curculio. bassiana is known to be particularly viru­ As with ail control stratégies, however, lent againstplum eu rculiowhen tempéra­ there are costs and benefits such that tures exceed 25°C (McGiffen and Meyer actions against one pest may influence 1986). Much work is needed to further the amount of damage caused by other evaluate the use of thèse potential path- pests (Prokopy et al. 1990; Roitberg and ogenic agents. Angerïlli 1986). The effectiveness of such In a preliminary study it was found that management approaches is limited by apple orchards treated with a formulation our knowledge of the entire pest System of Bacillus thuringiensis suffered seve- involved. rely from plum curculio attack (Reissig et al. 1984). Brossard and Hill (1990) con- ducted laboratory studies to détermine ACKNOWLEDGMENTS whetherornotnematodescouldkill plum curculio larvae as they enter the soil to Spécial thanks are extended to Dr. Nou- pupate. Among Steinernema feltiae (Fi- bar J. Bostanian, Agriculture Canada Re­ lipjev), S. carpocapsae (Weiser) and two search Station, Saint-Jean-sur-Richelieu, strains of Heterorhabditis bacteriophora Québec, Canada, for his support during Poinar,the Steinernema spp. appearedto the préparation of this paper and to Carole bethe most promising for use in commer­ Brodeur, for typing parts of the manu- cial orchards. Soil application would also script. hâve an impact on apple larvae, testudinea Kl ug (Vincent and Bélair 1992). REFERENCES

Alm, S. R., and F. R. Hall. 1986a. Antennal CONCLUSION sensory structure of Conotrachelus nénu­ phar (Coleoptera: Curculionidae). Ann. En- tomol. Soc. Am. 79: 324-333. Studies of plum curculio movements to Alm, S. R., and F. R. Hall. 1986b. Crabapple and from both apple orchards and over- cultivar préférences of the plum curculio wintering sites, and of its spring and fall Conotrachelus nénuphar (Herbst) (Coleop- behaviorwithin orchards and withintrees tera: Curculionidae). Fruit Var. J. 40: 83-87. provide a new basis for the management Anonymous. 1991. Pommier. Guide des trai­ of this pest. Approaches include manipu­ tements antiparasitaires. Conseil des pro­ lation of the environment, sélection of ductions végétales du Québec. 2 pp. less susceptible apple tree cultivars, and Armstrong,T. 1958. Life history and ecology of the plum curculio, Conotrachelus nénu­ better timing and targeting of sprays phar (Herbst) (Coleoptera: Curculionidae) (Chouinard et al. 1992a). Such manage­ in the Niagara Peninsula, Ontario. Can. ment tactics are particularly important in Entomol. 90:8-17. apple orchards because of the relative Baker, R. R., and J. G. Mather. 1982. Magnetic permanence of such agroecosystems. compass sensé in the large yellow under- Further improvements in control pro- wing moth Noctua pronuba L. Anim. Be- grams will dépend on gaining an even hav. 30: 543-548. better understanding of the relationships Bethume, C. J. S. 1907. Common insects af- between environmental conditions and fectingfruittrees. Ont. Dep. Agric.Bull. 158: the behavior and ecology of the plum 1-47. Bobb, M. L. 1949. Hibernation of the plum cur­ curculio. culio in Virginia. J. Econ. Entomol. 42: 19- In Québec, récent research hasfocused 22. on stratégies to control the plum curculio Brossard, J.-P., and S. B. Hill. 1990. Efficacité de deux espèces d'Heterorhabditis et de when it is invading thefirst border rows of Steinernema envers le charançon de la appletrees. Preliminary results using this prune, Conotrachelus nénuphar (Herbst) approach suggest that pesticide use can (Coleoptera: Curculionidae). Proc. Pest Man. be dramatically reduced (Chouinard et al. Soc. Can. 36: 101-104.

96 RACETTE ET AL.: PLU M CURCULIO IN APPLE ORCHARDS

Calkins, C. O., M. D. Huettel, and M. McKoy. Graham, C. 1938. The plum curculio. Md. 1976. Spatial and temporal distribution of Agric. Exp. Stn. Bull. 49: 309-345. oviposition by plum curculios, Conotra- Hagley, E. A. C, L. G. Monteith, D. H. C. Herne, chelus nénuphar. Fia. Entomol. 59:205-209 andR.Trottier. 1977. Pest population build- Calkins, C. O., A. J. Hill, M. D. Huettel, and E. R. up in apple orchards following omission Mitchell. 1977. Effect of diflubenzuron on of insecticide and acaricide sprays. Proc. plum curculio populations in laboratory Entomol. Soc. Ont. 108: 7-11. and field tests. J. Econ. Entomol. 70: 463- Hall, F. R. 1974. Bioeconomics of apple pests: 466.. costs appraisalofcropinjury data. J. Econ. Chandler, S. C. 1932. A seven year study of the Entomol. 67:517-521. plum curculio in southern Illinois. J. Econ. Hall, F. R. 1979. Effects of synthetic pyrethroids Entomol. 25: 101-106. on major insect and mite pests of apple. J. Econ. Entomol. 72: 441-446. Chandler, S. C. 1940. Control of plum curculio Hays, S. B. and J. H. Cochran. 1964. Evaluation on in Illinois. J. Econ. Entomol. 33: of compounds affecting the reproductive 451-453. potential of the plum curculio. J. Econ. Chapman, P. J. 1938. The plum curculio as an Entomol. 57: 217-219. apple pest. NY State Agric. Exp. Stn Bull. Hill, S. B. 1984. Ecological pest control, con- 684: 1-75. fronting the causes. Int. J. BioSoc. Res. 5:1- Chouinard, G. 1991. Spring field activity and 4. foraging behavior of plum curculio, Cono- Hill, S. B. 1990a. Pest control in sustainable trachelus nénuphar (Herbst), (Coleoptera: agriculture. Proc. Entomol. Soc. Ont. 121: Curculionidae), in insecticide treated and 5-12. untreated Québec apple orchards. Ph.D. Hill, S. B. 1990b. Plum curculio, the «hunch- thesis, McGill University, Montréal, Qué­ back» of the apple orchard. Macdonald J. bec. 238 pp. 51(1): 12-13. Chouinard, G., S. B. Hill, C. Vincent, and N. N. Holloway, R. L. 1977. A bibliography of the Barthakur. 1992a. Border row sprays for plum curculio, Conotrachelus nénuphar control of the plum curculio, Conotrachelus (Coleoptera: Curculionidae). S.C. Agric. Exp. nénuphar (Herbst), in apple orchards: a Stn. Tech. Bull. 1064: 1-14. behavioral study. J. Econ. Entomol. 85: Howard, L. O. 1906. The plum curculio. U. S. 1307-1317. Dep. Agric. Bur. Entomol. Cire. 73: 1-10. Chouinard, G., C. Vincent, S. B. Hill, and B. Hoyt, S. C, J. R. Leeper, G. C. Brown, and B. A. Panneton. 1992b. Cyclic behavior of plum Croft. 1983. Basic biology and management curculio, Conotrachelus nénuphar(Herbst) components for insect IPM. Pages 93-151. (Coleoptera: Curculionidae), within caged in B. A. Croft and S. C. Hoyt (eds.), Integra- dwarfappletrees in spring. J.InsectBehav. ted management of insect pests of pome 5: 385-394. and stone fruits. Wiley, New York. Cox, J. A. 1951. Plum curculio control on pru­ Huettel, M. D., C. O. Calkins, and A. J. Hill. nes. J. Econ. Entomol. 44: 499-504. 1976. Allozyme markers in the study of Crandall, C. S. 1905. The curculio and the ap­ sperm precedence in the plum curculio, ple. III. Agric. Exp. Stn. Bull. 98: 467-560. Conotrachelus nénuphar. Ann. Entomol. Soc. Am. 69: 465-468. Featherson, N. H., and S. B. Hays. 1971. Dia- pause in crosses of a laboratory and a wild Jacklin, S. W., E. G. Richardson, and C. E. Younce. 1970. Substerilizing doses of strain of the plum curculio, Conotrachelus gamma irradiation to produce population nénuphar. J. Ga. Entomol. Soc. 6: 96-101. suppression in plum curculio. J. Econ. En­ Freedman, B., D. K. Reer, R. G. Powell, R. V. tomol. 63: 1053-1057. Madriga, and C. R. Smith. 1982. Biological Johnson, C. G. 1969. Migration and dispersai activities of Trewia nudiflora extracts of insectsbyflight. Chaucer Press. London. against certain economically important in- 763 pp. sect pests. J. Chem. Ecol. 8: 409-418. Lafleur, G. 1985. Dispersai and overwintering Garman, P., and M. P. Zappe. 1929. Control behavior of plum curculio, Conotrachelus studies on the plum curculio in Connecticut nénuphar (Herbst), (Coleoptera, Curculio­ apple orchards. Conn. Agric. Exp. Stn. Bull. nidae) in southern Québec. Ph.D. thesis, 301:373-437. McGill University, Montréal, Québec. 216 Glass, E. H., and L. Lienk. 1971. Apple insect pp. and mite populations developing after dis- Lafleur G., and S. B. Hill. 1984. Etude de la dis­ continuance of insecticides: 10-year record. persion et du comportement du charançon J. Econ. Entomol. 64: 23-26. de la prune, Conotrachelus nénuphar Gould, J. L. 1984. Magnetic field sensitivity in (Herbst) (Coleoptera: Curculionidae), à l'aide animais. Annu. Rev. Physiol. 46: 585-598. de traceurs radioactifs au Québec. Pages Gould, F. 1991. behavior and the 25-37 in C. Vincent and N. J. Bostanian efficacy of plant protectants. Annu. Rev. (eds.), Bull. Stn. Rech. Saint-Jean-sur-Rich­ Entomol. 36: 305-330. elieu. Québec. Volume 19.

97 Lafleur, G., and S. B. Hill. 1987. Spring migra­ McGiffen, M. E., and J. R. Meyer. 1986. Effect of tion, within-orchard dispersai, and apple environmental factors on overwintering tree préférence of plumcurculio (Coleopte- phenomena and spring migration of the ra: Curculionidae) in southern Québec. J. plum curculio, Conotrachelus nénuphar Econ. Entomol. 80: 1173-1187. (Coleoptera: Curculionidae). Environ. En­ Lafleur, G., S. B. Hill, and N. N. Barthakur. 1985. tomol. 15: 884-888. Observations on mortality, détection, dis­ Neiswander, R. B. 1948. Plum curculio on tance, and rate of loss of label in plum and plums in Ohio. J. Econ. Ento­ curculio (Coleoptera: Curculionidae), using mol. 41: 450-453. improved techniques for topical applica­ Owens, E. D., K. I. Hauschild, G. L. Hubbel, and tion of radioisotopes on insects. J. Econ. R. J. Prokopy. 1982. Diurnal behavior of Entomol. 78: 1157-1165. plum curculio (Coleoptera: Curculionidae) Lafleur, G., S. B. Hill, and C. Vincent. 1987. Fall adults within host trees in nature. Ann. migration, hibernation site sélection, and Entomol. Soc. Am. 75: 357-362. associated winter mortality of plum curcu­ Padula, A. L, and E. H. Smith. 1971. Repro­ lio (Coleoptera: Curculionidae) in a Québec ductive incompatibility between univoltine apple orchard. J. Econ. Entomol. 80: 1152- and multivoltine females of the plum cur­ 1172. culio. Ann. Entomol. Soc. Am. 64: 665-668. Lathrop, F. H. 1949. Biology of the plum cur­ Paradis, R. 0.1956a. La lutte contre le charan­ culio in Maine. J. Econ. Entomol. 42:12-18. çon de la prune, dans le sud-ouest du Le Blanc, J.-P. R. 1982. Trapping and monito- Québec. Annu. Rep. Que. Soc. Prot. Plants ring techniques for plum curculio, Cono- 1955.37:88-100. trachelus nénuphar (Herbst), (Coleoptera: Paradis, R. 0.1956b. Observations sur le cycle Curculionidae), in a southwestern Québec évolutif du charançon de la prune, Cono­ apple orchard. Ph.D. thesis, McGill Univer- trachelus nénuphar (Hbst), sur la pomme sity, Montréal, Québec. 170 pp. dans le Québec. Ann. Soc. Entomol. Que. 2: Le Blanc, J.-P. R., S. B. Hill, and R. O. Paradis. 60-70. 1981. Essais de piégeage du charançon de Paradis, R. O. 1957. Observations sur les dé­ la prune, Conotrachelus nénuphar (Hbst.) gâts causés par le charançon de la prune, (Coleoptera: Curculionidae) dans une Conotrachelus nénuphar (Hbst.), sur les pommeraie du sud-ouest du Québec. Ann. pommes dans le sud-ouest du Québec. Soc. Entomol. Que. 26: 182-190. Can. Entomol. 89: 496-502. Le Blanc, J.-P. R., S. B. Hill, and R. O. Paradis. Paradis, R. 0.1979. Comment réduire l'emploi 1984. Oviposition in scout green apples by des pesticides en vergers de pommiers. plum curculio, Conotrachelus nénuphar Phytoprotection 60: 69-78. (Herbst) (Coleoptera: Curculionidae) and Petch, C. E. 1927. The plum curculio (Cono­ its relationship to subséquent damage. trachelus nénuphar Herbst) and itscontrol Environ. Entomol. 13: 286-291. in Québec. Can. Dep. Agric. Cire. 27: 1-4.1. LeRoux, E. J. 1961. Variation between samples Prokopy, R. J. 1985. A low-spray apple pest of fruit, and of fruit damages mainly from management program for small orchards. insect pests, on apple in Québec. Can. En­ Can. Entomol. 117: 581-585. tomol. 93: 680-694. Prokopy, R. J., W. M. Coli, R. G. Hislop, and K. Levine, E., and F. R. Hall. 1977. Effect of feeding I. Hauschild. 1980. Integrated management and oviposition by the plum curculio on of insect and mite pests in commercial apple and plum abcission. J. Econ. Ento­ apple orchards in Massachusetts. J. Econ. mol. 76: 603-607. Entomol. 73: 529-535. Levine, E., and F. R. Hall. 1978a. Pectinases and Prokopy, R. J., S. A. Johnson, and M. T. cellulases from plum curculio larvae, pos­ O'Brien. 1990. Second stage integrated sible causes of apple and plum fruit abcis­ management of apple arthropod pests. sion. Entomol. Exp. Appl. 23: 259-268. Entomol. Exp. Appl. 54: 9-19. Levine, E., and F. R. Hall. 1978b. Physiology of Quaintance, A. L., and E. L. Jenne. 1912. The plum fruit abcission induced by larvae of plum curculio. Bull. U. S. Dep. Agric. Bur. the plum curculio. Hortscience 13: 161. Entomol. 103: 1-250. Maier, C. T. 1990. Native and exotic rosaceous Racette, G. 1988. Daily activity of plum curcu­ hosts of apple, plum, and curculio lio, Conotrachelus nénuphar (Herbst), larvae (Coleoptera: Curculionidae) in the (Coleoptera: Curculionidae), and implica­ northeastern United States. J. Econ. Ento­ tions for control. M.Se. thesis., McGill Uni- mol. 83: 1326-1332. versity, Montréal, Québec. 145 pp. Mampe,C. D.,andH. H. Neunzig. 1966. Function Racette, G., S. B. Hill, and C. Vincent. 1990. of the stridulating organs of Conotrachelus Actographs for recording daily activity of nénuphar (Coleoptera: Curculionidae). Ann. plum curculio (Coleoptera: Curculionidae). Entomol. Soc. Am. 59: 624-615. J. Econ. Entomol. 83: 2386-2392.

98 RACETTE ET AL.: PLUM CURCULIO IN APPLE ORCHARDS

Racette G., G. Chouinard, S. B. Hill, and C. Snapp,O.1.1923. Récentdevelopments in plum Vincent. 1991. Activityofadult plum curcu- curculio investigations in Georgia. J. Econ. lio (Coleoptera: Curculionidae) on apple Entomol. 16:275-283. trees in spring. J. Econ. Entomol. 84:1827- Snapp, 0.1.1930. Life history and habits of the 1832. plum curculio in the Georgia peach belts. Radke, S. L. 1982. Dispersai and overwintering U.S. Dep. Agric. Tech. Bull. 188: 1-90. of the plum curculio, Conotrachelus nénu­ Snapp, 0.1.1931. A preliminary report on the phar (Herbst), (Coleoptera: Curculionidae), toxic value of fluosilicates and arsenates as in southern New Hampshire apple orchards. tested on the plum curculio. J. Econ. Ento­ M.Se. Thesis, New Hampshire University, mol. 21: 175-178. Durham. N. H. 43 pp. Snapp, 0.1.1940. Further studies on the plum Reissig, W. H., R. W. Weires, G. C. Forshey, W. curculio in the Georgia peach belt. J. Econ. L. Roelofs, R. C. Lamb, and H. S. Aldwinc- Entomol. 33: 453-456. kle. 1984. Insect management in disease- Snapp, O. I. 1951. Plum curculio control with resitant dwarf and semi-dwarf apple trees. neworganic insecticides. J. Econ. Entomol. Environ. Entomol. 13: 1201-1207. 50: 457-459. Rings, R. W. 1952. Expérimental control of plum Snapp, O. l.,andJ. R. Thompson. 1931. Burying curculio on peaches. J. Econ. Entomol. 45: peach drops to prevent the escape of plum 436-444. curculio adults. J. Econ. Entomol. 24: 559- Roach, S. H., and J. A. Buxton. 1965. Apholate 560. and tepa as chemosterilants of the plum Steiner, H. M., and H. N. Worthley. 1941. The curculio. J. Econ. Entomol. 58: 802-803. plum curculio problem on peach in Pensyl- Roitberg, B. D., and N. P. D. Angerilli. 1986. vania. J. Econ. Entomol. 34: 249-255. Management oftemperate-zonedeciduous Stelzer, L R., and C. L Fluke. 1958. Soil in­ fruit pests: applied behavioral ecology. secticides for plum curculio in Wisconsin. Agric. Zool. Rev. 1: 137-165. J. Econ. Entomol. 51: 131-133. Saunders, D. S. 1982. Insect docks. Pergamon Stevenson, J. O., and E. H. Smith. 1961. Fe- Press, New York. 409 pp. cundity and fertility of two strains of the Schmidt-Koenig, K. 1979. Directions of migra- plum curculio, reciprocal crosses and the F1 ting monarch butterflies in some parts of générations. J. Econ. Entomol. 54:283-284. the eastern United States. Behav. Proces­ Tedders, W. L., D. J. Weaver, E. J. Wehunt, and ses 4: 73-78. C. R. Gentry. 1982. Bioassay of Meta- Schoene, W. J. 1936. Partial second brood of rhizium anisopliae, Beauveria bassiana and the plum curculio in Virginia. J. Econ. Ento­ Neoaplectana carpocapse against larvae mol. 29: 571-573. of the plum curculio, Conotrachelus nénu­ Shaw, R. G. 1982. Wind movement within ca- phar (Herbst) (Coleoptera: Curculionidae). nopies. Pages 17-41 in J.L. Hatfield and I.J. Environ. Entomol. 11: 901-904. Thomason (eds.), Biometeorology in inte- Van Driesche, R., and E. Carey. 1987. Oppor­ grated pest management. Académie Press, tunités for increased biological control in New York. Massachusetts. Univ. Mass. Res. Bull. 718, Slingerland, M. V., and C. R. Crosby. 1914. 141 pp. Manual of fruit insects. The MacMillan Vincent, C, and G. Bélair. 1992. Biocontrol of Compagny, New York. 503 pp. the apple sawfly, , Smith, CF. 1948. Plum curculio control in North with entomogenous nematodes. Entomo- Carolina. J. Econ. Entomol. 41: 871-879. phaga 37: 575-582. Smith, E. H. 1954. Factors influencing the sus- Vincent, C, and N. J. Bostanian. 1988. La ceptibility of the plum curculio to lead arse- protection des vergers de pommiers au nate. J. Econ. Entomol. 47: 871-879. Québec: état de la question. Nat. Can. 115: Smith, E. H. 1957. A method for rearing the 261-276. plum curculio under laboratory conditions Vincent, C, and M. Roy. 1992. Entomological including some biological observations. J. limits to biological control programs in Econ. Entomol. 50: 187-190. Québec apple orchards. Acta Phytopathol. Smith, E. H., and J. K. Flessel. 1968. Hiberna­ Entomol Hung. 27: 649-657 tion of the plum curculio and its spring Wehner, R. 1984. Astronavigation in insects. migration to host trees. J. Econ. Entomol. Annu. Rev. Entomol. 29: 277-298. 61: 193-203. Whalon,M.E.,andB.A.Croft.1984.ApplelPM Smith, E. H., and E. H. Salkeld. 1964. Ovary implementation in North America. Annu. development and oviposition rates in the Rev. Entomol. 29: 435-470. plum curculio, Conotrachelus nénuphar Whitcomb, W. D. 1929. The plum curculio in (Coleoptera: Curculionidae). Ann. Entomol. apples in Massachusetts. Mass. Agric. Exp. Soc. Am. 57: 781-787. Stn. Bull. 249: 26-52.

99 Whitcomb, W. D. 1932. The relation of tempe- rature totheactivity and controlofthe plum curculio in apples. Mass. Agric. Exp. Stn. Bull. 285: 1-16. Wigglesworth, V. B. 1953. The principles of insect physiology. Methuen & Co. Ltd. Lon- don. 546 pp. Woodside, A. M. 1935. The plum curculio in Virginia. Va. Pol. Inst. Agric. Exp. Stn. 297: 1-20. Wylie,W.D. 1951. Technique in jarring for plum curculio. J. Econ. Entomol. 44: 818-819.