Insect Pests Of Crops Research Articles

Image Recognition of Crop Diseases and Insect Pests Based on Deep Learning

Deep learning algorithms have the advantages of clear structure and high accuracy in image recognition. Accurate identification of pests and diseases in crops can improve the pertinence of pest control in farmland, which is beneficial to agricultural production. This paper proposes a DCNN‐G model based on deep learning and fusion of Google data analysis, using this model to train 640 data samples, and then using 5000 test samples for testing, selecting 80% as the training set and 20% as the test set, and compare the accuracy of the model with the conventional recognition model. Research results show that after degrading a quality level 1 image using the degradation parameters above, 9 quality level images are obtained. Use YOLO’s improved network, YOLO‐V4, to test and validate images after quality level classification. Images of different quality levels, especially images of adjacent levels, are subjectively observed by human eyes, and it is difficult to distinguish the quality of the images. Using the algorithm model proposed in this article, the recognition accuracy is 95%, which is much higher than the basic 84% of the DCNN model. The quality level classification of crop disease and insect pest images can provide important prior information for the understanding of crop disease and insect pest images and can also provide a scientific basis for testing the imaging capabilities of sensors and objectively evaluating the image quality of crop diseases and pests. The use of convolutional neural networks to realize the classification of crop pest and disease image quality not only expands the application field of deep learning but also provides a new method for crop pest and disease image quality assessment.

Spatio and temporal variations in population abundance and distribution of peach fruit fly, Bactrocera zonata (Saunders) during future climate change scenarios based on temperature driven phenology model

The peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) is a poylphagous and serious insect pest of horticultural crops. The purpose of study was to understand the spatial and temporal variations in population abundance and distribution of B. zonata in response to climate change-based variations in temperature across the India. To examine the likely possibilities of changes in abundance and distribution of B. zonata, temperature driven process based phenology models were linked with climatic data of multiple General Circulation Model (eight models) and climate change scenarios (RCP 2.6, 4.5, 6.0 and 8.5) using the Insect Life Cycle Modeling (ILCYM) software. The risk indices (establishment, generation, and activity index) were mapped and quantified the changes in respect to locations, scenarios, models and times (2050 & 2070). The risk indices results revealed that, 1.73 (0.8–1.0 establishment risk), 14.15 (>16 high abundance) and 59.69% (>8.0 generation per year) area is projected to be highly suitable for B. zonata regarding establishment, abundance and generation indices, respectively in India under current climatic conditions. In spite of decreased permanent establishment (Establishment Risk Index > 0.6) in future climatic conditions, it is predicted that abundance and generation indices would increase in all the locations of the country. The variation in the results due to use of multiple GCM-scenario combinations suggested that choice of GCM and scenario combinations have impact on future prediction of the species. Overall, results indicate that B. zonata would be significant threat to horticultural crops in India. Therefore, present findings are of immensly useful to provide important information to design integrated pest management strategies and phytosanitary measurements for local, regional and national level to restrain the insect pest activity across different layers.

Arboreal Tiger Beetles Recorded from Lowland Crop Cultivations in Sri Lanka

Purpose : Thirty-one species of arboreal tiger beetles are known from Sri Lanka of which 25 species are endemic. However, their habitat types are poorly documented and the available records are far outdated. Therefore, a survey of tiger beetles was carried out to determine their present occurrence with emphasis on agricultural habitat types. Research Method : Forty-six locations of the country, covering eighteen districts, all provinces, representing a majority of bioclimatic zones except those in Montane Sri Lanka were surveyed for arboreal tiger beetles. Sampling was conducted using the visual encounter method. Collected beetles were identified using taxonomic keys and descriptions. Findings : Eight species of arboreal tiger beetles were collected from the survey. Majority of the species (06) were collected from crop cultivations of coconut and also from tea, fruit farms, betel leaf, cinnamon and pepper. Four species of Derocrania and two species of Tricondyla were recorded from the cultivations and all had fused elytra and hence unable to fly. Derocrania scitiscabra was the dominant arboreal tiger beetle species in the crop cultivations. Originality/ Value : The study documents hitherto unrecorded habitat types for a poorly documented important beetle group of Sri Lanka. It further provides information for future research on the possibility of using arboreal tiger beetles as bio-control agents of insect pests of agricultural crops.

Oviposition preferences of the native budworm,

The native budworm, Helicoverpa punctigera (Wallengren), is an important economic insect pest of cotton and other crops. It is widely distributed in Australia and has been recorded on a range of host plants including native, non-crop hosts in inland regions. To date, there are few records of its occurrence on plants with the C4 photosynthetic pathway. Here, we assessed the oviposition preferences of H. punctigera for naturally occurring C3 and C4 plants under glasshouse conditions, to establish their potential as hosts. We conducted bioassays on two C4 plants, saltbushes Atriplex nummularia Lindl. and Atriplex vesicaria Heward ex Benth.; and two C3 plants, legumes Medicago polymorpha L. (burr medic) and Cullen cinereum (Lindl.) J.W.Grimes (annual verbine). The two C4 plants attract egg laying in the field; however, C3 plants are the preferred hosts. Ovipositing females showed a preference for the C3 over the C4 plants but oviposition occurred on both. Of the C4 plants, females preferred to oviposit on A. nummularia (77%) over A. vesicaria (24%) in both a multi- and two-choice test. In addition, ovipositing females preferred the upper leaf surface of A. nummularia (68%) and the under leaf surface of A. vesicaria (64%) as their oviposition site. Our findings suggest that under field conditions, when C4 plants such as saltbushes grow near C3 plants, as occurs in inland regions, the C4 plants could receive eggs along with the C3 plants, enabling the initial stages of larval recruitment to occur in C3 plants.

Qualitative detection of different enzymes from the gut and salivary glands of Nezara viridula Linn. using the chemical inference

Globally the crop insect pests damage the 30% of agriculture production due to insect spoil, and the situation is very awful in particularly developing countries such as India. There are large number of insect pest families are well known which induce the critical destroy to agriculture crops. Crop insect pest’s harm is one of the significant features that ruin the agriculture crop productivity, although the large-scale utilization of chemical pesticides. The successfulness of the pesticides depends upon the interaction of chemicals with the physiology of the insect of the pests. In India, the Nezara viridula Linn, is one of the critical insects because of its destructive feeding on major crop which is the utmost source of economic deprivation in agriculture. The enzymes present in the gut and salivary glands of the N. Viridula play key role in the feeding behaviour. Presently very little is investigated about the gut and salivary glands of the N. Viridula at minute level. We first time investigated the different enzymes existing in the gut and salivary gland using the chemical inference. This research work is carried out to analysis the enzymes for digestive and feeding behaviour of N. Viridula which will assist the biologists to manage the challenges are created by their resistance to the traditional chemical insecticides used for prevention of N. Viridula (a type of southern green stink bug) inhabitants and high reproductive amplitude. The extensive statistics of invertase enzymes, maltase, alpha galactosidase, amylase, esterase, proteinase and polypeptidase enzymes for the N. Viridula in salivary glands and gut inspired by this research imparts supplementary resource for further understanding of the biology of this Pentatomidae (Heteroptera) species.

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Phytophagous stink bugs (Hemiptera, Pentatomidae) are economically important insect pests of fruit, vegetable, nut and field crops. This study was carried out during the season of 2013 in orchards within Erbil city, to follow the stink bug Mustha spinulosa (Lefebvre, 1831) seasonal fluctuation on some fruit trees: olive, plum, apricot, pear, apple and almond. The stink bug reaches its maximum abundance throughout the second week of August (38.2/tree) coinciding with mean temperature and relative humidity of 33.40°C and 28.14% respectively, and the highest total mean of the number of the insect was recorded on the olive trees (181.8/tree). The study reveals that the stink bug attacked 22 trees (fruit and forest) while it has not attack any herbal plant.

Olive Production Threatened by a Resurgent Pest Liothrips oleae (Costa, 1857) (Thysanoptera: Phlaeothripidae) in Southern Italy.

Simple SummaryLiothrips oleae (Costa, 1857) (Thysanoptera: Phlaeothripidae) is widespread in the Mediterranean area, and in all regions, it is reputed to be a secondary pest in olive crops, mainly associated with damage to leaves and secondarily with damage to drupes, for which this thrips pest has a marginal impact on olive production. Taking into account the increase in the frequency of extreme damage by this species in Southern Italy in the last decade, this research aimed to elucidate the real impact (i.e., damage to leaves and drupes) by feeding thrips’ activity in olive orchards. Our results revealed that the impact of thrips was significant in all monitored olive orchards and the estimated damage level on drupes and leaves was higher in organic olive than in integrated olive management. A detailed morphological description of the Italian specimens and their molecular characterization are also provided.This study investigated a resurgence of Liothrips oleae Costa (Thysanoptera: Phlaeothripidae), an insect pest of olive crops, in a focal Southern Italian olive-producing area (Calabria Region). The young and adult olive thrips feed on the leaves and fruits of wild and cultivated olive trees, producing distortions, necrosis, and premature dropping of fruit. In our study, organic and integrated olive groves were compared for two years in order to establish the relationship between leaf and fruit damage among olive groves managed under different phytosanitary conditions. Sampling techniques were used in order to collect and count leaves and fruits (on plants and dropped premature drupes) presenting symptoms of thrips’ feeding activity. The impact of the thrips was significant in all orchards, and the estimated damage level on drupes and leaves was higher in organic olive management in each year. A morphological description of the adult females of the species is provided, and the first molecular characterization of the Calabrian olive thrips population was performed by using three different genetic regions (cytochrome c oxidase subunit I (COI), 28S ribosomal subunit (28S), and internal transcribed spacer 2 (ITS2)).

Review on the Bio-insecticidal Properties of Some Plant Secondary Metabolites: Types, Formulations, Modes of Action, Advantages and Limitations

Bio-pesticides are biological derived agents that are usually applied in a manner similar to synthetic pesticides but achieve pest management in an environmental friendly way. Bioinsecticides have the advantages of been reportedly eco-friendly both to man and the environment, are target specific, lack problem of residue, least persistent in environment, locally available, easily processed and inexpensive, though with the limitation of requiring repeated applications for the achievement of optimal control of insect pests while enhancing crop protection. The mode of action of bioinsecticides on insects includes repellent action, antifeedant activity, oviposition deterrent properties, growth and development inhibition, toxicity, attractants, sterility and death. Hence, bioinsecticides can be included in integrated pest management programs for crop protection and insect pest control. The review on biopesticidal properties of some plant secondary metabolites in the leaves, stems, bark, fruits, flowers, cloves, rhizomes, grains and seeds of plants and their interference with the growth, feeding, reproduction of insect pestsfor pest management has been elaborated.

Electrophysiological Responses to Cuelure of Raspberry Ketone-Fed Queensland Fruit Flies.

The sterile insect technique (SIT) and male annihilation technique (MAT) are important tools for the control of Queensland fruit fly (Q-fly), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a major insect pest of horticultural crops in Australia. In MAT, mature Q-fly males are attracted to a toxic bait using Cuelure, a synthetic analog of raspberry ketone (RK). Substantial improvements in control could be achieved by simultaneous use of SIT and MAT, but this requires suppression of the Cuelure response in released sterile flies. Recent studies report that prerelease feeding with RK during the first 48 h after emergence can reduce the response of mature Q-fly males to Cuelure, but the mechanism underpinning this is unknown. Here, to test whether reduced sensory sensitivity to Cuelure is involved, we evaluated the effects of RK supplements, adult diet (yeast-supplemented diet throughout adult stage vs yeast-supplemented diet only for 48 h), and age on electroantennogram (EAG) and electropalpogram (EPG) responses of Q-flies to Cuelure stimuli. EAG responses did not vary with RK supplements, sex, or age of Q-flies fed yeast-supplemented diet throughout the adult stage, but the responses of Q-flies fed other diet regime decreased with age. EPG responses of both sexes of Q-flies were affected by RK supplements, age, and their interaction, but without patterns that might indicate reduced maxillary palp response of RK supplemented flies to Cuelure. Our findings do not support the hypothesis that reduced Cuelure response of male Q-flies fed RK supplements is explained by reduced electrophysiological response in antennae or maxillary palps.

Predatory spider fauna in fruit crops of Punjab, India along with new records

Spiders are important predatory organisms in the orchards. Keeping in view their role in the natural biological control, the present studies were conducted from May 2012 to October 2019 in orchards belonging to 21 fruit crops, viz. apple (Malus sp.), amla (Phyllanthus emblica), citrus (Citrus spp.), banana (Musa spp.), ber (Zizyphus mauritiana), fig (Ficus carica), grapes (Vitis vinifera), guava (Psidium guajava), jamun (Syzygium cumini), litchi (Litchi chinensis), loquat (Eriobotrya japonica), mango (Mangifera indica), olive (Olea europaea), papaya (Carica papaya), peach (Prunus persica), pear (Pyrus communis), plum (Prunus domestica), pomegranate (Punica granatum), phalsa (Grewia asiatica), rasbhari (Physalis peruviana) and sapota (Manilkara zapota) in 13 districts of the Punjab, India, with an objective to record the prevalence of different families of spider fauna. The study revealed the presence of several predatory spiders involved in controlling various insect-pests of fruit crops. The 43 species of spiders belonging to 23 genera and 13 families were recorded during the study. Families like Salticidae, Araneidae and Oxyopidae exhibited more diversity. Salticidae family showed maximum diversity. High genetic diversity was found in Salticidae, Araneidae, Oxyopidae and Tetragnathidae. Study highlights the importance of protecting natural predators in controlling the insect pests in orchards. Epeus flavobilineatus Doleschall, Epocilla calcarata (Karsch) (Family: Salticidae); Gasteracantha cancriformis (Linnaeus) and Neoscona punctigera (Doleschall) (Family Araneidae) are new species records for India.

Insecticide resistance monitoring in whitefly (Bemisia tabaci) (Hemiptera: Aleyrodidae) in Oman

• All B. tabaci populations were at the initial stages of resistance development. • A likelihood analysis showed the possibility for control failure in Barka and Salalah populations. • One B. tabaci population had reduced susceptibility to deltamethrin between 2017 and 2019. • Farmers in Oman should rotate among the classes of insecticides with different mode of action. The sweet potato whitefly, Bemisia tabaci Gennadius, is an important insect pest of many crops including vegetables through direct feeding damage and as a vector of several plant viruses. Intensive use of insecticides has led to the development of insecticide resistance in global B. tabaci populations . This study was conducted to establish susceptibility levels to deltamethrin, thiamethoxam and pyriproxyfen in seven geographically different populations of B. tabaci MEAM1 adults in Oman. All B. tabaci populations showed very low to low level of resistance (2.1–12.3 fold) to deltamethrin. All B. tabaci populations showed no resistance to very low level of resistance to thiamethoxam (2.2–6.2 fold) and pyriproxyfen (2.4–3.5 fold). A likelihood analysis showed the possibility for control failure in two populations (Barka and Salalah) to deltamethrin, however, no possible failure was detected in all populations for thiamethoxam and pyriproxyfen. An insecticide resistance dynamics study in one population (SQU-1) showed a loss in susceptibility to deltamethrin with increase in the LC 50 value from 25.1 mg L −1 to 84.5 mg L −1 between 2017 and 2019 resulting in 5.3 fold increase in RF. The study results determined that several B. tabaci populations are at the initial stages of resistance development to deltamethrin and cross-resistance with thiamethoxam and pyriproxyfen. Vegetable farmers in Oman, the Barka and Salalah regions in particular, should be cautious in the repeated use of one class of insecticide alone.

Effects of Spray Volume and Application Frequency on Insecticide Efficacy Against Adult Western Flower Thrips (Frankliniella Occidentalis) under Greenhouse Conditions

The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major insect pest of greenhouse-grown horticultural crops. Western flower thrips causes direct and indirect damage by feeding on plant leaves, flowers, and fruits, and by transmitting viruses that can result in greenhouse producers experiencing substantial economic losses. Consequently, insecticides are used to suppress western flower thrips populations. However, issues associated with applying insecticides may affect the suppression of western flower thrips populations. Therefore, experiments were conducted under greenhouse conditions to determine the effects of the spray volume applied and application frequency on insecticide efficacy against western flower thrips adults located in transvaal daisy, Gerbera jamesonii, cut flowers. Four spray volumes (5.0, 10.0, 12.5, and 25.0 mL), two application frequencies (one or two spray applications), and three insecticides [spinosad (Conserve), chlorfenapyr (Pylon), and flonicamid (Aria)], each with a different mode of action, were tested. The insecticide treatments had the greatest effects on the mean percent mortality of western flower thrips adults regardless of spray volume or application frequency. However, in Expt. 3, the 5.0- and 10.0-mL spray volumes resulted in a higher mean percent mortality of western flower thrips adults than the 2.5-mL spray volume. Spinosad and chlorfenapyr resulted in a mean percent mortality of more than 72% for western flower thrips adults, whereas flonicamid resulted in mean percent mortality between 40% and 91%. Our study demonstrates that certain insecticides are more effective against western flower thrips adults located in transvaal daisy flowers than others, which will help greenhouse producers effectively manage western flower thrips populations.

Plantas medicinales y aromáticas como hospederas de enemigos naturales de Saissetia oleaeen arreglos espacio-temporales para el cultivo agroecológico de Olea europea

Medicinal and aromatic plants can be considered as “multifunctional plants” due to the diverse properties and ecosystem services they provide in agroecosystems. Among the latter, they regulate the populations of insect pests in crops, harboring their natural enemies. In order to determine the plant species with the greatest presence of natural enemies of Saissetia oleae in an agro-ecological crop of Olea europea, biological corridors with species of medicinal and aromatic plants were established in three sectors of the farm. The plants were collected together with the farmers of the Maipo Province and sticky pheromone traps, vacuum cleaner and entomological umbrella were used to collect the arthropods. The results indicate that Calendula officinalis, Borago officinalis, Aquilea millefolium, Linun usitatissimun, Chamaemulum nobile, Origanum vulgare, Artemisia agrotanum and Symphytum officinale are the species with the highest presence of S. oleae natural enemies identified as Coccophagus sp., Metaphycus helvolus, Metaphycus lounsbury, Metaphycus sp., Rhyzobius lophanthae, Scutellista caerulea.

Predation and reproduction of the generalist predator Nabis pseudoferus preying on Tuta absoluta

AbstractThe damsel bug, Nabis pseudoferus Remane (Hemiptera: Namidae), is a generalist predator of small arthropods, including key insect pests of vegetable crops. In this study, we characterized the predation and development of various N. pseudoferus life stages when preying on the eggs and first‐ and fourth‐instar nymphs of the invasive South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). These findings were compared to those of the bug’s common prey, cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae). Of the life stages tested, females showed the highest predation rate on all tested prey, due to their high longevity, large body, and great energy requirements for reproduction. The predator’s oviposition rate was clearly influenced by prey type, and was highest when feeding on fourth instars of T. absoluta. Considering the zoophytophagy of most of the life stages of other mirid species of tomato, and the lower propensity of N. pseudoferus to feed on plants, these results show that this species can be considered as a key indigenous natural enemy for sustainable pest control packages against T. absoluta in newly invaded areas.

Bioaugmentation of Entomopathogenic Fungi for Sustainable Agriotes Larvae (Wireworms) Management in Maize.

Soil microorganisms influence biotic and abiotic stress tolerance of crops. Most interactions between plant symbiotic and non-symbiotic soil microorganisms and plants occur in the rhizosphere and are sustained through plant exudation/rhizodeposition. Bioaugmentation, i.e., the introduction or amplification of certain plant beneficial microbes (e.g., entomopathogenic fungi) into the rhizosphere, could contribute to controlling insect crop pests and replacing chemical, environmentally unfriendly insecticides. Wireworms, the soil-burrowing larval stages of click beetles (Coleoptera: Elateridae), are major pests of crops including maize, wheat and potatoes, worldwide. Alternative strategies for controlling wireworms are needed because several chemical pesticides used successfully in the past are being phased out because of their ecotoxicity. Therefore, virulence to Agriotes lineatus L. wireworms and plant beneficial traits of entomopathogenic fungi were investigated in a series of laboratory experiments. Tested taxa included environmentally retrieved Metarhizium brunneum Petch. (two strains), M. robertsii Bisch., Rehner & Humber (Hypocreales: Clavicipitaceae), and Beauveria brongniartii (Sacc.) Petch. and commercially formulated B. bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae) and Bacillus thuringiensis Berliner 1915 var. kurstaki. In-house reared larvae were dipped in conidial suspension, and maize and wheat seeds were coated with fungal conidia. Metarhizium brunneum strains 1154 and 1868 significantly increased wireworm mortality. Fungi were significantly more often re-isolated from maize than wheat rhizoplanes in laboratory assays. The strains tested were rarely isolated as endophytes. Metarhizium brunneum strain 1154 stimulated wheat growth, while M. robertsii 1880 stimulated maize growth, whereas M. brunneum 1868 and others did not affect root or shoot length or plant biomass significantly in laboratory settings. Metarhizium brunneum strain 1868, re-isolated most often from maize rhizoplane, caused the highest wireworm mortality. It was further evaluated whether M. brunneum 1868 can protect maize varieties FeroXXY, LG 34.90 and Chapalu from wireworm damage and promote plant growth at field conditions. Plants of all three varieties stemming from seeds treated with conidia of M. brunneum 1868 showed significantly less wireworm damage 3 to 4 weeks after sowing (5- to 6-leaf stage) resulting in a significantly higher initial maize stand. However, only in the variety LG 34.90 a significant increase of the maize stand was observed at harvest time.

Natural insecticides from native plants of the Mediterranean basin and their activity for the control of major insect pests in vegetable crops: shifting from the past to the future

The Mediterranean basin thrives in native plant species are able to produce numerous derivatives that can be used for insect pest control. This article provides an up-to-date overview of the most important native plant species commonly found in this region that have a certain insecticidal value in vegetable crops. Regarding the insecticidal activity of extracts from selected native species, results from both laboratory and field experiments will be also presented to highlight the potential of the latter as alternatives to synthetic insecticides. Considering the great diversity in ingredients among the various plant species, it is essential to record and describe the chemical composition of these species, in conjunction with their insecticidal activity against the main insect pests of vegetable crops. The review concludes in underlining the critical points for increasing the effectiveness and consequently the practical use of natural insecticides in crop protection. Moreover, emphasis is given in understanding the importance of the production of standardized and stable natural resource-based insecticides through the development of suitable formulations, such as capsule suspension that protects the active ingredients from environmental degradation and improves their residual activity.

Mass trapping is a viable alternative to insecticides for management of Anastrepha fraterculus (Diptera: Tephritidae) in apple orchards in Brazil

We evaluated a new integrated pest-management system for Anastrepha fraterculus (Wiedemann, 1830), the main insect pest of apple crops in Brazil. Our strategy combined mass trapping and application of toxic baits in crop systems without (Area 1) and with (Area 3) anti-hail netting. The treatments were compared with the conventional management (applications of toxic baits and insecticides as cover sprays) in two areas without (Area 2) and with (Area 4) anti-hail netting. The study was conducted for two consecutive years (2017–2018 and 2018–2019 seasons). In areas with mass trapping (Area 1 and Area 3), 120 PET traps (600 mL), baited with 300 mL of CeraTrap® hydrolyzed protein, were used per hectare. Fewer A. fraterculus adults were caught in crop systems without anti-hail netting using McPhail monitoring traps in Area 1 (mass trapping) than under conventional management (Area 2). The infestation of A. fraterculus was similar in areas with anti-hail netting with mass trapping (A3) and under conventional management (A4). In the 2017–2018 season, the areas with mass trapping (A1 and A3) had fewer damaged fruits (%) either without (0.4%) and with (0.7%) anti-hail netting than in the areas with conventional management (A2 and A4) without (1.7%) and with (0.8%) anti-hail netting. However, in the 2018–2019 season, fruit damage was similar in all areas studied. Mass trapping combined with the use of toxic baits can be an alternative to the conventional management of A. fraterculus.

Sublethal effects of three insecticides on fitness parameters and population projection of Brevicoryne brassicae (Hemiptera: Aphididae).

The cabbage aphid, Brevicoryne brassicae (L.), is one of the major insect pests of cole crops in Iran. In most instances outbreaks are normally kept under control by application of insecticides. In this study, the sublethal effects (LC30) of three insecticides, acetamiprid, buprofezin, and thiamethoxam-lambda cyhalothrin, (TLC) were evaluated on the population growth rate of the progeny of insecticide-treated cabbage aphid adults. The age-stage, two-sex life table method was used to analyze the collected data. The results indicated that the insecticide applications affected the duration of the preadult period, their survival, reproduction, life span/longevity, and consequently, the population growth rate of the F1 generation. The indicators of the greatest sublethal effects were noted in the progeny of the TLC-treated adults. These included the lowest net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and the longest mean generation time (T). The highest values of r, λ, R, and the lowest value of T occurred in the control group followed by, in order, the acetamiprid and buprofezin groups. These research findings will be useful in the development and implementation of future aphid management programs.

The effect of Bt crops on soil invertebrates: a systematic review and quantitative meta-analysis.

The ongoing debate about the ecological effects of Bt-crops calls for thorough reviews about the impact on soil biodiversity and their ecosystem services. Transgenic Bt-crops have been genetically modified by inserting a Bacillus thuriengensis gene so the plant expresses a Cry toxin aimed for insect crop pests. Non-target soil invertebrates are particularly recognized for their contribution to plant nutrient availability and turnover of organic matter and it is therefore relevant to protect these invertebrate taxa. A number of studies have compared the population abundance and biomass of soil invertebrates in agricultural fields planted with genetically modified Bt crops and their conventional counterparts. Here, were review and analyze a selection of studies on Protista, nematodes, Collembola, mites, enchytraeids, and earthworms systematically to empower the evidence for asking the question whether population abundances and biomasses of soil invertebrates are changed by Bt crops compared to conventional crops. 6110 titles were captured, of which 38 studies passed our inclusion criteria, and a final number of 22 publications were subject to data extraction. A database with 2046 records was compiled covering 36 locations and the Bt types Cry1Ab, Cry1Ac, Cry3Bb1 and Cry3Aa. Comparative effect sizes in terms of Hedges' g were calculated irrespectively of statistical significance of effects of the source studies. Cry effects on populations were compared across the studies in a meta-analysis employing a hierarchical Bayesian approach of weighted data according to the level of replication. The temporal development of effect sizes was modelled, thereby taking into account the variable duration of the field experiments. There was considerable variation among soil invertebrate orders, but the sample size was insufficient and the sample heterogeneity too large to draw any credible conclusions on the effect of Cry at the order level. However, across orders there was no significant effect of Cry on soil invertebrates.

The antifeedant, insecticidal and insect growth inhibitory activities of triterpenoid saponins from Clematis aethusifolia Turcz against Plutella xylostella (L.).

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a global insect pest of crops, leading to a reduction of agricultural products in productivity and quality. Plant saponins are rich sources for the discovery of candidates to control insect pests. This study focused on discovery of triterpenoid saponins from Clematis aethusifolia Turcz and evaluation of their antifeedant, insecticidal and insect growth inhibitory activities against the 3rd instar larvae of P. xylostella. Seven triterpenoid saponins (1-7) were isolated for the first time from the n-BuOH extract of C. aethusifolia. Monodesmosides 1, 2, and 5 with a free 28-COOH group showed much higher antifeedant activity (DC50 were 733.67-844.77 μg mL-1 at 24 h, and 737.19-748.28 μg mL-1 at 48 h) than bidesmosides 3-4 and 6-7 (DC50 were 1284.35-2053.98 μg mL-1 at 24 h, and 1183.72-1990.96 μg mL-1 at 48 h). Similarly, monodesmosides 1, 2, and 5 (LC50 were 1462.78-1785.96 μg mL-1 ) showed stronger insecticidal activity than bidesmosides 3-4 and 6-7 (LC50 were 2219.22-3050.51 μg mL-1 ) against P. xylostella at 72 h. These results suggest the 28-COOH group is an important functional group for their antifeedant and insecticidal activity. Besides, monodesmosides 1, 2, and 5 showed insect growth inhibitory activity against P. xylostella through reduction of larval growth and percentage of pupation, associated with prolongation of larval and pupal stages. The present results provide evidence that triterpenoid saponins from C. aethusifolia, particularly those monodesmosidic saponins with a free 28-COOH group, have the potential to be developed as pesticides to control P. xylostella.