摘要:

Effects of commercially available pheromone blends and release rates, dispenser type, and trap design on catches of malemullein bugs, Campylomma verbasci(Meyer), in pheromone-baited traps were investigated. In the Okanagan Valley of British Columbia, a 16:1 blend of butyl butyrate (BB) and 2(E)-crotyl butyrate (CB)had the highest mean trap catch combined with lowest coefficient of variation. Comparable results from Nova Scotia suggest that trapping technology developed in British Columbia can be applied throughout the east-west range ofC. verbasciin Canada. Further tests in British Columbia showed that a 16:1 blend of BB and CB captured a high number of maleC. verbasciwhen released at rates from 0.8 to 2.8 mg/d (as measured at 25°C), and a rate of 5 mg/d caught the lowest number of males. A release rate of 0.2 mg/d should be sufficiently attractive for use in a pheromone-based monitoring program. Wing traps fitted with 3-cm-long drinking-straw spacers between the trap top and bottom captured more maleC. verbasci, and had a lower coefficient of variation, than wing traps without spacers. A recently developed polymer release device was found to be effective for use in a monitoring program forC. verbasci.

DOI:10.1093/ee/23.2.442

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Oviposition responses of three conifer-feedingChoristoneuraspecies (C. fumiferana[Clemens],C. occidentalisFreeman, andC. pinusFreeman) and one deciduous-feedingChoristoneuraspecies (C. conflictana[Walker]) to host cues were studied in arenas containing filter paper as the main oviposition substrate. Generally, all species laid more eggs on filter paper treated with hexane extracts of host foliage than with hexane alone, but the number of eggs deposited per egg mass was not significantly different. For the conifer-feeding species, the stimulating effect of host chemicals was independent of physical stimuli associated with host foliage. Oviposition byC. fumiferanafemales was also stimulated by extracts of nonhost conifers and trembling aspen, a deciduous species.C. pinusandC. occidentaliswere stimulated by some nonhost coniferous extracts but not by extracts of trembling aspen.C. conflictanafemales were not stimulated by coniferous extracts. Oviposition responses to host physical stimuli were evaluated with artificial (plastic) coniferous twigs with needle lengths of 1.25, 2.5, or 3.5 cm. In most cases, females of the conifer-feeding species preferred the artificial twigs to the filter-paper substrate. Needle lengths of the preferred twigs corresponded to the range of needle lengths found on the hosts of each species.C. conflictanaoviposited exclusively on the filter-paper substrate, which corresponds to the flat surface of aspen leaves. When given a choice between ovipositing on surrogate twigs or on filter paper treated with host extract,C. fumiferanafemales preferred the surrogate twigs, suggesting that the effects of tactile cues predominated over close-range chemical cues.

DOI:10.1093/ee/23.2.447

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Investigations were conducted on effect of temperature on development of parasitoids of the southern pine beetle,Dendroctonus frontalisZimmermann.Coeloides pissodes(Ashmead),Dendrosoter sulcatusMuesebeck,Spathius pallidusAshmead,Dinotiscus dendroctoni(Ashmead), andHeydenia unicaCook&Davis were studied in the field and at constant temperatures of 15, 20, 25, and 30°C in the laboratory. Development of parasitoids from egg to adult at field temperatures during August 1991 required ≈2 wk for all species. The southern pine beetle requires ≈1 mo to complete development at optimum temperatures. There was little difference in development times among these parasitoid species at 20°C. All parasitoid species required approximately twice as long to develop at 20°C than at the two higher temperatures. Males generally developed more rapidly than females at all temperatures. Survival of all species exceptD. dendroctonidecreased at 15°C. The greatest numbers of parasitoids were reared from study trees that contained an ≈1:1 host-stage ratio of late instars to pupae.

DOI:10.1093/ee/23.2.457

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Three independent studies were conducted on the effects of constant temperatures (0, 3, 6, 9, 12, 15, 18, and 25°C) with numerous exposure times (15 to 240 d) on diapausing embryos of the northern corn rootworm,Diabrotica barberiSmith and Lawrence. All three studies had similar results. The temperahlres 15 and 18°C appeared to enhance diapause development and subsequent diapause termination when compared with the lower temperatures (O–3°C). However, the temperature range 9–12°C was optimum for minimum mortality and maximum hatch at nearly all exposure times used. At this range and in particular 9°C, hatch was as high as 60% after 180 d exposure. Exposures of 15 and 30 d produced minimal hatch,<20%, at any temperature. Days to hatch tended to decrease as temperature increased but varied with experiment. Hatching time also decreased as exposure increased for all temperatures. Eggs exposed only to the developmental optima of 25°C had<20% hatch in all studies, and ≥50% of the eggs were still in the diapause state at the conclusion of the studies. We concluded that mostD. barberiembryos require low temperature to terminate diapause and complete embryogenesis. These studies support the hypothesis thatD. barberihas a propensity to be continuously variable in diapause length. Also, variable diapause length has allowed this species to adapt to natural and artificial perturbations, in particular, crop rotation.

DOI:10.1093/ee/23.2.464

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Mechanical wounding and wounding plus inoculation with a blue-stain fungus,Leptographium abietinum(Peck), associated with the spruce beetle,Dendroctonus rufipennis(Kirby), caused an induced reaction zone or lesion around the wound sites in Lutz spruce,Picea lutziiLittle, Sitka spruce,P. sitchensis(Bong.) Carr., and white spruce,P. glauca(Moench) Voss, in south-central Alaska. The effects of tree species on lesion length were nonsignificant; however, the effects of wounding versus wounding plus blue-stain inoculate were highly significant. Lesion length was significantly longer in high-flow Lutz spruce compared with low-flow trees that were wounded. There was a significant change in monoterpene composition in the induced reaction zones of wounded phloem compared with unwounded phloem. The total percentage of potential toxic monoterpenes such as limonene, myrcene, 3-carene, and beta phellandrene increased in all three host species. Egg gallery length and the area of phloem consumed by larvae outside of lesions was significantly less for trees with wounds caused by fungal inoculation compared with mechanical wounds only. Trees with fungal inoculations appeared to deter larval feeding. Hydroxystilbenes were not found in the three species of spruce; however, differences were found in the chemical content of the reaction and the nonreaction zones. Two unknown chemicals present in nonreaction zones were not found in the induced reaction zone. One chemical appears to be a dimer with a carbohydrate moeity. A low molecular weight chemical found in the induced reaction zone could not be identified by mass spectroscopy.

DOI:10.1093/ee/23.2.472

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The population growth and survival ofMesocyclops aspericornis(Daday) andMesocyclops darwini(Dussart&Fernando) were compared in rainwater tanks at Amity Point, Stradbroke Island, and natural breeding habitats in other Queensland localities. The biological and physicochemical attributes of these biotopes were measured and it was found that pH, protozoan numbers, and chlorophyll level all significantly affectedMesocyclopspersistence and population growth. While these three factors accounted for 82% of the variation, low food levels were considered to be the major factor limiting growth and survival. Protozoan and algal levels in tanks were one-fifth that of natural breeding sites. In a series of laboratory trials,Mesocyclopspopulation growth was maximal in the pH range of 6.0–8.0 and in salinities below 1.66 parts per thousand. Greatest growth also occurred in media with both protozoans and algae at levels greater than 32,000 per ml and 3.9μg/liter, respectively. The variability of and low food levels in rainwater tanks will limit broad scale use of copepods for biocontrol ofAedeslarvae in these sites.

DOI:10.1093/ee/23.2.479

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The relationship of insect diet to pathogenicity and reproduction of an entomogenous nematode,Steinernema carpocapsaeAll strain (Nematode: Steinernematidae) was investigated in the black cutworm,Agrotis ipsilon(Hufnagel). Cutworms fed on collard foliage or on artificial diet were equally infected by and killed byS. carpocapsae.However, nematode progeny production was lower in collard-fed cutworm larvae. The difference in progeny production corresponded to difference in lipid content of cutworms; 210 nematodes per mg were produced from collard-fed larvae, which contained 8% lipids, while 390 nematodes per mg were produced from artificial diet-fed larvae, which contained 16% lipids. Addition of commercially obtained sinigrin, a glucosinolate allelochemical found in collards, to artificial diet at biologically relevant levels also demonstrated suppression of nematode progeny production. It appears that host diet is a salient characteristic in progeny production of entomogenous nematodes.

DOI:10.1093/ee/23.2.487

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The honey bee,Apis melliferaL., is a highly efficient forager on numerous flowering plants that host phytophagous insect pests. Because of these associations, honey bees theoretically provide an economical and nonintrusive means of conveying biorational mortality agents against pest species. This hypothesis was tested during April 1989 by employing a specially designed plexiglass and sheet metal applicator that causes honey bees to disseminate a talc formulation ofHeliothisnuclear polyhedrosis virus (HNPV) into fields of crimson clover,Trifolium incarnatumL. The device when integrated into a specifically designed substructure of a conventional beehive provided separate entry and departure pathways for honey bees, which allowed bees to be surface-contaminated with the HNPV formulation as they exited the hive. The mean percentage of HNPV-induced mortality was significantly higher amongHelicoverpa zea(Boddie) larvae that fed on clover heads from fields foraged by HNPV-contaminatedA. melliferaand amongHeliothisorHelicoverpaspp. larvae collected from those fields than among similarly exposed control larvae. HNPV in honey collected from treatment hives and stored at 26 ± 1°C in total darkness remained active for at least 170 d. The extent to which the technology for usingA. melliferato disseminate insect pathogens is applicable for pest control will depend on an improved understanding of the interrelationships amongA. mellifera, flowering plants on which they forage, targeted phytophages which reside on the plants, and the availability of pathogens which attack the phytophages.

DOI:10.1093/ee/23.2.492

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The effect of mycelial and conidial formulations of the insect pathogenic fungi,M. anisopliae, on the survival and behavior Japanese beetle,Popillia japonicaNewman, larvae and ovipositing adults in turfgrass-soil microcosms was explored. Changes in Japanese beetle grub feeding site selection on sod roots, movement patterns, and survival inMetarhizium anisopliaeinoculated soil were examined in greenhouse studies and through the use of radiographic analysis in the laboratory. Our studies indicate that the application of mycelial particles in soil affected the behavior of both larval and adult Japanese beetles. Japanese beetle grubs avoided soil that contained high concentrations of pathogen for up to 20 d after application. Conversely, the incorporation of mycelial particles increased oviposition in both choice and no choice studies. Our findings on scarab response to inundative applications ofM. anisopliaemycelium may help explain some of the inconsistency in results that often occur when fungal pathogens are used to control insects in the field.

DOI:10.1093/ee/23.2.502

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Entomopathogenic fungiBeauveria bassiana(Balsamo) Vuillemin,Metarhizium anisopliae(Metschnikoff) Sorokin,M. flavoviride(Gams&Rozsypal),Paecilomyces fumosoroseus(Wise) Brown&Smith, andVerticillium lecanii(Zimmerman) Viegas were evaluated for pathogenicity and virulence to pear psylla,Cacopsylla pyricola(Foerster), nymphs using a detached-leaf bioassay. Isolates withinB. bassianaandP. fumosoroseuswere also compared. Conidia suspended in water were applied to first and second instars at various concentrations and evaluated 3, 5, and 7 d after application. All of the fungal isolates tested were pathogenic to pear psylla nymphs.B. bassiana, P. farinosus, andV. lecaniiwere significantly more virulent than theMetarhiziumspp. (mortality range, 92.5–99.6% versus 42.3–54.7%, respectively, on 7 d at 107conidia/ml). Similarly, the LC50s did not significantly differ for all isolates except theMetarhiziumspp. and ranged between 1.4 × 102– 2.0 × 104conidia/ml on 7 d.Metarhiziumspp. had significantly lower LC50s than the other isolates, that ranged from 2.3 × 107– 11.7 × 1010conidia/ml on 7 d. The fastest acting isolate when applied at 107conidia/ml wasP. fumosoroseusARSEF #2658 with an LC50of 1.8 d, which was significantly higher than other isolates exceptB. bassiana.The LC50could not be calculated forM. anisopliaebecause percent mortality did not increase with time. Based on LT50, LT50, and percent mortality comparisons,P. fumosoroseusARSEF #2658 was the most virulent fungal isolate followed byB. bassianaAHSEF #2860. The potential of these isolates as mycoinsecticides for the control of pear psylla nymphs in orchards is discussed.

DOI:10.1093/ee/23.2.514

出版商:Oxford University Press    

年代:1994

数据来源: OUP