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The sunn pest, Eurygaster integriceps Puton, is a serious pest of wheat and other cereals in the Firouzabad region of Ardabil Province, Iran. In this study, we examined the spatial distribution of sunn pest eggs and their parasitism by Trissolcus spp., primarily Trissolcus grandis Thomson, during the growing seasons of 2008 and 2009. Ten quadrats of 1 m2 were established in each of the ten experimental fields and sampled every 3 days beginning at Feekes growth stage 6 (beginning of stem elongation) through stage 11 (ripening). The numbers of sunn pest eggs, both parasitized and unparasitized, were tallied in each quadrat on each sampling date. Sunn pest oviposition peaked during the onset of flowering in both years, while parasitism peaked at the completion of anthesis in 2008, and at anthesis complete to early milk stage in 2009. Iwao's regression provided a better fit to the data than did Taylor's power law. Both models indicated an aggregated distribution of eggs and parasitism. Temporally, there was a negative overlap between egg density and parasitism from inflorescence emergence until the beginning of anthesis, and positive overlap from anthesis complete until the soft dough stage, such that parasitism ranged from 0% of eggs laid early, to virtually 100% of eggs laid late. Thus, despite good spatial correspondence between egg density and egg parasitism, the time lag between peak bug oviposition and peak parasitism enabled large numbers of early-laid host eggs to hatch and diminished the potential efficacy of biological control by Trissolcus spp. The implications of these results are discussed in the context of integrated management of sunn pest in wheat fields and the possible benefits of early season augmentation of the parasitoid population. [ABSTRACT FROM AUTHOR]

The conifer needle scale, Nuculaspis abietis (Schrank) emerged as an important pest of conifers in the Kelardasht region of Mazandaran province, Iran, in the late 1990’s. This pest feeds on conifer needles and twigs causing needle drop and branch desiccation. Its discovery in Kelardasht in Mazandaran Province necessitated a local quarantine of conifers in the genera Picea, Abies, and Pinus. We studied the life history and ecology of this scale on Norway spruce, Picea abies, under laboratory and natural field conditions. The complete life cycle of females required 206.4 ± 5.7 days in the laboratory (25 ± 1°C, 65–75% RH, 14L : 10D) and 315.7 ± 9.3 days under field conditions. In Kelardasht, numbers of adult males and females peaked in mid-June and early May, respectively, and numbers of first and second instar nymphs in mid-July and early September. Lifetime fecundity was estimated to be 57.3 ± 5.1 eggs and 54.0 ± 4.4 nymphs per female under laboratory conditions. The sex ratio ranged from 59% female for second instar nymphs to 71% female for adults. Aspidiotiphagus citrinus (Crawford) (Hymenoptera: Aphelinidae) was found naturally parasitizing the scale and overwintering in the larval stage on second instar nymphs. First generation adult wasps emerged in spring from overwintered second instar nymphs to parasitize 64.75% of first instar scales. Second generation wasps emerged from early September to mid-October and parasitized 19.75% of second instar scales, for a cumulative parasitism rate of 84.5%. [ABSTRACT FROM AUTHOR]

We evaluated the efficacy of four entomopathogenic fungi (EPF) and their compatibility with the bioinsecticide spinosad for control of Ephestia kuehniella (Zeller) under laboratory conditions. Three EPF, including Beauveria bassiana (Balsamo-Criveili) Vuillemin isolates Z1 and Iran 1395C, Lecanicillium (= Verticillium) lecanii (Zimmerman) Zare & Gams, isolate Iran 229, and Purpureocillium (Paecilomyces) lilacinum (Thom) Luangs-ard, Hywel-Jones & Samson, isolate Iran 1026 were tested against third and fifth larval instars of Ephestia kuehniella using a filter paper bioassay. Mortality caused by the EPF ranged from 63.3-72.5% for third instars and 50-65.5% for fifth instars, with LT50 ranging from 8.4-10.5 d and 10.1-12.9 d, respectively. The effect of spinosad at LC10 (= 26.2 ppm) on EPF spore germination was evaluated and found to be negligible, ranging from 0% for B. bassiana Z1 to 5.7% for P. lilacinum. The LC50 values for spinosad against third and fifth instar E. kuehniella larvae were 452.5 and 1446 ppm, respectively. Subsequently, spinosad at LC10 was applied to third instar E. kuehniella larvae 24 h before application of the EPFs at LC50. The addition of spinosad to applications of L. lecanii and B. bassiana Z1 and Iran1395C isolates synergized their pathogenicity to E. kuehniella larvae, whereas the effect was merely additive for P. lilacinum. Our results suggest that these EPF isolates can be used effectively in combination with spinosad for management of E. kuehniella in stored products. [ABSTRACT FROM AUTHOR]

The stink bugs Acrosternum arabicum Wagner and Brachynema germari Kolenati (Hemiptera: Pentatomidae) damage developing pistachio nuts in Iran. Ooencyrtus egeria Huang and Noyes (Hymenoptera: Encyrtidae) parasitizes eggs of both species, alternating between them seasonally. We compared the biological and life history attributes of O. egeria reared for 3 generations on each host species with those that had been transferred to the alternate host for 2 generations. We also tested female responses to host egg density. Eggs of B. germari were parasitized at higher rates and yielded faster wasp development, heavier female progeny with greater fecundity, and a more female-biased sex ratio, than eggs of A. arabicum. Rearing on A. arabicum did not diminish wasp fitness on B. germari, and the F1 progeny of wasps switched to A. arabicum inherited some beneficial parental effects from rearing on B. germari. Regardless of host species, females parasitized fewer eggs in 8 h as density increased from 10 to 30 eggs, but progeny sex ratio (% female) increased. The anomalous response to host density appears to arise from a combination of behavioral and egg load constraints. Females mature only 10-12 eggs per day. Carefully inspect egg clusters before selecting the most suitable eggs for oviposition, a more time-consuming process for large clusters. Our results indicate that rearing O. egeria on eggs of A. arabicum, which are more convenient and cost-effective to produce than those of B. germari, will not diminish its performance on B. germari following augmentative release, beyond a slight reduction in female fecundity., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The egg parasitoid Trissolcus vassilievi (Mayr) (Hymenoptera: Scelionidae) is a significant natural enemy of the sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), the most important pest of wheat in Iran. This study examined the developmental time and egg-to-adult survival of two geographically separate populations of T. vassilievi on two corresponding host populations at five constant temperatures ranging from 15.0 to 35.0 ± 1°C. No wasps of either population emerged at 15.0°C and the temperature threshold for development was similar between populations, ranging from 13.1 ± 0.3 to 13.8 ± 0.4°C for males and 12.2 ± 0.1 to 12.6 ± 0.1°C for females, but the thermal constant varied with gender and parasitoid population. Development of wasps from the colder Tabriz location was slower, with thermal constants for males and females of 172.6 ± 3.1 and 204.1 ± 1.2 degree-days, respectively, compared to Varamin wasps with 164.7 ± 3.0 and 195.6 ± 1.3 degree-days, respectively. Based on genetic inheritance patterns, reciprocal crosses between the two populations were expected to result in females with thermal phenotypes intermediate to their parental populations, and males that resembled their mothers. However, female progeny of crosses more closely resembled their maternal population, indicating a maternal effect on thermal phenotype. Furthermore, the magnitude of the maternal effect on the thermal constant was asymmetric and was more strongly expressed by Varmin than Tabriz females. These results suggest the possibility of using selective crosses between wasp populations, in combination with artificial selection in the laboratory, to tune the thermal phenotype of parasitoids to specific regions prior to augmentative releases.

Life table studies of sunn pest were carried out in Varamin, Iran, from 1998-2001 in order to determine stage-specific mortalities and the impact of specific natural enemies on population dynamics. Populations were sampled 2-3 times weekly in agricultural fields during the growing season and monthly during the period of dormancy at resting sites in nearby mountains some 30 km away from cereal fields. Adults spend a period of 9-10 months in diapause and suffered overcompensatory, density-dependent mortality during this period. Variation in adult overwintering survival was inferred to be largely a function of the physiological condition of bugs that is reduced in a density-dependent manner by intraspecific competition for food among newly molted adults prior to migration to resting sites. Adult mortality emerged as the primary factor in key factor analysis, contributing 73% of the total variance in mortality. Other important factors were egg parasitism by Trissolcus vassilievi Mayr and adult parasitism by several species of Tachinidae. Although T. vassilievi made only a minor contribution to overall variance in total mortality, it had a significant effect on the number of newly molted adults, the life stage that is most damaging to cereal crops. The equilibrium level of the pest population in wheat fields was inferred to be ca. 72.6 adults m(-2), a number that substantially exceeds the economic threshold that ranges from 3-5 adults m(-2).