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.     

Habitat preferences of aphidophagous coccinellids [Coleoptera]

From May to July 1982 and 1983, coccinellids were sampled in habitats that differed in aphid density, insolation, and host plant type. The number of adults ofCoccinella 7-punctata (CS),C. 5-punctata (CQ),Propylea 14-punctata (PQ),Adonia variegata (AV),Adalia bipunctata (AB),A. 10-punctata (AD), andCalvia 14-guttata (CA) were recorded. AB, AV and CS preferred high, while CQ tolerated low aphid density. CQ, CS, AB and AV preferred sunny, while AD and CA tolerated shaded conditions. CS and AV preferred herbaceous plants, AD and CA large plants, particularly trees, AB showed little specialization, CQ preferred trees early in the season and sparse herbaceous plants later. PQ appeared to be a generalist with a wide tolerance of all these factors, but with a tendency to move from trees to herbaceous plants as the season progressed. Habitats with a high abundance of a species were assumed to be those with on optimum combination of the preferred conditions. There were slight differences in the breadth of habitat preferences, and a little habitat overlap between species. The tendency to aggregate was greater in AB than in other species. Annual variations in species abundance influenced the number of habitats occupied, but not the abundance in the favoured places.     

Assessment of temperature-dependent development in the general population and among isofemale lines ofCoccinella trifasciata (Col.: Coccinellidae)

Temperature-dependent development ofCoccinella trifasciata LeConte from Corvallis, Oregon, was assessed for the general population and compared among a subset of isofemale lines. All eggs died at 10 and 34°C. Survival ranged between 63.3–96.7% from 18–34°C. Development from oviposition to adult ranged from 44.2 days at 18°C to 11.1 days at 34°C. Mean adult weight did not differ among temperatures, and was 15.2 mg overall. For the species, heat-unit requirements for development from egg to adult were 227 degree-days above a developmental threshold of 12.7°C. Values for the developmental threshold differed among isofemale lines, and ranged from 11.4–14.5°C with heat-unit requirements ranging from 186–260 degree-days above their respective threshold. The isofemale line producing the fastest rate of immature development at 18°C was characterized by a heat-unit requirement of 260 degree-days above a developmental threshold of 11.4°C. The isofemale line producing the slowest rate of immature development at 18°C was characterized by a heat-unit requirement of 186 degree-days above a developmental threshold of 14.5°C. Implications of using isofemale lines in culturing biological control agents are discussed.

---

Résumé L'effet de la température sur le développement deCoccinella trifasciata (provenant de Corvallis, Oregon) a été étudié pour la population générale et comparé entre lignées isofemelles. Aucum œuf ne survit à 10 et 34°C. Le taux de survie est compris entre 63,3% et 96,7% pour des températures situées entre 18 et 34°C. La durée du développement, de la ponte à l'état adulte, dure de 44,2 jours à 18°C à 11,1 jours pour une température de 34°C. Le poids moyen de l'adulte ne change pas en fonction de la température et il est de 15,2 mg. Pour l'espèce, les besoins pour le développement complet de l'œuf à l'adulte, sont de 227 degrés-jour au-dessus du seuil de développement de 12,7°C. Les valeurs de ce seuil diffèrent entre les lignées isofemelles et sont comprises entre 11,4 et 14,5°C pour des durées se situant entre 186 et 260 degrés-jour au-dessus des seuils respectifs. La lignée isofemelle ayant la vitesse de développement larvaire la plus rapide à 18°C est caractérisée par un besoin de 260 degrés-jour au-dessus du seuil de 11,4°C. Celle ayant la vitesse de développement la plus lente à 18°C est caractérisée par un besoin de 186 degrés-jour au-dessus du seuil de 14,5°C. L'intérêt de l'utilisation de lignées isofemelles dans l'élevage d'agents de lutte biologique est discuté.

     

Response ofNabis roseipennis [Heteroptera: Nabidae] to Larvae of Mexican bean beetle,Epilachna varivestis [Col.: Coccinellidae]

Laboratory studies were done to measure predation by adult damsel bugs,Nabis roseipennis Reuter [Heteroptera: Nabidae], on 3^rd instar larvae of Mexican bean beetle (MBB),Epilachna varivestis Mulsant [Coleoptera: Coccinellidae], and to measure longevity and body weight of the nabids. In the 1^st experiment, field-collected nabids were isolated for 24h in 9 cm Petri dishes with lima bean foliage (Phaseolus lunatus L.) and were assigned to one of 3 prey treatments: either 4 3^rd-instar MBB larvae, 4 3^rd-instar larvae of boll weevil (BW),Anthonomus grandis Boheman [Coleoptera: Curculionidae], or 2 larvae of each species. No MBB larvae were attacked in either the MBB treatment or 2-species treatment. In contrast, BW larvae were attacked in both BW and 2-species treatments. Significantly more BW larvae were attacked in the BW treatment than in the 2-species treatment, and both were greater than the number of MBB larvae attacked. Nabids that did not attack prey lost weight during the 24 h, whereas those that attacked prey gained weight. In the 2^nd experiment, nabids that had attacked prey were isolated with lima foliage, and nabids that had not attacked prey were kept with MBB and lima foliage until an attack or death. In no instances were MBB attacked. Longevity and the pattern of weight loss did not differ between nabids that did or did not attack prey. We discuss possible reasons for the failure ofN. roseipennis to attack MBB larvae, as well as the implications for using nabids to influence pest populations in the field.      

Effect of temperature on the development of the immature stages ofBembidion lampros [Coleoptera: Carabidae]

The effects of temperature on survival and development of immature stages ofBembidion lampros were examined under controlled conditions in the laboratory. The duration of development was examined at 5°C, 12°C, 17°C, 19°C, 22°C, 25°C, 30°C and 32°C and found to be inversely related to temperature. Between 12°C and 30°C there was a significant difference in duration of egg development, but no significant difference in percentage of eggs hatched. The upper and lower lethal limits for egg development were estimated (c 31°C and 4°C respectively). There are 3 larval instars and one pupal stage. Development of larva plus pupa required a minimum of 20.9 days at 30°C. Between 22°C and 30°C survival from larva to the adult stage was 80%.      

Life history of the importedScymnus (Nephus) Reunioni [Col.: Coccinellidae] predator of mealybugs

The life history ofNephus reunioni, introduced from the Reunioni island has been studied. Optimum temperature for the development of the entomophagous insect is 24–25°C. In this case the population has the highest survival at preimaginal stages, life duration of adults and reproductive capacity. The rate of population growth was calculated by the formula:

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.      

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.      

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 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.      

The effect of host age ofLymantria dispar larvae [Lep.: Lymantriidae] on the development ofGlyptapanteles liparidis [Hym.: Braconidae]

The endoparasitic development ofG. liparidis was examined in 3 different host stages of gypsy moth larvae. Hatching ofG. liparidis-larvae occurred 3 to 5 days after oviposition in hosts parasitized during their premoulting period, and after 5 to 7 days in those parasitized in the 3^rd midinstar state. The parasites generally moulted to the 2^nd larval instar between the 11^th and 13^th day in the first group, and between the 13^th and 15^th day in the latter, when they had reached a volume of 0.04–0.05 mm³. The positive correlation between host ecdysis and the ecdysis of 1^st stadium larvae to L₂ suggested that host moulting influenced the development of the parasitoid larvae. Emergence from the host larvae occurred at 20°C after 27 days on average, and coincided with the parasites moulting to the 3^rd instar. Five to 7 days after spinning their cocoons near the developmentally arrested host larva, the male, and 1 to 2 days later the female wasps eclosed. Due to the variation in the number of parasites per host, no difference was observed between the hosts parasitized at various stages; however, a tendency for later parasitized hosts to contain more parasite larvae was evident. The nutritional conditions of the moth parental generation influenced both host and parasite development. On the other hand no influence of host age was observed on emergence dates of larvae and wasps.      

The biology and host specificity of the stem-boring weevilListronotus setosipennis [Col.: Curculionidae] A potential biocontrol agent forParthenium hysterophorus [Asteraceae]

The stem-boring weevilListronotus setosipennis (Hustache) is widespread and damaging to its hostParthenium hysterophorus L. in northern Argentina and southern Brazil. In detailed host-testing it was shown to have a restricted host-range and, despite some feeding and development on sunflower in tests, to be a safe biological control agent againstP. hysterophorus. Field releases in Queensland, Australia took place from 1982 to 1986 and the weevil has established over several thousand hectares at numerous sites. Spread is however slow and the effect on the plant still negligible.      

Susceptibility of two Coconut Pests,Oryctes rhinoceros [Col.: Scarabaeidae] andTirathaba rufivena [Lep.: Pyralidae], to the entomoparasitic nematodeSteinernema feltiae [= Neoaplectana carpocapsae]

Bioassay indicated that 1 st instar larvae ofOryctes rhinoceros are resistant to infections by the nematodeSteinernema feltiae (estimated LD₅₀: 90 nematodes) but thatTirathaba rufivena larvae larger than 15 mm are highly susceptible (estimated LD₅₀: 3 nematodes). The “All” strain and the “mexican” strain ofS. feltiae gave very similar responses. In a field trial 300,000 nematodes were sprayed on each of 25 palms to controlT. rufivena. Although some mortality from nematodes was observed, the treatment failed to reduce the pest population significantly.     

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.     

Occurrence and pathogenicity ofBeauveria bassiana infesting larvalSitona discoideus [Col.: Curculionidae] in the Mediterranean region

Field survey showed that the fungusBeauveria bassiana Vuillemin was the predominant natural enemy ofSitona discoideus Gyllenhal larvae and pupae in the Mediterranean region. The present area of distribution of the disease does not, however, include the parts of North Africa, Cyprus, Syria and Iraq with a Mediterranean climate. At localities regularly investigated in southern France over the period 1973–79, the population dynamics of larvalSitona on volunteerMedicato species appeared to be correlated to some extent with the impact of the fungal disese, which could produce up to 100% mortality on its host larval populations. Several isolates of the pathogen were tested in laboratory bioassays to determine their potential activity. One accession from southern France proved particularly virulent toS. discoideus larvae and pupae at the relatively low concentration of 10⁵ conidia/g of soil. This accession seemed worth considering for further quarantine testing and introduction into Australia. Differences between isolates were however confounded by varying ages of the cultures involved.

---

Résumé Les recherches entreprises de 1973 à 1984 ont montré que le champignon entomophatogèneBeauveria bassiana Vuillemin était largement répandu sur larves deSitona spp. en rǵeion méditerranéenne. Il y fait toutefois défaut (tableau 2) dans les zones pastorales d'Afrique du Nord, de Chypre, de Syrie et d'Irak. La mortalité larvaire due à cette mycose parait en mesure d'influencer l'évolution dynamique des populations deSitona discoideus Gyllenhal (tableau 3). En effet,B. bassiana est susceptible d'affecteur jusqu'à 100% des larves deS. discoiduus s'attaquant aux dieverses espèces deMedicago, suivant les sites considérés en France méditerranéenne. Lors de tests en laboratoire une souche méridionale deB. bassiana s'est révélée paritculièrement infectieuse à des doses relativement faibles, de l'ordre de 10⁵ conidies par gramme de terre (tableau 4). Une telle virulence perment d'envisager d'éventuelles applications de plein champ contreS. discoideus en Australie méridionale. Une expérimentation plus détaillée est`a prévoir, qui devra cependant tenir compte d'un affaiblissement graduel du pouvoir infectieux des isolats au cours de leur conservation en mycothéque.

     

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.     

Distribution and effectiveness ofAnaphes diana [=Patasson lameerei] [Hym.: Mymaridae], a parasitoid ofSitona spp. Eggs [Col.: Curculionidae] in the Mediterranean region

Surveys conducted from 1973 to 1984 showed thatAnaphes diana Girault was the predominant parasitoid ofSitona spp. eggs throughout the Mediterranean range of Spain, France, Italy, Greece, Bulgaria, Romania, Turkey and Syria. In each of these countries, the mean percentage parasitism of eggs fluctuated between 1.9 and 23.9%. The impact of the mymarid on its host increased considerably from autumn to spring. Two biotypes ofA. diana, one reproducing bisexually, the other being strictly thelytokous, occur sympatrically in the Mediterranean region. The origin of various consignments ofSitona eggs parasitized byA. diana shipped to Australia for field release of the mymarid is recorded. Egg parasitoids were found in the Damascus area (Syria) that may be adapted to and effective under the hot and dry climatic conditions of South Australia.     

Effect of parent density on fecundity of two parasitoids [Hym.: Pteromalidae] of the olive beetle,Phloeotribus scarabaeoides [Col.: Scolytidae]

Under laboratory conditions (22±2°C, 60%±5% H.R.; and 16L.: 8D. photoperiod), the rearing of the 2 main parasitoids ofPhloeotribus scarabaeoides (Bernard, 1788) in Southern Spain:Cheiropachus quadrum (Fabricius, 1787) andRaphitelus maculatus Walker, 1834 (Hym.: Pteromalidae) has been carried out. Several densities of population of the parasitoids have been tested in order to determine their reproductive behaviour, and this is significant if the output of a rearing is to be increased. A great competition among the individuals of the same sex has been observed; in the case of the ΦΦ, a potential negative correlation with the increase of density of population, has been noted. The biotic potential belonging to the 2 principal parasitoids species with and without competition, are calculated, and the aspects concerning the parasitoid colonization of the olive tree beetle infestation spots, are discussed.      

Removal of Benzo[a]pyrene by a fungus Aspergillus sp. BAP14

A fungal strain BAP14 isolated from marine sediments of coast in Xiamen city, was found to have the ability to degrade benzo[a]pyrene (BaP), and identified as Aspergillus sp. based on 18S rRNA gene sequence. Aspergillus sp. BAP14 was able to remove about 30 and 60% of BaP with initial concentration of 10 mg l⁻¹ in 3 and 12 days of incubation, respectively. Addition of saccharides and low molecular weight polycyclic aromatic hydrocarbons appeared to have effect on the degradation ability, in particularly the addition of lactose and naphthalene. Furthermore, we demonstrated that lipidic particles could be observed in the presence of benzo[a]pyrene based on the morphologic performance of Aspergillus sp. BAP14 through scanning electronic microscopy (SEM) and atomic force microscopy (AFM), respectively.     

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.