Pest Larvae Research Articles

Synergy between parasitoids and pathogens for biological control of Helicoverpa armigera in chickpea

AbstractThe chickpea pod borer, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an important pest of many legume crops, including chickpea, Cicer arietinum L. (Fabaceae). We field‐tested the efficacy of two pathogens, Helicoverpa armigera nucleopolyhedrosis virus (HaNPV) and Bacillus thuringiensis Berliner subsp. kurstaki (Btk), both alone and in combination with the parasitoid Habrobracon hebetor Say (Hh) (Hymenoptera: Braconidae), for control of H. armigera larvae in chickpea fields. A randomized complete block design was used at two sites, so that wasp release treatments at one site would not contaminate pathogen‐only treatments at the other. Pathogens were applied when most pest larvae were in the second instar, and wasp releases were made 2 days later. Number of H. armigera larvae per plant, number of damaged pods, yield (kg ha−1), treatment cost (US$ ha−1), and benefit:cost ratio were all determined. Treatments separated significantly at 14 days after treatment, with the HaNPV+Hh and Btk+Hh treatments providing the best control, suggesting a synergistic impact of the wasp and the pathogens when applied together. These treatments also produced the fewest damaged pods, the highest yields, and the greatest yield increments in comparison to untreated controls. However, costs were also highest for these combined treatments, which reduced their net benefit in comparison to use of Hh or Btk alone, although more efficient mass production of the pathogens might make combined applications feasible. We conclude that both HaNPV and Btk are suitable for integration with releases of H. hebetor against H. armigera in chickpea fields, provided parasitoid releases are delayed until 2 days after pathogen application.

Phenological Features of (Mamestra Brassicae L. 1758) Development in Agrocoenosis of Cabbage in the Kamin-Kashyrskyi District (Volyn Region, Ukraine)

The animal world of Ukraine is characterized by a large variety of species. Among the lepidoptera there are a lot of pests whose larvae cause significant damage to agriculture. In the paper, we investigated the seasonal and perennial dynamics of vegetable crops pests’ population of Mamestra brassicae in the agrobiocenoses of white cabbage. The basis of our study was the investigation of the relative quantity of the pest larvae, we demonstrated the damage to plants, as well as the periods of intensive emergence of the imago and the number of generations per year. In future, this will enable the development of effective ecologically sound methods for controlling the number of species of white cabbage pests in the conditions of Kamin-Kashyrskyi district of Volyn region. Kamin-Kashyrskyi area has a flat terrain and is characterized by a warm temperate continental climate with sufficient amount of moisture, the presence of impoverished sod-podzolic soils. The area is mostly plain, with large marsh massifs, which are favorable conditions for the existence of Mamestra brassicae, as this species is moisture-loving. Observation of biocenotic connections in the agrobiocenoses of white cabbage and stationary research on the development of protection, testing and implementation systems was carried out during 2017-2018 at the garden sites of Kamin-Kashirsky district during the entire vegetation period of the plants. White cabbage is damaged throughout the period of vegetation, however, the damage that appear after emergence of seedlings and planting of seedlings into the soil are dangerous due to their consequences. In the second half of summer and in autumn, the larvae of Mamestra brassicae caused significant damage to cabbage plants in the gardens of Novi Chervyshcha. Within this area, Mamestra brassicae develops two generations per year, causing tangible damage to the agrocoenosis of cabbage of different sowing dates. The contamination of cabbage by the larva of the first and second generations approximately accounts to 24%, where 2-3 larvae live on one plant. The massive emergence of the imago occurs in the middle of May the first half of June while the average daily temperature is +20°С to +22°С. The first egg laying was recorded at the end of May, which the female lays in groups, 20-80 units on the underside of the leaves, and the embryonic development lasts 6 to 8 days. Pupae hibernate in the soil, at a depth of 8-12 cm. Significant damage to white cabbage plants was caused by the larvae of the first generation in June and early July, and of the second generation in August and early September. They intensively feed at night and at dawn, and in the daytime there is a decline in mobility and nutritional activity. Second-generation larvae often bite into cabbage heads where they make holes and pollute them with their liquid excrement, which leads to a decrease in crops. The use of microbiological drugs Dimilin and Insehar are some of the most effective ways to get rid of Lepidoptera, including larvae of Mamestra brassicae, which provide protection of cabbage plants by 93-97%.

Express method of accounting and forecasting brown-tail moth (Euproktis chrisorrhoea l.) in forest and garden plantations

The biological peculiarities of brown-tail moth, a dangerous pest of many tree and garden plantings, were studiedin order to develop a rapid method for obtaining sufficientlyfast and reliable accounting and forecasting data. A comparative description of the existing methods of accounting ofbrown-tail moth in forest plantations and in garden ones hasbeen carried out. It has been established that the accounting methods adopted in production are devoid of statisticaljustification and data on the size and number of accountingunits. It is shown that the most informative indicator for obtaining data on the population of stands is the developmentof phytophage at the caterpillar phase in winter nests. Masscounts of winter nests with a simultaneous estimate of thenumber of caterpillars in them and the degree of nibblingof plantations made it possible to identify the relationshipbetween these values. Tables for quick determination of therequired sample size with three levels of accuracy are developed. A table establishing the number of pest larvae depending on the size of wintering nests has been developed. Amodel that allows predicting the degree of expected damageto plantings by a pest has been obtained.

Pest categorisation of Arrhenodesminutus.

The Panel on Plant Health performed a pest categorisation of Arrhenodes minutus, a well‐defined wood‐boring insect species in the family Brentidae (Insecta: Coleoptera). It can be identified using taxonomic keys. A. minutus is only present in southern Canada and eastern USA down to Florida. The main host plants of A. minutus are species of the genera Quercus, Ulmus, Fagus and Populus. The pest larvae bore galleries in the wood, causing structural damage to the timber. The pest is also a vector of the quarantine pest Breziella (Ceratocystis) fagacearum. A. minutus most often lays its eggs in wounded parts of the trees where sap is oozing. The female bores minute holes with her snout and deposits one egg in each of them. The larvae bore a straight gallery against the grain. When the gallery nearly reaches the other side of the bole, it makes a sharp U‐turn towards the point of origin. These galleries cause structural damage to the timber. The life cycle lasts generally 3 years, but some individuals develop in 2 years and a few require 4 years. The main pathways are wood and possibly plants for planting. Specific phytosanitary requirements exist for Quercus and Populus only, while Ulmus is regulated in relation to other pests. Establishment would be favoured by the wide distribution of host trees in the EU territory and by climatic conditions locally comparable to those of the pest's native range. A. minutus meets all the criteria assessed by EFSA for consideration as potential Union quarantine pest. The criteria for considering it as a potential Union regulated non‐quarantine pest are not met since the species is absent from the EU.

Navigating on a chemical radar: Usage of root exudates by foragingDiabrotica virgifera virgiferalarvae

AbstractIn the darkness of the soil matrix, the larva of the western corn rootworm (WCR)Diabrotica virgifera virgiferaLeConte relies on chemical cues to locate and accept its host plant roots. For almost 40 years, entomologists and chemical ecologists have tackled the challenge of isolating and identifying active chemical compounds emitted by host plant roots (most of the research has been conducted on maizeZea maysL.) and used by the foraging insect pest larvae. A number of molecules of interest have been documented but have so far only been implemented with little success in the current arms race to manageWCR(and soil‐dwelling pests). An in‐depth understanding of the mechanisms underlying the insect foraging behaviour is certainly critical to the development of highly effective and sustainable pest control strategies. This contribution reviews the progress and highlights the gaps in our current knowledge on the chemical ecology ofWCRlarvae. An individual‐based model of the larval behaviour in response to root volatiles has been developed based on data from the literature. It also proposes avenues (tested or theoretical) to eventually implement this knowledge in integrated pest management of this major maize pest, a critical approach asWCRhas evolved resistance to several control strategies.

The Traditional Uses, Phytochemistry and Pharmacological Properties of Cassia fistula

Introduction: Due to the numerous unfavorable impact of present day drugs individuals used to incline toward herbal medications. The traditional prescriptions are progressively requested through the traditional experts and herbalists in the treatment of irresistible ailments. Medicinal plants assume a fundamental part for the improvement of new medications. Cassia fistula is a medicinal plant and belongs to a Caesalpiniaceae family which is usually recognized as Amulthus as well as ‘Indian Laburnum’ is an English term used for Amulthus, generally employed as a part of medicine ayurvedic system on behalf of different infirmities. Objective: To search out traditional uses by the local population, medicinal substances, their qualities and effects as well as chemical constituents in Cassia fistula are the aims of article that makes available a complete detail. Findings: Cassis fistula is a medium size short-lived tree with long and cylindrical fruits containing pulp and furthermore with a splendid yellow shaded flower. The tree is local to Pakistan, generally discovered east of the Indus in the fields and proceeding with north into the Himalayas to a rise of roughly 1200 meters. In Pakistan it is developed all through the field region. The present article gives a record of refreshed data on its phytochemical and pharmacological properties. The audit uncovers that wide quantities of phytochemical constituents have been separated from the plant perform activity such as destroying parasitic worms especially of the intestine, reduce fever, inhibit oxidation, killing larval pests, destroying fungi, anti-leishmaniatic function, destroying bacteria and other microbes, also anti-fiery activity, activity against tumor, as well as cough suppressant, activity of central nervous system, impact of clastogenic, having tendency to loosen or relax means producing bowel moment as well as relieving constipation, Impact against anxiety, impact of comforting, a damage mending impact, Hypolipidemic action, Hypocholesterolemic, Leukotriene restraint, Hepatoprotective as well as hypoglycemic activity. Conclusion: The dynamic standards ought to stay confined and plan to cure distinctive distresses by trail clinically performing concentrates to grasp the instrument of sub-atomic activity, searching for lead particles from common assets.

The Traditional Uses, Phytochemistry and Pharmacological Properties of Cassia fistula

Introduction: Due to the numerous unfavorable impact of present day drugs individuals used to incline toward herbal medications. The traditional prescriptions are progressively requested through the traditional experts and herbalists in the treatment of irresistible ailments. Medicinal plants assume a fundamental part for the improvement of new medications. Cassia fistula is a medicinal plant and belongs to a Caesalpiniaceae family which is usually recognized as Amulthus as well as ‘Indian Laburnum’ is an English term used for Amulthus, generally employed as a part of medicine ayurvedic system on behalf of different infirmities. Objective: To search out traditional uses by the local population, medicinal substances, their qualities and effects as well as chemical constituents in Cassia fistula are the aims of article that makes available a complete detail. Findings: Cassis fistula is a medium size short-lived tree with long and cylindrical fruits containing pulp and furthermore with a splendid yellow shaded flower. The tree is local to Pakistan, generally discovered east of the Indus in the fields and proceeding with north into the Himalayas to a rise of roughly 1200 meters. In Pakistan it is developed all through the field region. The present article gives a record of refreshed data on its phytochemical and pharmacological properties. The audit uncovers that wide quantities of phytochemical constituents have been separated from the plant perform activity such as destroying parasitic worms especially of the intestine, reduce fever, inhibit oxidation, killing larval pests, destroying fungi, anti-leishmaniatic function, destroying bacteria and other microbes, also anti-fiery activity, activity against tumor, as well as cough suppressant, activity of central nervous system, impact of clastogenic, having tendency to loosen or relax means producing bowel moment as well as relieving constipation, Impact against anxiety, impact of comforting, a damage mending impact, Hypolipidemic action, Hypocholesterolemic, Leukotriene restraint, Hepatoprotective as well as hypoglycemic activity. Conclusion: The dynamic standards ought to stay confined and plan to cure distinctive distresses by trail clinically performing concentrates to grasp the instrument of sub-atomic activity, searching for lead particles from common assets.

Spatiotemporal distribution and impact of diamondback moth parasitoids in the Dakar Niayes in Senegal

Conservation biological control, which fosters the optimal use of indigenous natural enemies, is a promising way for reducing pesticide reliance in horticultural systems. The objective of this study is to determine the distribution of parasitoid species, their parasitism rates on pest populations in relation to environmental conditions in the main Senegalese market garden area (Niayes). To do this, one hundred and sixteen cabbage plots, distributed in the Niaye segmented into three areas, along a South-North transect, are chosen. These plots were observed during four crop seasons from October 2012 to May 2014. Pest larvae were counted every three weeks using 24 randomly chosen cabbage plants per plot. Four hymenopteran parasitoid species were identified; Oomyzus sololowskii (Kurdjumov), (Eulophidae), Brachymeria sp. (Chalcididae), Apanteles litae Nixon and Cotesia vestalis (Haliday) both Braconidae. The percentage of parasitism varied between the plots, the geographical locations and the sampling period. O. sokolowskii and A. litae species were predominant and were affected by the growing season. The species distribution in the three sampling areas revealed that O. Sokolowskii was more efficient during the cold dry season, whereas A. litae was more efficient during the hot dry season. These results aim at identifying conditions favorable to the regulation of populations of cabbage moth by natural enemies. Parasitoids can play a promising role as biological control agents in Senegal. In order to do this, studies such as these must be carried out and the results communicated to farmers who often misunderstand the primordial role that natural enemies can play in pest control. Keywords : Cabbage, parasitism percentage, dry season, West Africa, Plutella xylostella .

Evaluation of the effects of some insecticides based on neonicotinoids on entomopathogenic nematodes, Steinernema feltiae and S. carpocapsae

Used of entomopathogenic nematodes (EPNs) are one biological control way against some insect pests, which especially pass one stage of their life in the soil. There have been a lot of developments and new discoveries in the field of entomopathogenic nematology. In spite of developments in the field of biological control, pesticides are still widely used for plant protection. These pesticides have side effects on soil biotop such as EPN species. In this study, we evaluated the effects of two insecticides (acetamiprid and imidacloprid) belong to neonicotinoid group on two EPNs (Steinernema carpocapsae and Steinernema feltiae). The present experiments were carried out in the laboratory. Mortality rate of the EPN species was performed at 24, 48 and 96 h, after treatment. Inspired by the compatibility observed between the neonicotinoid insecticides and EPNs against insect pest larvae, it was evaluated the direct effects of those insecticides on EPNs. Our results showed less mortality by imidacloprid and mortality rates are a little higher by acetamiprid. These results confirm the high compatibility of imidacloprid with EPNs and the low synergism with acetamiprid. Despite their effects on pollinators and other useful organisms of the biotop, these insecticides can be used effectively against soil dwelling insect pests without high risk on EPNs.

Plant Growth Promoting Rhizobacteria (PGPR) and Plutella xylostella (L.) (Lepidoptera: Plutellidae) interaction as a resistance inductor factor in Brassica oleracea var. capitata

Resistance of Plutella xylostella populations to chemical insecticides has made its management difficult, and the utilization of resistant cabbage cultivars has been shown to be a useful alternative. The objective of this study was to demonstrate the induction of cabbage plant resistance to P. xylostella using PGPR and injuries caused by the pest larvae as elicitors. Therefore, we evaluated the insects’ responses utilizing a specific bioassay. Furthermore, this assay was used for selecting a PGPR strain that affects the insect’s biology, and to examine molecular and biochemical responses of the plants influenced by the plant-microbe-insect interaction. Among the strains used in this study, Kluyvera ascorbata showed the most relevant results by influencing biological characteristics of the insect. Thus, the following tests demonstrated that the cited strain possesses a high influence on plant metabolism when it undergoes different types of stress such as injuries caused by the pest. These findings were determined from the different responses obtained by the chemical analyses of the tested plants and from the differentiation in the genetic sequences obtained from plants inoculated with or without PGPR that were injured by the pest. The PGPR K. ascorbata alters the metabolism of cabbage plants, which directs a specific plant defense against P. xylostella.

A comparative toxic effect of Cedrus deodara oil on larval protein contents and its behavioral effect on larvae of mealworm beetle (Tenebrio molitor) (Coleoptera: Tenebrionidae).

Cedrus deodara (deodar) is practically used, as insect repellent, in the northern areas of Pakistan but no data available therefore this study was conducted to evaluate the effectiveness of deodar oil as an alternate of conventional insecticides against the larval pest stage of mealworm beetle (Tenebrio molitor), by feeding method. The aim of the study was to investigate the effectiveness of deodar oil as an alternate of conventional insecticides against the larval pest stage of mealworm beetle (Tenebrio molitor), by feeding method. All tested chemicals showed efficacy against the pests. The LC50 was determined by probit analysis and was found to be 3.41, 0.086 and 0.023% of larvae treated with deodar oil, Carbosulfan and Imidacloprid respectively The LC50 treated larvae were subjected to the evaluation of protein activity, qualitatively and quantitatively. The protein level in tested insects was enhanced when treated with Imidacloprid, Carbosulfan and deodar oil. The electrophoretic profile of treated insects showed more bands in insects treated with Cedrus deodara oil. This electrophoretic profile appeared in 4, 5, 7 and 8 bands for tested chemicals including control. Antifeedant activity was observed for C. deodara as larvae were deterred to feed on the food found in the container.

Predator Preference for Bt-Fed Spodoptera frugiperda (Lepidoptera: Noctuidae) Prey: Implications for Insect Resistance Management in Bt Maize Seed Blends.

Understanding indirect, trophic-level effects of genetically engineered plants, expressing insecticidal proteins derived from the bacterium, Bacillus thuringiensis (Bt), is essential to the ecological risk assessment process. In this study, we examine potential indirect, trophic-level effects of Bt-sensitive prey using the predator, Harmonia axyridis (Pallas), feeding upon Spodoptera frugiperda (J.E. Smith) larvae, which had delayed development (lower body mass) following ingestion of Cry1Ab maize leaves. We found no adverse effects on development and survival when H. axyridis larvae were fed S. frugiperda larvae that had fed on Cry1Ab maize tissue. Presence of Cry1Ab in H. axyridis decreased considerably after switching to another diet within 48 h. In a no-choice assay, H. axyridis larvae consumed more Bt-fed S. frugiperda than non-Bt-fed larvae. Preference for S.frugiperda feeding on Bt maize was confirmed in subsequent choice assays with H. axyridis predation on Bt-fed, 1-5-d-old S. frugiperda larvae. We suggest that H. axyridis preferred prey, not based on whether it had fed on Bt or non-Bt maize, but rather on larval mass, and they compensated for the nutritional deficiency of lighter larvae through increased consumption. Pest larvae with variable levels of resistance developing on Bt diet are often stunted versus sensitive larvae developing on non-Bt diet. It is possible that such larvae may be preferentially removed from local field populations. These results may have implications for insect resistance management and may be played out under field conditions where seed blends of Bt and non-Bt hybrids are planted.

Identification of three internal feeders from Korla fragrant pears by quantitative real-time polymerase chain reaction

Cydia pomonella, Euzophera pyriella Yang, and Grapholitha molesta are destructive pest species of Korla fragrant pears in Xinjiang. They are also quarantine pests of concern in a number of countries. Identification of these small pest larvae by morphological characters is difficult, and misidentifications will influence appropriate quarantine decisions. Here, a 520 bp fragment of mitochondrial cytochrome oxidase subunit I (COI) was first amplified and sequenced from each species, and a diagnostic region was observed. Subsequently, the species-specific primer and probe sets of quantitative real-time PCR (qPCR) were designed, which amplified a 114–116 bp fragment of COI genes. This method was validated by amplification DNA extracted from single, multiple, and mixed pest samples. Results indicated that this method allows rapid discrimination and reliable identification of larvae, pupae, and adult specimens of all three species, which could help the international export trading of Korla fragrant pears and related products.

New sources of resistance to leafminers (Liriomyza sativae) in melon (Cucumis melo L.) germplasm

Leafminers (Liriomyza sativae) are the main melon (Cucumis melo L.) pests in Northeast Brazil, which is the main region for the production and export of the fruit in Brazil. Of the integrated management strategies available, genetic resistance is the best method of preventing damage by these insects. The aim of this study was to select sources of resistance to leafminers in melon germplasm. Seven experiments were conducted in the laboratory, field, and greenhouse, with and without choice, using 52 melon accessions and 4 commercial hybrids as controls. Genetic variability among the accessions made it possible to select four new sources of resistance: 'CNPH 11-1072' and 'CNPH 11-1077', because they exhibited lower levels of infestation by the insect (antixenosis); and 'CNPH 00-915(R)' and 'BAGMEL 56(R)', because the pest larvae died soon after beginning to feed on the leaf mesophyll (antibiosis).

Biocontrol potential of Halotolerant bacterial chitinase from high yielding novel Bacillus Pumilus MCB-7 autochthonous to mangrove ecosystem

The multifaceted role of chitinase in medicine, agriculture, environmental remediation and various other industries greatly demands the isolation of high yielding chitinase producing microorganisms with improved properties. The current study aimed to investigate the isolation, characterization and biocontrol prospective of chitinase producing bacterial strains autochthonous to the extreme conditions of mangrove ecosystems. Among the 51 bacterial isolates screened, Bacillus pumilus MCB-7 with highest chitinase production potential was identified and confirmed by 16S rDNA typing. Chitinase enzyme of MCB-7 was purified; the chitin degradation was evaluated by SEM and LC-MS. Unlike previously reported B.pumilus isolates, MCB-7 exhibited highest chitinase activity of 3.36U/mL, active even at high salt concentrations and temperature up to 60°C. The crude as well as purified enzyme showed significant antimycotic activity against agricultural pathogens such as Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus, Ceratorhiza hydrophila and Fusarium oxysporum. The enzyme also exhibited biopesticidal role against larvae of Scirpophaga incertulas (Walker). [Lep.: Pyralidae], a serious agricultural pest of rice. The high chitinolytic and antimycotic potential of MCB-7 increases the prospects of the isolate as an excellent biocontrol agent. To the best of our knowledge, this is the first report of high chitinase yielding Bacillus pumilus strain from mangrove ecosystem with a biocontrol role against phytopathogenic fungi and insect larval pests.

De novo sequencing and transcriptome analysis of female venom glands of ectoparasitoid Bracon hebetor (Say.) (Hymenoptera: Braconidae)

Venom is a key-factor in the regulation of host physiology by parasitic Hymenoptera and a potentially rich source of novel bioactive substances for biotechnological applications. The limited study of venom from the ectoparasitoid Bracon hebetor, a tiny wasp that attacks larval pest insects of field and stored products and is thus a potential insect control agent, has not described the full complement and composition of these biomolecules. To have a comprehensive picture of genes expressed in the venom glands of B. hebetor, a venom gland transcriptome was assembled by using next generation sequencing technologies followed by de novo assemblies of the 10.81 M sequence reads yielded 22,425 contigs, of which 10,581 had significant BLASTx hits to know genes. The majority of hits were to Diachasma alloeum, an ectoparasitoid from same taxonomic family, as well as other wasps. Gene ontology grouped the sequences into molecular functions in which catalytic activity with 42.2% was maximum, cellular components in which cells with 33.8% and biological processes among which metabolic process with 30% had the most representatives. In this study, we highlight the most abundant sequences, and those that are likely to be functional components of the venom for parasitization. Full length ORFs of Calreticulin, Venom Acid Phosphatase Acph-1 like protein and arginine kinase proteins were isolated and their tissue specific expression was studied by RT-PCR. Our report is the first to characterize components of the B. hebetor venom glands that may be useful for developing control tools for insect pests and other applications.

An alphabaculovirus isolated from dead Lymantria dispar larvae shows high genetic similarity to baculovirus previously isolated from Lymantria monacha – An example of adaptation to a new host

A new isolate of baculovirus, Lymantria dispar multiple nucleopolyhedrovirus-BNP (LdMNPV-BNP), was found in dead gypsy moth (L. dispar) caterpillars collected in the Biebrzanski National Park in Poland. Here, we examined its biological activity, structure, genetic content and phylogeny. Multiple nucleocapsids of LdMNPV-BNP are enveloped together in 2–26 virions embedded in occluded bodies (OBs) very similar to the OBs previously described in viruses infecting Lymantriinae. This isolate kills pest larvae in a relatively short time (LT50 of approximately 9days for a dose of 2×107OBs/ml), highlighting the possibility for its use as a biopesticide. Next-generation sequencing of LdMNPV-BNP revealed gene content (e.g. DNA photolyase) that is not present in any LdMNPV isolate sequenced to date. The genome is 157,270 base pairs long and has a notably lower G+C content in comparison to other LdMNPVs (50.3% G+C content compared to an average of 57.4% among other LdMNPVs). According to our phylogenetic analysis based on 37 core genes, LdMNPV-BNP is a member of group II alphabaculoviruses, which are closely related to LdMNPV and LyxyMNPV (Lymantria xylina multiple nucleopolyhedrovirus). Molecular evolution inference based on the partial sequence of lef-8, lef-9 and polh genes shows that LdMNPV-BNP and isolates of Lymantria monacha nucleopolyhedrovirus (LymoNPV) may share a very recent common ancestor or be isolates of the same virus species. LdMNPV-BNP, like other baculoviruses, could be beneficial as an active component of biopesticides that can be used during forest integrated pest management.

Increased Risk of Insect Injury to Corn Following Rye Cover Crop.

Decreased pest pressure is sometimes associated with more diverse agroecosystems, including the addition of a rye cover crop (Secale cereale L.). However, not all pests respond similarly to greater vegetational diversity. Polyphagous pests, such as true armyworm (Mythimna unipuncta Haworth), black cutworm (Agrotis ipsilon Hufnagel), and common stalk borer (Papaipema nebris Guenee), whose host range includes rye have the potential to cause injury to crops following a rye cover crop. The objectives of this study were to compare the abundance of early-season insect pests and injury to corn (Zea mays L.) from fields with and without a rye cover crop on commercial farms. Fields were sampled weekly to quantify adult and larval pests and feeding injury to corn plants from mid-April until corn reached V8 stage, during 2014 and 2015. Measurements within fields were collected along transects that extended perpendicularly from field edges into the interior of cornfields. Adult true armyworm and adult black cutworm were captured around all cornfields, but most lepidopteran larvae captured within cornfields were true armyworm and common stalk borer. Cornfields with a rye cover crop had significantly greater abundance of true armyworm and greater proportion of injured corn. Both true armyworm abundance and feeding injury were significantly greater in the interior of cornfields with rye. Common stalk borer abundance did not differ between cornfields with or without rye cover. Farmers planting corn following a rye cover crop should be aware of the potential for increased presence of true armyworm and for greater injury to corn.

Entomopathogenic fungi as promising biocontrol agents for the rosaceous longhorn beetle, Osphranteria coerulescens

During a survey for natural enemies of the rosaceous longhorn beetle (RLHB), Osphranteria coerulescens, two isolates of entomopathogenic fungi (EPF) were found in Razavi Khorasan province of Iran. These isolates were determined to be of the species Beauveria bassiana and Metarhiziumanisopliae using morphological characteristics and molecular analysis. Subsequently, the mycosis process of the isolates on larvae of RLHB was documented using scanning electron microscopy (SEM). In order to assess virulence of these indigenous isolates of EPF, a series of trials were conducted against RLHB larvae, pupae and adult stages. In laboratory bioassays the pest was susceptible to both EPF isolates, but the B. bassiana isolate caused significantly higher mortality than the M. anisopliae isolate in all life stages tested. In a semi-field trial EPF suspension containing 2.5 × 1010 viable conidia per ml was sprayed directly against pest larvae beneath tree bark under two conditions: apricot branches covered with a polyvinyl cover and without cover. The B. bassiana isolate showed a higher infection rate than M. anisopliae and the cover had significant effect on larval mortality, ranging from 67 % for covered infested apricot branches to 31 % without cover in the B. bassiana treatments. Our findings revealed that polyvinyl covers were necessary to improve conidial persistence under field conditions. In a supplementary survey on the semi-mass production potential of the fungal conidia, the ability of B. bassiana and M. anisopliae to germinate was studied using three solid media. Sugar beet pulp provided the highest yield of conidia for both EPF species, and can be considered as an effective solid medium for fungal growth. These findings highlighted the potential of EPFs as biocontrol agents of O. coerulescens.

Short and long term effects of some bio-insecticides on Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) and its coexisting generalist predators in tomato fields

Tomato leaf miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is one of the most destructive pests of tomato in many parts of the world including Iran. Field studies were conducted to determine the short and long term effects of Bacillus thuringiensis var Kurstaki (Bt), azadirachtin (AZ), a mix of AZ + Bt, and indoxacarb, as a current chemical insecticide, on T. absoluta larvae. Also, effects of the insecticides were studied on the coexisting generalist predators, Coccinella septempunctata L., Chrysoperla carnea Stephens and Syritta sp. Sampling of T. absoluta and its coexisting generalist predators were performed 1 day before treatment (DBT) and one, 5, 8, 14 and 19 days after treatment (DAT). The results indicated significant short term effect of indoxacarb on the pest larvae. Indoxacarb reduced T. absoluta density and damages. Bt, AZ and mixture of them significantly suppressed the larval density at 19 DAT and caused significant reduction in leaf, stem and fruit damage. The highest long term effect on the pest abundance and damage were observed in Az + Bt caused 100% reduction in fruit and foliage damage compared to the control. The highest and lowest adverse effects on C. carnea, C. septempunctat and Serrita sp. were observed in indoxacarb and Bt treatments, respectively. Findings of this study imply that the mixture of Az + Bt has the highest selective toxicity on the pest and the lowest effect on its coexisting generalist predators.