Host specificity and biology ofMegacyllene mellyi [Col.: Cerambycidae] introduced into australia for the biological control ofBaccharis halimifolia [Compositae]

Biology and host plant specificity of the stem boring cerambycidMegacyllene mellyi (Chevrolat) were studied in Brazil to determine its suitability for introduction into Australia for control of the shrubBaccharis halimifolia L. Multiple choice host preference testing of plants related toBaccharis, of desirable plants from a range of plant families, and of the host plants of otherMegacyllene species, showed thatM. mellyi was restricted toBaccharis spp. It was introduced into Australia in 1975 and released in 1978. Recoveries were made 3 years after release and some stems were killed, although damage was slight relative to the number ofB. halimifolia plants in the release area.     

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.      

Evaluation ofStethorus nigripes [Col.: Coccinellidae] for biological control of spider mites in California almond orchards

Stethorus nigripes Kapur (=S. loxtoni Britton & Lee) was imported from Australia in 1978 and released in California during 1978–1980. Laboratory and field cage studies evaluated aspects ofS. nigripes' biology considered likely to affect establishment. Our tests indicated that most ♀♀ became nonreproductive during late fall. The females' reproductive arrest seems not to be a true diapause, but may be due to chill experienced by pupae. Survival over winter of both sexes was low if they were not provided abundant prey; honey or water alone were inadequate.S. nigripes adults and larvae could not feed onPanonychus ulmi (Koch) orP. citri (McGregor) eggs and avoided all stadia ofBryobia rubrioculus (Scheuten) in laboratory tests, so it is not a “generalist” predator of spider mites.S. nigripes also is susceptible to pesticides used to control key insect pests in almonds, including the pyrethroid, permethrin (LC 50 value=0.48 g A.I./100 liter water). Releases to establish this predator were discontinued after 3 years, asS. nigripes' sensitivity to pesticides and its requirement for prey during winter seem sufficient to account for its failure to establish. Even if established, these factors might preventS. nigripes from becoming an effective spider mite predator in pesticide-treated almond orchards in California.     

Host-specificity and biology ofMetallactus patagonicus [Col.: Chrysomelidae] introduced into Australia for the biological control ofBaccharis halimifolia [Compositae]

Biology and host-specificity of the foliage-feeding chrysomelidMetallactus patagonicus Suffrian were studied in Brazil to determine its suitability for introduction into Australia to control the shrubBaccharis halimifolia L. Multiple-choice host preference testing of plants related toBaccharis and of desirable plants from a range of plant families, showed thatM. patagonicus was restricted toBaccharis spp. It was released in Australia in 1975, but did not establish.      

Host specificity and biology ofLioplacis elliptica [Col.: Chrysomelidae] introduced into Australia for the biological control ofBaccharis halimifolia [Compositae]

The nocturnal foliage feeding ChrysomelidLioplacis elliptica Stal occurs onBaccharis gaudichaudiana DC. in Brazil. Studies of its biology and host plant specificity showed it was restricted tobaccharis spp. It was introduced into Australia for the control ofB. halimifolia L. in 1976 and first released in 1977. Field colonies persisted for up to 3 years after which no further evidence of survival was found.      

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.      

Influence of larval rearing diet on the intensive searching behaviour ofHarmonia axyridis [Col.: Coccinellidae] Larvae

The capture of prey by last instar larvae of the aphidophagous coccinellidHarmonia axyridis Pallas (Col.,Coccinellidae) modified larval movement so that extensive search was replaced by intensive search. The continuous rearing of this species on eggs ofEphestia kühniella Zell. (Lep.,Pyralidae) or on the aphidAcyrthosiphon pisum Harris (Homopt.,Aphidae) led to conditioning. Only larvae that ate the same prey as they were reared on, adopted intensive searching movements after feeding. Using larvae reared on substitute prey in biological control systems may decrease the efficiency of the released predators.     

Naturally-occurring biological control of the boll weevil [Col.: Curculionidae]

Red imported fire ants,Solenopsis invicta Buren, are effective predators of the boll weevil,Anthonomus grandis Boheman, in east Texas cotton fields. Boll weevils caused no economic loss in 11 years due to mortality attributed primarily to ants. Removal of the ants resulted in an increase in crop damage by the boll weevil. Insecticides used for cotton pests greatly reduce the abundance of the ants. To capitalize on this effective predation of boll weevils by ants, unnecessary applications of insecticides should be eliminated.     

Preference for medium dense grass tussocks byHippodamia convergens [Col.: Coccinellidae]

The preference in the choice of hibernacula of the convergent lady beetle,Hippodamia convergens Guérin-Meneville, was investigated with regard to morphological aspects of 2 introduced range grasses,Panicum coloratum (L.), andEragrostis curvula (Schrad.) Beetles strongly preferred tussocks with a ratio in the range of 1.0–3.0 stems per cm² for lovegrass. Preference for klein grass tussocks ranging from 110–130 stems/clump was found. No preference was shown for a particular tussock circumference. It was demonstrated that tussocks could successfully be designated as suitable for beetle aggregation.     

Introduction and evaluation ofChilocorus bipustulatus [Col.: Coccinellidae] for control ofParlatoria blanchardi [Hom.: Diaspididae] in date groves of Niger

Chilocorus bipustulatus L. was successfully established in oases of the Aïr Mountain region of Northern Niger (West Africa), where it became the major cause of mortality among adult females of the armored scaleParlatoria blanchardi Targioni-Tozzetti. This resulted in significantly lower scale infestation of date palms in a test plot when compared to a control with no introduced ladybeetles. The coccinellids were able to reproduce year-round, but during the hot season were largely confined to natural refuges composed of dense stands of date palms. Dispersal and multiplication occurred primarily during the rainy season, toward the end of which the greatest suppression of scale populations was seen.     

Trophic regulation of postdiapause ovariole maturation inCoccinella septempunctata [Col.: Coccinellidae]

In 1977 the vernal maturation ofCoccinella septempunctata L. females was investigated in relation to the variation in aphid population density on alfalfa and cereals in central Bohemia. The ovarioles do not ripen unless the aphid population density reaches a certain threshold. This leads to considerable variability in the time of vernal reproductive activity (up to 1.5 months in the same geographic locality) among subpopulations living on crops with different aphid densities. This mechanism enables the reproduction of the aphidophagous insect to synchronize with the population development of the aphid.     

Ecological requirements for hibernatingPropylea quatuordecimpunctata (L.) andCoccinella septempunctata [Col.: Coccinellidae]

During 3 successive winters, we studied the dormancy sites ofPropylea quatuordecimpunctata (L.) andCoccinella septempunctata L., 2 species of ladybirds which hibernate in leaf litter. Samples of litter were taken from several kinds of forest to study the influence of 3 variables (exposure; altitude; sampling place: edge or inner wood) on the abundance of ladybirds. We found the ecological requirements of the 2 species of coccinellids to be quite different:C. septempunctata prefers forest edges orientated towards the South and the West.P. quatuordecimpunctata prefers the inner wood and does not show a preference for station exposure. For each species, the number of ladybirds collected in the samples is positively correlated with station altitude. In addition, some observations were carried out to examine the main mortality factors just before and during dormancy. In maize fields near dormancy sites, the harvest is very harmful forC. septempunctata. During the winter,P. quatuordecimpunctata andC. septempunctata suffer fromBeauveria ssp. and some ladybirds have parasitoïds.     

Development time ofCoccinella septempunctata in relation to constant temperatures[Col.: Coccinellidae]

Development times at constant temperatures were determined for the egg, larval and pupal stages ofCoccinella 7-punctata L., recently introduced to U.S.A. Males and females developed at the same rate. The egg stage lasted from 2.3 to 13.0 days at 30° and 15°C, respectively. Larvae feeding onAcyrthosiphon pisum (Harris), pea aphids, required from 6.2 to 31.1 days at 32.5°, and 17.0°C, respectively. These development rates are similar to those reported in the European literature.

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Résumé Les durées de développement à températures constantes ont été déterminées pour l'œuf, les stades larvaires et l'imago deCoccinella 7-punctate récemment introduit aux états-Unis. Les males et les femelles se développent au même rythme. Le stade œuf dure de 2,3 à, 13,0 j à 30° et 15°C, respectivement. L'alimentation des larves avec le puceron du poisAcyrtosiphon pisum (Harris) dure 6,2 et 31,1 j à 32,5 et 17,0°C, respectivement. Le stade nymphal est observé pendant 2,8 et 13,0 j à ces mêmes températures. Ces vitesses de développement sont les mêmes que celles données dans la littérature européenne.

     

Propagation of the Colorado potato beetle [Col.: Chrysomelidae] egg parasiteEdovum puttleri, [Hym.: Eulophidae]

The parasitic wasp,Edovum puttleri Grissell, was successfully reared onLeptinotarsa decemlineata (Say) in the laboratory and increased in sufficient numbers for inoculative release studies in the spring and summer. The effects of temperature on parasite development, and host-parasite ratios in the laboratory are presented. The sex ratio of parasites reared in the laboratory are compared to those released and recovered in the field.     

Biological control of alligator weed: Unsuccessful attempts to control terrestrial growth using the flea beetleDisonycha argentinensis [Col.: Chrysomelidae]

Biological control of alligator weed growing in aquatic habitats in Australia is successful but the agents, a flea beetleAgasicles hygrophila and a mothVogtia malloi, do not control terrestrial growth. Consequently another flea beetleDisonycha argentinensis was introduced into Australia specifically to control the terrestrial growth. Progeny of adults collected in Brazil from areas similar in climate and habitat to areas infested with alligator weed in Australia, were released but failed to become established. Eggs were laid by females released into a large field cage and some completed development, but the new adults failed to reproduce. Tentative conclusions are that microclimate or predation may have prevented establishment ofD. argentinensis but the results should not preclude attempts to establish this insect in North America, China or elsewhere.      

Host specificity ofDisonycha argentinensis [Col.: Chrysomelidae], an agent for the biological control ofalternanthera philoxeroides (Alligator weed) in Australia

The biology and host specificity of a South American flea beetle,Disonycha argentinensis Jacoby was investigated in quarantine facilities in Australia. Damage from feeding by larvae and adults ofD. argentinensis onAlternanthera philoxeroides (Mart.) Griseb (alligator weed) indicated that it might be a useful biological control agent for the plant when growing in terrestrial situations. Complete development of the immature stages took place only onAlternanthera philoxeroides. Adults produced a few feeding scars onBeta vulgaris L. (beetroot) andAmaranthus spinosus L. (spiny amaranth) but failed to oviposit. Host specificity studies indicated that establishment of this beetle in Australia would be without significant risk to nontarget plant species.D. argentinensis was first released in Australia in 1980.     

Les aptitudes trophiques et reproductrices des femelles deSemiadalia undecimnotata [Col.: Coccinellidae]

Résumé Les femelles de la coccinelleSemiadalia undecimnotata Schneider ingèrent environ 20 mg d'aphides par jour à 22°C lorsqu'il y a surabondance de proies. Dans les premiers jours qui suivent la mue imaginale, ces prises alimentaires provoquent une augmentation sensible du poids corporel des femelles qui par la suite oscille autour d'une valeur moyenne relativement stable. La rapidité de la maturation dépend de la ration alimentaire disponible pour les femelles. L'émission des premiers œufs se produit lorsque les femelles ont ingéré de 70 à 90 mg de proies. Pendant la période de ponte, il existe une relation linéaire étroite entre la consommation alimentaire et la ponte exprimées en poids frais et sous forme cumulée. Elle pourrait permettre d'envisager le dénombrement des œufs produits par les femelles comme un moyen d'estimer partiellement leur activité trophique. Toutefois au sein de la population considérée, les aptitudes reproductrices sont très hétérogènes. Cette variabilité, qui est observée dans des conditions constantes d'élevage et qui est indépendante du poids initial des individus, pourrait être d'origine génétique: dans cette éventualité, il est peut-être possible de sélectionner les femelles en fonction de leur efficacité trophique ou de leurs capacités reproductrices.

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Summary The females of the lady bird beetleS. undecimnotata Schneider ingest an average of 20 mg of aphids per day at a temperature of 22°C and in trophic conditions that are plethoric. In the first days after emergence, this feeding induces an appreciable increase of body-weight that later remains steady. Ovarian growth is depeneent on the number of prey available to females. The release of the first eggs occurs when females have ingested about 70 to 90 mg of prey. During the reproductive stage, a narrow linear relationship links feeding consumption to egg-laying, this being expressed cumulatively in mg. This relationship allows the counting of eggs produced by females to be considered as a means of partly estimating ingestion. In the population studied, the trophic and reproductive capacities are very dissimilar. This variability observed in steady conditions of breeding is not dependent on the initial body-weight of the females and seems to have a genetic source. In this eventuality, it is perhaps possible to select the females according to their trophic efficiency or to their reproductive capacities.

     

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.

     

Biological control ofMythimna separata [Lep.: noctuidae] in New Zealand and its bearing on biological control strategy

A survey of parasites ofAgrotis spp. was carried out in Pakistan to find promising species for trial against noctuids especiallyAgrotis spp. andMythimna separata (Walker) in New Zealand. The parasites recorded wereApanteles ruficrus Haliday,Macrocentrus collaris Spinola,Periscepsia carbonaria Panzer,Turanogonia smirnovi,Rohdain,Ctenichneumon panzeri Wesmael andAnthrax sp. All exceptAnthrax sp. were supplied to New Zealand whereA. ruficrus andM. collaris were released in large numbers.A. ruficrus became established and is giving excellent control ofM. separata resulting in enormous economic gains. Recently it has also been recovered fromAgrotis spp. This example of biological control is significant in thatM. separata has been controlled by a parasite that was previously known from it in New Zealand. The specific status of the “A. ruficrus” already present in New Zealand requires investigation.     

The observed sex ratio ofPediobius foveolatus [Hym.: Eulophidae] in field populations ofEpilachna varivestis [Col.: Coccinellidae]

Larvae ofEpilachna varivestis Mulsant, parasitized byPediobius foveolatus (Crawford), were collected in soybean fields in Maryland during 1975. AdultP. foveolatus emerging from the larvae were sexed and counted. The ratio of males to females increased as the availability of food within the host decreased. This information is useful in development of exponential models predicting hostparasite interactions.