Bionomics ofTetrastichus sesamiae [Hymenoptera: Eulophidae], a pupal endo-parasitoid ofMaruca testulalis [Lepidoptera: Pyralidae]

The biology and behaviour ofTetrastichus sesamiae Risbec, a pupal endoparasitoid ofMaruca testulalis Geyer, were studied under laboratory conditions. Most adults emerged from the host pupae between 08.00 h and 09.00 h and mating and oviposition started almost immediately. Both ♂♂ and ♀♀ mated repeatedly, and each ♀ could lay eggs for up to 6 days and in up to 5 host pupae. Progeny production ranged from 0–263 offspring per ♀ and adult longevity was from 4.3–13.9 days. The quality of food available to the adults was a major factor influencing progeny production, and longevity. The species was capable of parasitizing and completing development on pupae of such other major Lepidopteran crop pests asChilo partellus Swinhoe,Busseola fusca Fuller,Eldana saccharina Wlk andSpodoptera exempta Wlk, an important finding for biological control of these pests under intercropped agro ecosystems. Apart from parasitism, ♀♀ ofT. sesamiae also caused considerable mortality by stinging, and presumably paralyzing, host pupae without ovipositing.      

Observations on the oviposition behaviour ofGoniozus sensorius [Hymenoptera: Bethylidae] a parasite ofDiaphania indica [Lepidoptera: Pyralidae]

Goniozus sensorius Gordh (Hymenoptera: Bethylidae) was recorded as a major parasite of the pumpkin caterpillar,Diaphania indica (Saunders) (Lepidoptera: Pyralidae). This paper provides detailed information on the oviposition behaviour ofG. sensorius. Prior to oviposition, the parasite temporarily paralyses the host larva. The paralysed condition lasts for about 2 h. The egg laying process on each larva requires 30 to 60 min. The maximum number of eggs are laid on the 6^th and 7^th segment, and none in the terminal segments. Generally, oviposition is restricted to 1 segment of the host larva and occasionally on 3 segments. The maximum number of eggs are laid on the 2^nd and 3^rd day after emergence and the mean number of eggs laid on each host larva was 7.1.     

Notes on the biology of a spider parasiteColpomeria kincaidii Ashmead [Hymenoptera: Ichneumonidae]

C. kincaidii, an ectoparasite ofTetragnatha laboriosa Hentz, was found most commonly in spring and fall. Peak parasitism was 18%. They appeared to oviposit only on middle instar spiderlings, and winter as larvae attached to spiders.

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Résumé C. kincaidii, un ectoparasite deTetragnatha laboriosa Hentz, a été trouvé très communément au printemps et en automne avec un taux de parasitisme maximum de 18%. Il semble pondre seulement sur les stades juvéniles moyens de l’araignée et hiverner à l’état de larves fixées aux araignées adultes.

     

Observations on the biology and host specificity ofEpiblema strenuana [Lepidoptera,Tortricidae], a potential biocontrol agent forParthenium hysterophorus [Compositae]

The tortricid mothEpiblema strenuana (Walker), which attacksAmbrosia spp. over most of North America, is shown to have the annual weedParthenium hysterophorus L. [Compositae] as its main host in northern Mexico. The larvae produce galls in the stems and growing-points which can considerably stunt growth when young plants are attacked. In tests it was shown to have a restricted host-range and not to damage any composite of economic importance. Its release in Australia for trial as a biological control agent againstP. hysterophorus has been approved.      

Interactions betweenPleolophus basizonus andLophyroplectus luteator [Hym.: Ichneumonidae], two parasites ofNeodiprion sertifer [Hym.: Diprionidae]

Females ofPleolophus basizonus (Gray.) show a very strong avoidance of cocoonedNeodiprion sertifer (Geoff.) prepupae in which there are eggs, larvae or prepupae ofLophyroplectus luteator (Thunb.). When multiparasitism does occurP. basizonus is the successful competitor but adults are much smaller than those from hosts that were not multiparasitized.     

The biology of Diadromus collaris (Hymenoptera: Ichneumonidae), a pupal parasitoid of Plutella xylostella (Lepidoptera: Plutellidae), and its interactions with Oomyzus sokolowskii (Hymenoptera: Eulophidae)

The ichneumonid Diadromus collaris (Gravenhorst) has been recorded in many parts of the world as an important parasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. Some aspects of its biology and its interactions with Oomyzus sokolowskii (Kurdjumov), another major parasitoid of the same pest, were studied in the laboratory. At 25 degrees C, female wasps did not have mature eggs in their ovaries until about 12 h after emergence. Both males and females mated successfully 24-48 h after emergence, and females started to oviposit one to two days after emergence. Unmated females produced male progeny only; mated females produced progeny of both sexes. The development rate of the parasitoid increased linearly with temperature from 15 to 30 degrees C, with an estimated low temperature threshold of 7.4 degrees C and a thermal constant of 225.1 day-degrees for development from egg to adulthood. Rates of survival from larva to adulthood were about 90% between 20 and 28 degrees C and decreased as temperature decreased or increased. No immatures survived to adulthood at 35 degrees C. When provided with honey solution, the females lived on average 8.3, 11.5 and 7.0 days, and parasitized 26, 44 and 46 host pupae at 20, 25 and 30 degrees C, respectively. Female wasps could be stored at 15 degrees C for up to four weeks without detrimental effects on reproduction. Females of D. collaris attacked host pupae already parasitized by O. sokolowskii, inserting their ovipositor into the hosts at a similar frequency as into unparasitized host pupae, but they did not lay eggs inside the hosts.     

Three new species ofAphytis [Hymenoptera: Aphelinidae], parasites ofPseudaulacaspis spp. [Homoptera: Diaspididae] in India and Australia

Three new species ofAphytis Howard, parasitic upon species ofPseudaulacaspis MacGillivray, are described and illustrated:A. bangalorensis sp. nov. exP. barberi (Green) from India.A. sankarani sp. nov. exP. cockerelli (Cooley) from India, andA. landii sp. nov. ex an undescribedPseudaulacaspis sp. from Australia.

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Résumé Trois nouvelles espèces d'Aphytis Howard, parasites d'espèces du genrePseudaulacaspis MacGillivray, sont décrites et représentées:A. bangalorensis sp. nov. exP. barberi (Green) en provenance de l'Inde;A. Sankarani sp. nov. exP. cockerelli (Cooley) en provenance de l'Inde, etA. landii sp. nov. ex espèce non décrite dePseudaulacaspis spp. en provenance d'Australie.

     

The biology and behaviour ofIphiaulax varipalpis [Hymenoptera: Braconidae] as a parasite ofDirphya nigricornis [Coleoptera: Cerambycidae]

The ability of the braconid parasite,Iphiaulax varipalpis Cary to control the beetleDyrphya nigricornis Olivier was evaluated. Field collected samples and specimens reared in polyethylene paper tubes under laboratory conditions (23.0°C±1.0 at 70% r.h) were used. Field parasitism was low (10.72%) while laboratory parasitism was high (57.66%). The parasite detected the hosts very easily in the laboratory. This ability is minimised in thick canopies ofCoffea arabica L. Host colonization was brisk (90 seconds) and confined to a near absolute area of discovery, measuring 4.18±0.41 cm. The parasite reproduces gregariously with female lifespan being approximately double the male period. The parasites are very active at the age of 10 days. As they age their potential fecundity (232 oocytes) reduces drastically with oviposition.      

Sex pheromone composition of Ascotis selenaria (Lepidoptera: Geometridae) and its regional variation in Korea

This study was conducted to investigate sex pheromone composition of Ascotis selenaria (Lepidoptera: Geometridae) in Korea. Two sex pheromone compounds such as (Z,Z)-6,9-cis-3,4-epoxynonadecadiene (6Z,9Z-cis-3,4-epoxy-19:H) and (Z,Z,Z)-3,6,9-nonadecatriene (3Z,6Z,9Z-19:H) were identified in the glands of A. selenaria females by gas chromatography–mass spectrometry analysis. However, the component 3Z,6Z,9Z-19:H neither elicited an electroantennogram response nor increased the attractiveness for A. selenaria males in the field. The role of 3Z,6Z,9Z-19:H seems to be as an antagonistic signal for mating behavior of A. selenaria males.The blend ratios of two 6Z,9Z-cis-3,4-epoxy-19:H isomers such as, 6Z,9Z-cis-3R,4S-epoxy-19:H and 6Z,9Z-cis-3S,4R-epoxy-19:H, were critical to attract A. selenaria males. The blend ratios of the two isomers showing peak catch of A. selenaria males had large variations among the locations investigated. A. selenaria populations in Gunwi showed peak activity at ratios of 0.9:0.1 and 0.8:0.2, whereas the populations in Goheung, Yeongam, and Jeju (Aewol and Harye) showed peak activity at a 0.5:0.5 ratio. In Changnyeong, the peak activity occurred in a bimodal form at ratios of 0.7:0.3 and 0.4:0.6. Such variation was partially explained by geographical isolation due to mountain ranges. Consequently, the results of our study should be useful for designing a region-specific pheromone lure for successful A. selenaria monitoring.     

Emergence ofKeiferia lycopersicella [Lepidoptera: Gelechiidae], andApanteles sp. [Hymenoptera: Braconidae] from pupae and soil treated with insect growth regulators

Two insect growth regulators (IGR's), ZR-619 (ethylin-methoxy-3,7,11-trimethyl-(2E, 4E)-2,4-dodecadienethiolate), and ZR-777 (Prop-2 ynyl 3,7,11-trimethyl-(2E, 4E)-dodecadienoate) were tested for potential use against the tomato pinworm,Keiferia lycopersicella (Walsh.) The IGR's were applied to cocoons and to soil where cocoons were formed. Both IGR's, alone and in combination, suppressed pinworn adult emergence from 23 to 7% when applied direct but were ineffective when applied to the soil. All treatments of IGR's in both methods of application reduced emergence of the parasitoApanteles sp. to 0% from levels as high as 61%. Use of the IGR's in this situation resulted in greater harm to potential biological control agents than in benefit to pest control.

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Résumé Deux régulateurs de croissance des insectes: le ZR-619 (éthyl n-méthoxy-3, 7, 11-triméthyl-(2E, 4E)-2, 4-dodecadienethiolate) et le ZR 777 (Prop-2 ynyl-3, 7, 11-triméthyl-(2E, 4E)-dodecadienoate) ont été expérimentés pour lutter contre le ver de la tomateKeiferia lycopersicella (Walsh.). Le traitement a été réalisé dans le sol où s'effectue la nymphose de ce ravageur. Les deux produits, isolément ou en mélange, ont réduit la sortie des adultes de 23 à 7% lorsqu'its, sont appliqués directement sur les nymphes, ils sont inefficaces quand ils sont introduits dans le sol. Les deux méthodes d'emploi ont supprimé les sorties d'Apanteles sp. jusqu'à 0%, à partir d'un taux de parasitisme allant jusqu'à 61%. L'utilisation de ces régulateurs de croissance dans de telles conditions est donc plus dommageable aux antagonistes naturels qu'elle n'est profitable contre le ravageur.

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Florida Agricultural Experiment Stations Journal Series No. 5093.     

Observations on the biology and behaviour of the predaceous miteTyphlodromus italicus [Acarina: Phytoseiidae] in peach orchards

The results of investigations onTyphlodromus italicus Chant in some peach orchards in the Verona district, where the predator is wide-spread, are described. Both field and laboratory studies have shown thatT. italicus grows rapidly (egg to adult 6 days at 25°C.) and has a long reproductive period, especially when prey is available. It speedily recovers in number and has a high prey-searching capacity. It is fast-moving, and its distribution over the tree corresponds to that of the phytophagous mites. It can live and reproduce on the tree in the absence of prey. A density of 50–60T. italicus/100 leaves is reached in August. FemaleT. italicus are found on leaves till November feeding whenever prey is available, and wintering in a mated condition in bark crevices. Many enter diapause in late autumn. Overwinter mortality is high. These characteristics enableT. italicus to play a very significant role in the control of peach mites and in orchards, which are unsprayed, it keeps their populations at a low density from spring to autumn.     

On the adult longevity of the entomophagous parasite,Venturia canescens [Hymenoptera: Ichneumonidae]

The adult longevity of the California strain ofVenturia canescens (Gravenhorst) [Hymenoptera: Ichneumonidae], a larval parasite of the Mediterranean flour moth,Anagasta kuehniella (Zeller) [Lepidoptera: Phycitidae] was studied. The effects of the presence or absence of food (honey streak) in relationship to the ovipositional exertion as influenced by the presence or absence of hosts was considered. It was found that in the absence of any food, their longevity was drastically reduced and ovipositional exertion had no effect on this curtailment. However, in the presence of food, ovipositional activity was a major factor in the curtailment of adult longevity.     

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.     

RearingTrichogramma nubilale [Hymenoptera: Trichogrammatidae] on eggs of the tobacco hornworm,Manduca sexta [Lepidoptera: Sphingidae]

The fresh frozen egg of the tobacco hornworm (TBH)Manduca sexta (L.), is an efficient and superior host for mass production ofTrichogramma nubilale Ertle & Davis. Each host egg may produce 10.7±2.8 (n=7) large, robust, and activeT. nubilale. The proportion of ♀♀ stabilized at 80–90% with 69.9±26.6 (n=8) ovarian eggs per female. As many as 3 ♀♀ were observed ovipositing simultaneously into a single TBH egg. Superparasitism (>10 progeny) should be avoided because it may cause nutritional or space limitations on the development of effectiveT. nubilale.      

Incidence of parasites ofLymantria obfuscata [Lymantriidae: Lepidoptera] in Kashmir

Incidence of parasites ofLymantria obfuscata Walker [Lymantriidae: Lepidoptera] was studied in Kashmir during 1983 and 1984. The only egg parasite reared wasAnastatus kashmirensis Mathur parasitising between 4.49 to 11.92 percent of eggs. From 15 study sites as many as 10475 larvae of different stages and pupae were collected and reared in laboratory.Exorista rossica [Tachinidae: Diptera] was recorded to parasitize upto 8.42 per cent of larvae compared to 0.89 percent byCompsilura sp.Tetrastichus sp. [Eulophidae: Hymenoptera] was observed to be most dominant of the 6 pupal parasites, accounting for 33.41 percent of the measured parasitism, followed byPimpla sp. [Ichneumonidae: Hymenoptera] andTheronia atalantae atalantae [Ichneumonidae: Hymenoptera] which parasitized 6.84 and 4.03 per cent of pupae respectively.Brachymeria intermedia Nees [Chalcididae: Hymenoptera] was recorded to parasitize upto 2.98 per cent whereasBrachymeria lasus Walker recorded for the first time in Kashmir was found to parasitize up to 2.01 per cent, but was not widely distributed in the State.     

The biology ofLophyroplectus luteator [Hym.: Ichneumonidae] onNeodiprion sertifer [Hym.: Diprionidae] in Ontario

Adult femaleLophyroplectus luteator (Thunb.) oviposit in all feeding stages ofNeodiprion sertifer (Geoff.), although they prefer the smallest of any larvae present at a given time. Females tend to distribute eggs contagiously both within and between host feeding colonies. Eclosion of eggs does not occur until after the host has spun its cocoon. Larval development then requires approximately 1 month in the laboratory. There is an obligatory eonymphal diapause which requires a minimum of 60–80 days at 2°C to fulfil, and post-diapause development requires 3–4 weeks.     

Interactions betweenAcyrthosiphon kondoi [Homoptera: Aphidoidea] andAphelinus asychis [Hymenoptera: Chalcidoidea] and other parasites and hosts

In laboratory trials to investigate the parasite/host spectra of certain aphid pests and hymenopterous parasites, the aphidAcyrthosiphon kondoi Shinji encapsulated the egg of the aphelinid parasiteAphelinus asychis Walker. The resultant brown, sclerotic capsule was formed within 24 h of exposure of the aphid to parasitization and as far as is known prevented the development of the parasite to the larval stage. The capsule remained throughout the life of the aphid, whose longevity and fecundity were apparently not seriously impaired. A small number ofAphelinus escaped encapsulation, especially in aphids already containing capsule(s), and developed into normal, reproductive adults.A. kondoi did not encapsulate, andA. asychis was not encapsulated by any other species. However, thoughA. asychis readily parasitizedAphis citricola van der Goot,A. nerii Boyer de Fonscolombe andToxoptera citricidus (Kirkaldy), most of its progeny ceased development in these aphids before reaching the mummification stage, and died within the dead or dying, non-mummified aphid host.     

Study of the sound produced byPimpla instigator [Hymenoptera,Ichneumonidae] during host selection

When females ofPimpla instigator inspect objects as possible oviposition sites, they use their antennae to make the objects resonate. The antennae are not used as drum sticks, but serve merely to transmit shock waves generated within the female's body. Transmission of the shock waves to the substrate is mediated through vesicles situated at the extreme tip of the distal segment of each antenna. The present results support the hypothesis that acoustical inspection of the environment is a part of the exploratory behaviour of this insect.      

Comparison of Diadegma insulare (Hymenoptera: Ichneumonidae) and Microplitis plutellae (Hymenoptera: Braconidae) as biological control agents of Plutella xylostella (Lepidoptera: Plutellidae): field parasitism, insecticide susceptibility, and host-searching

Parasitism of Plutella xylostella (L.) third and fourth instars was evaluated in a cabbage field in Geneva, NY, in 1999. Over the entire season, average parasitism was 33.6% for third instars and 53.6% for fourth instars, and the main parasitoids were Diadegma insulare (Cresson) and Microplitis plutellae Muesbeck. In the early season, total parasitism was low, and mainly caused by D. insulare. However, later in the season, parasitism reached >80% for the fouth instars and 50% for the third instars. Our survey indicated that M. plutellae heavily parasitized P. xylostella, and provided higher parasitism rates than D. insulare in the late season. Comparison of these two species in laboratory bioassays indicated there were no significant differences in susceptibility to four insecticides commonly used in crucifer fields. For both parasitoids, an experience with P. xylostella on a damaged leaf increased their host-searching efficacy. Compared with M. plutellae, D. insulare was a better host-searcher both for the naive and the experienced adults. Although both parasitoids can cause high mortality rates of P. xylostella, D. insulare may be more suitable to be released in fields to enhance natural control against P. xylostella.     

Trichilogaster sp. [Hymenoptera: Pteromalidae], a potential biocontrol agent for the weedAcacia pycnantha [Fabaceae]

The gall wasp,Trichilogaster sp., was imported from Australia to assess its potential as an agent for the control of the invasive shrub/treeAcacia pycnantha Benth. in South Africa. Host specificity tests indicate safety for release; of 19 tree/shrub species tested, including 16 species closely related toA. pycnantha, galls developed only onA. pycnantha. However, galling intensity remained consistently low on the host plant; only 21–29% of the branches exposed to the wasp were galled during 3 years of rearing. Neither the prolonged presence of males in test cages (someTrichilogaster species are thelytokous) nor the stage of maturity of reproductive buds exposed to oviposition affected the percentage of branches galled. It is not recommended thatTrichilogaster sp. be released before the possibility of insect-plant homeostasis or mis-matching of wasp and host plant populations/strains/subspecies is investigated, especially since galling intensities of 30% were ineffective in reducing seed production of a relatedTrichilogaster species/Acacia association.