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Common green lacewings (Chrysoperla carnea species complex) are important predators of several insect pests, particularly aphids. Due to their potential in biological control, several efforts have been made to find means to retain common green lacewing adults or even to increase their numbers at a given site. In the course of field experiments conducted in Hungary and Norway, we tested the effect of a known ternary bait (phenylacetaldehyde, methyl salicylate, acetic acid) on oviposition and overwintering site choice of common green lacewings. In an orchard in Hungary, overwintering chambers were set up with and without baits. For the experiment on oviposition in Norway, a number of lacewing eggs were compared on trees with and without baits in selected sectors of the canopy. With the ternary bait, more common green lacewings could be attracted to overwintering chambers, and also significantly more eggs were found in the vicinity of baits than in other selected parts of the canopy, suggesting that this bait has the potential to manipulate both overwintering site choice and oviposition site choice of these important beneficial insects.

Insect pest management in wild blueberry (Vaccinium angustifolium Aiton) usually involves insecticidal sprays, which may have detrimental effects on non-target beneficial insects. Dogbane beetle (Chrysochus auratus Fabricius) (Coleoptera: Chrysomelidae) feeds almost exclusively on spreading dogbane (Apocynum androsaemifolium L.), an increasing weed problem in wild blueberry production. Because C. auratus is an important natural enemy of spreading dogbane, we assessed its susceptibility to several insecticides it may be exposed to during insect pest management. In laboratory bioassays, we found adult dogbane beetles were highly susceptible to field rates of phosmet (Imidan) and acetamiprid (Assail) by direct topical contact and ingestion of treated foliage, whereas no mortality was seen with spirotetramat (Movento) and chlorantraniliprole (Altacor). Topical applications of spinetoram (Delegate) did not cause significant mortality of beetles, but high mortality to beetles was found when they ingested spinetoram-treated foliage. The results suggest that while some insecticides used in blueberry management will be hazardous to C. auratus, options are available that will cause little harm to this natural enemy.

Post-market monitoring (PMM) consistent with Swiss and European Union legislation should ensure the detection and prevention of adverse effects on the environment possibly deriving from commercial cultivation of genetically modified (GM) crops. Insect-resistant GM crops (such as Bt-maize) raise particular questions regarding disturbances of biological control functions provided by beneficial insects such as predators and parasitoids (so-called natural enemies). Consensus among regulators, scientists and the agricultural biotech industry on appropriate PMM plans allowing the detection and possibly prevention of such adverse effects is still lacking. The aims of this study were to identify the necessity for PMM of Bt-maize expressing Cry1Ab on natural enemies and to develop an appropriate PMM plan. The approach chosen consisted in determining what type of monitoring is most appropriate to address potential effects of Bt-maize on natural enemies during commercial cultivation. This included identifying whether there remain substantial scientific uncertainties that would support case-specific monitoring. Existing pre-market risk assessment data indicate that Bt-maize (Cry1Ab) comprises a negligible risk for disturbances in biological control functions of natural enemies. As a consequence, a faunistic monitoring of specific groups of natural enemies is not considered an appropriate approach to detect failures in biological control functions. Alternatively, an approach is proposed that consists in indirectly analysing biological control functions by surveying outbreaks of maize herbivores. Unusual herbivore outbreaks could indicate failures in biological control functions of natural enemies. Data could be collected via questionnaires addressed to farmers growing Bt-maize. Significant correlations between unusual occurrences of specific maize herbivores and the cultivation of Bt-maize would subsequently need specific studies to determine possible causalities in more detail. The here proposed approach has the advantage of covering different natural enemy groups. It represents a cost-effective strategy to obtain scientifically sound data as a basis for regulatory decision-making.

This study investigated the effect of competition from wheat and below ground herbivory on the growth and reproduction of scentless chamomile, Tripleurospermum perforatum (Merat) Lainz (Asteraceae), a target plant for classical biological control. Field cages, in which scentless chamomile was planted, were established in 1994 near Neuenburg (Rhine Valley, Germany), and two weevil species, Diplapion confluens Kirby and Coryssomerus capucinus (Beck), were released alone (40 adults each) or together in a substitutive design (20 adults each). Wheat was sown alone or in combination with both herbivores as an additional stress factor. To test the cage effect on plant growth, an uncaged control was set up. At the end of the experiment, caged control plants were about 20 cm (18%) higher, and allocated more biomass to shoots and less to roots and seeds than uncaged plants. Competition from wheat reduced the number of shoots per T. perforatum plant from 7.6 to 3.2. As a consequence, the biomass of scentless chamomile plants that competed with wheat was reduced by 39% and reproductive output by 49%, compared with plants that were grown without competition. At the end of the experiment, 70–80% of T. perforatum plants had been attacked by an average of two to three D. confluens and 60–70% of plants by one to two C. capucinus. At these densities that were lower than expected, the two herbivores alone or in combination had no significant effect on any of the plant parameters measured. However, in the presence of wheat, herbivory further reduced the number of shoots per plant. We conclude that control of scentless chamomile using insect biocontrol agents will be more likely to be successful if agent densities are high, and agents are released in habitats where scentless chamomile is competing with other plant species.

An extended laboratory method was developed to study the side-effects of pesticides on plant-dwelling, walking beneficial insects such as anthocorids, coccinellids and chrysopids. By using a glass funnel with a slippery surface, larvae of Anthocoris nemoralis, a natural enemy of pear psylla, stayed mainly on the treated plant surface and access to untreated surfaces was discouraged. The optimal ventilation produced a favourable environment and low mortality in the control. Tests with seven insecticides on the anthocorid larvae produced consistent toxicity results.

In the course of three storage periods (1988-90) the predacious insects that occur in traditional maize stores in southern Togo were observed and their relationship to the introduced pest Prostephanus truncatus was investigated. The bug Xylocoris flavipes, a predator on a wide range of post-harvest pests, was the only one observed regularly and in higher numbers. Laboratory trials with P. truncatus showed that the larvae were preyed on, and no preference for any one of the three instars was detected. On average, 7.3 pest larvae were killed by larvae or adults of the predator. In glass jar trials on loose maize X. flavipes reduced the numbers of P. truncatus by 57.6% after 8 weeks. The losses and damage were reduced by 50 and 17.6%, respectively. Observations in traditional maize stores indicated a tendency to decreasing populations of X. flavipes when populations of P. truncatus increased, presumably due to the unfavourable environmental conditions created by the pest. Therefore, it is concluded that X. flavipes does not play an important role in the control of this pest.

Dispersal within agricultural fields and the effects of different barriers on between-field movement of the New Zealand hover fly Melanostoma fasciatum were studied using ingested pollen as markers. Hover flies did not generally disperse more than 20 m from the pollen source. Gravid females had no significant wind-directed movement pattern whereas males significantly flew downwind. Flies tended to avoid flying over barren land: a dirt track, an asphalt road or a ploughed field all seemed to hamper hover fly dispersal equally. The implications for spatial arrangement of the flowering strips to enhance the biocontrol potential of hover flies are discussed.

The toxicity of a mixture of two photoactive dyes, Phloxine B and Uranine, was determined for six species of beneficial insects in the laboratory. The dye had no measurable contact toxicity to any test insect. The dye, when mixed in protein baits, was significantly more toxic than the bait alone to Chrysopa carnea Stephens, Cryptolaemus montrouzieri Mulsant, Delphastes pusillus Le Conte and Goniozus legneri (Gordh). The toxicity of all dye and bait mixtures was significantly less to all test insects than that of the malathion and bait mixtures. Substituting the dye mixture for malathion in protein bait sprays used to eradicate exotic fruit flies from the United States should significantly reduce the kill of non-target beneficial insects.

Neem products are safe to spiders, adults of numerous beneficial insect species and eggs of many predators such as coccinellids. Nymphal/larval instars are more or less susceptible, especially under laboratory conditions. No or only slight side-effects are, as a rule, observed under semi-field or field conditions. Due to their relative selectivity (‘stage selectivity’) neem products can be recommended for many programmes of Integrated Pest Management as it is unlikely that they will cause severe disturbances in ecosystems. In a few exceptional cases caution is recommended but it should be borne in mind that many more so-called indifferent as well as beneficial insects and spiders are killed by synthetic pesticides as compared with neem products. Or in other words, the use of neem-based pesticides can be a substantial contribution towards preservation of biodiversity in ecosystems in spite of the fact that they are not completely safe to all stages of beneficial nematodes, mites, and insects.

The weaver ant Oecophylla longinoda Latr. attacks the coconut pest Pseudotheraptus wayi Brown. The big headed ant Pheidole megacephala Mayr is the most important enemy of O. longinoda. After the stop of weed control in a coconut site, the number of palms colonized by O. longinoda increased from 696 trees in April 1991 to 1776 palms in April 1992 because P. megacephala stopped attacking O. longinoda and started to forage on the weeds and bushes on the ground. From September 1991 until October 1992 60 068 nuts were harvested. The control of P. megacephala with Amdro in a neighbouring plot of the same size was less effective because the initial colonization by O. longinoda in the plot was much lower. These palms produced 28 413 nuts less. It is concluded that reduced weed control can enhance O. longinoda

Mapping and collection of ants in cocoa trees in a 1 ha plot in the south of Bahia, Brazil, revealed three dominant species of the ant mosaic : Wasmannia auropunctata, Ectatomma tuberculatum and Azteca chartifex spiriti. A. chartifex demonstrated a larger influence in the cocoa plantation due to its spatial and temporal (1 y) stability in the same cocoa trees, and its capacity for territorial expansion. The management of A. chartifex for controlling insect pests of cocoa is strongly recommended. Considerations of temporal permanence of mosaic dominant ants should be a necessary criteria for ant management in tropical tree crops.

In 1989 a total of 4471 spruce cones was harvested at 29 locations distributed over the five main geographic regions of Switzerland, i.e. Jura, Central Plateau, North, Central and South Alps. The cones were incubated in a controlled environment chamber and the emerging insects were collected and identified. This analysis excludes parasitoids except for the most abundant Torymus spp. Twelve insect species and some 14000 individuals in total were identified. On the average, every cone was inhabited by three insects. The most numerous species were Kaltenbachiola strobi (Winn.), Cydia strobilella (L.), and Torymus spp., amounting together to 95% of the total insect number. Though the abundance peaks varied for different species, most insects were reared from cones from the alpine area. Vegetation type (alliance) was related to the abundance of several species but did not correlate with total infestation rate. For two species their number was related to sampling site altitude. Likewise, a positive, linear correlation was found between the frequencies of the parasitoid Torymus spp. and its host K. strobi, the ratio between the two species averaging 0.7. Cone setting did not correlate with infestation level, but tree age was positively related to total insect number per cone. In the laboratory C. strobilella and K. strobi were the earliest species to emerge; they had the shortest emergence period as well. The percentage of K. strobi with prolonged diapause (emergence in second year after cone sampling) was 51%, while the corresponding values for all other species were lower than 20%. Neither sampling site elevation nor cone setting affected diapause length.

During the period from 1991 to 1993 3521 insect specimens representing 12 species were obtained from 629 Norway spruce cones. This material originated from the Babia Gora National Park 50 km southwest of Krakow and its surroundings. The coenotic groups of conophages, seminiphages and parasitoids were distinguished. For each group the index of dominance (D), stability of incidence (C), species diversity (d), and Agrell's index of species co-existence were calculated. Seed losses caused by insects were estimated on the basis of the analyses of 46 118 seeds.

In this paper we describe the introduction and establishment of the polyphagous parasitoid Aphidius colemani into Tonga in an attempt to control the banana aphid, Pentalonia nigronervosa. P. nigronervosa is a serious pest of Musa spp. because of direct feeding damage and, more importantly, as a vector for banana bunchy top virus disease. A. colemani was introduced to Tonga from Australia, cleared through post-entry quarantine and mass reared for field release. More than 32000 parasitoids were released on Tongatapu Island, Tonga, between April 1990 and November 1991. Results of surveys conducted during the project have not provided evidence for the parasitoid attacking P. nigronervosa in the field. However, A. colemani was recovered from Aphis gossypii on taro, Colocasia esculenta about 9 months after the cessation of releases confirming its establishment. A. gossypii is one of a number of other species present in the Tongan aphid fauna that are suitable hosts for Aphidius colemani. Experimental studies on the acceptance of alternate aphid hosts by A. colemani are presented; along with information on host suitability. These data show that P. nigronervosa is readily parasitized in the absence of ants.

Two introduced species of citrus whiteflies, Dialeurodes citri and Parabemisia myricae met in the east mediterranean area of Turkey and proved to be ecological homologues. P. myricae is the superior competitor on account of its faster development and broader ecological niche and started to replace D. citri. After a most effective parasitoid of P. myricae, the aphelinid Eretmocerus debachi was released and successfully suppressed this species, D. citri recovered and became dominant even in regions where it had not been present before. In this way the otherwise excellent economic success of the biological control of P. myricae was partly reduced. 1994 Blackwell Verlag GmbH

This study evaluates the potential of ants as natural biological control agents of the boll weevil (Anthonomus grandis), during the between-season period, in South-east Brazil. Active adults of Anthonomus were experimentally distributed on the ground of the cotton field. Results show that 20% of the adult Anthonomus are attacked and removed by foraging ants. The native ant Pheidole oliveirai was by far the most efficient predator, accounting for 94 % of the predation on Anthonomus. Recruited workers of P. oliveirai were usually very fast at transporting the weevils to their nests. The potential benefit of suppressing overwintering adult Anthonomus during the between-season period is mainly that of reducing the risk of high level infestations during the next cropping cycle.

It was established that Parthenolecanium corni (Bouche), Quadraspidiotus perniciosus (Comst.), and Dysaphis plantaginea (Pass.), had stable infestation patterns in the orchard over time. Other species had a stable distribution during part of the year and a random re-distribution at other times [Eriosoma lanigerum (Haus.), Aphidoletes sp.]. Other arthropods (Aphis sp., spiders, Coccinella septempunctata L.) had a random distribution pattern over time. The distribution pattern of insect species was determined variously by surrounding habitat (P. corni; Q. perniciosus; D. plantaginea), or by host plant susceptibility (E. lanigerum; Aphis spp.) which, in part, was a result of different size trees. We were able to detect the arrival of colonizing populations from outside the orchard using analysis of spatial distribution. The distribution pattern of predators was not always determined by the distribution of apple pests, but by alternate prey on weeds or in surrounding vegetation. For a better understanding of spatial distribution of insects in orchards it was necessary to combine several analysis techniques such as graphical methods, analysis of variance, correlation analysis, and chi-square; each method providing different types of information. The knowledge of aggregated distribution of pests can help to reduce the amount of pesticides using local treatments, saving with it natural enemies and increasing the possibilities of ecological plant protection. Zusammenfassung Uber die raumliche Verteilung einiger schadlicher Homopteren und nutzlicher Insekten in einer Apfelplantage und ihre Bedeutung im okologischen Pflanzenschutz Die Untersuchungen in einer ungespritzten amerikanischen Apfelplantage zeigten, daβ Parthenolecanium corni (Bouche), Quadraspidiotus perniciosus (Comst.) und Dysaphis plantaginea (Pass.) zeitlich stabile Befallsmuster aufwiesen. Andere Arten Arten zeigten stabile Verteilung nur zu einer bestimmten Jahreszeit und daruberhinaus eine instabile Zufallsverteilung (Eriosoma lanigerum (Haus.), Aphidoletes sp.). Weitere Arthropoden (Aphis spp., Spinnen, Coccinella septempunctata L.) lieβen nur zeitliche Zufallsverteilungen erkennen. Das Verteilungsmuster der Insektenarten wurde in verschiedener Weise von Umweltfaktoren bestimmt (P. corni, Q. perniciosus, D. plantaginea) oder von der Empfindlichkeit der Wirtspflanze, die vor allem vom Baumalter abhing (E. lanigerum, Aphis spp.). Mit Hilfe der Analyse der raumlichen Verteilung konnte der Beginn der Kolonisierung bestimmt werden. Das Verteilungsmuster von Predatoren hing nicht immer von der Verteilung der Apfelschadlinge ab, sondern wurde auch von den Beutetieren auf der umgebenden Vegetation bestimmt. Zum besseren Verstandnis der raumlichen Verteilung der Insekten in der Apfelplantage war es notwendig, verschiedene Analyse-Techniken wie grafische Methoden sowie Varianz-, Korrelations- und x2-Analyse zu kombinieren. Jede Methode fuhrte zu eigenen Informationen. Die Kenntnis der Verteilung der Schadinsekten in einer Obstplantage kann dazu beitragen, die Menge an Pestiziden zu verringern und dadurch die naturlichen Schadlingsfeinde im Sinne eines okologischen Pflanzenschutzes zu unterstutzen.

The cone entomofauna of native Norway spruce was compared to that of 28 exotic spruce species introduced in 2 French arboreta. Thirty-two insect species, including 12 phytophagous, have been observed. Most of them were native to Norway spruce. The seed wasp Megastigmus atedius was the only phytophagous pest introduced with its hosts from North America. It was recorded for the first time in France. The number of insect species that colonized cones was directly related to the phylogenetic and geographic proximity of the exotic spruce from Picea abies and to its flowering phenology. Early-flowering spruce species of abies group, originating from Hymalaya and central China, were the most attacked by insects, followed by Euro-Caucasian species of omorica group. Host range observed in each phytophage showed that damage was the more related to spruce phylogeny as insects were specialized in cone exploitation. The importance of entomological studies in arboreta was clearly demonstrated, as evidenced by the potential for native insects to shift to exotic species and the detection of introduced seed chalcids. Resume Les degâts d'insectes des cones sur les Coniferes exotiques introduits en arboretum. I. Variations interspecifiques au sein du genre Picea La colonisation par les insectes des cones de 28 especes exotiques d'epiceas introduites dans 2 arboreta francais a ete etudiee en reference a la faune entomologique connue sur l'essence native, l'epicea commun. Trente-deux especes d'insectes, incluant 12 ravageurs phytophages, ont ete observees. Un seul de ces phytophages, chalcidien des graines nouveau pour la faune de France, a ete introduit avec son hote depuis l'Amerique du Nord. Les autres especes appartenaient a la faune autochtone des cones d'epicea. L'importance de la colonisation des essences exotiques depend de leur proximite phylogenetique et d'origine geographique vis-a-vis de Picea abies, ainsi que de leur precocite de floraison. Les essences a floraison precoce du groupe abies, d'origine hymalayenne et de Chine centrale, sont les plus attaquees globalement, suivies par les essences euro-caucasiennes du groupe omorica. L'etude du spectre de colonisation de chaque espece d'insecte montre que ce lien avec la phylogenie du genre Picea est encore plus accentue chez les insectes specialistes. L'interet des etudes entomologiques dans les arboreta est finalement mis en evidence, notamment pour un inventaire precoce des potentialites des insectes autochtones a passer sur les essences exotiques et pour la decouverte de ravageurs des graines nouvellement introduits. Zusammenfassung Uber Insektenschaden an Zapfen exotischer, in Arboreten angebauten Koniferenarten. 1. Interspezifische Variationen in der Gattung Picea Es wurde die Entomofauna der Zapfen der einheimischen Norwegischen Fichte, Picea abies, mit jener von 28 exotischen Fichtenarten, die in 2 franzosischen Arboreten eingefuhrt worden waren, verglichen. Dabei wurden 32 Insektenarten festgestellt, darunter 12 Phytophagen, von denen die meisten an der Norwegischen Fichte heimisch waren. Die Samenwespe Megastigmus atedius war der einzige Schadling, der mit seinen Wirtsfichtenarten aus Nordamerika eingefuhrt wurde. Sie wurde zum ersten Mal in Frankreich registriert. Die Zahl der Insektenarten in Zapfen war direkt korreliert mit der phylogenetischen und geographischen Nahe der exotischen Fichte zur einheimischen Fichte, P. abies und zu deren Bluh-Phanologie. Fruh bluhende Fichtenarten der abies-Gruppe, die aus dem Himalaya und aus Zentralchina stammten, waren von Insekten am starksten befallen, gefolgt von den eurokaukasischen Arten der omorica-Gruppe. Die Wirtsreihe jedes Phytophagen zeigte, das der Schaden um so starker mit der Fichten-Phylogenie verbunden war, je besser die Insekten an die Verwertung des Zapfens angepast waren. Die Bedeutung von entomologischen Studien in Arboreten wurde klar dargestellt: die Erkennung des Potentials einheimischer Insekten, auf exotische Baumarten uberzugehen sowie die Entdeckung eingefuhrter Samenschadlinge.

Ecological pest management (EPM) uses many elements of integrated pest management (IPM) but it is based on keeping and supporting the natural stability of the agro-ecosystem and suppressing pest outbreaks at the very beginning when the pest population density is still low. The stability of the agro-ecosystem and high biodiversity may be achieved by certain combinations of different crops and lands with natural complexes of plants. If naturally beneficial insects cannot suppress the growth of the pest population density, artificially reared enemies of this pest should be used. The release in spring of artificially reared insects which eat weeds is supposed to be especially useful because these insects may also be a good food base for many predators and parasites. The biological method is supposed to be more effective when the density of the pest population is still low. The usage of chemical pesticides should be brought to a stop because they always decrease the ecosystem stability. EPM is proposed to replace IPM in future.

The eggs of the coconut stick insect Graeffea crouanii develop on the ground beneath the palms where they are subject to desiccation and attacks by parasitoids or predators. Eggs were exposed in petri dishes to assess the significance of natural enemies in the field. After 1 year the parasitoids Paranastatus verticalis and P. nigriscutellatus had emerged from only 1% of a total of 240 eggs, predators had attacked 70%. Eggs were offered to potential predators. The ants Pheidole megacephala and Tapinoma melanocephalum and the rodents Rattus exulans and R. rattus accepted them. Egg mortality after exposure to different temperatures was observed in climatic chambers. Nymphs emerged from 62% of a total of 120 eggs kept at 20°C. All eggs exposed to 30°C and 40°C became desiccated.

Semiochemicals can be exploited for rearing and monitoring natural enemies involved in biological control. The predator Rhizophagus grandis, which is used against Dendroctonus micans, is now artificially mass‐produced using synthetic oviposition stimuli. Recent results from the laboratory and the field also suggest that R. grandis population levels could be monitored using synthetic attractants. Verhaltensmodifizierende Duftstoffe im Management von Rhizophagus grandis Gyll. (Col. Rhizophagidae) zur biologischen Bekämpfung von Dendroctonus micans Kug. (Col. Scolytidae) Duftstoffe können in der Zucht und in der Überwachung natürlicher Feinde bei der biologischen Bekämpfung eingesetzt werden. Der räuberische Rhizophagus grandis, der gegen Dendroctonus micans eingesetzt wird, ist heute Gegenstand künstlicher Massenzuchten, bei denen synthetische Eiablagestimulantien verwendet werden. Neuere Ergebnisse aus Labor und Freiland weisen darauf hin, daß die Populationsdichten von R. grandis mit synthetischen Lockstoffen ermittelt werden können. 1992 Blackwell Verlag GmbH, SCOPUS: ar.j, info:eu-repo/semantics/published

Observations on catches of non-target species in pheromon-baited traps in orchards and their prevention Sticky traps baited with the synthetic sex pheromones (Hoechst AG) of six tortricid moths: Laspeyresia pomonella L., Grapholitha funebrana Tr., Adoxophyes reticulana Hb., Hedya nubiferana Haw., Pandemis heparana Den. & Schiff, und Archips podanus Scop, were operated 1985 in untreated orchards in the vicinity of Giessen, W. Germany. In addition to large numbers of the target species, males of other tortricids and noctuids were captured. They were attracted to the various pheromone baits. Other non-target insects like honey bees and hover flies were mostly captured in the white coloured traps. Two methods, namely a change in trap-colour to black and the trap-opening covered with wire-netting decrease those unfavourable catches. Further experiments are planned in 1986 to find out the best trap colour for minimizing catches of hover flies and other beneficial insects. Zusammenfassung Pheromonfallenerhebungen im Jahre 1985 in unbehandelten Obstpflanzungen im Raum Giesen erbrachten aufschlusreiche Aussagen zum Auftreten von Tortriciden-Nebenfangen. In den schwarz- und weisgefarbten Pheromonfallen (Biotrap) der Zielschadlinge Laspeyresia pomonella L., Grapholitha funebrana Tr., Hedya nubiferana Haw., Adoxophyes reticulana Hb., Archips podanus Scop. und Pandemis heparana Den. & Schiff, traten “indifferente” Tortriciden- und Noctuiden-Arten mit ahnlichem Lockstoffbukett, wie das des Zielschadlings, auf. Die Schwarzfarbung und Verdrahtung der Einflugoffnung der Fallen verhinderte den Fang von Syrphiden, Honig- und Solitarbienen. Der spezifische Zielschadling wurde jedoch durch die Verdrahtung beeinflust, so das zukunftig mit verschiedenen Fallenfarbungen zwecks Nutzlingsschonung gearbeitet werden mus.