Biology ofIphiaulax kimballi [Hym.: Braconidae], a parasite ofDiatraea grandiosella [Lep.: Pyralidae]

Iphiaulax kimballi Kirkland is a gregarious ectoparasite of the mature larval stage ofDiatraea grandiosella Dyar in Mexico. The developmental rate from egg to adult is 16.3±1.0 (x±S.D.) at 29°C. The sex ratio is 1.7∶1 (♀∶♂) in the field. Following host paralysis the female deposits 63.5±2.1 eggs during der 28.6±6.4 day adult-life span; laying 4.6±3.1 eggs on each host. Females held at 10°C lived a maximum of 3 months.     

Biological control ofDiatraea saccharalis [Lep.: Pyralidae] in Florida by periodic releases ofLixophaga diatraeae [Dipt.: Tachinidae]

Lixophaga diatraeae (Townsend) parasitized 20 to 78% ofDiatraea saccharalis (F) larval populations within 3 weeks after release. The flies (4 to 6 days old) did not migrate from the release area, but the progeny dispersed as much as 3 km into adjacent untreated areas within 5 generations. Progeny dispersal, apparently during the prelarviposition period, resulted in 100% parasitization ofD. saccharalis larvae in some plots. In 2 of the 3 tests, the host population decreased after the releases. Percentage damaged internodes increased with distance from the release site.

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Résumé Des lachers de la mouche parasite, appelée vulgairement mouche de Cuba, dans les champs de anne, en Floride, ont limité les populations du foreur de la canne. La tachinaire a parasité 20 à 78% des foreurs. En outre, la descendance des parasites a été retrouvée à plus de 3 km des points de lacher. Les dégats aux cannes à sucre furent moindres dans les champs où les lachers ont été effectués que dans les champs voisins.

     

Biology ofPhanerotoma hendecasisella [Hym: Braconidae] a parasitoid ofDiaphania indica [Lep.: Pyralidae]

Studies were conducted on the solitary egg-larval endoparasitoidPhanerotoma hendecasisella Cam. [Hymenoptera: Braconidae] to determine its biology onDiaphania indica (Saunders) [Lepidoptera: Pyralidae]. Larvae pass through 3 stages as determined by the shape and size of the mandibles. Mean developmental period from egg to adult was 26.51 days at 26.06 °C and 73.88% RH. There is no preoviposition period. The sex ratio was 1∶1.12 (male/female). Mean adult longevity was not different for ♂♂ and ♀♀.      

Parasites ofSpodoptera exigua,S. eridania [Lep.: Noctuidae] andHerpetogramma bipunctalis [Lep.: Pyralidae] collected fromAmaranthus hybridus in field corn

Three species of lepidopterous larvae were collected fromAmaranthus hybridus L. growing in field corn during 1975 and 1976 at Hastings, Florida.Spodoptera exigua (Hubner) was the predominant species in May.Spodoptera eridania (Cramer) was predominant in June andHerpetogramma bipunctalis (F.) in July and August. Nine native species of parasites, representing theBraconidae, Eulophidae, Ichneumonidae andTachinidae, emerged from these larvae.Meteorus autographae Muesebeck emerged from bothS. exigua andS. eridania. TheTachinidae, Winthemia rufopicta (Bigot),Eucelatori rubentis (Coquillett) andLespensia sp., emerged from mixtures ofS. exigua andS. eridania. Apanteles marginiventris (Cresson),Temelucha sp., andChelonus texanus Cresson emerged from bothS. exigua andH. bipunctalis larvae, andEuplectrus platyhypenae Howard andOphion sp. emerged fromS. eridania. All the species of parasites from the lepidopterous larvae that feed onAmaranthus hybridus are also reported as parasites ofS. frugiperda, a serious pest of corn. Therefore these larvae onA. hybridus may be a source of the parasites found attackingS. frugiperda.     

Response ofOstrinia nubilalis [Lep.: Pyralidae] infected withNosema pyrausta [Microsporida: Nosematidae] to insecticides

Bacillus thuringiensis Berliner, carbaryl, carbofuran, and infection withNosema pyrausta (Paillot) acted independently in reducing stalk damage by larvalOstrinia nubilalis (Hübner). There were significant interactions of insecticide X days after application for the number and weight of 1st-generation larvae. There also were significant inter-actions of disease class X days after application of insecticide for: larvae/plant in the 2nd generation, weights of larvae in the 1st generation, percentageNosema-infected larvae and intensity of infection of larvae in both generations.     

Introduction and establishment ofApanteles flavipes [Hym.: Braconidae] onDiatraea saccharalis [Lep.: Pyralidae] in texas

The braconid parasite,Apanteles flavipes (Cameron), was introduced into the Lower Rio Grande Valley of Texas in 1977 and has become established onDiatraea saccharalis (F.) attacking 4 species of host plants. Approximately 71% of the 26,971 adult parasites released were released in sugarcane,Saccharum officinarum L., with the remainder being released on field corn,Zea mays L., broomcorn,Sorghum vulgare technicum (Koern.) and Johnson grass,Sorghum halepense (L.). Recoveries indicate dispersal of at least 4 km from release sites.     

Parasitoids of the corn borerOstrinia furnacalis [Lep.: Pyralidae] in the Mariana Islands

A survey of the parasitoids of the Asian corn borer,Ostrinia furnacalis (Guenee), in the Mariana Islands showed that few of the borers were parasitized. Parasitoids were reared from only 30 pupae out of more than 4 500 sampled. Three species of pupal parasitoids were found:Xanthopimpla punctata (F.),Brachymeria albotibialis (Ashmead) andTetrastichus? inferens Yoshimoto. No parasitoids were reared from mature larvae. The only egg parasitoid observed wasTrichogramma chilonis Ishii. During the month prior to the sweet corn harvest, which was the peak period of moth oviposition, about 40% of the egg masses had at least one egg parasitized. An average of about 35% of the eggs within a mass were parasitized.     

Mise en évidence d'une densonucléose chezDiatraea saccharalis [Lep.: Pyralidae]

Résumé Ravageur important de la canne à sucre, le LépidoptèreDiatraea saccharalis F. est sensible à une virose de type densonucléose. Le virus se multiplie intensément dans les noyaux des cellules de différents tissues, comportant de l'ADN et mesurant 22 mμ, il peut être rangé parmi lesParvovirus et attribué au genreDensovirus.

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Summary Diatraea saccharalis is a pest of sugar cane crop and is susceptible to a virus disease of the densonucleosis type. The virus multiplies in the cell nuclei of different tissues, it contains DNA and measures 22 mμ. It may be included in theDensovirus genus of Parvoviruses.

     

Life tables and intrinsic rate of natural increase ofPediobius furvus [Hym.: Eulophidae] onChilo partellus [Lep.: Pyralidae]

In the present studies, life table data and intrinsic rate of natural increase (r_m) of the eulophid pupal parasitoid,P. furvus (Gahan) were obtained fromChilo partellus (Swinhoe) at a constant temperature of 26.7±0.6°C, 52.3±2.7% RH in the laboratory. Development of immature stages took 19.1±0.3 days; adult females lived for 7.9±3.3 (range, 2–13) days and produced a mean of 91.9±22.4 progeny per female, with a sex ratio of 1:2.9 (♂:♀). The intrinsic rate of natural increase (rm) was 0.2558/female/day; the net reproductive rate (R₀), 237.25; the capacity for increase (r_c) of 0.252; and the finite rate of increase (λ) of 1.29/female/day; thus, each female contributed 231.42 individuals to the population in a mean generation time of 21.38 days.      

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.

     

Mortality fecundity and longevity of parasitoids of the spotted tentiform leafminer,Phyllonorycter blancardella [Lep.: Gracillariidae] at constant temperatures in the laboratory

The results of laboratory tests showed that mortality of adult eulophids, primarily,Sympiesis sericeicornis (Nees),S. marylandensis Girault andPnigalio flavipes (Ashmead), was significantly (P<0.05) lower than that of adultPholetesor ornigis (Weed) when exposed to temperatures between 20° and 36°C for 48 h. However, adultP. ornigis lived longer than those of the eulophids at 15°C, but were shorter liver at 33°C. The fecundity ofP. ornigis was little affected at temperatures of 15°, 20°, 24° and 33°C. Exposure of adultP. ornigis to 30°C for 16 h resulted in reduced longevity of both sexes but did not affect fecundity or the proportion of females ovipositing. Mortality of pupae of the eulophids was significantly lower than that of pupae ofP. ornigis at temperatures of 20°, 30° and 33°C. The sex ratio of surviving adults was not affected by temperature.      

Parasitoids ofPectinophora gossypiella [Lep.: Gelechiidae] andEarias spp. [Lep.: Noctuidae] in the Punjab

Observations on the parasitoids of cotton bollworms in the Punjab were made during 1978 and 1979. The 2 trichogrammatid egg parasitoids, viz.Trichogramma achaeae Nagaraja & Nagarkatti andTrichogrammatoidea sp. nearguamensis Nagaraja (MS) were recovered fromPectinophora gossypiella (Saunders) in addition to 1 braconid egg-larval parasitoidChelonus sp. and 7 larval parasitoids, viz. 4 braconidsApanteles angaleti Muesebeck,Bracon greeni Ashsmead,Camptothlipsis sp. andRogas sp., 1 elasmid,Elasmus johnstoni Ferrière, 1 bethylid,Goniozus sp. and 1 ichneumonid,Scambus lineipes (Morley). FromEarias insulana Boisduval andEarias vittella F., 3 trichogrammatid egg parasitoids,T. achaeae, Trichogramma chilonis Ishii, andT. sp. nearguamensis 2 braconid larval parasitoids,B. greeni andRogas sp. and 1 chalcid pupal parasitoid,Brachymeria nephantidis Gahan, were recovered. One eurytomid hyperparasitoid,Eurytoma braconidis Ferrière was also recovered from the cocoons ofB. greeni. Of these parasitoids,T. achaeae, T. sp. nearguamensis, Camptothlipsis sp. andS. lineipes fromP. gossypiella, T. achaeae andB. nephantidis fromEarias spp. andE. braconidis fromB. greeni are new records.     

Influence d'une infection aBeauveria bassiana sur les survivants et la descendance deChilo suppressalis [Lep.: Pyralidae]

Les répercussions secondaires d'une infection subléthale àBeauveria bassiana des chenilles et chrysalides deChilo suppressalis sont étudiées du point de vue de la réduction de la fécondité des femelles et de la fertilité des œufs. Ces phénomènes semblent pouvoir être considérés comme assez généraux en raison des divers exemples connus aussi bien chez les lépidoptères que les coléoptères. Compte tenu de cette propriété, l'interprétation des expérimentations de lutte microbiologique à l'aide de champignons entomopathogènes est discutée. Summary Chilo suppressalis mature larvae and pupae reared on a semi-synthetic medium were infected by spraying titrated spore suspensions ofBeauveria bassiana. Potentialities of the imagos having survived to the mycosis were evaluated by measuring the fecundity of female adults and the egg fertility. The mature larvae contaminated with a spore suspension titrated at 3×10⁷ conidia/ml, as well as the pupae and imagos, were attacked by the muscardine disease. The fertility of the eggs laid by the surviving insects (25% of the total) was very low compared with the control insects. Some pupae, contaminated under the same conditions but with concentrations of inocula varying between 3,3×10⁵ et 3,3×10⁶ conidia/ml also showed mycosis in the pupal and adult stages (53 to 87% of the insects were contaminated, according to the spore concentration). The number of eggs laid by the surviving insects seemed in inverse ratio to the spore dosage, and they showed no fertility, apart from the pupae infected with the weaker suspension.

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Ce travail fait partie d'une thèse de docteur ingénieur soutenue le 28 mai 1975 devant la Commission de l'Université Paul-Sabatier de Toulouse, France.     

Egg laying and host stage preference at constant temperatures inEncarsia tricolor [Hym.: Aphelinidae]

Encarsia tricolor Foërster is a facultative autoparasitoid that develops on the important pestTrialeurodes vaporariorum (Westwood) in outdoor crop conditions, which makes this aphelinid species promising for biological control programs in regions where field and protected crops coexist. In this paper we report the results obtained in the study of daily and totalE. tricolor egg laying and of adult female preference for different host stages in which to lay eggs at constant temperatures in the range 10 to 32 °C. Only whitefly nymphs were present in the searching arena (tomato leaflets). The mean number of eggs laid per female in one day ranged from 4.0 (10 °C and 32 °C) to 15.2 (24 °C). The mean total number of eggs increased with temperature from 10 to 28 °C, reaching a maximum of 123 eggs per female at 28 °C, and decreased sharply from 28 to 32 °C. The relation between the intrinsic rate of increase (r_m) and temperature in the range 10 to 28 °C followed a straight line whose equation was r_m=?0.076+0.011*T (R²=0.99). The r_m ofE. tricolor was greater than the r_m ofT. vaporariorum when temperature was higher than 9.2 °C. The preference for any particular host instar in which to lay eggs was not always significant. However, N4 was the host instar preferred whenever preference was statistically significant.     

Contribution to the knowledge of the natural enemies ofBissetia steniellus (Hampson) [Lep.: Pyralidae]

Résumé La recherche des ennemis naturels deBissetia steniellus (Hampson) [Lep. Pyralidae] gravement nuisible à la canne à sucre dans la province du Punjab, a permis de découvrir six espèces parasites des chenilles et deux autres parasites des chrysalides. Aucune de ces espèces n'avait été trouvée auparavant sur cet h?te. L'auteur suggère l'extension de cette étude en vue de vérifier le r?le du BraconideStenobracon deesae Cameron vis-à-vis de ce Lépidoptère d'une part, et de rechercher au Vietnam de nouveaux parasites de cette espèce pour leur introduction ultérieure en Inde d'autre part.

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This research has been financed in part by a grant made by the United States Department of Agriculture under P.L. 480.     

Efficacy of two nuclear polyhedrosis viruses againstOstrinia nubilalis [Lep.: Pyralidae] in the laboratory and field

Nuclear polyhedrosis viruses isolated from the alfalfa looper,Autographa californica (Speyer) (AcMNPV), and a mint looper,Rachiplusia ou (Guenée) (RoMNPV), were assayed against the European corn borer,Ostrinia nubilalis Hübner), and applied to field corn for suppression of this insect. Fourteen days post-treatment, LC₅₀ values were 46.50 abd 0.95×10⁵ PIB/ml diet for AcMNPV and RoMNPV, respectively. Both viruses caused significant reductions in number of larvae per plant and in plant damage when the material was applied with a backpack sprayer. Data indicate that RoMNPV kills in less time than AcMNPV. When the viruses were applied with a commercial highboy applicator, the centimeters of damage to cornstalks was reduced by 65% with RoMNPV during the 1st generation and by 32.9% in the 2nd generation.     

The elimination of supernumerary larvae of the gregarious egg-parasitoidTrichogramma embryophagum [Hym.: Trichogrammatidae] in eggs of the hostEphestia kuehniella [Lep.: Pyralidae]

Larvae ofTrichogramma embryophagum Htg., the gregarious parasitoid of eggs of Lepidoptera, ingest the ooplasm of the host by pharyngeal sucking. In the case of a supernumerary number of larvae, some die shortly after all the food has been ingested, although all larvae are still at an early stage of development. The food previously swallowed by the dead animals flows back into the host chorion, and this is ingested by the surviving larvae. As a result of this, there is no wastage of food, and in eggs ofEphestia kuehniella Z. up to 3 larvae always survive to the adult stage.     

Effects of parasitism byApanteles sagax [Hym.: Braconidae] on growth,food consumption and food utilization inSylepta derogata larvae [Lep.: Pyralidae]

Laboratory studies were made of the growth, food consumption and food utilization by parasitized and unparasitizedSylepta derogata (F.) larvae. Growth was lower in parasitized than in unparasitized larvae. Parasitized larvae consumed significantly less food than unparasitized larvae. The dry weightfresh weight consumption index did not differ significantly between the 2 types of larva. Parasitism increased the efficiency of digestion but had no effect on the efficiencies of conversion of ingested and digested food to body matter.

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Résumé On a étudié en laboratoire la croissance, la consommation et l'utilisation des aliments de larves deSylepta derogata (F.) parasitées ou non. La croissance est moindre chez les larves parasitées et elles consomment significativement moins de nourriture que les chenilles non parasitées. L'indice de consommation poids sec-poids frais n'est pas différent de manière significative chez les 2 catégories de larves. Le parasitisme diminue l'efficacité digestive mais n'a pas d'influence sur l'efficacité de la conversion des aliments ingérés et digérés en matières corporelles.

     

Sensibilité de la pyrale du mais (Ostrinia nubilalis) [Lep.: Pyralidae] aux hyphomycetes entomopathogenes

Résumé Les œufs de la pyrale du ma?s,Ostrinia nubilalis (Hübner), sont très sensibles àMetarhizium anisopliae (Metsch.)/Sorokin etPaecilomyces fumosoroseus (Wize) (Brown-Smith). Toutes conditions égales par ailleurs, les premiers stades larvaires meurent plus vite mais dans une proportion plus faible que les stades plus agés.Beauveria bassiana (Bals.) (Vuillemin) n^o 147 etM. anisopliae n^o 139 sont particulièrement pathogènes pour ce stade tandis queP. fumoso-roseus attaque facilement les chrysalides. Par adjonction d'une dose faible de chlorpyriphos on sensibilise les larves à la mycose. Les chenilles diapausantes sont très sensibles à la mycose puisque même des doses très faibles (40 sp/cm²) tuent plus de 50% de la population.

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Summary The egges of the European corn borer,Ostrinia nubilalis (Hübner) are very susceptible toMetarhizium anisopliae (Metsch.) Sorokin andPaecilomyces fumoso-roseus (Wize) (Brown-Smith). Whereas all the other conditions are equal, the 1 st larval instars die quicker but in a lower proportion than the later.Beauveria bassiana (Bals.) Vuillemin n^o 147 andM. anisopliae n^o 139 are especially pathogenic to this instar whereasP. fumoso-roseus easily attacks the pupae. By adding a low dose of chlorpyriphos the larvae are more susceptible to mycosis. The diapausing caterpillars are very susceptible to mycosis since doses even very low (40 sp/cm² kill more than 50 % of the population.

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Avec la collaboration technique de Mmes J. Goussard & L. Sénéchal.     

Egg parasitism of the yellow rice borer,Scirpophaga incertulas [Lep.: Pyralidae] in Bangladesh deepwater rice

Studies on deepwater rice in Bangladesh from 1977 to 1980 showed that 61–89% of the egg masses of the yellow rice borer,Scirpophaga incertulas (Walker), were attacked by hymenopterous parasites. Egg parasitism increased from 43–48% in broods 2–4 (May–August) to 64–88% in broods 5–6 (September–November). Parasitism was reduced in broods 4 and 5 in 1979 (because of lower host densities) and in 1980 (possibly due to extreme late flooding). Telenomus rowani (Gahan), active throughout the year, parasitized 64% of the eggs in the masses it attacked, 32 larvae/mass surviving.Tetrastichus schoenobii Ferrière first appearing at medium host densities, increased rapidly to attack half of the brood 5 and 6 masses. More than 98% of the eggs in the attacked masses were parasitized, leaving only 1.6 surviving larvae/mass. In 1979 its appearance was delayed by 10 weeks and fewer masses were parasitized due to lower host densities.Trichogramma japonicum Ashmead andTelenomus sp. (a new record) were less important. Multiple parasitism of masses rose from 7% in brood 2 to 28% in brood 5. Egg parasites clearly reduce the numbers ofS. incertulas, a major pest, and thus probably improve the yields of deepwater rice.