Affects of two cotton varieties on levels of boll weevil parasitism [Col.: Curculionidae]

The cotton plant has a profound affect on the behavior and ability of parasites to successfully attack the boll weevil,Anthonomus grandis Boheman. The most important native parasite of the boll weevil,Bracon mellitor Say, prefers to oviposit on Frego bract cotton rather than normal bract cotton. An imported parasite,Heterolaccus grandis Burks prefers ovipositions on normal bract cotton rather than Frego.     

Killing power of the red imported fire ant [Hym.: Formicidae]: a key predator of the boll weevil [Col.: Curculionidae]

The red imported fire ant,Solenopsis invicta Buren, was identified as a key predator of the boll weevil,Anthonomus grandis Boheman. Although key factor analysis does not guarantee that the key factor is the causative agent, the evidence of boll weevil mortality was so clear that the fire ant could be identified as causing the mortality. Ant predation on immature boll weevils during the summer of 1981 averaged 84%. When this predation was combined with other natural mortality factors, the weevil population density throughout the season never exceeded levels that required control measures.     

Laboratory rearing ofAnaphes sordidatus [Hym.: Mymaridae] on carrot weevil eggs [Col.: Curculionidae]

A technique for rearingAnaphes sordidatus (Girault) on eggs of laboratory-reared carrot weevil,Listronotus oregonensis (Le Conte), is described. Individual rearing was possible by using polyethylene embedding capsules that enabled easy manipulation of parasitized carrot weevil eggs for use in subsequent experimental procedures. The technique described resulted in 65% parasitization of carrot weevil eggs and 90 mn per day were sufficient to obtainca. 200 parasites daily.      

Lixus cribricollis [Col.: Curculionidae] for biological control of the weedsEmex spp. andRumex crispus in Australia

The biology and host specificity of a colony ofLixus cribricollis Boheman originating in Morocco were studied in quarantine in Australia.L. cribricollis adults are long lived, have an aestivation and are univoltine.Rumex crispus L.,Emex australis Steinheil andE. spinosa (L.)Campdera were shown to be the only satisfactory hosts of 40 species of plants from 17 families that were exposed to sexually mature adults ofL. cribricollis. Normal feeding and occasional oviposition were observed on some other plants within the same family,Polygonaceae, including the minor crops rhubarb and buckwheat, but almost invariably larvae died in the 1st instar. It was concluded thatL. cribricollis may be a useful biological control agent for the weedsR. crispus, E. australis andE. spinosa and that establishment of this weevil in Australia would be without risk to non-target plants.     

Eriocereophaga humeridens [Col.: Curculionidae], a potential agent for the biological control ofEriocereus martinii [Cactaceae] in Australia

The weevilEriocereophaga humeridens O'Brien attacks the cactusEriocereus adscendens (Gurke) in N.E. Brazil. Laboratory tests and field observations demonstrate that it will also acceptEriocereus martinii Lab. as host, and does not damage plants except in the sub-familyCereanae of theCactaceae. Young plants and regrowth are preferentially attacked and larval feeding inE. martinii results in the death of attacked stems.E. humeridens was approved for liberation in Queensland, Australia in February 1976, for the control ofEriocereus spp., and field releases were made in 1976.

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Résumé Le coléoptèreEriocereophaga humeridens O'Brien attaque le cactusEriocereus adscendens (Gurke) qui est indigène du Nord-Est du Brésil. Il a été établi par des essais en laboratoire ainsi que par des observations en champ d'expérimentation, qu'E. humeridens peut également vivre surEriocereus martinii Lab., et qu'il n'est nuisible que pour les plantes de la sous-familleCereanae desCactaceae. Il attaque de préférence les jeunes pousses et les rejetons; et ses larves tuent en les mangeant les tiges d'E. martinii qui sont atteintes. En février 1976, afin de limiter les espèces d'Eriocereus, l'approbation fut donnée de lacherE. humeridens en Queensland, Australie, ce qu'on a fait sur les lieux au cours de la même année.

     

Mating behavior ofBathyplectes curculionis [Hym.: Ichneumonidae] a parasitoid of the alfalfa weevil,Hypera postica Col.: Curculionidae]

We describe the courtship behavior of male and femaleBathyplectes curculionis (Thomson). FemaleB. curculionis are polygamous and sexually receptive for up to 2 days after eclosion. The high activity levels of virgin females combined with their polygamy and long period of sexual receptivity allow for post-dispersal mating which may facilitate maximum gene flow between localB. curculionis populations. This high genetic diversity may be partially responsible for the widespread occurrence ofB. curculionis in North America.

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Résumé Nous décrivons le comportement sexuel deBathyplectes curculionis (Thomson) male et femelle. Les femelles deB. curculionis sont polygames et réceptives 2 jours après l'éclosion. L'activité des femelles vierges et leur polygamie associées à la longue période de réceptivité sexuelle permettent un maximum d'échanges génétiques entre les populations locales. Cette grande diversité génétique peut être en partie responsable de l'étendue de la distribution deB. curculionis en Amérique du Nord.

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Partially supported by funds from both the Department of Entomology and the Graduate School of The Ohio State University.

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Submitted to the Graduate School of The Ohio State University in partial fulfillment of the requirements of the degree of Doctor of Philosophy. Present address: Agricultural Research Center, University of Florida, 3205 S. W. 70th Avenue, Ft. Lauderdale, Florida, U.S.A., 33314.     

Notes on the biology ofOdynerus dilectus [Hym.: Eumenidae], a predator of the alfalfa weevil,Hypera postica [Col.: Curculionidae]

We describe the nest construction and architecture, and the prey collection and storage behavior ofOdynerus dilectus Saussure, a ground-nesting eumenid wasp of North America that exclusively utilizes weevil larvae of the genusHypera as prey. This species may have potential as a biological control agent of alfalfa and clover weevils in the genusHypera because of its rapid collection of weevil larvae, its gregarious nesting habit, and the apparent ease with which individuals can be transplanted. Other European congeners have many similar characteristics. The potential for adverse interactions betweenO. dilectus andBathyplectes curculionis (Thomson), a parasite ofHypera, is discussed.     

Life cycle and host specificity of the heliotrope weevil,Pachycerus cordiger (=Madidus auct.) [Col.: Curculionidae]

Pachycerus cordiger Germar (Curculionidae: Cleonini) is a potential agent for the biological control ofHeliotropium europaeum L. (Boraginaceae) in Australia. Adults feed on the leaves and larvae feed on the main roots of the weed within an earthen cell. These is one generation per year. Adults overwinter in the cells before emerging in late spring when they begin to feed, mate and oviposit on their host plants from late May until late July. Seven Boraginaceae and 31 economically important crop species were tested using adults and 1^st instar larvae.P. cordiger was found to be specific to the Boraginaceae. Field observations strongly suggested that the weevil is restricted to summer-annualHeliotropium species. A widespread egg parasite,Caenocrepis? bothynoderi Gromakov [Hymenoptera: Pteromalidae], caused up to 18% mortality.     

Predation of eggs ofSitona hispidulus [Col.: Curculionidae] in alfalfa

The predation on egg populations ofSitona hispidus (Fabricius) [Col.: Curculionidae] in a stand of alfalfa was evaluated in 1982 and 1983. By using pitfall traps, catches of reproductive adults ofS. hispidulus were correlated with catches of carabid species, and potential egg predators were identified for further evaluation. Results indicated that predators removed 28 % of eggs under field conditions.Amara aenea DeGeer was found to be particularly efficient on eggs ofS. hispidulus under caged-field conditions.      

Laboratory rearing of the predatory coccinellidCleobora mellyi [Col.: Coccinellidae] for biological control ofParopsis charybdis [Col.: Chrysomelidae] in New Zealand

Cleobora mellyi Mulstant has been introduced into New Zealand in an attempt to controlParopsis charybdis Stål. Artificial diets and a practical method for rearing the predatory Australian ladybird,C. mellyi, are described.     

Temperature-dependent development and reproduction of the boll weevil (Coleoptera: Curculionidae)

Abstract Effects of temperature on development, survival, and fecundity of boll weevil, Anthonomus grandis grandis Boheman, were assessed at 10, 11, 12, 15,20,25,30,35,45, and 46 °C; 65% relative humidity; and a photoperiod of 13:11 (L: D) h. The mortality of boll weevil immature stages was 100% at 12°C and decreased to 36.4% as the temperature increased to 25°C. When the temperature increased from 30 °C to 45 °C, the mortality of weevils also increased from 50.1% to 100%. From 15°C to 35°C, the bollweevilpreimaginal development rate was linearly related to temperature. The average development time of total boll weevil immature lifestages decreased 3.6-fold and the preovipositional period decreased 3.3-fold when the temperature was increased from 15°C to 30°C. The lower threshold for development was estimated at 10.9, 6.6, 7.0, and 9.0 °C for eggs, larval, pupal, and total immature stages, respectively, with total thermal time requirement to complete immature stages of 281.8 DD (degree day) (15°C) and 247.8 DD (35 °C). At 1LC and 46°C, weevil females did not oviposit. Longevity of adult females decreased 4.6-fold with increasing temperatures from 15°C to 35°C. Fecundity increased with increasing temperatures up to 30°C and significantly decreased thereafter. These findings will be useful in creating a temperature-based degree-day model for predicting the occurrence of key life stages in the field. An accurate predictor of a pest's development can be very important in determining sampling protocols, timing insecticide applications, or implementing an integrated pest management control strategy targeting susceptible life stages.     

Investigations on the parasitism ofOtiorrhynchus salicicola andO. Sulcatus [Col.: Curculionidae] byHeterorhabditis sp. [Nematoda]

Experiments were conducted to study the efficacy of the insect parasitic nematodeHeterorhabditis sp. (HW79) as a biological control agent ofOtiorrhynchus salicicola. This weevil species is reported as a pest of ornamental plants in Switzerland and Italy. Dipping plastic boxes containing heavily infested cuttings of laurel (Prunus laurocerasus) in a nematode suspension resulted in approximately 100% parasitisation of full-grown larvae, pupae and non-emerged young adults. The average dose resulting from dipping varied between 56,000 and 62,000 nematodes per liter soil. This experiment was run under natural outdoor conditions. In a further outdoor experiment, pottedLigustrum plants were inoculated with eggs ofO. salicicola and later 20,000 infective juvenile nematodes per liter soil were added to the soil surface. The resulting weevil mortality in the treated pots was 78%. In seven greenhouse tests using the same nematode dose in pots with horticultural soil to which weevil larvae had been added, weevil mortality varied between 76% and 100%, the arithmetic average being 90%. These results indicate that Heterorhabditid nematodes may provide an effective means of controllingO. salicicola. In an other experiment usingO. sulcatus larvae, the influence of application time on nematode efficacy was investigated. When nematodes were added a few days before weevil larvae had hatched from the eggs, no parasitic effect was obtained. Nematode applications done shortly after larval hatching however, resulted in complete weevil control. These results are of significance in timing nematode applications in practice.      

Size-dependent feeding and reproduction by boll weevil (Coleoptera: Curculionidae)

The considerable variation in adult size of the boll weevil, Anthonomus grandis grandis Boheman, has been well documented, but the influences of adult size on reproductive rate are not known. We examined the relationship between the size of boll weevils and their feeding and oviposition. Weevils weighed to the nearest milligram were grouped into five categories based on pupal weight: < or =5, 6-10, 11-15, 16-20, and >20 mg. Numbers of lifetime punctures produced in flower buds (squares) of cotton, Gossypium hirsutum L., by both sexes of adults tended to increase with pupal weight. Boll weevil females with pupal weights >10 mg produced progeny with significantly higher survival to adulthood and also produced a higher percentage of female progeny than those with pupal weights < or =10 mg. The population growth indices for females having pupal weights >10 mg averaged 1.8-fold higher than those of females weighing < or =10 mg. Survivorship of adults of both sexes also tended to increase with pupal weight. The percentage of females laying eggs on any given day averaged 2.1 times higher when their pupal weights were >10 mg than when their pupal weights were < or =10 mg. Although small size negatively affected female reproductive potential, even extremely small females produced some viable offspring. However, the penalties of small adult size, in terms of longevity and reproductive potential, suggest that cultural practices that result in the production of small adults may be used to impact weevil populations.     

Effect on waterhyacinth ofNeochetina eichhorniae [Col.: Curculionidae] combined withOrthogalumna terebrantis [Acari: Galumnidae]

Seven hundred mottled waterhyacinth weevils,Neochetina eichhorniae Warner, were released in a Fort Lauderdale, Florida, canal on a mat of waterhyacinth,Eichhornia crassipes (Mart.) Solms-Laubach. At the time of weevil release, the mat contained ca. 100 adult waterhyacinth mites,Orthogalumna terebrantis Wall-work/plant, and ca. 15 immature waterhyacinth mites/cm². Waterhyacinth weevil populations increased to ca. 4 adults and 5 larvae/plant after 50 weeks, and were unaffected by weather. Waterhyacinth mite populations reached a peak of ca. 840/plant after 16 weeks, at which time they were reduced in number by low temperatures. Decrease in size and density of waterhyacinth closely followed buildup of weevil populations, with petiole length decreasing by 35% and plant density reduced by 45% over a 50 week period. The phytopathogenic fungusAcremonium zonatum (Saw.) Gams., which causes zonate leaf spot disease of waterhyacinth, developed in waterhyacinth mite tunnels after the adult mite created an emergence hole, but was not observed in weevil feeding spots.     

Predators ofBathyplectes curculionis [Hym.: Ichneumonidae], a parasite ofHypera postica [Col.: Curculionidae]

Invertebrate predation was shown to be the greatest mortality factor on diapausing larvae ofBathyplectes curculionis (Thomson) in Illinois. Feeding tests were conducted in which specific predators were determined by exposingB. curculionis larvae to various surface dwelling invertebrates found in alfalfa fields. In addition, field plantings of parasite larvae in modified cages were used to determine the size of predators, and also, if litter density affected predation. Seasonal activity ofB. curculionis predators was also measured from 4 April 1975 to 18 November 1975 via 15 pitfall traps located in 3 alfalfa fields. Results from feeding studies showed that spiders,Cicindelidae, Formicidae and smallStaphylinidae never preyed uponB. curculionis larvae in cocoons. The 2 groups of predators which consumed the larvae were field crickets,Gryllus pennsylvanicus Burm., and various species ofCarabidae. Predation on the parasite larvae planted in the field was mainly caused by moderately sized invertebrates, and was not significantly affected by litter density. The greatest number of total predators (G. pennsylvanicus plus Carabids) caught/day/pitfall trap, and the greatest predation on field-plantedB. curculionis larvae, occurred concurrently during September and October. These data suggest that predation during September and October may be significant in reducing field populations of diapausing parasite larvae. Based on feeding studies and pitfall trap catches,Gryllus pennsylvanicus and the carabids,Abacidus permundus (Say),Evarthrus sodalis LeConte,Harpalus pennsylvanicus DeGeer andScarites subterraneus Fab., were the most important predators onB. curculionis larvae.

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Résumé Il a été montré que les prédateurs invertébrés sont le plus grand facteur de mortalité des larves en diapause deBathyplectes curculionis (Thomson) en Illinois. On a fait des essais alimentaires dans lesquels on a déterminé des prédateurs spécifiques en exposant les larves deB. curculionis à divers invertébrés trouvés dans les champs de luzerne. De plus, des larves du parasite, dans des cages modifiées implantées dans les champs, ont été employées pour vérifier la taille des prédateurs et aussi pour savoir si la densité de la litière a influencé les prédateurs. L'activité saisonnière des prédateurs deB. curculionis a été mesurée du 4 avril 1975 au 18 novembre 1975 au moyen de 15 pièges placés dans 3 champs de luzerne. Les résultats des essais alimentaires montrent que les araignées,Cicindelidae, Formicidae et de petitsStaphylinidae n'ont jamais utilisé comme proie les larves en cocon deB. curculionis. Deux groupes de prédateurs ont consommé les larves: les grillons,Gryllus pennsylvanicus Burm., et des espèces variées deCarabidae. Pour la plupart ce sont des invertébrés de taille modérée qui ont utilisé comme proie les larves implantées dans les champs, la densité de litière n'étant pas significative. Le plus grand nombre de prédateurs au total (G. pennsylvanicus plusCarabidae) attrapés par jour et par piège et la plus grande consommation de larves deB. curculionis se sont produits concurremment en septembre et en octobre. Ces données indiquent que les prédateurs en septembre et octobre peuvent être très importants pour réduire le nombre de larves parasites en diapause. Si l'on juge selon les essais alimentaires et selon ce qu'on a attrapé dans les pièges,Gryllus pennsylvanicus et lesCarabidae, Abacidus permundus (Say)tEvarthrus sodalis LeConte,Harpalus pennsylvanicus DeGeer,et Scarites subterraneus Fab., on, constitué les prédateurs spécifiques les plus importants des larves deB. curculionis.

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This publication was supported by the Illinois Natural History Survey, The Illinois Agricultural Experiment Station, National Science Foundation, and the U.S. Environmental Protection Agency, through a grant (NSF GB-34718) to the University of California. The findings, opinions and recommentations expressed herein are those of the author(s) and not necessarily those of the University of California, the National Science Foundation and the Environmental Protection Agency.     

Host-specificity of fiveAnacassis species [Col.: Chrysomelidae] introduced into australia for the biological control ofBaccharis halimifolia [Compositae]

Foliage-feeding beetles of the genusAnacassis [A. phaeopoda Buzzi,A. fuscata (Klug),A. fuscata var.unicolor (Burmeister),A. cribrum (Klug) andA. dubia (Boheman)] were collected fromBaccharis spp. andBaccharidastrum spp. in South America. Specificity studies showed that they were restricted to these 2 host genera. Between 1974 and 1976 these species were introduced into Australia for the control ofBaccharis halimifolia. A. phaeopoda andA. fuscata were first released in 1976. One field colony ofA. fuscata persisted for up to 3 years but no recoveries ofA. phaeopoda were made after the 1st field generation. The other species died out in quarantine and were not released.      

Competition betweenBracon mellitor [Hym.: Braconidae] andCatolaccus grandis [Hym.: Pteromalidae] for their hostAnthonomus grandis [Col.: Curculionidae]

BioControl - Laboratory studies of competition between populations of 2 parasitoids of the cotton boll weevil,Anthonomus grandis Boheman, showed that populations ofCatolaccus grandis (Burks)...     

Attractant for the sugar-beet weevil Conorrhynchus (Cleonus) mendicus (Col.: Curculionidae)

Abstract:  Traps baited with a 1 : 1 : 1 mixture of Grandlure I [ cis -1-methyl-2-(1-methylenethenyl)-cyclobutaneethanol], Grandlure II [( Z )-2-ochtoden-1-ol; ( Z )-2-(3,3-dimethylcyclohexylidene)ethanol] and Grandlure III–IV [( Z )- and ( E )-2-ochtodenal; ( Z )- and ( E )-(3,3-dimethyl)cyclohexylidene)acetaldehyde] caught significantly more Conorrhynchus (Cleonus) mendicus Germar (Col.: Curculionidae) weevils than traps without bait. Later tests revealed that only Grandlure III–IV was responsible for attractivity. Both sexes were attracted according to a random sample of captures. C. mendicus appeared to be very similar in its responses to the synthetic aggregation attractant as the closely related Bothynoderes (Cleonus) punctiventris (Germar), in which species, the attraction to Grandluree III–IV has recently been published. Doses from 500 to 5000  μ g of Grandlure III–IV on rubber dispensers performed satisfactorily in monitoring trials and can be recommended for use in practical trapping applications for C. mendicus .     

Comparisons of standard and extended-life boll weevil (Coleoptera: Curculionidae) pheromone lures

The Southeastern Boll Weevil Eradication Program has proposed reducing maintenance program costs in eradicated zones by using an extended-life "superlure" in traps to detect populations of the boll weevil, Anthonomus grandis grandis Boheman. However, superlure effectiveness has not been extensively evaluated. We compared the superlure (30 mg of eugenol plus 25 mg of grandlure) to a standard lure (10 mg of grandlure) based on captures of weevils and changes in lure pheromone content. Lure treatments (standard and superlure, replaced biweekly or not replaced) were compared in 4-mo-long trapping periods. Captures of weevils did not generally reflect differences among lure treatments indicated by assays of lure contents. During the first 2 wk of exposure, amounts of pheromone released by the superlure were generally comparable with those of the standard lure, but pheromone composition was more stable. During the second 2 wk of exposure, the superlure usually released more pheromone than similarly aged standard lures, but less than half as much as the standard lure replaced biweekly. Based on numbers of captured weevils during the last 2 wk of an extended trapping period, the superlure performed similarly to the standard lure replaced biweekly. However, corresponding pheromone releases by the superlure were less than those by the standard lure replaced biweekly. This inconsistency suggests that numbers of captured weevils alone may be inadequate for evaluation of pheromone formulations. Our results suggest that better understanding of the consequences of reduced pheromone release during an extended trapping period is needed before adoption of the superlure can be recommended.     

The challenge of biological control of Cosmopolites sordidus Germar (Col. Curculionidae): A review

The banana weevil (also known as banana root borer) Cosmopolites sordidus Germar (Coleoptera Curculionidae) is the major pest of banana and plantain. Because banana ranks 2nd in fruit production worldwide, this pest has substantial social and economic importance. The biological control of the C. sordidus remains challenging because of its behaviour and resistance to parasitism and predation. The last review concerning the biological control of C. sordidus was published two decades ago, and relevant knowledge and methods have developed in the interim. The present paper provides an update of that knowledge and summarizes past and current challenges as well as providing perspectives on achieving sustainable control of C. sordidus. We first discuss studies on the classical biological control of C. sordidus, underlining the limits of classical biological control methods such as the importation of predators, parasitoids or pathogens. Next, we consider conservation biological control of C. sordidus, with a focus on ants. We also highlight an ‘arthropod bias’ that has led to a lack of information on the role of vertebrates in the regulation of C. sordidus.