Demographic Parameters of Nezara viridula (Heteroptera: Pentatomidae) Reared on Two Diets Developed for Lygus spp.

Two artificial diets developed for rearing Lygus spp., a fresh yolk chicken egg based-diet (FYD) and a dry yolk chicken egg based-diet (DYD), were evaluated as an alternative food source for rearing the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae). Survival to adult was 97.3 and 74.67%, respectively, on the fresh and dry yolk diets. Insects fed FYD had 100% survival of nymphs from first through fourth instars. Adult development was significantly shorter on FYD (30.37 ± SE 0.30 d) as compared with DYD (32.77 ± SE 0.16 d). Increased male and female longevity, higher fecundity, and larger egg mass sizes were also observed with N. viridula-fed FYD. However, fertility and hatchability was higher on DYD. A complete cohort life table was constructed to describe the development of N. viridula on both diets.     

Relative Fitness of Helicoverpa armigera (Lepidoptera: Noctuidae) on Seven Host Plants: A Perspective for IPM in Brazil

The cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a widespread pest of many cultivated and wild plants in Europe, Africa, Asia, and Australia. In 2013, this species was reported in Brazil, attacking various host crops in the midwestern and northeastern regions of the country and is now found countrywide. Aiming to understand the effects of different host plants on the life cycle of H. armigera, we selected seven species of host plants that mature in different seasons and are commonly grown in these regions: cotton (Gossypium hirsutum, “FM993”), corn (Zea mays, “2B587”), soybean (Glycine max, “99R01”), rattlepods (Crotalaria spectabilis), millet (Pennisetum glaucum, “ADR300”), sorghum (Sorghum bicolor, “AGROMEN70G35”), and cowpea (Vigna unguiculata, “SEMPRE VERDE”). The development time of immatures, body weight, survivorship, and fecundity of H. armigera were evaluated on each host plant under laboratory conditions. The bollworms did not survive on corn, millet, or sorghum and showed very low survival rates on rattlepods. Survival rates were highest on soybean, followed by cotton and cowpea. The values for relative fitness found on soybean, cotton, cowpea, and rattlepods were 1, 0.5, 0.43, and 0.03, respectively. Survivorship, faster development time, and fecundity on soybean, cotton, and cowpea were positively correlated. Larger pupae and greater fecundity were found on soybean and cotton. The results indicated that soybean, cotton, and cowpea are the most suitable plants to support the reproduction of H. armigera in the field.     

Influence of plant leaf surface on the development,reproduction and life table parameters of the predacious mite, Agistemus exsertus Gonzalez (Acari: Stigmaeidae)

The influence of leaf surfaces of different host plants on the biology and life table parameters of the predacious mite, Agistemus exsertus Gonzalez was studied in the laboratory. A. exsertus successfully developed and reproduced on all tested plant leaves. Smooth, glabrous pear leaves accelerated the development of A. exsertus and showed the shortest mean generation time. Slightly rough, slightly hairy leaves of mulberry and acalypha were the most suitable surface for oviposition of the predator. These leaves exhibited the highest fecundity and net reproductive rate. On the other hand, leaves of rough, pubescent apple and scabrous, bristly lantana were the least suitable surface for oviposition of A. exsertus. They showed the lowest fecundity and net reproductive rate. Acalypha leaves exhibited the highest intrinsic rate of increase for the predator, whereas lantana leaves showed the lowest value. This difference in the predator response to leaf surfaces of host plants should be considered to enhance the role of the predator in biological control programs.     

Influence of Constant Temperature on Reproductive Parameters of Holotrichia oblita (Coleoptera: Scarabaeidae)

Holotrichia oblita Faldermann (Coleoptera: Scarabaeidae) is a major pest both in field crops and forests because the larvae could eat the roots of most crops in the field, and the adults damage the leaves of trees and field crops. In this study, we focused on the effects of temperature on H. oblita reproductive parameters. The results indicated H. oblita female adults at 25°C could lay more eggs (84.0 eggs per female) and have the shortest preoviposition period (19.1 d), the greatest oviposition rate (2.8 eggs per female per 3 d), and largest percentage of life span spent in oviposition (59.5%). The longevity and the time to 50% egg laying decreased with increasing temperature, and female longevity was always longer than male longevity. The preoviposition and postoviposition period decreased with increasing temperature from 15 to 25°C and then increased when the temperature increased from 25 to 30°C. These results show that 25°C is the optimal temperature for reproduction of H. oblita.     

Host Plant-Based Artificial Diets Enhance Development,Survival and Fecundity of the Edible Long-Horned Grasshopper Ruspolia differens (Orthoptera: Tettigoniidae)

Wild swarms of the long-horned grasshoppers Ruspolia differens (Serville) which are widely harvested for consumption and sale in Africa are seasonal and unsustainable, hence the need for innovative ways of artificially producing the insects. We investigated the development, survival, and reproduction of R. differens in the laboratory on diets mixed with host plants [Digitaria gayana Kunth, Cynodon dactylon (L.) and Megathyrsus maximus Jacq (Poales: Poaceae); Ageratum conyzoides L. (Asterales: Asteraceae)] identified from guts of their wild conspecifics with a view to developing a suitable diet for artificial mass rearing of the edible insect. A standard diet comprising ground black soldier fly, Hermetia illucens L. (Diptera: Startiomyidae) larvae, soybean flour, maize flour, vitamin premix, and ground bones was tested for rearing R. differens as a control against the same ingredients incorporated with individual powders of the different host plants. Whereas R. differens developed more slowly in the diet mixed with D. gayana than in the control diet; its development was faster in the diet mixed with C. dactylon. Mortalities of R. differens in host plant-based diets were 42.5–52.5%, far lower than in the control diet with 71% mortality. The insects raised on the diet mixed with M. maximus laid approximately twice more eggs compared to R. differens fecundities from the rest of the diets. However, inclusion of host plants in the diets had no detectable influence on R. differens adult weight and longevity. These findings support inclusion of specific host plants in artificial diets used for mass rearing of R. differens to enhance its survival, development, and fecundity.     

Thermal Biology of Liorhyssus hyalinus (Hemiptera: Rhopalidae) and Nysius simulans (Hemiptera: Lygaeidae), Fed on the Milky Stage of Maize Grains

When quinoa, Chenopodium quinoa Willd., is cultivated in South America outside of its Andean origin, the heteropterans Liorhyssus hyalinus (Fabricius) and Nysius simulans Stål may emerge as important pests. Here we studied the development and reproduction of both species at different constant temperatures in the laboratory. Egg and nymphal development were investigated at 18, 22, 26, 30, 34, and 36°C. For both species, egg incubation time significantly decreased as the temperature increased. Nymphs did not successfully develop at 18°C and the total nymphal time significantly decreased as the temperature increased from 22 to 36°C. Based on a linear day-degree (DD) model, the lower developmental threshold (LDT) temperatures for eggs and nymphs were estimated to be 16.0 and 17.9°C for L. hyalinus, and 16.1 and 19.7°C for N. simulans, respectively. Thermal requirements for egg and nymphal development were 68.6 and 114.8 DD for L. hyalinus, and 77.7 and 190.3 DD for N. simulans, respectively. Reproduction and adult longevity were studied at 22, 26, 30, and 34°C. For both species preoviposition time decreased as temperature increased, and the oviposition period was longest at 26°C. The highest fecundity and egg viability were observed at 30°C, whereas longevities were higher at 22–26°C than at 30–34°C. As the lowest tested temperatures were not suitable to both heteropterans and 30°C was found to be the optimal temperature for development and reproduction, peak densities are expected in warm areas and seasons.     

Effect of temperature on the developmental time,survival of immatures and adult longevity of Aganaspis daci (Hymenoptera: Figitidae), a natural enemy of Ceratitis capitata (Diptera: Tephritidae)

Longevity, developmental time and offspring survival of parasitoid wasps are decisive in their effective performance as biocontrol agents. Optimum temperature range determines parasitoid survival, development and reproduction. Thus, controlling this abiotic factor is a key to the success of pest management programs. Adult longevity, developmental time from egg to adult and survival of immatures of Aganaspis daci were assessed in the laboratory under different constant temperatures; adult longevity without hosts, but with the provision of water and honey, and developmental time and survival of immatures from host pupae, whose larvae had been exposed to parasitoids. Results showed that longevity depended on temperature decreasing in the range 15–20 °C (36 – 25 days), but was lower in the range 25–35 °C (10 – 7 days). Regarding developmental time from egg to adult and survival of immatures, our results showed that 20 and 25 °C are the most suitable temperatures. At 15 and 30 °C mortality of the immature stages was very high (>90%) or developmental time to adult was very slow (>3 months). Immatures did not survive at 35 °C. We found no significant differences in developmental time to adult or survival of immatures between 20 and 25 °C. The sex ratio of parasitoid progeny was female biased at 25 °C; the proportion of females increased at all cases with temperature. The t_o and K for total development were 8.5 °C and 500 DD, respectively. Our findings provide some guidance for future inundative or inoculative field releases of this parasitoid for the management of Ceratitis capitata in Spain.     

Evaluation of soybean for resistance to soybean rust in Vietnam

Soybean rust, caused by Phakopsora pachyrhizi Sydow, is a severe foliar disease of soybean [Glycine max (L.) Merr.] that occurs throughout most soybean producing regions of the world. The objective of this research was to evaluate selected soybean genotypes for resistance to soybean rust in Vietnam. Five field experiments in Vietnam were completed from 2006 to 2009. The area-under-the-disease-progress-curve (AUDPC) was calculated for each soybean genotype based on four disease assessments taken during the reproductive growth stages. AUDPC units among soybean genotypes in each experiment differed (P < 0.05). Over the five experiments, the resistant check DT 2000 was most often the genotype with the lowest AUDPC units while the sources of rust resistance (Rpp1-5) did not always have low AUDPC units in each experiment, although PI 230970 (Rpp2) appeared to be more stable. A few genotypes with non-characterized genes for resistance, such as PI 398998, PI 437323, and PI 549017, had the lowest AUDPC units in at least one of the experiments. These genetic resources may be useful for host plant resistance studies and breeding soybeans for rust resistance in Vietnam and other locations like Brazil and the United States that have more recently been inundated with soybean rust. A significant (P < 0.001) experiment × genotype interaction was found when the AUDPC data of 14 soybean genotypes tested in Experiments 1, 2, and 3 were combined and analyzed. This result indicates the potential importance of changing fungal races and/or biotypes that occur in the rust population.     

Absence of Transgenerational Phenotypic Plasticity in Fecundity in the Parasitoid Anagrus erythroneurae (Hymenoptera: Mymaridae)

To improve biological pest control, we would like to understand the main factors that limit the reproductive success of key biological control agents, including parasitoid wasps. Previous research with proovigenic parasitoids in the genus Anagrus collected from multiple field sites revealed positive correlations between parasitoid fecundity and local host density. In this article, we test whether this variation in fecundity is a reflection of transgenerational phenotypic plasticity. We exposed females in laboratory microcosms to either low or high host densities and then quantified the fecundity of their adult daughters. Mean fecundity of daughters did not differ across host density treatments, arguing against the operation of phenotypic plasticity. Significant variation in mean fecundity across different families instead suggested the possibility that genetic variation may underlie the observed fecundity differences.     

Developmental Biology of Zeugodacus cucurbitae (Diptera: Tephritidae) in Three Cucurbitaceous Hosts at Different Temperature Regimes

Fruit flies are key pests of cucurbits in many parts of the world, including Tanzania. Developmental biology of Zeugodacus cucurbitae (Coquillett) has been determined across temperature regimes in some cucurbitaceous hosts, in limited geographies. This study was conducted to determine duration and survival rates of immature stages of Z. cucurbitae in three cucurbitaceous hosts, at different temperature regimes. It was hypothesized that temperature and cucurbitaceous hosts influence duration and survival of immature stages of Z. cucurbitae. We conducted experiments in the environmental chamber set at 75 ± 10% RH and a photoperiod of 12:12 (L:D) h, at temperatures of 20, 25, and 30°. Our results showed that duration and survival of immature stages of Z. cucurbitae differed significantly among the temperature regimes but not among the hosts. Egg incubation period as well as larval and pupal stages were significantly longer (P < 0.0001) at low temperature in all three hosts Likewise, survival rate of all immature stages were significantly higher (P < 0.0001) at higher than lower temperatures. The three hosts, cucumber (Cucumis sativus), watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai), and pumpkin (Cucurbita pepo) did not significantly affect duration or survival rates of immature stages of Z. cucurbitae. The low developmental thresholds were estimated at 15.88, 13.44, and 12.62 for egg, larva and pupa, respectively. These results further confirm that Z. cucurbitae is well adapted to warm climate, which dominates many areas of Tanzania.     

环境胁迫对亚洲玉米螟及其主要寄生性天敌的影响

亚洲玉米螟是我国粮食主产区玉米等作物上的主要害虫。综述了气候等环境因子对玉米螟及其主要寄生性天敌的胁迫作用。过高及过低的温、湿度对玉米螟的生长发育等均有不同程度的影响,同时还间接影响玉米螟寄生性天敌的存活和寄生效率;水分和食料对玉米螟幼虫生长发育、幼虫滞育和滞育解除等也有重要影响。总之,异常环境条件会极大地影响玉米螟及其寄生性天敌的种群消长。     

Effects of crop rotation of soybean with corn on severity of sudden death syndrome and population densities of Heterodera glycines in naturally infested soil

Sudden death syndrome, caused by Fusarium virguliforme, and the soybean cyst nematode, Heterodera glycines, combined cause the highest yield losses in soybean. The objective of this study was to determine the effectiveness of corn rotated annually with soybean on reducing severity of sudden death syndrome (SDS) and if such crop rotation is beneficial to soybean root health and thus improves disease management strategies. Experiments were conducted from 2003 to 2006 through two cycles of a corn–soybean rotation on two commercial fields in Indiana. With one exception, the rotation of soybean with corn did not provide yield benefits compared to monoculture of soybean. Severity of foliar and root symptoms of SDS in rotation plots were never less than in soybean monoculture plots. At one location, soybean monoculture resulted in suppression of SDS compared to the corn–soybean rotation, while H. glycines reproduced freely. At the other location, monoculture of soybean resulted in suppressiveness against H. glycines, while SDS was limited in all treatments. The data suggest that soil suppressiveness can independently impact the pathogens that are important in SDS development. Because H. glycines can increase SDS symptoms, its suppression may also reduce severity of SDS. Current production systems consisting of yearly rotation of soybean with corn are highly vulnerable to the development of severe soil-borne disease complexes. The simple year-to-year rotation of corn and soybean is not considered sustainable. While monoculture of soybean resulted in some disease suppression in these trials, reliance on monoculture may be detrimental due to other environmental considerations beyond the scope of these trials. Including other crops may be beneficial in improving the sustainability of soybean and corn production systems.     

Effects of host plant on the development, survivorship and reproduction of Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudoccocidae)

The effects of four host plants (Agave sisalana, Ag. americana var. marginata, Ananas comosus Baili and An. comosus Smooth Cayenne) on the biology of the mealybug Dysmicoccus neobrevipes Beardsley were studied in the laboratory at 26 ± 1 °C, 75-90% RH and 14:10 (L:D) photoperiod. The development, survivorship, longevity, reproduction and life table parameters of D. neobrevipes differed among the host plants. The shortest developmental period (from the first instar nymph to adult) was recorded on An. comosus Smooth Cayenne (22.4 days for females and 21.3 days for males), whereas the longest was recorded on An. comosus Baili (25.6 days for females and 24.7 days for males). The highest survivorship was found on An. comosus Baili (98% for both females and males) and the lowest was on Ag. americana var. marginata (39.6% for females and 50% for males). Meanwhile the sex ratio and fecundity were highest and the pre-lay period was shortest on Ag. sisalana. The longest longevity of females was 62.5 days on An. comosus Baili, whereas the other host plants did not differ significantly with grand mean longevities of 51.0 days for females, while the longest and shortest longevities of males were 4.6 days and 2.3 days on Ag. americana var. marginata and Ag. sisalana, respectively. Values for net reproductive rate, intrinsic rate of increase and finite rate of increase were highest on Ag. sisalana, whereas the mean generation time was shortest on An. comosus Smooth Cayenne. The results indicated that Ag. sisalana is the most suitable host for D. neobrevipes among the four tested plants. When reared on Ag. sisalana, D. neobrevipes had a short developmental period (females 22.7 days and males 23.8 days), high reproduction (418 nymphs/female) and a high intrinsic rate of increase (0.106). Results of this study indicated that host plant can largely influence the population dynamics of D. neobrevipes, and our findings are useful in understanding the roles of host plants in integrated management of this pest, including exploitation of these host plants in push-pull control.     

Food choice and impact of food sources from farms on blood coagulation in rodenticide resistant Norway rats

Rodents are mostly controlled by using anticoagulant rodenticides to minimise adverse effects along the food production chain. Genetic resistance to anticoagulant compounds occurs in populations of Norway rats (Rattus norvergicus) and other rodents throughout the world. This can be problematic for control operations and put predators and scavengers at risk because resistant prey individuals carry high anticoagulant loads. Single nucleotide polymorphisms (SNPs) in the vitamin K reductase complex subunit 1 (VKORC1) gene that are associated with rodenticide resistance are related to several pleiotropic effects including increased vitamin K requirement. The uptake of dietary vitamin K available from food sources present on farms including corn silage and garden herbs may mitigate such effects. We tested the preference for food rich in vitamin K1/3 in Norway rats susceptible or resistant to bromadiolone due to the homozygous amino acid variant Tyr139Cys. We also studied the effect of vitamin K consumption from several food sources on blood clotting in bromadiolone resistant and susceptible Norway rats. There was no general preference of rats for food sources rich in vitamin K. Surprisingly, there was no effect of vitamin K uptake on blood clotting times. However, the consumption of 4 of 5 corn silages prevented the rise in blood clotting times that otherwise occurred in vitamin K deficient bromadiolone resistant rats. This seemed to be due to substances with vitamin K activity present in silage and may contribute to the sustaining and spreading SNPs that are related to rodenticide resistance. As corn silage is becoming increasingly available to rats due to the expansion in generating bio-energy from corn silage, there may be a future increase in the occurrence of anticoagulant resistant Norway rats and associated problems in agro-ecosystems.     

Spatial and Temporal Dynamics of Stink Bugs in Southeastern Farmscapes

A 3-yr study (2009–2011) was conducted to examine the spatial and temporal dynamics of stink bugs in three commercial farmscapes. Study locations were replicated in South Carolina and Georgia, in an agriculturally diverse region known as the southeastern coastal plain. Crops included wheat, Triticum aestivum (L.), corn, Zea mays (L.), soybean, Glycine max (L.), cotton, Gossypium hirsutum (L.), and peanut, Arachis hypogaea (L.). Farmscapes were sampled weekly using whole-plant examinations for corn, with all other crops sampled using sweep nets. The predominant pest species of phytophagous stink bugs were the brown stink bug, Euschistus servus (Say), the green stink bug, Chinavia hilaris (Say), and the southern green stink bug, Nezara viridula (L.). Chi-square tests indicated a departure from a normal distribution in 77% of analyses of the variance to mean ratio, with 37% of slopes of Taylor’s power law and 30% of coefficient β of Iwao’s patchiness regression significantly greater than one, indicating aggregated distributions. Spatial Analyses by Distance IndicEs (SADIE) indicated aggregated patterns of stink bugs in 18% of year-end totals and 42% of weekly counts, with 80% of adults and nymphs positively associated using the SADIE association tool. Maximum stink bug densities in each crop occurred when the plants were producing fruit. Stink bugs exhibited greater densities in crops adjacent to soybean in Barnwell and Lee Counties compared with crops adjacent to corn or fallow areas. The diversity of crops and relatively small size of fields in the Southeast leads to colonization of patches within a farmscape. The ecological and management implications of the spatial and temporal distribution of stink bugs within farmscapes are discussed.     

Characterization of Solanum chomatophilum resistance to 2 aphid potato pests, Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer)

The aphids Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) are responsible for yield reduction in potato (Solanum tuberosum) production by direct phloem feeding and by spreading viruses. Breeding resistant traits from Solanum chomatophilum into the potato germplasm provides alternative means to control aphid infestations. Integrated pest management strategy, using plant resistance, benefits from the characterization of the resistance and of its impact on aphid biology. Our objective was to characterize the resistance of S. chomatophilum by assessing the effects of accessions, plant parts on aphid performance, and by assessing the impact of the resistance factors on different aphid developmental stages and on alate morph production. Detailed aphid performance was obtained by measuring fecundity, survival, percentage of nymphs that reached adult moult, and population growth using whole plant and clip cage experimental designs. Accession and plant physiological age, but not aphid developmental stage, influenced all life-history parameters, except for alate morph production which was not induced on the resistant accessions. Plant part influence was independent of plant species and accession. Both experimental designs resulted in congruent resistance levels at the accession level for each of the two aphid species, supporting the use of any of them in S. chomatophilum resistance screening. PI243340 was resistant to both aphid species, while PI365324 and PI310990 were also resistant to M. euphorbiae and M. persicae, respectively.     

An Evaluation of Frankliniella occidentalis (Thysanoptera: Thripidae) and Frankliniella intonsa (Thysanoptera: Thripidae) Performance on Different Plant Leaves Based on Life History Characteristics

To compare the performance of Frankliniella occidentalis (Pergande) and native Frankliniella intonsa (Trybom) on cucumber and tomato leaves in laboratory, life history characters were investigated, and life tables were constructed using the method of age-stage, two-sex table life. Compared with tomato leaf, there were shorter total preoviposition period (TPOP), higher fecundity, longer female longevity, and higher intrinsic rate of increase (r) of both F. occidentalis and F. intonsa on cucumber leaf. Meanwhile, on cucumber leaf, the shorter TPOP, higher fecundity, longer female longevity, and higher value of r were found on population of F. intonsa but on tomato leaf which were found on population of F. occidentalis. From above, cucumber leaf was the preference to population development of both F. occidentalis and F. intonsa compared with tomato leaf. Nevertheless, on cucumber leaf, population of F. intonsa would grow faster than that of F. occidentalis, which was the opposite on tomato leaf. As to the population development in fields, much more factors would be taken into account, such as pollen, insecticide resistance, and effects of natural enemies etc.     

A preliminary study on the effects of a transgenic corn event on the non-target pest Dalbulus maidis (Hemiptera: Cicadellidae)

The inclusion of the cry gene in corn may produce direct effects on non-target pests. Our research was focused on the relationship between Bt corn germplasm, expressing the cry1F protein to control the fall armyworm [Spodoptera frugiperda (Noctuidae)], and a non-target pest, the corn leafhopper [Dalbulus maidis (Cicadellidae)]. The aim of this contribution was to elucidate if Bt corn plants have influence on the oviposition preference of the leafhopper and to evaluate the effect of the transgenic plant on the hatching rate of egg. Female corn leafhoppers were released in cages each containing two potted plants in the V2 stage: a Bt germplasm and the corresponding isogenic hybrid. Laid eggs were counted and the number of hatched nymphs recorded. D. maidis females oviposited and laid more eggs in Bt plants. The egg hatching rate was negatively affected by the Bt germplasm. In addition, a field study was conducted in order to determine the abundance of D. maidis adults in Bt corn and the corresponding non-Bt isoline. Two corn plots sown with the same germplasms as used in the laboratory bioassays were sampled weekly. In the field, the population of the corn leafhopper was higher in the Bt corn plot than in the non-Bt isoline. Possible hypotheses for the differences in abundance of the vector in the field are: a) that pleiotropic effects of Bt corn could attract adults; b) the existence of a possible direct competition between the corn leafhopper and the target pest in order to utilize the whorls of corn plants as refuge and feeding sites, so the high populations of the vector could be due to the large supply of healthy whorls in the transgenic plot; and/or c) a differential attack of natural enemies occurring in non-Bt plots.     

假眼小绿叶蝉卵缨小蜂的生物学特性研究

缨小蜂是假眼小绿叶蝉的主要卵寄生蜂,本文结合田间观察和室内实验,对缨小蜂的生物学特性进行了初步的研究。结果获知:缨小蜂成蜂的活动与温度、光照密切相关,该蜂可兼营两性生殖和孤雌生殖,但孤雌生殖未见雌性后代。在25℃条件下,缨小蜂从卵到成蜂羽化的发育历期为21.40±0.26d,以10%蜂蜜水作为补充营养能显著延长雌蜂寿命。微小裂骨缨小蜂单雌平均怀卵量36.83±0.81粒,叶蝉三棒缨小蜂单雌平均怀卵量22.33±0.48粒。同时,采用共景深成像系统拍摄了2种缨小蜂各虫态发育过程及其形态特征。     

Transovarial Effect of Novaluron on Tribolium castaneum (Coleoptera: Tenebrionidae) After Termination of Direct Contact

The insect growth regulator novaluron (Rimon 10 EC, Makhteshim-Agan Ltd, Israel) is used against many field pests on corn, vegetables, orchards, forests, and cotton plantations. Previously, we studied various effects of novaluron on stored grain pests. Termination in Tribolium castaneum (Herbst) eggs hatching after treating adults with novaluron and following restoration after adult transfer to untreated media was observed. The objective of this study was to investigate the restoration of T. castaneum egg hatch following transfer of adults from treated media to untreated favorable and unfavorable media. The time needed for hatching restoration of 50% of eggs laid by adults transferred from novaluron (1 ppm) treated flour to untreated flour (RT₅₀) was 2.7 d. RT₅₀ for those transferred to untreated wheat grain was 4.1 d. RT₉₀ in flour was 3.6 d, in grain—6.1 d. Varieties of RTs in grain and in flour with nonoverlapping confidence intervals indicate that RTs were significantly different. Delay of eggs hatching restoration for adults transferred from treated flour to unfavorable media (Petri dishes with limited amount of flour, lying of eggs not detected) was observed. RT₅₀ in flour was 2.1 d and RT₉₀—3.1 d, while RT₅₀ in the unfavorable media was 3.4 d and RT₉₀ 6.5 d. Delayed effect of egg hatching restoration after adult transfer to unfavorable media provides evidence of the significant role of insect physiological state in novaluron excretion and (or) degradation by T. castaneum females.