And Otiorhynchus Ovatus (Linnaeus) (Coleoptera: Curculionidae) from the Pacific North-West of the United States of America on Selected Host Plants

Agricultural and Forest Entomology (2006) 8, 281–287 DOI:10.1111/j.1461-9563.2006.00309.x

Fecundity, longevity and establishment of Otiorhynchus sulcatus (Fabricius) and Otiorhynchus ovatus (Linnaeus) (Coleoptera: Curculionidae) from the Pacific North-west of the United States of America on selected host plants

James R . Fisher United States Department of Agriculture, Agricultural Research Service, Horticultural Crops Research Laboratory, 3420 North West Orchard Avenue, Corvallis, OR 97330, U.S.A.

Abstract 1 The fecundity, longevity and establishment of Otiorhynchus sulcatus and Otiorhynchus ovatus from the Pacific North-west U.S.A. was studied on five selected host plants: Picea abies ‘Nidiformis’, Picea glauca ‘Conica’, Taxus baccata , Rhododendron catawbiense ‘Boursault’ and Fragaria × ananassa ‘Totem’. 2 Teneral adults were used to study adult longevity and reproductive success. Leaves of these host plants were used for sustenance for 9 months. Larval establishment was studied by infesting potted host plants with eggs. 3 Fragaria × ananassa ‘Totem’ produced the longest survival, shortest preoviposition time, the greatest number of eggs, and the highest fertility for adults of both species. Picea spp. were not good adult hosts for O. sulcatus. Taxus was a good adult host for O. sulcatus , but was a nonhost for adults and larvae of O. ovatus . 4 Adult hosts did not affect preoviposition time or egg viability with O. ovatus adults. With O. sulcatus, preoviposition time was greatly increased and egg viability was < 50% on Picea spp. 5 The best larval host was F. × ananassa ‘Totem’ for O. sulcatus and P. glauca ‘Conica’ for O. ovatus . Rhododendron was a poor larval host for both species. 6 When all of the studies on these two pests are considered, O. sulcatus appears to have varying host preferences from among its many geographical areas of occurrence whereas O. ovatus has a more universal host selection. Keywords Adult host , black vine weevil , host plants , larval host , strawberry root w e e v i l .

Introduction girding the trunks of hosts at soil level or eating large roots close to the main trunk and killing the plant. Adult leaf- Several otiorhynchid weevils (Coleoptera: Curculionidae) are feeding (notching) is of little consequence to small fruits but pests of horticultural crops in the Pacific North-west U.S.A. is a cosmetic blemish on nursery stock. Even though both of Of these, the black vine weevil Otiorhynchus sulcatus these insects are nearly ubiquitous throughout the northern (Fabricius) and the strawberry root weevil Otiorhynchus ova- tier (> 40° latitude) of North America ( Warner & Negley, tus (Linneaus) are of particular importance to the small fruit 1976 ), sellers of nursery stock from the Pacific North-west and nursery industries. Economic damage by these insects is are often penalized from completing sales of material ex- primarily caused by larvae feeding on and inside roots, often ported to other states by buyer refusals on finding the presence of these pests. Both insects have similar univoltine life Correspondence: J. R. Fisher, United States Department of cycles, have apomictic parthenogenesis, and are flightless Agriculture, Agricultural Research Service, Horticultural Crops ( Downes, 1922; Smith, 1932; Suomalainen et al. , 1987 ). Research Laboratory, 3420 North West Orchard Avenue, Corvallis, Eggs are laid from the early summer to autumn. Overwintering OR 97330, U.S.A. Tel.: +1 406 446 9942; fax: +1 541 738 4925; occurs in the larval stage and pupation and transformation to e-mail: [email protected] the adult stage occurs from the late spring to early summer.

Occasionally, adults of both species have been found to (J. R. Fisher, unpublished observations). Hanula (1988) dem- overwinter in the United States ( Treherne, 1914; Smith, onstrated that the previous feeding experience by larvae or 1932 ) and in Ireland ( Blackshaw, 1992 ). preovipositing adults of O. sulcatus from Connecticut did not A number of hosts have been listed for both species. Over influence where subsequent oviposition occurred; the major- 40 varieties from a number of families from grasses to coni- ity of eggs were laid on or in pots with Taxus cuspidata fers have been recorded for O. ovatus ( Patch, 1905; Treherne, Siebold and Zucc. (Japanese yew). However, Hanula (1988) 1914; Wilcox et al. , 1934; Gambrell, 1938; Schread, 1950; did not employ a control for each of the tested plant varieties Emenegger, 1976; Brandt et al. , 1995; Wheeler, 1999 ). Over except for Taxus. Otiorhynchus sulcatus from the Pacific 150 species of an even more expansive list has been recorded North-west appear to have a preference for strawberry, for O. sulcatus (Smith, 1932; Warner & Negley, 1976; Masaki whereas little is known about the effect of host on the repro- et al., 1984). However, a number of studies have found that ductive success of O. ovatus . The present study investigated evidence of damage, particularly by adults, does not neces- the effect of host plant foliage on the reproductive success of sarily denote that the plant is a viable host ( Cram, 1965, both weevil species as well as the ability of larvae of each 1970, 1980; Cram & Pearson, 1965; Penman & Scott, 1976; species to establish on one of five host plants, P. abies Shanks, 1980; Maier, 1981; Nielsen & Dunlap, 1981; Cram ‘Nidiformis’, T. baccata , P. glauca ‘Conica’, F. × ananassa & Daubeny, 1982; Hanula, 1988; Van Tol & Visser, 1998; ‘Totem’ and R. catawbiense ‘Boursault’. Van Tol et al., 2004). Even cultivars within the same species of host have shown differences in the fecundity of O. sulcatus (Cram, 1970, 1980; Nielsen & Dunlap, 1981; Cram & Daubeny, 1982; Shanks & Doss, 1986 ). Additionally, adult Materials and methods O. sulcatus have been found to show differential feeding The study comprised two parts. First, callow adults of each preferences for various cultivars of strawberry Fragaria × species were individually placed on a range of different host ananassa Duchesne and rhododendron ( Doss, 1983; Shanks plant foliage and data were collected with respect to preovi- et al., 1984; Doss & Shanks, 1988; Doss et al. , 1991 ; Cowles, position time, longevity and fecundity. Second, pots con- 2004 ). taining the same selection of host plants were infested with In the Willamette Valley of Oregon, O. ovatus has often eggs of each species and subsequently examined for larval been found to be the primary pest species in one nursery and establishment. O. sulcatus would be the primary pest species in another nursery (J. R. Fisher, unpublished observations). Generally, movement of O. sulcatus and O. ovatus , other than that af- Insects forded by humans in the movement of nursery stock from Larvae of O. sulcatus and O. ovatus were collected in the place to place, appears to be limited ( Emenegger, 1978; late winter (2003) from strawberries and nursery stock in the Maier, 1978). Otiorhynchus sulcatus adults from Pennsylvania Willamette Valley of Oregon. The larvae were then reared in (Smith, 1932). as well as those studied by Shanks (1980) a carrot – peat moss system, similar to that described by from Washington and Ohio, all had better reproductive suc- Masaki & Sugimoto (1991) , in plastic food containers (0.5 L; cess on strawberry (Fragaria spp.) compared with yew (Taxus Reynolds Metal Co., Richmond, Virginia). Carrot slices and spp.). However, in a study comparing strawberry and yew as peat moss were renewed as necessary until pupation. Pupae hosts, Hanula (1988) stated that O. sulcatus had a secondary were transferred to similar containers that contained only preference for strawberry. Nielsen & Dunlap (1981) com- moist peat moss. All larvae were reared in complete darkness pared longevity and egg production of O. sulcatus in Ohio on at 21.0 ± 0.5 °C. several Taxus and Rhododendron species. Their results were extremely variable among three seasons of study but they concluded that Taxus spp. were better hosts than Adult host plant study Rhododendron spp. Recent studies by Van Tol et al. (2004) in the Netherlands found that Taxus baccata, Aronia melamo- As the larvae eclosed, teneral adults were placed individually carpa , F. × ananassa ‘Elsanta’ and Euonymus fortunei were in vented Petri dishes (100 × 25 mm; (Fisher Scientific, equally suitable hosts. Rhododendron catawbiense ‘Boursault’ Pittsburgh, Pennsylvania) (one per dish) that contained a and several other plants were hosts but the number of eggs piece of moistened filter paper (Whatman #1; Whatman plc, laid was significantly lower and adult mortality was higher. U.K.) and a leaf or sprig of a selected host plant in a floral In the state of Oregon, English yew T. baccata Linneaus, water-pic (Syndidate Sales Inc., Kokomo, Indiana). Adults were R. catawbiense Michaux, strawberry F. × ananassa ‘Totem’, maintained in an incubator at 21 ± 0.5 °C under an 18 : 6 h bird’s nest spruce Picea abies (Linneaus) ‘Nidiformis’ or light/dark photoperiod ( Nielsen & Dunlap, 1981; Umble & ‘Mariana Nana’, and Alberta spruce Picea glauca (Moench) Fisher, 2002). Every 3– 5 days, the dishes were examined for ‘Conica’ are frequently mentioned by growers to be varieties eggs, the plant material renewed and the dishes changed to with ‘root weevil’ problems. However, complaints vary as to minimize mold and faecal deposits. Weevils were maintained the severity of the problem on hosts beyond strawberry and until death occurred or not more than 9 months. bird’s nest spruce. Yet, when adults of either species are fed To estimate egg viability, samples of eggs were randomly only bird’s nest spruce, mortality appears to occur quickly removed with a camel hair brush and placed on moistened (within a few weeks) and egg production is minimal filter paper (Whatman #1) in a snap lid Petri dish (50 × 9 mm,

Becton Dickinson and Co., Franklin Lakes, New Jersey). On data are the number of larvae found and the proportion of each collection date and host type, up to four dishes each larvae/eggs infested. Again, some counts were zero to near with 25 eggs were prepared and maintained at 21 ± 0.5 °C zero and some proportions were very small. Thus, data were for a maximum of 4 weeks. Eggs were examined for hatch transformed and analysed as described above. Additional every 3 – 4 days. The reported hatch is the mean of all sam- data presented include the proportion of pots of the 20 per ples per host type. treatment where larvae established. Four parameters that could be expressed as a mean were recorded: (i) adult survival (days); (ii) preoviposition time (days); (iii) fecundity; and (iv) egg viability (%). Some of the data for all parameters had zero to near zero occurrences and Results some proportions were very small. Therefore to adjust the data + Adult host plant study for normality, count data were transformed to the loge ( x 1) and proportion data were transformed to the arcsine (Ö x). For O. sulcatus, there were significant differences among Thereupon, all data were submitted to general linear model means for all of the measured parameters concerning the five analysis of variance (glm anova) (NCSS, 2004). After analy- selected host plants: survival (F = 8.50; d.f. = 4, 145; P < sis, differences among means were examined with the Tukey – 0.01), preoviposition (F = 22.4, d.f. = 4, 84; P < 0.01), fe- Kramer test ( NCSS, 2004 ). Data are presented as original cundity (eggs per female) (F = 27.65, d.f. = 4, 145; P < untransformed mean ± SE. Additional data presented include 0.01) and percent fertility (F = 8.93; d.f. = 4, 83; P < 0.01) the proportion of individuals that oviposited from the 30 ( Table 1). The two conifers in were relatively poor hosts with weevils tested on each host plant. limited survival time, long preoviposition times, few eggs and reduced fertility. Taxus baccata was a relatively good host, but not as good overall as R . catawbiense for which Larval host plant study survival time was less and preoviposition time increased. Host plants were obtained as liner (nursery stock) or trans- Rhododendron catawbiense was not significantly different plants (strawberry) and potted in a black plastic nursery con- from strawberry as a host for survival, preoviposition and tainer (738 ml, McConkey and Co., Sumner, Washington) egg production. However, egg viability on R. catawbiense with the potting media, OBC North-west Nursery Mix #1 was less than on strawberry and similar to that obtained from (OBC North-west, Inc., Canby, Oregon). Plants were allowed eggs oviposited when fed Taxus baccata . to establish in the pot for approximately 2 months. Once the With O. ovatus , there were no significant host differences plants were established (late July 2003), 20 eggs of O. sulcatus for preoviposition period (F = 1.47; d.f. = 3, 60; P = 0.23) or 100 eggs of O. ovatus were placed in a shallow hole or egg viability (F = 0.62; d.f. = 3, 50; P = 0.60) ( Table 1 ). (approximately 35 –50 mm deep) dug in the soil mix next to However, there were significant differences among host the plant, and then, refilled with the soil mix. There were 20 plants for adult survival (F = 5.49; d.f. = 4, 145; P < 0.01) replicates (pots) of each weevil species/host plant combina- and fecundity (F = 10.13; d.f. = 3, 60; P < 0.01) ( Table 1 ). tion. Once infested, the pots were allowed to grow in a The only ‘host’ studied that did not qualify as a suitable host screenhouse for 5 months. At that time, the pots were emp- was T. baccata , on which no eggs were laid. The number of tied and the soil and roots examined for larvae. Reported eggs produced on R. catawbiense was significantly less than

Table 1 Survival and reproductive parameters (mean ± SE) for initially teneral adult Otiorhynchus sulcatus and Otiorhynchus ovatus when fed one of five host plants for up to 9 months

Host plant

Picea abies Rhododendron catawbiense Fragaria × anan assa Picea glauca Life parameter ‘Nidiformis’ Taxus baccata ‘ Boursault’ ‘Totem’ ‘Conica’

Otiorhynchus sulcatus Survival (days) 97.63 ± 19.02 c 150.63 ± 17.44 b 174.47 ± 15.95a 215.07 ± 16.40 a 89.60 ± 12.44c Preoviposition (days) 109.13 ± 12.68 a,b 78.42 ± 11.63 b 69.12 ± 5.41b,c 34.70 ± 1.31 c 111.89 ± 12.38a Fecundity (eggs/ᤅ ) 41.67 ± 16.26 c 157.83 ± 39.99b 267.00 ± 40.86a,b 880.63 ± 132.51 a 7.20 ± 3.60 C ᤅ /30 ovipositing 0.27 0.63 0.80 0.93 0.27 Egg viability (%) 47.34 ± 8.84b,c,d 59.90 ± 5.20b,c 63.83 ± 4.26b,c 79.00 ± 2.52 a 26.55 ± 6.89C,d Otiorhynchus ovatus Survival (days) 116.23 ± 16.35a 35.60 ± 1.50 b,c 80.67 ± 9.00 a,b,c 138.09 ± 18.31a 77.20 ± 11.29a,b,c Preoviposition (days) 51.19 ± 10.54a 0.00 ± 0.00 * 46.06 ± 8.01 a 31.38 ± 1.65 a 41.43 ± 7.26a Fecundity (eggs/ᤅ ) 163.06 ± 23.97a,b 0.00 ± 0.00 * 72.18 ± 14.08 b,c 474.29 ± 89.58 a 75.86 ± 21.75b ᤅ /30 ovipositing 0.53 0.00 0.57 0.80 0.23 Egg viability (%) 82.78 ± 1.84a 0.00 ± 0.00 * 86.13 ± 1.57a 86.30 ± 1.36 a 83.40 ± 4.45a

Means followed by the same letter within a row are not significantly different from each other, Tukey– Kramer test, P < 0.05.

* T. baccata data not included in the ANOVA because no eggs were oviposited.

© 2006 The Author Journal compilation © 2006 The Royal Entomological Society, Agricultural and Forest Entomology, 8, 281–287 284 J. R. Fisher the number produced on strawberry (15%) but adult survival was nearly the same as when fed strawberry . Picea abies appeared to be nearly as good a host as F. × ananassa with similar survival, preoviposition, egg production and egg viability. Of the five selected hosts for the two weevil species (O. sulcatus and O. ovatus ), strawberry (F. × ananassa ) produced the longest adult survival, shortest preoviposition time, the greatest number of eggs laid and the highest egg viability (Table 1 ). Even so, O. sulcatus produced more than 1.8-fold the number of eggs on F. × ananassa compared with O. ovatus. In comparison, O. ovatus produced nearly four-fold as many eggs as O. sulcatus when P. abies was the sole host. Picea glauca was the poorest host for O. sulcatus but appeared to be a mediocre to good host for O. ovatus . Both species appeared to find R. catawbiense a relatively good host Figure 1 Larvae (mean ± SE) recovered after infesting host plants ( Table 1 ). with either 20 eggs of Otiorhynchus sulcatus or 100 eggs of Otiorhynchus ovatus . For each weevil species, bars followed by the same letter are not significantly different ( P = 0.05) from each Larval host plant study other (Tukey – Kramer test). There were significant differences in larval establishment among the five host plants: O. sulcatus (F = 14.28; d.f. = 4, context that describes many of the previously described 95; P < 0.01); O . ovatus (F = 8.22; d.f = 4, 95; P < 0.01) ‘hosts’ of the two Otiorhynchus species discussed here. ( Fig. 1). Similarly, for both weevil species, there were sig- However, Pedigo (1999: 437) also clarifies his definition of nificant differences in the proportion of larvae recovered host plant as: ‘If nutrients are adequate and no toxicity oc- among the five host plants: O. sulcatus (F = 13.97; d.f. = 4, curs, the insect completes development within a normal time 95; P < 0.01); O. ovatus (F = 7.77; d.f. = 4, 95; P < 0.01). period and becomes an adult. Also sufficiency is indicated in Fragaria × ananassa was the best host for larval establish- normal adult longevity and fecundity’. This is a more appro- ment by either species ( Figs 1 and 2). At least one larva was priate definition for this discussion. recovered in 80% of the pots infested with each species Of the many refereed publications that mention host plants ( Table 2). With O. sulcatus , R. catawbiense was a poor host for O. sulcatus , only three genera of gymnosperms, other for larval establishment; larvae were recovered in only 5% of than Taxus, have been noted as adult host plants, the egg infested pots ( Figs 1 and 2; Table 2 ). With O. ovatus , Chamaecyparis , Thuja and Tsuga ( Smith, 1932, Maier, 1981; R. catawbiense also was a poor larval host with larvae being Maier, 1986 ). The proclivity of larvae for Taxus is well docu- found in only 35% of the pots ( Figs 1 and 2; Table 2 ). Taxus mented ( Smith, 1932; Shanks, 1980; Maier, 1981; Nielsen & baccata was clearly a nonhost for O. ovatus with no larvae Dunlap, 1981; Hanula, 1988; Van Tol et al., 2004). Van Tol recovered from the infested pots. Both T. baccata and et al. (2004) included species of Thuja and Taxus from the P. glauca were relatively poor hosts for O. sulcatus with larvae found in only 40% of the pots infested. The number of larvae of O. ovatus found on P. abies and P. glauca was greater than the number of O. sulcatus larvae. Even though both otiorhynchids had the best establishment on F. × ananassa , O. ovatus had the greatest survival on P. glauca with P. abies and F. × ananassa secondary. For O. sulcatus , the best survival was on F. × ananassa with P. abies being the next best larval host.

Discussion Numerous studies have investigated the host preferences of Proportion larvae / eggs infested O. sulcatus. Only a few studies have investigated the host plant range of O. ovatus , but it is nearly as broad as O. sulcatus . Much of the available literature on either species has considered a plant as a host when adult weevils have been observed Figure 2 Proportion of larvae recovered/eggs infested (mean ± feeding on the foliage or if larvae feed when confined on SE) for each host plant. For each weevil species, bars followed by some roots. Pedigo (1999) defined a host in the glossary as the same letter are not significantly different (P = 0.05) from each ‘a plant on which an insect feeds’. This appears to be the other (Tukey – Kramer test).

Table 2 Proportion of pots for each host species (20 pots/host) having at least one larva of either Otiorhynchus sulcatus or Otiorhynchus ovatus (20 eggs or 100 eggs infested, respectively)

Picea abies Rhododendron catawbiense Fragaria × ananassa Picea glauca Species of weevil ‘Nidiformis’ Taxus baccata ‘Bursault’ ‘Totem’ ‘Conica’

Otiorhynchus sulcatus 0.70 0.40 0.05 0.80 0.40 Otiorhynchus ovatus 0.50 0.00 0.35 0.80 0.60 gymnosperms among numerous species of angiosperms in America, O. sulcatus appears to favour certain Rosales (i.e. their studies of adult longevity and reproductive perform- strawberry, blackberries and raspberries), Ericales (i.e. cer- ance. The authors concluded that Taxus was the only tain rhododendrons), blueberries and salal, and members of gymnosperm in Europe qualifying as a true host plant and the gymnosperm families, Taxaceae and Pinaceae. Studies that determination of host plants from studies using only by Cram (1965) and Shanks (1980) have shown that certain feeding tests gives an overestimation of true host plant species of Fragaria are superior for egg production com- range. pared with other plants. Furthermore, Shanks (1980) found In Western North America, O. sulcatus is not only a pest that, when larvae from Washington or Ohio were allowed to of rhododendron, Taxus spp., strawberry, other members of feed on strawberry or yew, strawberry produced more survi- the Roseaceae and numerous other angiosperms, but also vors to the adult stage. The present study also found straw- nursery growers continually report economic damage by lar- berry to be a superior host. Also, R. catawbiense was a better vae to many members of the gymnosperm family Pinaceae. adult host for O. sulcatus than Taxus baccata or Picea spp. As Indeed, some studies note that O. sulcatus feeds on members a larval host for O. sulcatus , F. × ananassa was superior, P. of the Pinaceae ( Cowles, 1995; Cowles et al., 1997). In abies was mediocre and Taxus was poor. However, R. cataw- Japan, Masaki et al. (1984) found that there was slight dam- biense was the poorest larval host for O. sulcatus . Even age to Pinus thunbergii as a result of adult feeding. However, though this species is of central European origin ( Van Tol et the ability of these plants to sustain O. sulcatus larvae or al. , 2004 ), it may be adapting to the crops in areas where adults has not been documented. The present study clearly they have colonized. Alternatively, with the worldwide demonstrates that genera of the Pinaceae, particularly Picea movement of nursery plant material over the past several spp., can be viable hosts for O. sulcatus , particularly for centuries, this species has probably been introduced to its re- larvae. spective areas of occurrence many different times. This sug- When the previous studies on host plants and reproductive gests that further studies should consider biological and performance of O. sulcatus are considered together with the genetic comparisons of populations of O. sulcatus from dif- findings of the present study, there appear to be differences ferent areas of the same continent and throughout the world. between different areas of origin (i.e. Europe, Eastern U.S.A. Contrary to O. sulcatus, O. ovatus is known to damage a and Western U.S.A.). In Europe, Taxus spp. appear to be the number of families in the plant order Coniferales ( McDaniel, only viable gymnosperm hosts for adults on which reproduc- 1930; Whitecomb, 1931; Wilcox et al. , 1934; Gambrell, tive maturation occurs ( Van Tol et al. , 2004 ). The presence of 1938; Warner & Negley, 1976; Brandt et al., 1995). terpenes, which may be feeding deterrents, are the probable Whitecomb (1931) claimed that O. ovatus was a pest of reason that they do not feed on other gymnosperms ( Van Tol Japanese yew, T. cuspidata , in North-eastern U.S.A. In the et al., 2004). However, Van Tol et al. (2004) only allowed present study, Taxus spp. would not qualify as a viable larval feeding on their chosen hosts for 52 days from adult emer- or adult host. Unlike O. sulcatus , host plants other than yew gence. In the present study, when the adults were fed Picea did not affect preoviposition maturation time. Treherne spp., the preoviposition period was greater than 100 days. (1914) and Wilcox et al. (1934) gave the preovipositional pe- In other studies with less favourable plants such as Cornus riod for O. ovatus as 8– 33 days. However, these authors used florida , Kalmia latiforia and R. smirnowii ( Maier, 1981; field-collected weevils that were fed strawberry. Brandt et al. Nielsen & Dunlap, 1981 ), the preoviposition period was (1995) used teneral adults that were fed leaves of Picea spp. longer than 50 days. It is possible that Van Tol et al. (2004) resulting in a preovipositional period of 30 – 33 days. This did not allow enough time for preovipositional maturation, would be within the range found on all host plants in the although they did not list preovipositional times in their present study. Furthermore, this would suggest that O. ovatus study. In both the Eastern U.S.A. and in Europe, O. sulcatus may not be as dependent as O. sulcatus on nutrients derived appears to feed primarily on a number of angiosperms be- from strawberry or rhododendron, and that some gymno- longing to the plant orders Rosales, Primulales, Saxifragales sperms may provide enough nutrition for ovarian maturation. and, to a lesser extent, the Ericales. In several studies, straw- Longevity or survival of O. ovatus adults in the present study berry was not found to be the favoured host ( Smith, 1932; was longest on strawberry (approximately 138 days) and was Maier, 1981; Nielsen & Dunlap, 1981; Hanula, 1988; Van significantly shorter on P. glauca and R. catawbiense . Tol et al. , 2004 ). However, recent studies in Connecticut Treherne (1914) reported the minimum longevity on straw- ( Cowles, 2004 ), Scotland ( Watt et al. , 1999; Graham et al. , berry was 62.5 days from field-collected adults. Brandt et al. 2002 ) and Norway (Hesjedal, 1984 ) note that O. sulcatus has (1995) reported longevity approximated 71 days when teneral been a very important pest of strawberries. In Western North adults were fed Picea spp. and kept at 20 °C. It is apparent

© 2006 The Author Journal compilation © 2006 The Royal Entomological Society, Agricultural and Forest Entomology, 8, 281–287 286 J. R. Fisher that the host plant does affect adult survivorship. Egg viabil- Cowles , R . S . , Gilrein , D . O . & Alm , S . R . ( 1997 ) The Trojan horse of ity on all of the host plants, except Taxus on which no eggs the nursery industry . American Nurseryman , 186 , 51 – 57 . were laid, was not significant and approximated Cram , W . T . ( 1965 ) Fecundity of the root weevils Brachyrhinus sul- 80 – 90%. Brandt et al. (1995) found a viability of 78% from catus and Sciopithes obscurus on strawberry in the laboratory and adults fed Picea spp. Treherne (1914) found an approximate outdoors . Canadian Journal of Plant Science , 45 , 169 – 176 . Cram , W . T . ( 1970 ) Acceptability of cultivars of highbush blueberry 80% viability when fed strawberry and Emenegger & Berry at varying temperature by adult black vine weevils (Col. (1978) found an approximate 80% viability when fed pep- Curculionidae) . Journal of the Entomological Society of British × permint (Mentha piperita ). It is apparent that adult host Columbia , 67 , 6 – 7 . plant does not affect egg viability. Cram , W . T . (1980 ) Fecundity of the black vine weevil, Otiorhynchus The present study is the first to detail larval host suitability sulcatus (Coleoptera: Curculionidae), fed foliage from some of O. ovatus . Taxus baccata was clearly a nonhost. P. glauca current cultivars and advance selections of strawberry in British produced the most larvae and the greatest proportion of lar- Columbia. Journal of the Entomological Society of British vae recovered. Fragaria × ananassa and P. abies produced Columbia , 77 , 25 – 26 . fewer larvae than P. glauca but were similar statistically. Cram , W . T . & Pearson , W . D . (1965 ) Fecundity of the black vine Rhododendron appeared to be a poor host. This suggests that weevil, Brachyrhinus sulcatus (F.), fed on foliage of blueberry, the larval host range in the present study is similar to that of cranberry and weeds from peat bogs . Proceedings of the Entomo- O. sulcatus , except for Taxus . logical Society of British Columbia , 62 , 25 – 27 . Cram . W . T . & Daubeny , H . A . ( 1982 ) Responses of black vine weevil When all of the studies on these two pests are considered adults fed foliage from genotypes of strawberry, red raspberry and together, O. sulcatus appears to have varying host prefer- red raspberry – blackberry hybrids . Hortscience , 17 , 771 – 773 . ences from among its many geographical areas of occurrence, Doss , R . P . ( 1983 ) Root weevil feeding on Rhododendron : a review . whereas O. ovatus has a more universal host selection. In Journal of Environmental Horticulture , 1 , 67 – 71 . North America, the occurrence of O. sulcatus is divided and Doss , R . P . & Shanks , C . H . Jr (1988 ) The influence of leaf pubes- isolated between the East and the West of the continent. The cence on the resistance of selected clones of beach strawberry difference in host preferences could be due to local adapta- (Fragaria chiloensis (L.) Duchesne) to adult black vine weevils tion and/or this could be the result of many reintroductions (Otiorhynchus sulcatus F.) . Scientia Horticulturae , 34 , 47 – 54 . by human shipment of nursery stock within North American Doss , R . P . , Shanks , C . H . Jr , Sjulin , T . M . & Garth , J . K . L . (1991 ) regions and from many different areas of the world. Further Evaluation of some Fragaria chiloensis x (F. X ananassa) seed- studies with O. sulcatus should consider biological and ge- lings for resistance to black vine weevil . Scientia Horticulturae , netic comparative studies among geographical areas. Further 48 , 233 – 239 . Downes , W . ( 1922 ) The Strawberry Root Weevil with Notes on Other studies with O. ovatus should consider expanding the knowl- Insects Affecting Strawberries. Pamphlet 5. New Series. Canadian edge of larval and adult hosts. Department of Agriculture , Canada . Emenegger , D . B . ( 1976 ) Biology and population regulation of the strawberry root weevil (Otiorhynchus Ovatus. L.) (Coleoptera: Acknowledgements Curculionidae). Master of Science Thesis, Oregon State University . I gratefully acknowledge the technical expertise of David Emenegger , D . B . ( 1978 ) Biology of strawberry root weevil on pep- Edwards, Biological Laboratory Technician, USDA, ARS, permint in western Oregon. Environmental Entomology , 7 , HCRL, for rearing the weevils and assisting with these stud- 495 – 498 . ies. I also thank Denny Bruck, USDA, ARS, and Glenn Gambrell , F . L . ( 1938 ) The strawberry root weevil as a pest of coni- Fisher, Oregon State University, for earlier reviews of the fers in nursery plantings . Journal of Economic Entomology , 31 , 107 – 113 . manuscript and their critical input. The resources for these Graham , J . , Gordon , S . C . , Smith , K . , McNicol , R . J . & McNicol , J . W . studies were provided by the USDA, ARS, Horticultural ( 2002 ) The effect of the cowpea trypspin inhibitor in strawberry Crops Research Laboratory and funds provided by USDA, on damage by vine weevil under field conditions . Journal of Hor- CRIS # 5538-22000-032-00D. ticultural Science and Biotechnology , 77 , 33 – 40 . Hanula , J . L . (1988 ) Oviposition preference and host recognition by the black vine weevil, Otiorhynchus sulcatus (Coleoptera; Curculionidae) . Environmental Entomology , 17 , 694 – 698 . References Hesjedal , K . ( 1984 ) Influence of nitrogen content in strawberry Blackshaw , R . P . (1992 ) Black vine weevil ( Otiorhynchus sulcatus leaves on the fecundity of the vine weevil, Otiorhynchus sulcatus (F.) oviposition on polyanthus plants outdoors in Northern Ireland . F. (Coleoptera: Curculionidae). Acta Agricultura Scandinavica , Journal of Horticultural Science , 67 , 641 – 646 . 34 , 188 – 192 . Brandt , J . P . , Smith , S . M . & Hubbes , M . ( 1995 ) Bionomics of straw- Maier , C . T . ( 1978 ) Dispersal of adults of the black vine weevil, berry root weevil adults, Otiorhynchus ovatus (L.) (Coleoptera: Otiorhynchus sulcatus (Coleoptera: Curculionidae) . Environmen- Curculionidae), on young ornamental conifer trees in southern tal Entomology , 7 , 854 – 857 . Ontario . Canadian Entomologist , 127 , 595 – 604 . Maier , C . T . ( 1981 ) Reproductive success of the black vine weevil, Cowles , R . S . ( 1995 ) Black vine weevil biology and management . Otiorhynchus sulcatus (F.), fed different foliar diets and evalua- Journal of the American Rhododendron Society , 49 , 94 – 97 . tion of techniques for predicting fecundity . Environmental Ento- Cowles , R . S . ( 2004 ) Susceptibility of strawberry cultivars to the vine mology , 10 , 928 – 932 . weevil Otiorhynchus sulcatus (Coleoptera: Curculionidae). Agri- Maier , C . T . ( 1986 ) Relative abundance of adults of Callirhopalus cultural and Forest Entomology , 6 , 279 – 284 . bifasciatus (Roelofs) and three Otiorhynchu s spp. (Coleoptera:

Curculionidae) on certain cultivated and wild plants in Connecticut. Suomalainen , E . , Saura , A . & Lokki , J . ( 1987 ) Cytology and Evolu- Journal of the New York Entomological Society , 94 , 70 – 77 . tion in Parthenogenesis . CRC Press , Boca Raton, Florida . Masaki , M . , Ohmura , K . & Ichinohe , F . ( 1984 ) Host range studies Treherne , R . C . ( 1914 ) The Strawberry Root Weevil (Otiorhynchus of the black vine weevil, Otiorhynchus sulcatus (Fabricius) (Coleop- ovatus Linn.) in British Columbia With Notes on Other Insects At- tera: Curculionidae). Applied Entomology and Zoology , 19 , tacking Strawberry Plants in the Lower Fraser Valley . Dominion 95 – 106 . of Canada Department of Agriculture, Experimental Farms, Divi- Masaki , M . & Sugimoto , S . ( 1991) Rearing methods of larvae of sion of Entomology, Entomological Bulletin 8. Department of black vine weevil, Otiorhynchus sulcatus (Fabricius) and some Agriculture , Canada . other Otiorhynchid weevils (Coleoptera: Curculionidae) . Research Umble , J . R . & Fisher , J . R . ( 2002 ) Influence of temperature and pho- Bulletin of the Plant Protection Service Japan , 27 , 7 – 11 . toperiod on the preoviposition duration and oviposition of Otio- McDaniel , E . I . ( 1930 ) The strawberry root weevil as a pest in coni- rhynchus ovatus (L.) (Coleoptera: Curculionidae). Annals fer nurseries . Michigan Quarterly Bulletin , 12 , 102 – 105 . Entomological Society of America , 95 , 231 – 235 . NCSS ( 2004 ) Number Cruncher Statistical System (Statistical Soft- Van Tol , R . W . H . M . , Van Dijk , N . & Sabelis , M . W . (2004 ) Host ware) . NCSS, Kaysville , Utah . plant preference and performance of the vine weevil Otiorhynchus Nielsen , D . G . & Dunlap , M . J . ( 1981 ) Black vine weevil: reproduc- sulcatus . Agricultural and Forest Entomology , 6 , 267 – 278 . tive potential on selected plants. Annals of the Entomological So- Van Tol , R . W . H . M . & Visser , J . H . ( 1998 ) Host-plant preference and ciety of America , 74 , 60 – 65 . antennal responses of the black vine weevil ( Otiorhynchus sulca- Patch , E . M . ( 1905 ) Strawberry crown girdler . Maine Agriculture tus ) to plant volatiles . Proceedings of Experimental and Applied Experiment Station Technical Bulletin , 123 , 206 – 228 . Entomology Netherlands Entomological Society of Amsterdam , 9 , Pedigo , L . P . ( 1999 ) Entomology and Pest Management , 3rd edn . 35 – 40 . Prentice Hall , Upper Saddle River, New Jersey . Warner , R . E . & Negley , F . B . ( 1976 ) The genus Otiorhynchus in Penman , D . R . & Scott , R . R . ( 1976 ) Adult emergence and egg pro- America North of Mexico (Coleoptera: Curculionidae) . Proceed- duction of the black vine weevil in Canterbury . New Zealand ings of the Entomological Society of Washington , 78 , 240 – 262 . Journal of Experimental Agriculture , 4 , 385 – 389 . Watt , K . , Graham , J . , Gordon , S . C . , Woodhead , M . & McNicol , R . J. Schread , J . C . ( 1950 ) The strawberry root weevil in nursery planting . ( 1999 ) Current and future transgenic control strategies to vine Connecticut Agriculture Experiment Station Circular , 174 , weevil and other insect resistance in strawberry . Journal of Horti- 1 – 8 . cultural Science and Biotechnology , 74 , 409 – 421 . Shanks , C . H . Jr (1980 ) Strawberry and yew as hosts of adult black Wheeler , A . G . Jr (1999 ) Otiorhynchus ovatus, O. rugosostriatus , vine weevil and effects on oviposition and development of prog- and O. sulcatus (Coleoptera: Curculionidae): exotic weevils in eny . Environmental Entomology , 9 , 530 – 532 . natural communities, mainly mid-Appalachian shale barrens and Shanks , C . H . Jr & Doss , R . P . ( 1986 ) Black vine weevil (Coleoptera: outcrops . Proceedings of the Entomological Society of Washing- Curculionidae) feeding and oviposition on leaves of weevil- ton , 101 , 689 – 692 . resistant and -susceptible strawberry clones presented in various Whitecomb , W . D . ( 1931 ) Control of root weevils on Taxus and other quantities . Environmental Entomology , 15 , 1074 – 1077 . nursery plants . American Nurseryman , 39 , 33 – 35 . Shanks , C . H . Jr , Chase , D . L . & Chamberlain , J . D . ( 1984 ) Resistance Wilcox , J . , Mote , D . C . & Childs , L . ( 1934 ) The Root Weevils Injuri- of clones of wild strawberry, Fragaria chiloensis , to adult Otio- ous to Strawberries in Oregon . Oregon State Agricultural College rhynchus sulcatus and O. ovatus . Environmental Entomology , 13 , Agricultural Experiment Station Bulletin 330. Oregon State Agri- 1042 – 1045 . cultural College , Corvallis, Oregon . Smith , F . F . ( 1932 ) Biology and Control of the Black Vine Weevil . United States Department of Agriculture Technical Bulletin, 325. Accepted 2 June 2006 USDA, Washington , District of Colombia . First published online 13 September 2006