Nymphal Survival Research Articles

Gold-nanoparticles ingestion disrupts reproduction and development in the German cockroach

The present work shows the effects of gold nanoparticles (AuNPs) orally administered on reproduction and development of the insect Blattella germanica. Newly emerged females were provided with food containing AuNPs (87.44μg/g) of a size between 15 and 30nm (mean 21.8nm), and were allowed to mate with males. Food ingestion, mortality, reproductive parameters (time to ootheca formation and eclosion, ootheca viability and fertility) as well as postembryonic developmental parameters of the first ootheca (nymphal survival and life span) were recorded throughout the experiment. Gold from AuNPs was accumulated by adults of B. germanica with a bioaccumulation factor of 0.1. Ingestion of AuNPs did not disturb the time for ootheca formation nor ootheca eclosion. However, ootheca viability was decreased almost by 25% in AuNPs treated females in comparison to controls. At the same time the number of hatched nymphs was decreased by 32.8% (p<0.001) in AuNP group respect to control one. The postembryonic developmental parameters were also affected by AuNPs treatment, with a 35.8% of decrease (p<0.01) in number of nymphs that moulted to second and third instars and a reduction of their life span. Ingestion of AuNPs causes sublethal effects in B. germanica that compromises life-traits involved in population dynamics. B. germanica is proposed as a model species in nanotoxicological studies for urban environments.

Rearing Orius strigicollis (Hemiptera: Anthocoridae) on an alternative diet of brine shrimp, Artemia salina (Anostraca: Artemiidae)

We investigated the use of cysts of the brine shrimp Artemia salina Linnaeus as an alternative diet to eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller, in rearing the biological control agent Orius strigicollis (Poppius). Although 3rd- and 4th-instar nymphs and 1st to 5th-instar nymphs took longer to develop when fed on brine shrimp cysts with shells than on E. kuehniella eggs, the difference was within or approximately 1 day. The nymphal survival and development were considered to be similar in O. strigicollis fed the two diets. In reproductive characteristics, adult female bugs fed eggs of E. kuehniella or brine shrimp cysts with shells performed better than those fed brine shrimp cysts without shells. Brine shrimp cysts with shells would, thus, be useful for reliably and economically rearing O. strigicollis. This rearing method may also prove useful as part of the quality assurance for commercially produced O. strigicollis.

Non-targeted insecticidal stress on the Neotropical brown stink bug Euschistus heros

Lethal and sublethal insecticide effects on non-targeted pest species are frequently neglected but have potential consequences for pest management and secondary pest outbreaks. Here, the lethal and demographic effects of four soybean insecticides (chlorantraniliprole, deltamethrin, pyriproxyfen, and spinosad, which are used against caterpillars, whiteflies, and green stink bugs) on the brown stink bug Euschistus heros (F.), the main stink bug species currently attacking Neotropical soybean fields, were assessed. Deltamethrin exhibited drastic acute mortality in adult females of E. heros with a median lethal time (LT50) of 0.6 days, whereas pyriproxyfen treated females exhibited a survival similar to that of water-treated insects (LT50 of 89 and 67 days, respectively). Chlorantraniliprole and spinosad-treated females exhibited intermediate survival with a TL50 of 54 and 47 days, respectively. Further scrutiny of the three most selective insecticides (i.e., chlorantraniliprole, pyriproxyfen, and spinosad) using age-structured matrices to assess the demographic impact of these compounds under earlier exposure indicated that both pyriproxyfen and spinosad significantly reduced the population growth of the pest species by compromising the survival of eggs (<17% hatching) and 1st nymphs (LT50 of 3 and 2 days, respectively) and fertility; these results were unlike those obtained for chlorantraniliprole- and water-treated controls, which exhibited less than 50% mortality during development. However, chlorantraniliprole significantly compromised the fertility of adult insects (>50% reduction compared with water-treated insects) to a greater extent than pyriproxyfen and spinosad, but without impairing insect population growth as much. Therefore, although pyriproxyfen and spinosad, besides deltamethrin, are not used to target the Neotropical brown stink bug, these insecticides adversely affected this pest species at the dose recommended for application on the label, thereby preventing its outbreak under such conditions.

How will Mahanarva spectabilis (Hemiptera: Cercopidae) Respond to Global Warming?

The aim of this study was to determine the favorable constant temperature range for Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) development as well as to generate geographic distribution maps of this insect pest for future climate scenarios. M. spectabilis eggs were reared on two host plants (Brachiaria ruziziensis (Germain and Edvard) and Pennisetum purpureum (Schumach)), with individual plants kept at temperatures of 16, 20, 24, 28, and 32°C. Nymphal stage duration, nymphal survival, adult longevity, and egg production were recorded for each temperature*host plant combination. Using the favorable temperature ranges for M. spectabilis development, it was possible to generate geographic distribution. Nymphal survival was highest at 24.4°C, with estimates of 44 and 8% on Pennisetum and Brachiaria, respectively. Nymphal stage duration was greater on Brachiaria than on Pennisetum at 20 and 24°C but equal at 28°C. Egg production was higher on Pennisetum at 24 and 28°C than at 20°C, and adult longevity on Pennisetum was higher at 28°C than at 20°C, whereas adult longevity at 24°C did not differ from that at 20 and 28°C. With these results, it was possible to predict a reduction in M. spectabilis densities in most regions of Brazil in future climate scenarios.

Population-Specific Effects of Interbreeding and Admixture on Reproductive Decisions and Offspring Quality

We investigated interbreeding and admixture in Tetrix subulata grasshoppers from two maternal-origin populations that differed in life-history and dispersal traits. We compared reproductive output of females that had been experimentally mated with males from the same or from a different population. Interbreeding affected clutch size and number of clutches: in one population, females in the admixed treatment produced smaller clutches; in the other population, females in the admixed treatment produced more clutches. Behavioral observations indicated that individuals can discriminate scents emitted by individuals from different populations, so that females might adjust reproductive allocation depending on male origin. However, hatchability of eggs and survival of nymphs were not affected by the mating treatment. Admixture affected the production of viable offspring in the F2 generation, but the effect was opposite in the two populations of maternal origin. Results suggested that responses to interbreeding an...

Survival of UnfedAmblyomma americanum(Acari: Ixodidae) Nymphs Under Laboratory Conditions for Two Years

Amblyomma americanum (L.) (lone star tick) is an aggressive, three-host tick that is commonly found throughout the southeastern United States (Goddard and Varela-Stokes 2009, Vet. Parasitol. 160: 1–12). This tick utilizes an array of vertebrates for hosts, including humans (Bishopp and Trembley 1945, J. Parasitol. 31: 1–54), and has even been demonstrated to imbibe hemolymph from invertebrates (Portugal and Goddard 2015, J. Vector Ecol. 40: 202–204). Lone star ticks are associated with multiple human pathogens and recently have been implicated in cases of heartland virus (Savage et al. 2013, Am. J. Trop. Med. Hyg. 89: 445–452) and red meat allergies (Commins et al. 2011, J. Allergy Clin. Immunol. 127: 1286–1293). Unusual longevity has been described in ixodid ticks, with some Ixodes spp. surviving up to 7 yr (Apanaskevich and Oliver, 2014, Pp. 59–73, In Sonenshine and Roe [eds.], Biology of Ticks. Oxford Univ. Press, Oxford) and in adult A. americanum up to 3 yr (Hair and Howell, 1970, Oklahoma Agric. Exp. Stn. Bull. B-679: 47). Larvae of this species have been noted in the literature to survive without feeding for up to ;9 mo (Hooker et al. 1912, USDA Bull. 106), while unfed nymphs have been reported surviving up to ;18 mo (Koch 1984, J. Med. Entomol. 21: 69–79). This note describes nymphal survival for a full 2 yr under laboratory conditions. Nymphal A. americanum ticks in this observation, which had molted into nymphs on 1 May 2013, were obtained from a colony at the Oklahoma State University Tick Rearing Facility. Amblyomma americanum in this colony are reared on sheep and rabbits, and the most recent introduction of new material (collected from the field) was 15 June 2012. Ticks were received in our lab on 23 May 2013 and were immediately labeled and placed in a desiccator jar containing a concentrated salt

光周期对两种色型豌豆蚜种群参数的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 光周期对两种色型豌豆蚜种群参数的影响 DOI: 10.5846/stxb201412092435 作者: 作者单位: 甘肃农业大学资源与环境学院 兰州,甘肃农业大学草业学院 草业生态系统教育部重点实验室 兰州 作者简介: 通讯作者: 中图分类号: 基金项目: 高等学校博士学科点专项科研基金博导类资助课题（20136202110007）；国家自然科学基金项目（31260433） Effect of photoperiod on population parameters of two color morphs of the pea aphid Acyrthosiphon pisum Author: Affiliation: College of Resource and Environmental, Gansu Agricultural University,College of Grassland Sciences, Gansu Agricultural University, Key Laboratory of Grassland Ecosystem of Ministry of Education Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨光周期对红绿两种色型豌豆蚜种群增长的影响，于室内模拟光周期22L：2D、16L：8D、10L：14D和4L：20D四个水平，研究了红绿两种色型豌豆蚜的发育、繁殖和生命表。结果表明：相对于其它光周期，在光周期22L：2D时，红绿两种色型豌豆蚜若蚜存活率最高，繁殖力最强；其红色型豌豆蚜种群增长内禀增长率（rm=0.3263）高于绿色型豌豆（rm=0.2863）。光周期16L：8D时，红色型豌豆蚜的若蚜存活率（72.22%）高于绿色型豌豆蚜（69.45%），而成蚜寿命（6.58d）较短；但绿色型豌豆蚜内禀增长率（rm=0.2648）高于红色型豌豆蚜（rm=0.2249），其种群繁殖力强。光周期10L：14D时，红色型豌豆蚜与绿色型豌豆蚜相比，若蚜存活率（80.55%）高，内禀增长率（rm=0.2490）高，种群增长力强，而绿色型豌豆蚜成蚜寿命（12.71d）较长。光周期4L：20D时，两种色型豌豆蚜若蚜存活率最低，繁殖力最弱，成蚜寿命显著延长；红色型豌豆蚜若蚜存活率（64.67%）高于绿色型（35.50%），成蚜没有产生后代；绿色型豌豆蚜内禀增长率（rm=-0.0366），其种群为负增长。综上，短光照条件（4L：20D）延长了两种色型豌豆蚜的若蚜发育历期及成蚜寿命，降低了若蚜存活率、繁殖力及生命表各项参数；长光照条件（22L：2D）缩短了两种色型豌豆蚜的若蚜发育历期及成蚜寿命，若蚜存活率高、繁殖力强；红色型豌豆蚜更适宜光周期10L：14D，而绿色型豌豆蚜更适宜光周期16L：8D。 Abstract:To investigate the effects of photoperiod on population growth of the red and green color morphs of the pea aphid Acyrthosiphon pisum (Harris), the development, reproduction, and life table parameters were examined for various photoperiods (22 L:2 D, 16 L:8 D, 10 L:14 D, and 4 L:20 D), controlling for light intensity (103 μmol m-2 s-1). For the 22 L:2 D photoperiod, the red and green color morphs of the pea aphid had the highest nymphal survival rates (90.28% and 88.89% respectively), the shortest duration of development (5.63 d and 6.26 d), the highest net reproductive rates (49.3472 and 47.8103), the highest average fecundity (54.56 and 55.16), the highest maximum fecundity (121 and 112 offspring per female aphid), and the highest intrinsic rate of increase (rm =0.3263 and 0.2863, respectively). Population growth was higher for the red color morph than the green color morph for the 22 L:2 D photoperiod. For the 16 L:8 D photoperiod, the red color morph of the pea aphid had a higher nymphal survival rate (72.22%) and shorter adult longevity (6.58 d) than those of the green color morph (69.45% and 7.08 d, respectively). However, the green color morph had a higher intrinsic rate of increase (0.2648 vs. 0.2249), indicating a higher population fecundity of the green color morph than the red color morph for the particular photoperiod. For the 10 L:14 D photoperiod, the red color morph had a higher nymphal survival rate (80.55%) and intrinsic rate of increase (0.2490) than those of the green color morph (79.17% and 0.2277, respectively). However, the green color morph had a longer duration of development (7.92 d) and adult longevity (12.71 d) than those of the red color morph (7.60 and 6.88 d, respectively). For the shortest photoperiod (4 L:20 D), the red and green color morphs of the pea aphid had the lowest nymphal survival rate (64.67% and 35.50%, respectively) and the longest duration of development (13.26 and 13.61 d). Moreover, the red color morph did not produce offspring and had a fecundity of zero. However, its intrinsic rate of increase, -0.0366, indicated negative population growth of the green color morph. In conclusion, extremely short durations of light (4 L:20 D) can prolong development and adult longevity, but reduces nymphal survival rate and the intrinsic rate of increase of two pea aphid color morphs. However, extremely long durations of light (22 L:2 D photoperiod) resulted in shortened development and decreased adult longevity, but an increased nymphal survival rate and fecundity for the two pea aphid color morphs. Moreover, the 10 L:14 D photoperiod was a more suitable condition with respect to population growth for the red color morph, but for the green color morph a photoperiod of 16 L:8 D was better. Therefore, the results of this study may facilitate artificial breeding of pea aphids and the prevention and treatment of pea aphid attacks on field crops. Furthermore, the mechanism underlying the response to photoperiod differed between the red and green color morphs of pea aphids. Further studies are needed to examine these mechanisms. 参考文献 相似文献 引证文献

Impact of Food Diversity on Biological Parameters ofApolygus lucorum(Hemiptera: Heteroptera: Miridae)

Abstract Apolygus lucorum (Meyer-Dur) (Hemiptera: Heteroptera: Miridae) is an important insect pest of cotton and other crops, but the species also feeds on some insect pests. In this study, the effect of 5 food condition treatments, including corn kernel, cotton leaves, eggs of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), a combination of corn + H. armigera eggs, and of cotton leaves + H. armigera eggs, on the biological parameters of A. lucorum was evaluated in the laboratory. Mixed foods (e.g., corn + H. armigera eggs) significantly increased nymphal survival, prolonged adult longevity, and improved female fecundity. The survival rate of nymphs with only H. armigera egg was the lowest, and development times with cotton leaves were the longest. Under mixed food conditions, nymphs preyed on more eggs in the combination with cotton leaves than with corn. These results indicate that A. lucorum does have a certain ability to prey on H. armigera eggs, but that during the growth and development of A....

Genetic parameters and selection of Brachiaria decumbens hybrids for agronomic traits and resistance to spittlebugs

Abstract The objective of this work was to estimate genetic parameters for agronomic traits and resistance to spittlebugs in B. decumbens hybrids and to select the ones with best performance. For that, 324 hybrids were evaluated in field plots for agronomic traits and in the greenhouse for resistance to spittlebugs. Genetic variability amongst the hybrids was observed for all traits analyzed. The heritability estimates between genotypes means were higher than 0.52 for all agronomic traits and 0.98 and 0.99 for nymphal survival and nymphal period duration respectively. Hybrids with better performance than cultivar Basilisk for each individual trait were identified and also through a selection index combining all traits. Assigning weights to the different traits in the selection index did not significantly alter the rank for superior hybrids. Those were selected to continue on to the next phases of the breeding program.

Effects of spirotetramat on development and reproduction of Myzus persicae (Hemiptera: Aphididae)

AbstractThe Green Peach Aphid Myzus persicae (Sulzer, 1776) is one of the most destructive pests of cultivated crops worldwide. Spirotetramat is an insecticide with a novel mode of action on aphids and other sucking pests. Here, we studied the effects of spirotetramat on the biology and development of M. persicae under laboratory condition. The results showed that spirotetramat at sublethal doses caused a decrease in nymph survival. However, we did not find sublethal effects on developmental duration of treated aphids or their offspring when exposed to LC5 (0.2736 mg/L), LC15 (0.5163 mg/L) and LC25 (0.7531 mg/L) concentrations. Treatments with LC30 (0.8808 mg/L), LC60 (1.9830 mg/L) and the recommended concentration for field usage (60 mg/L) significantly reduced the longevity and fecundity of adult aphids. Gross fertility was reduced by 65.34%, 81.80% and 86.51% at LC30, LC60 and recommended concentrations, respectively. The most significant feature of spirotetramat is that it induces nonviable nymphs, leading to a significant reduction in adult fecundity. The proportion of nonviable nymphs significantly increased with the concentration of spirotetramat. The gross and net reproductive rates were reduced by 68.91%, 83.97%, 97.25% and 65.61%, 81.94%, 97.10% at LC30, LC60, and recommended concentrations, respectively. The intrinsic rate of increase decreased to 0 when aphids were exposed to the recommended concentration. Our study showed that the reproductive toxicity of spirotetramat should be fully considered when attempting to evaluate the pesticide's action on insects.

Evaluation of rice genotypes for rice brown plant hopper resistance through phenotypic reaction and genotypic analysis

Fifty eight rice genotypes including 39 landraces from Odisha state, India were phenotyped against a brown plant hopper (BPH) population at the Central Rice Research Institute (CRRI), Cuttack through the modified seed box technique, the nymphal survival test and the nin-hydrin test of feeding. High levels of resistance was found in nine genotypes, namely Baiganamanji, Champa, Assamchudi-K, Akula, Balibhanjana-T, Assamchudi-B, Champeisali-B, Ganjeijata-P and Harishankar-D. Known gene differentials for BPH such as IR 64 (Bph1), IR 36 (bph2), ASD 7 (bph2), Swarnalata (Bph6), T 12 (bph7), Chinsaba (bph8), Pokkali (bph9) and Rathu Heenati (Bph3+Bph17)) included in the study for comparision showed susceptible reactions to the CRRI BPH population. The genotype Babawee (bph4) was moderately resistant whereas three others (Bph18, Bph20/21 and bph2+Bph3) were highly resistant along with previously CRRI- identified donors of BPH such as Salkathi, Dhobnumbari, Jalakanthi and Dhoiya bankoi of CRRI. Genetic diversity analysis of all the genotypes through 22 gene-linked markers of BPH resistance categorized them into 4 major clusters with the 40% level of genetic similarity. The phenotypically highly resistant genotypes were grouped together under the same major cluster I indicating their similar genetic background, but there were other resistant materials which were grouped differently showing their genetic diversity. The resistant genotypes can be utilized as efficient donors for developing rice varieties with resistance to BPH.

Ecdysone receptor isoform-B mediates soluble trehalase expression to regulate growth and development in the mirid bug, Apolygus lucorum (Meyer-Dür).

Ecdysone receptor (EcR) is the hormonal receptor of ecdysteroids and strictly regulates growth and development in insects. However, the action mechanism of EcR is not very clear. In this study, the cDNA of EcR isoform-B was cloned from Apolygus lucorum (AlEcR-B) and its expression profile was investigated. We reduced AlEcR-B mRNA expression using systemic RNA interference in vivo, and obtained knockdown specimens. Examination of these specimens indicated that AlEcR-B is required for nymphal survival, and that reduced expression is associated with longer development time and lower nymphal weight. To investigate the underlying molecular mechanism of the observed suppression effects, we selected trehalase for a detailed study. Transcript encoding soluble trehalase (AlTre-1) was up-regulated by 20-hydroxyecdysone and in agreement with the mRNA expression of AlEcR-B. The expression profile of AlTre-1, soluble trehalase activity and translated protein level in the midgut of surviving nymphs were down-regulated, compared with controls, after the knockdown expression of AlEcR-B. By contrast, membrane-bound trehalase activity, the related gene expression and translated protein level remained at their initial levels. However, trehalose content significantly increased and the glucose content significantly decreased under the same conditions. We propose that AlEcR-B controls normal carbohydrate metabolism by mediating the expression of AlTre-1 to regulate the growth and development in A. lucorum, which provide an extended information into the functions of AlEcR-B.

Interactions Between Bt-Bioinsecticides and Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae), a Predator of Plutella xylostella (L.) (Lepidoptera: Plutellidae).

Bioinsecticides are being increasingly used to protect vegetable crops against herbivores, but data on the side effects of such strategy on the third trophic level are still required. We investigated the influence of the Bacillus thuringiensis subsp. kurstaki HD-1 strain and of the commercial bioinsecticide Agree® on the biological aspects of the predator Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) when feeding on Plutella xylostella (L.) (Lepidoptera: Plutellidae)-infected larvae. On average, infected larvae were consumed more often than the non-infected larvae throughout the predator nymphal development, and no effect on nymph survival was observed. Population growth parameters (R 0, r m, and λ) resulting from the fertility life tables did not differ among treatments. The results led to the conclusion that P. nigrispinus can be used in combination with the product Agree® or the strain HD-1 for the control of P. xylostella. The combined use of these control agents helps to maintain the balance of the ecosystem and contributes for the production of food for healthy human consumption.

Effects of three novel resistant black raspberry selections on Amphorophora agathonica feeding behavior and performance

Host plant resistance is a practical and cost-effective approach for growers to manage insect pests. Recently, three new sources of resistance in black raspberry (Rubus occidentalis; selections ORUS 3778-1, ORUS 3817-1, and ORUS 4109-1) against the large raspberry aphid, Amphorophora agathonica, were identified. We studied stages of host plant acceptance: host plant attraction, parturition (deposition of nymphs), nymph survival, and adult feeding behavior (using the electrical penetration graph [EPG]) to identify the location of the plant resistance. Aphids were more attracted to the susceptible cultivar ‘Munger’ (control) than the resistant selections. Parturition occurred on the resistant selections, but fewer nymphs were deposited on resistant lines relative to the susceptible control. Nymphs survived only an average of 3.3–3.6 days on resistant selections, whereas 94 % were still alive after 11 days on ‘Munger.’ There were differences in feeding behavior between the susceptible control and the resistant selections, but no differences between the three resistant selections. The tissues responsible for resistance appear to be the mesophyll and phloem sieve elements. Aphids had a reduced probability of salivation into the phloem sieve elements of resistant selections, and only one aphid each on ORUS 3778-1 and ORUS 4109-1 successfully ingested from the phloem. Because feeding behavior of A. agathonica did not differ between resistant selections, independent confirmation that resistance is conferred by unique genes should be obtained before pyramiding these sources together.

Postharvest Quarantine Treatments for Diaphorina citri on Infested Curry Leaves.

Studies were conducted to evaluate treatments that reduce survival and attachment of Diaphorina citri nymphs on infested curry leaves (Bergera koenigii). Decontamination of curry leaves infested with D. citri in relation to disinfectant (none or Pro-San), temperature (0, 40, and 50°C), and treatment duration (0, 5, 10, and 20 min) was examined using a split-split plot design. Experiments were performed three times. Treatment duration did not significantly affect D. citri nymph survival or removal (P > 0.2). Temperature and disinfectant each significantly affected D. citri nymph survival and removal (P < 0.031). The interaction of temperature and disinfectant was significant with respect to nymph survival (P < 0.0001) but did not significantly affect removal (P = 0.4589). Tissue damage was significantly affected by temperature (P = 0.0056), duration (P = 0.0023), the interaction of temperature and duration (P = 0.0320), and the interaction of disinfectant, temperature, and duration (P = 0.0410). Of the treatments resulting in 100% D. citri nymph mortality on infested curry leaves, 40°C for 5 min with Pro-San was accompanied with the least proportion of curry leaf tissue damage (0.14 greater than untreated control, P = 0.25). Results from these studies may be useful in formulation of future regulatory policies regarding trade of citrus foliage, especially those used as condiments.

Effectiveness of Cyantraniliprole for Managing Bemisia tabaci (Hemiptera: Aleyrodidae) and Interfering with Transmission of Tomato Yellow Leaf Curl Virus on Tomato.

Cyantraniliprole is the second xylem-systemic active ingredient in the new anthranilic diamide class. Greenhouse (2006), growth chamber (2007), and field studies (2009-2010) were conducted to determine the efficacy of cyantraniliprole for managing Bemisia tabaci (Gennadius) biotype B and in interfering with transmission of tomato yellow leaf curl virus (TYLCV) by this whitefly. Cyantraniliprole applied as soil treatments (200 SC) or foliar sprays (100 OD) provided excellent adult whitefly control, TYLCV suppression, and reduced oviposition and nymph survival, comparable to current standards. The positive results observed in these greenhouse experiments with a high level of insect pressure (10× the field threshold of one adult per plant) and disease pressure (five adults per plant, with a high level of confidence that TYLCV virulent adults were used), indicate a great potential for cyantraniliprole to be used in a whitefly management program. Field evaluations of soil drench treatments confirmed the suppression of TYLCV transmission demonstrated in the greenhouse studies. Field studies in 2009 and 2010 showed that cyantraniliprole (200 SC) provided TYLCV suppression for 2 wk after a drench application, when using a susceptible (2009) or imidacloprid-tolerant (2010) whitefly population. Cyantraniliprole was demonstrated to be a promising tool for management of TYLCV in tomato production, which is very difficult and expensive, and which has limited options. The integration of cyantraniliprole into a resistance management program will help to ensure the continued sustainability of this and current insecticides used for the management of insect vectors, including whiteflies and the TYLCV they spreads.

Temperature-Dependent Fecundity and Life Table of the Fennel Aphid Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae).

Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae) is a cosmopolitan species and the main pest of fennel in northeastern Brazil. Understanding the relationship between temperature variations and the population growth rates of H. foeniculi is essential to predict the population dynamics of this aphid in the fennel crop. The aim of this study was to measure the effect of constant temperature on the adult prereproductive period and the life table fertility parameters (infinitesimal increase ratio (rm), gross reproduction rate (GRR), net reproduction rate (R0), finite increase ratio (λ), generation time (GT), the time required for the population to double in the number of individuals (DT), and the reproduction value (RVx)) of the fennel pest H. foeniculi. The values of lx (survival of nymphs at age x) increased as the temperature rose from 15 to 28°C and fell at 30°C, whereas mx (number of nymphs produced by each nymph of age x) increased from 15 to 25°C and fell at 28 and 30°C. The net reproduction rates (R0) of populations of H. foeniculi increased with temperature and ranged from 1.9 at 15°C to 12.23 at 28°C for each generation. The highest population increase occurred with the apterous aphids at 28°C. The rate of population increase per unit time (rm) (day) ranged from 0.0033 (15°C) to 0.1995 (28°C). The highest values of rm were recorded at temperatures of 28°C and 30°C. The rm values were a good fit to the models tested, with R2 > 0.91 and R2 adj > 0.88. The models tested (Davidson, Sharpe and DeMichele modified by Schoolfield et al., Logan et al., Lamb, and Briere et al.) were very good fits for the rm values observed, with R2 > 0.91 and R2 adj > 0.88. The only exception was the Davidson model. Of the parameters studied, the reproductive capacity was higher in the apterous aphids, with the unique exception of daily fecundity at 28°C, which was higher in the alate aphids of H. foeniculi. Parameters relating to the age-specific fertility table for H. foeniculi were heavily influenced by temperature, with the highest biotic potential and population growth capacity found at 34°C. Therefore, the results obtained in this study could be of practical significance for predicting outbreaks of fennel aphids and improving the management of this aphid in fennel crops.

Donor validation studies on rice differential varieties against rice brown planthopper, Nilaparvata lugens (Stal.)

Six differential varieties along with standard checks were evaluated for donor validation against rice brown plant hopper at glasshouse, Department of Entomology, IGKV, Raipur during 2013- 14. All the differentials were resistant to Raipur BPH population. Among the differential tested, ARC 10550 exhibited list plant damage score (0.64) followed by Sinna Sivappu (0.75). Honeydew excretion values were minimum in Sinna Sivappu (15.3 mm 2 ) followed by Rathu Heenati (15.8 mm 2 ). The average probing marks were maximum in Sinna Sivappu (38.3) followed by Rathu Heenati (30.7) which were significantly higher than TN1, while nymphal survival value was minimum in variety INRC 3021 (29.21%). All the differentials showed resistant reaction in all the tests performed against Raipur population. These differentials were designated as the potential donors for BPH resistance.

Surviving a flood: effects of inundation period, temperature and embryonic development stage in locust eggs.

The Australian plague locust, Chortoicetes terminifera (Walker), is an important agricultural pest and oviposits into compacted soil across vast semi-arid and arid regions prone to irregular heavy summer rainfall. This study aimed to quantify the effects of flooding (control, 7, 14, 21, 28 and 35 days) at different temperatures (15, 20 and 25°C) and embryonic development stages (25 and 75%) on egg viability, hatchling nymph body mass and survival to second-instar. Egg viability after flooding was dependent on temperature and flood duration. Eggs inundated at 15°C showed ≥53.5% survival regardless of flood duration and development stage compared with ≤29.6% for eggs at 25°C for ≥21 days early in development and ≥14 days late in development. Hatchling nymphs did not differ in body mass relative to temperature or flood duration, but weighed more from eggs inundated early in development rather than late. Survival to second-instar was ≤55.1% at 15 and 20°C when eggs were flooded for ≥28 days late in development, ≤35.6% at 25°C when flooded for ≥28 days early in development, and zero when flooded for ≥21 days late in development. These results suggest that prolonged flooding in summer and early autumn may cause very high egg mortality and first-instar nymph mortality of any survivors, but is likely to only ever affect a small proportion of the metapopulation. More common flash flooding for ≤14 days is unlikely to cause high mortality and have any direct effect on distribution and abundance.

Elimination of Arsenophonus and decrease in the bacterial symbionts diversity by antibiotic treatment leads to increase in fitness of whitefly, Bemisia tabaci

Bemisia tabaci is an invasive agricultural pest with more than 24 genetic groups harboring different bacterial endosymbionts categorized into obligatory and facultative endosymbionts. Arsenophonus is one of the facultative endosymbionts prevalent in B. tabaci of Indian sub-continent. Not much is known about the functional role of this endosymbiont in its host. Some studies have revealed its involvement in virus transmission by B. tabaci, but how it effects the biology of B. tabaci is unknown. In this study, tetracycline was used to eliminate Arsenophonus from B. tabaci to study its effects with regard to development and other fitness parameters. Bacteria specific 16S Polymerase chain reaction (PCR) was used to ascertain Arsenophonus absence with differential effects on other secondary endosymbionts present in B. tabaci. Our results revealed that Arsenophonus negative (A−) whiteflies had more fecundity, increased juvenile developmental time, increased nymphal survival and increased adult life span as compared to control (A+) whiteflies. Thus, our results demonstrate that A+ whiteflies have lesser fitness as compared to A− whiteflies. These observations give a new insight about the probable role of Arsenophonus in B. tabaci, that need to be explored further.