Pest Of Cereals Research Articles

The unstable ‘clone’: evidence from monitoring AFLP-based mutations for short-term clonal genetic variation in two asexual lineages of the grain aphid, Sitobion avenae (F.)

Clones have been in the forefront of biological interest for many years. Even so, open discussions continue to surround the concept of clonality, which has been recently much debated in the scientific literature, both in terms of philosophical meaning as well as empirical determination. Philosophically, the clone is the horizontally produced lineage from a single fertlized egg (e.g. mammals by division of the fertilized egg and representing a single generation) or vertically produced offspring (e.g. aphids representing different successive generations) from a single asexual stem mother (originally for a particular lineage, following hatching of the overwintering sexual egg in the spring); empirically, the aspect of genetic fidelity is also considered important, so-called clones being assumed to have an identical genome among clone mates. In reality of course, such members of a clonal lineage must differ at various regions of the genome, since mutation is a fundamental property of the DNA itself. Yet few studies have so far set out to show this empirically in eukaryotic organisms, which indulge in periods of asexual reproduction, sometimes, as in aphids, over many generations. In the present study, we have investigated asexual lineages of the grain aphid, Sitobion avenae (F.), a global pest of cereals, over five successive generations employing AFLP-PCR molecular techniques. Our main interest was to see how much variation was present in the early generations and if this variation was transmitted through the asexual lineages. By monitoring AFLP-based polymorphisms, we show that, in this aphid species, of a total of 110 individuals from two lineages tested (termed SA and SB), random mutations (band deletions, more rarely additions) were apparent from the third generation onwards, and although some mutations were found to be transmitted transgenerationally, others were rarely transmitted through the particular lineages they were detected in. Using Arlequin v. 2.0, average gene diversity within the lineages was found to be 0.024±0.013 and 0.031±0.016 for SA and SB, respectively. It was also found from the rearing of the lineages that one lineage, SA, was more fecund than the other lineage, SB, over the five generations (N=818 vs. N=358 total stem mothers plus nymphs for the two lineages, respectively).

Opinion 2306 (Case 3542)TrachelusJurine, 1807 (Hymenoptera, cephidae): precedence given overAstatusPanzer, [1801

The Commission has conserved the current usage of the widely used sawfly genus name Trachelus Jurine, 1807 by giving it precedence over its senior synonym Astatus Panzer, [1801]. The ‘black grain stem sawfly’, Trachelus tabidus (Fabricius, 1775), is a pest of cereals in the southern West Palaearctic and in North America.

Molecular characterization of cereal cyst nematodes from the South Anatolian Region in Turkey using ITS-rDNA sequences

Summary The Heterodera avenae group includes 12 species feeding on roots of cereals. Three species, Heterodera avenae Wollenweber, 1924, Heterodera filipjevi (Madzhidov, 1981) Stelter, 1984 and Heterodera latipons Franklin, 1969 are among the most economically important cyst nematode pests of cereals cultivated in different parts of Turkey. In this study, forty seven cereal cyst nematode isolates collected from cereal growing areas of the South

High toxicity and specificity of the saponin 3-GlcA-28-AraRhaxyl-medicagenate, from Medicago truncatula seeds, for Sitophilus oryzae

BackgroundBecause of the increasingly concern of consumers and public policy about problems for environment and for public health due to chemical pesticides, the search for molecules more safe is currently of great importance. Particularly, plants are able to fight the pathogens as insects, bacteria or fungi; so that plants could represent a valuable source of new molecules.ResultsIt was observed that Medicago truncatula seed flour displayed a strong toxic activity towards the adults of the rice weevil Sitophilus oryzae (Coleoptera), a major pest of stored cereals. The molecule responsible for toxicity was purified, by solvent extraction and HPLC, and identified as a saponin, namely 3-GlcA-28-AraRhaxyl-medicagenate. Saponins are detergents, and the CMC of this molecule was found to be 0.65 mg per mL. Neither the worm Caenorhabditis elegans nor the bacteria E. coli were found to be sensitive to this saponin, but growth of the yeast Saccharomyces cerevisiae was inhibited at concentrations higher than 100 μg per mL. The purified molecule is toxic for the adults of the rice weevils at concentrations down to 100 μg per g of food, but this does not apply to the others insects tested, including the coleopteran Tribolium castaneum and the Sf9 insect cultured cells.ConclusionsThis specificity for the weevil led us to investigate this saponin potential for pest control and to propose the hypothesis that this saponin has a specific mode of action, rather than acting via its non-specific detergent properties.

The natural home for agricultural entomologists?

With the plethora of entomological journals, applied and otherwise, now available, why should an entomologist attempt to publish in Annals of Applied Biology? At first sight it may seem a less than obvious choice, but the Annals of Applied Biology has a long and distinguished tradition of entomological publishing and in the first ever editorial the point is made very strongly that applied entomologists were very much seen as important readers and contributors to the journal (Maxwell-Lefory, 1914). During the 1920s and 1930s almost half the papers published were entomological in nature and many focused on cereal crops (Petheridge, 1921). The current emphasis on statistical excellence was also evident in those early days with statisticians from Rothamsted Experimental Station (Mathetes, 1924) leading the way. Then as now, however, the crops covered were not all cereals, as a study by Newton (1934) investigating an attack of chrysomelid beetles on henbane (Hyoscyamus niger) reveals. During the war years, although papers on plant pathogens were in the ascendant, studies of insect pests on cereals were still prevalent (Barnes & Weil, 1944). During the 1950s the Annals led the way in publicising new monitoring technology such as the early development of the Rothamsted suction traps (Johnson & Taylor, 1955) and the understanding of the modes of action of insecticides (Stringer et al., 1955). During the 1960s plant pathology dominated the journal but entomologists still saw the Annals as a useful outlet for work on orchard pests (Avery & Briggs, 1968). The advent of large scale cereal aphid outbreaks in the 1970s saw important pioneering work appearing in the journal throughout the 1970s and early 1980s (Dean, 1973, 1974; Watt, 1979; Leather & Dixon, 1981). The Annals continued to be a home for papers investigating pests of cereals during the 1990s (Howard & Dixon, 1995) and despite the presence of rivals such as Journal of Economic Entomology and Bulletin of Entomological Research and the launch of Agricultural & Forest Entomology in 1999, continued to attract good quality agricultural and forest entomology papers from around the world as the 21st century began (Kaspi & Parrella, 2003; Oberg & Ekbom, 2006; Timms & Leather, 2008). Now as we progress through the second decade of the century, the Annals has become ever more international and topical, publishing papers on the effective rearing of biological control agents (Colinet & Hance, 2010), pests of coconuts (Gitau et al., 2011), hemipteran virus vectors (Kirchner et al., 2011), the effects of Bt maize on pests and natural enemies (Petzold-Maxwell et al., 2012), modern insecticide efficacy (Tome et al., 2012) and the ever present pests of cereals (Aqueel & Leather, 2012). The Annals of Applied Biology also publishes influential reviews such as that examining insect pest movement in agricultural landscapes (Mazzi & Dorn, 2012). Many of us these days are encouraged by our employers to submit to journals with the highest impact factors. This is not necessarily good for our science or our intended audience. It is much better to target a journal where we will get the widest readership, and a high impact factor does not necessarily go hand in hand with readership. Applied journals tend to be read much more than they are cited, as their readership includes a high number of practitioners, for example in the case of a journal such as the Annals of Applied Biology, advisory and extension entomologists, agronomists, people from the agro-chemical industry, biological control practitioners etc. In 2010 for example there were 73 170 full-text downloads from the Annals and in 2011 this had risen to almost 82 000. Thus, as an agricultural entomologist it makes a great deal of sense to publish in a journal such as the Annals of Applied Biology that speaks directly to the agricultural and associated sectors as well as to the research community. We are particularly interested in receiving submissions dealing with global food security issues, in particular innovative crop protection methods, for example, modern approaches to biological control and integrated pest management. We also welcome papers dealing with the

Utilization of prey-rich patches leads to reproductive advantages for clustered individuals of a web-building spider

The ideal free distribution (IFD) model predicts that consumers match the distribution of resources across habitat patches and that this association should lead to equal individual fitness among individuals in a population. Here we studied to what extent predators utilize different prey groups and if the resulting spatial patterns relate to the reproductive success of individuals in a population of a web-building spider species (Phylloneta impressa Theridiidae). Web-building spiders, their prey remains, egg sacs, and spiderlings were collected in a wheat field, and coordinates of web sites were recorded for spatial point pattern analysis using pair and mark correlation functions. Spiders were aggregated in the study area, but only postreproductive females were aggregated over the full range of spatial scales. Web-owners in clusters caught a higher proportion of hemipteran prey than expected by the mean, suggesting that the availability of this prey type contributed to the clustering of individuals and the higher reproductive success of females in clusters. However, 2 abundant prey groups (Syrphidae and Hymenoptera) were not more common than expected by the mean at any distance, and another prey group (Elateridae) was even less common in webs close to each other. At least 2 prey groups (Hemiptera and Elateridae) showed deviations from the assumption of the IFD model that predators in clusters should have similar prey capture success compared to predators that are not located in clusters. Both prey groups include many cereal pest species, and our results suggest that spatially explicit information about prey utilization and predator fitness may contribute to a better understanding of the role of natural enemies in biological control.

Case 3576OscinellaBecker, 1909 (Insecta, diptera, chloropidae): proposed conservation by reversal of precedence withMelanochaetaBezzi, 1906 and Pachychaetina Hendel, 1907

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the widely used generic name Oscinella Becker, 1909 (chloropidae). The name Oscinella is threatened by its senior subjective synonyms Melanochaeta Bezzi, 1906 and Pachychaetina Hendel, 1907. Strict application of the Code would result in the name Oscinella frit (Linnaeus, 1758), uniformly used for ‘frit fly’, one of the most serious pests of cereals in the Palaearctic, having to change its generic epithet. It is proposed that Oscinella be given precedence over Melanochaeta and its objective synonym Pachychaetina over Oscinella Becker, 1909 whenever these names are considered to be synonyms.

Efficacy of intercropping and harvest time modification for reducing field infestation of maize by Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Most management practices of Sitophilus zeamais Motschulsky, a field-to-post-harvest insect pest of cereals, have focused on post harvest control methods. This experiment was designed to investigate the potential of cropping system and modification of time of harvest to control S. zeamais. Intercropping and harvest time modification had significant (P < 0.05) effect on the number of S. zeamais emerging 42 days post-harvest. For the early harvest (15 weeks after planting (WAP)), the mean number of S. zeamais recorded from a maize monoculture (7.39) was significantly (P < 0.05) higher than the mean numbers of weevils emerging from a maize–soybean intercrop (2.31), but not significantly higher than the number recorded in maize–groundnut (3.87) intercrop. For the late harvest (18 WAP), the mean number of emerged adult observed in the maize–soybean intercrop (6.13) was significantly lower than the mean number of adult emerging from the monocrop maize (13.24). Maize–groundnut intercrop did not significantly reduce field infestation of S. zeamais compared with monocrop maize. Percentage weight loss observed in early harvested maize was significantly (P < 0.0001) lower than what was observed in late-harvested maize. Percentage weight loss was highest in stored maize harvested from monocrop maize plots for the early harvest, whereas intercropping maize with soybean reduced percentage weight loss when harvest was delayed.

Resistance and susceptibility of some wheat lines to bird cherry-oat aphid Rhopalosiphum padi (Hemiptera: Aphididae)

Bird cherry-oat aphid, Rhopalosiphum padi (L.), is one of the most serious pests of cereals, with an almost worldwide distribution. A primary screening test was carried out to gauge the resistance or susceptibility of 40 wheat lines to R. padi, and follow-up experiments were conducted to determine the development and fecundity rates of R. padi on eight lines. The forty wheat lines examined were classified into two major classes and four subclasses: A (e.g., ERWYT 87-1) and B (e.g., ERWYT 87-20, ERWYT 87-11), with the highest average number of aphids 14 days after infestation, subclass C (e.g., ERWYT 88-8, ERWYT 87-6, ERWYT 87-4), with the lowest average number of aphids, and subclass D (e.g., ERWYT 88-12, ERWYT 88-13), with intermediate status. Aphid nymph developmental time and survival both differed among the wheat lines. Differences were also observed in the fecundity of R. padi, the intrinsic rate of increase (rm), and other parameters among the wheat lines tested. The highest and lowest values of rm were obtained for ERWYT 87-1 and ERWYT 88-8 (0.36 and 0.26 nymphs/female/day, respectively). Three lines (ERWYT 87-4, ERWYT 87-6, ERWYT 88-8) were relatively resistant to R. padi, which could prove useful in the development of IPM programs for this aphid in wheat fields.

First record of Bracon lissogaster (Hymenoptera: Braconidae) in Canada – a potentially important parasitoid of Cephus cinctus (Hymenoptera: Cephidae) in the prairies

Bracon lissogaster Mues., a key parasitoid of Cephus cinctus Norton in northern Montana USA, is reported in Canada for the first time. Resurgence of C. cinctus in Alberta and Saskatchewan has led to renewed interest in biological control of this cereal pest in Canada.

Cryptic species within the wheat curl mite Aceria tosichella (Keifer) (Acari : Eriophyoidea), revealed by mitochondrial, nuclear and morphometric data

The wheat curl mite (WCM), Aceria tosichella (Keifer, 1969), is one of the primary pests of wheat and other cereals throughout the world. Traditional taxonomy recognises WCM as a single eriophyoid species; however, a recent study suggested that two genetic lineages of WCM in Australia might represent putative species. Here, we investigate WCM populations from different host plants in Australia, South America and Europe and test the hypothesis that WCM is, in fact, a complex of cryptic species. We used morphological data in combination with nucleotide sequences of the mitochondrial cytochromec oxidase subunitI (COI) and nuclear D2 region of 28S rDNA and internal transcribed spacer region (ITS1, ITS2) sequences. The molecular analyses did not support the monophyly of A. tosichella because the outgroup A. tulipae (Keifer, 1938) is grouped within WCM. The molecular datasets indicated the existence of distinct lineages within WCM, with the distances between lineages corresponding to interspecific divergence. Morphological analyses failed to clearly separate WCM populations and lineages, but completely separated A. tulipae from A. tosichella. The results suggest that what has been recognised historically as a single species is, in fact, a complex of several genetically isolated evolutionary lineages that demonstrate potential as cryptic species. Hence, their discrimination using solely morphological criteria may be misleading. These findings are particularly significant because of the economic importance of WCM as a direct pest and vector of plant viruses.

Characteristics of the changes in the structure of aphid species composition based on catches of Johnsons suction trap in 1999–2010Charakterystyka zmian w strukturze składu gatunkowego mszyc migrujących w odłowach aspiratorem Johnsona w latach 1999–2010

Summary Studies on aphid’s migration with the use of Johnson’s suction trap were carried out at the Agricultural Experimental Station in Winna Gora (Wielkopolska province) in 1999–2010. Total 128 species of caught aphid individuals were classified in five groups: eudominants, dominants, subdominants, recedents and subrecedents according to the hierarchical structure. The subrecedents group was the most diversified in terms of species, the least numerous and included aphids of minor economic importance. The group of eudominants was the most numerous one and representd by the only species Rhopalosiphum padi – economically important cereal pest. Other identified species belonged to the groups of dominants, subdominants and recedents.

Identification of proteases from leaf beetle (Oulema spp.) by selective protease inhibitorsIdentyfikacja proteaz skrzypionek (Oulema spp.) za pomocą selektywnych inhibitorów proteaz

Summary The aim of the study was the identification of gut proteases of leaf beetle Oulema spp. Leaf beetles like aphids or saddle gall midge belong to main cereal pests in Poland. Two species of leaf beetles are common in Poland: cereal leaf beetle (Oulema melanopus, Linnaeus 1758) and grey leaf beetle (Oulema gallaeciana, Heydel 1870). The larvae of both species damage the assimilation surface of plant leaves. Leaf beetles were collected from the fields. The larvae of leaf beetles were immobilized on ice and then homogenized. For identification of different gut proteases polyacrylamide gel separation (in-gel protease assay condition) and selective inhibitors E-64 (trans-epoxysuccinyl-L-leucylamido(4-guanidino)butane) for cysteine protease and PMSF (Phenylmethylsulfonyl fluoride) for serine protease were used. Two kind of proteases: serine and cysteine were identified in guts of leaf beetles. This aspect is very important because insects utilize proteases to digest plant material and to gain exogenous amino acids.

Within‐generation dynamics of leatherjackets (Tipula paludosa Meig.)

AbstractLarvae of Tipula paludosa (leatherjackets) are pests of grassland and cereals, and important prey items for a range of farmland birds. Their population dynamics from year to year have been the subject of study, but within‐generation dynamics have received much less attention. The duration and occurrence of instars and size of the population is important to both pest management and bird conservation. Leatherjackets were collected monthly from four grass fields over five generations (October to September). Count data were analysed for sources of variability and used to estimate the timing and duration of instars and population changes over a single generation. Instar durations were correlated with temperature. From the first to third instars, sample counts were strongly influenced by the location of the site and the generation. Fourth instar larvae showed a similar decline in numbers across all sites and generations. The duration and timing of first to third instars was more variable than that of the fourth instar, but there was limited evidence that this was influenced by temperature. Only the durations of the third and fourth instars were correlated. The population decline from April to September coincided with the onset of the fourth instar. Our results show that the factors influencing leatherjacket numbers change over the life cycle, but by the fourth instar, these are biotically driven. The predictability of its numerical decline indicates defined windows for crop damage and availability as prey. The stability of its timing suggests that day length may synchronize the annual cycle. Fixed timing of the fourth instar will have important consequences for the timing of crop damage and the conservation of farmland birds as climate changes.

Effects of ozone on gene expression and lipid peroxidation in adults and larvae of the red flour beetle ( Tribolium castaneum)

Ozone has in recent years been increasingly investigated for its potential use in the control of insect pests of stored cereals. Ozone is a powerful oxidizing agent that can react directly, or via production of reactive oxygen species, with proteins, DNA and double bonds of polyunsaturated fatty acids (PUFA). The aim of the present study was to investigate the mode of action in ozone toxicity using the red flour beetle, Tribolium castaneum (Herbst), as a relevant model. Transcription of focal genes thought to be involved in protection against ozone, and repair of cellular damage caused by ozone exposure, was studied together with the composition of storage lipid fatty acids and membrane phospholipid fatty acids in order to detect lipid peroxidation. Contrary to expectations, transcription of focal genes ( Cu/Zn-Superoxide Dismutase, Catalase, Glutathione Peroxidase, Glutathione S-Transferase, Δ-9 Desaturase 1, Δ-12 Desaturase, DNA Ligase IV, Heat Shock Proteins 60, 70, 83) was either decreased or unchanged in larvae and adults exposed to 40 ppm ozone for 6 or 24 h, respectively, as compared to parallel control samples. No, or only little, peroxidation of lipid fractions occurred during exposure to 40 ppm ozone, although it was demonstrated that this concentration is sufficient to kill both larvae and adults of the red flour beetle. Possible explanations for these observations may be that the time-scale of the experimentation was such that any up-regulatory change may have been missed, or that ozone had caused a general depression of metabolism (including transcription of reactive oxygen species detoxifying genes) as the insects had been oxygen-deprived due to longer than normal closure of the spiracles.

Case 3542TrachelusJurine, 1807 (Hymenoptera, cephidae): proposed precedence overAstatusPanzer, [1801

The purpose of this application, under Article 23.9.3 of the Code, is to conserve the widely used genus name Trachelus Jurine, 1807 in its accustomed usage. The name Trachelus is threatened by its senior synonym Astatus Panzer, [1801]. Strict application of the Principle of Priority would also involve the recombination with a new genus name for the ‘black grain stem sawfly’, Trachelus tabidus (Fabricius, 1775), which is a pest of cereals in the southern West Palaearctic and in North America. It is proposed that Trachelus should be given precedence over Astatus whenever the two are considered to be synonyms.

Karyotype analysis of the Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) reveals a large X chromosome with rRNA and histone gene families

The Russsian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a worldwide pest of cereals. Despite its economic importance, little is known about its genome. Here we investigated physical genomic features in RWA by karyotype analysis using differential staining with AgNO(3), CMA(3), and DAPI, by chromosomal localization of ribosomal DNA (rDNA), H3 and H4 histone genes, and the "arthropod" telomeric sequence (TTAGG)(n) using fluorescence in situ hybridization (FISH), and by measuring the RWA genome size using flow cytometry. The female karyotype, 2n = 10, is composed of four autosome pairs and a pair of X chromosomes, whereas the male karyotype, 2n = 9, has a single X. The X chromosome is the largest element in the karyotype. All three molecular markers used, i.e., 18S rRNA and both H3 and H4 probes are co-localized at one end of the X chromosome. The FISH probes revealed that the AgNO(3)-positive bridge between two prometaphase X chromosomes of females, which is believed to be responsible for the elimination of one X chromosome in aphid oocytes determined to undergo male development, contains clusters of both histone genes, in addition to an rDNA cluster. Interestingly, RWA lacks the (TTAGG)(n) telomeric sequence in its genome, in contrast to several previously investigated aphid species. Additionally, we compared female and male genome sizes. The female genome size is 2C = 0.86 pg, whereas the male genome size is 2C = 0.70 pg. The difference between the DNA content in the two genders suggests that the RWA X chromosome occupies about 35% of the female haploid genome (1C = 0.43 pg), which makes it one of the largest sex chromosomes in the animal kingdom.

Spatial and temporal correspondence of sunn pest oviposition and egg parasitism by Trissolcus spp. in Iran

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.

Host plant selection behaviour of Chilo partellus and its implication for effectiveness of a trap crop

Female lepidopterans can display a hierarchy of preference among potential host species, a trait thought to arise from the balance between attractants and deterrents to which the insects respond. Host plant ranking by moths and larvae of Chilo partellus Swinhoe (Lepidoptera: Crambidae), an important pest of cereals in Africa, was investigated, and whether eggs deposited on specific host plants yield larvae of particular host preferences. Trap plants are used in management of this pest. However, any 'disagreement' in host ranking between moths and larvae could potentially reduce effectiveness of trap crops as larvae emigrate to the main crop from the parent's preferred trap plant. We also investigated whether host plant preference is influenced by the diet upon which larvae fed as part of an integrated assessment of the relationship between host plant selection and learning in C. partellus. Five host plants (all Poaceae) were used: maize (Zea mays L.), sorghum (Sorghum bicolor Moench), Napier grass (Pennisetum purpureum Schumach), and two varieties of signal grass [Brachiaria brizantha (A. Rich.) Stapf], viz., local (henceforth signal grass) and improved ('Mulato'). In multiple choice tests, C. partellus female moths preferentially oviposited on Napier grass, followed by sorghum, maize, and signal grass, and least preferred 'Mulato'. Larvae however equally orientated and settled on leaf cuts of maize, sorghum, signal grass, and Napier grass, but least preferred 'Mulato'. Moreover, eggs from specific host plants did not yield larvae of particular host preferences. Furthermore, oviposition preference was not altered by the larval food. These results imply only a slight 'disagreement' in host ranking behaviour between moths and larvae, which is beneficial for trap cropping as larvae would not 'reject' the trap plant and appreciably disperse to the neighboring plants. Moreover, absence of larval learning behaviour indicates that regardless of the larval food C. partellus moths would still be attracted to the selected trap plant.

Effect of an anti-juvenile hormone agent (Precocene I) on Sunn pest, Eurygaster integriceps (Hemiptera: Scutelleridae) development and reproduction

Sunn pest ( Eurygaster integriceps Put.) (Hemiptera: Scutelleridae) is a serious pest of cereals causing severe quantitative and qualitative damage by feeding on leaves, stems and grains. Pesticide application is the main method of Sunn pest control, thus a search for developing new control methods is needed to diminish reliance on insecticides for insect control. So in the current study, the effect of an anti-juvenile hormone agent (precocene I) on the growth, reproductive biology and adult hemolymph proteins of E. integriceps females and males were investigated. The results indicated that precocene I had no acute toxicity to adults and second instars of E. integriceps . The treatment of second instars did not lead to death even in high doses, nor did it induce abnormality. The treatment of the third instar nymphs caused disorder in the physiology and increased mortality. The mortality of third instar was dose dependent (R 2 = 0.9774). Hemolymph protein concentrations in control males and females were high (2497.95 ± 0.04 and 2088 ± 0.04, respectively), but they decreased with the starting of oviposition. Hemolymph protein concentrations in treated females were lower than the control, at first day after treatment. With passage of time, hemolymph protein concentrations remained constant and decreased near oviposition. Total protein concentration in males and females was nearly equal, and there were no significant differences among them (P > 0.01). Precocene I also affected the number of eggs laid by females and the percentage of hatched eggs. It can be said that the effect of precocene I was stage- and age-specific, that is, its effects were varied with stage of the insect and its age in that stage. When used in early growth stage, its effect was less. However, when used in the late developmental stage its effect was more apparent and increased mortality as well as abnormalities. Keywords: Eurygaster integriceps Put, precocene I, hemolymph protein concentration, immature development, reproduction African Journal of Biotechnology Vol. 9(36), pp. 5859-5868, 6 September, 2010