Aphid Brevicoryne Brassicae Research Articles

Influence of the Surrounding Plants by Rapeseed Field on Population Density of Cabbage Aphid (Brevicoryne brassicae L.) and its Biological Enemies

The result revealed that the peak of population density of cabbage aphid Brevicoryne brassicae was 523.20 individuals/plant on 21 March in edges of rapeseed field and was 1141.67 individuals/plant in center of the field. Results revealed that population density of cabbage aphid in rapeseed fields surrounded by cover crops significantly were low compared with that of monoculture rapeseed. The location of rapeseed plants (in edges or in center) significantly affected (p

SUSTAINABLE STRATEGIES FOR INTEGRATED MANAGEMENT OF BREVICORYNE BRASSICAE IN CABBAGE CULTURE: ECOLOGICAL APPROACHES AND IMPACT ON BIOLOGICAL CONTROL IN MOZAMBIQUE

Cabbage (Brassica oleracea) is a vegetable widely cultivated due to its nutritional and economic value, especially for small farmers. However, kale production faces significant challenges, mainly due to attacks by aphids (Brevicoryne brassicae), a pest that causes wilting and deformations in plants and acts as a virus vector. In regions such as Southern Africa, inadequate control of this pest has resulted in considerable losses in production, reaching 40% in Mozambique.The adult stage of Brevicoryne brassicae is the most damaging, especially affecting the cabbage crop during its vegetative phase, when the plants are most vulnerable. Effective management of this pest involves continuous monitoring and the use of Integrated Pest Management (IPM) practices, which include cultural, biological and chemical methods. Applying these techniques in an integrated way, adapted to local conditions, can significantly reduce damage and improve agricultural productivity, promoting food security and sustainability for small Mozambican farmers.

Important Insect Pests on Cabbage in Lao PDR

This study was conducted in Xiengkhouang province, Vientiane province, Saravane province, Champasak province, Vientiane Capital, and Plant Protection Center, from January to March 2017. The aims of study were to investigate to major insect pests on cabbage and compared the efficacy of Jeevatu, Jeevatu+botanical pesticide and chemical pesticide to control Diamondback moth in laboratory condition. The study was divided into two treatments: 1) survey important insect pests of cabbage in 3 purposive sampling areas (field)/village, 10 points/rai, and 3 cabbages/point to identify insect pests and survey the life cycle of Diamondback moth of cabbage, and 2) conduct the efficacy experiment of Jeevatu, Jeevatu+botanical pesticide and chemical pesticide to Diamondback moth in laboratory. The experiment was done by Completely Randomized Design (CRD) with 5 treatments and 4 replications. The survey showed that there are 8 species of insect pests on cabbage and the most important species is Diamondback moth (Plutella xylostella) which was found in all provinces that had been survey than followed by striped flea beetle (Phyllotreta striolata), cabbage aphid (Brevicoryne brassicae), cabbage butterfly (Pieris rapae), taro caterpillar (Spodoptera litura), cabbage webworm (Hellula undalis), cabbage looper (Trichoplasia ni) and flea beetle (phyllotreta cruciferae). Life cycle of Diamondback moth was investigated in that laboratory, and it showed that the total of life cycle took about 14-21 days that included 3-5 days for egg stage, 8-12 days for lavae stage, 3-4 days for pupae stage, and 13-31 days of bebeing mature. The efficacy of Jeevatu+Sugar apple leaf extracts, Jeevatu+Neem extracts, and Jeevatu with water for control Diamondback moth indicated that after 5 days sprayed, the mortality percentage was up to 90%, 80% and 57% respectively. For chemical sprayed for 2 days, the mortality percentage was up to 100%. The results of this study showed that the Jeevatu+botanical pesticide can be used as a substitute for substituting chemical in preventing the control Diamondback moth.

Toxicity and efficacy of azadirachtin, and oxymatrine-based biopesticides against cabbage aphid and their impacts on predator insects

The aphidicidal activity and efficacy of azadirachtin- and oxymatrine-based biopesticides on the cabbage aphid Brevicoryne brassicae (Linnaeus, 1758) (Hemiptera: Aphididae), and their impacts on the main insect predators of this aphid were assessed under laboratory, semi-field, or field conditions. Laboratory results showed that azadirachtin- and oxymatrine-based biopesticides provided high acute toxicity against B. brassicae nymphs and adult females, in a manner dependent on the concentration, developmental stage, and exposure time of insects to residues. Among the insect's developmental stages, B. brassicae nymphs were more susceptible to biopesticides than adult females. In addition to acute toxicity, the biopesticides reduced the number of offspring and the amount of honeydew excreted by B. brassicae adult females. Furthermore, the biopesticides induced a repellent effect on B. brassicae adult females. Despite their high toxicity, in semi-field conditions, the azadirachtin- and oxymatrine-based biopesticides showed low biological persistence [mortality >80% up to 3 and 1 day after spraying (DAS), respectively] in comparison to the synthetic insecticide flupyradifurone (mortality >80% up to 7 DAS), which was used as a positive control. However, in the field, the biopesticides demonstrated high efficacy in controlling the B. brassicae population, with no significant impact on the population levels of different species of lacewings, ladybugs, and syrphids, which are considered the main insect predators of the cabbage aphid in agroecosystems. Therefore, azadirachtin- and oxymatrine-based biopesticides constitute an important management measure for B. brassicae in agroecosystems, including those with an ecological basis where management tools are limited, and effective control tactics must be incorporated.

Computer-driven Evolution of Myrosinase from the Cabbage Aphid for Efficient Production of (R)-Sulforaphane.

Myrosinase (Myr) catalyzes the hydrolysis of glucosinolates, yielding biologically active metabolites. In this study, glucoraphanin (GRA) extracted from broccoli seeds was effectively hydrolyzed using a Myr-obtained cabbage aphid (Brevicoryne brassicae) (BbMyr) to produce (R)-sulforaphane (SFN). The gene encoding BbMyr was successfully heterologously expressed in Escherichia coli, resulting in the production of 1.6 g/L (R)-SFN, with a remarkable yield of 20.8 mg/gbroccoli seeds, achieved using recombination E. coli whole-cell catalysis under optimal conditions (pH 4.5, 45 °C). Subsequently, BbMyr underwent combinatorial simulation-driven mutagenesis, yielding a mutant, DE9 (N321D/Y426S), showing a remarkable 2.91-fold increase in the catalytic efficiency (kcat/KM) compared with the original enzyme. Molecular dynamics simulations demonstrated that the N321D mutation in loopA of mutant DE9 enhanced loopA stability by inducing favorable alterations in hydrogen bonds, while the Y426S mutation in loopB decreased spatial resistance. This research lays a foundation for the environmentally sustainable enzymatic (R)-SFN synthesis.

Long‐term effects of elevated CO2 on the nutrition provided to parasitoids by their herbivorous hosts

AbstractElevated concentrations of atmospheric carbon dioxide (CO2), a consequence of anthropogenic global change, may profoundly interfere with natural ecological processes, perhaps even interactions across trophic levels. Even the survival prospects of organisms at higher trophic levels could be affected, as follows. We showed previously that the endoparasitoid Diaeretiella rapae, a specialized parasitoid of the cabbage aphid Brevicoryne brassicae, exposed to elevated CO2 concentrations (800 ppm) for up to 10 weeks, performed far worse (e.g., lower survival and parasitism rates) compared with ambient CO2 (400 ppm). To investigate whether these CO2‐related effects in the parasitoids were mediated by changes in the quality of the aphids as hosts, we measured the nutritional and energy content of cabbage aphids under the above conditions. Specifically, we measured lipid, protein and water‐soluble carbohydrate concentrations. We tested the hypothesis that when insects feed from plants with altered nutritional content, they incur a cost in dealing with such biotic stresses. That cost reduces their metabolic well‐being and, thus, reduces their nutritional status with respect to parasitoids developing at their expense. We found that CO2 had significant effects on aphid body mass (i.e., wet weight) and chemical composition, with elevated CO2 concentrations reducing aphid mass by more than 50%. Aphids grown under elevated CO2 also had significantly reduced soluble carbohydrates but significantly more lipids, on a weight‐per‐weight basis, than aphids grown under ambient CO2. A significant decrease in total energy reserves (i.e., the sum of total proteins, lipids, and water‐soluble carbohydrates) thus typified aphids grown under elevated CO2. Our results contribute to explaining the impaired performance of the aphid B. brassicae and its parasitoid D. rapae previously reported under elevated CO2, and provide evidence that under future climate change, host plants might affect the development and performance of parasitoids through their impacts on the nutritional quality of their herbivorous hosts.

Entomocomplex of Radish in Open-field Cultivation in the Central Part of the Right-Bank Forest-Steppe of Ukraine

Goal. To specify the species composition of insect pests affecting radish (Raphanus sativus (L.) convar. radicula (Pers) Sazon.) in open-field cultivation conditions in the central part of the Right-Bank Forest-Steppe of Ukraine.
 Methods. The study was conducted following commonly accepted methods in entomology and vegetable growing. From 2008 to 2022, we investigated the species diversity of insects, dominant species, their abundance, and the structure of the harmful entomocomplex in radish crops grown in open-field conditions on household plots and farms in the Cherkasy region.
 Results. In the entomological complex of radish, 59 species of phytophagous insects from 20 families and 8 orders were identified: Coleoptera — 29%, Lepidoptera — 27%, Homoptera — 15%, Diptera — 10%, Orthoptera — 9%, Thysanoptera — 5%, Hemiptera — 3%, Hymenoptera — 2%. Sixteen dominant species of phytophagous insects were found in radish crops, including diamondback moth (Plutella maculipennis Curt.), crucifer flea beetles (Phyllotreta cruciferae Goeze), striped flea beetle (Phyllotreta undulata Kutsch.), cabbage white butterfly (Pieris brassicae L.), turnip moth (Agrotis segetum Denis&Schiff.) and owlet moth (Lacanobia oleracea L.), crucifer shield bug (Eurydema ventralis Kol.), cabbage aphid (Brevicoryne brassicae L.), spring root maggot (Delia brassicae Bouche) and summer root maggot (Delia floralis Fallen), seedcorn maggot (Delia platura Mg.), sawfly (Athalia rosae L.), stem weevil (Ceutorrhynchus quadridens Panz.), tobacco thrips (Thrips tabaci Lindeman), turnip sawfly (Entomoscelis adonidis Pallas), and crucifer webworm (Evergestis extimalis Scop.). Through multi-year studies, the periods of insect damage corresponding to radish developmental stages were determined. The most critical damage to radish plants by harmful insects occurred during the initial stages of development (ВВСН 0—9) and from emergence to the growth and formation of the root crop (BBCH 42—48).
 Conclusions. It was found that among the identified phytophagous insects in radish crops, the most economically significant damage was caused by the cabbage aphid, crucifer flea beetles, striped flea beetle, spring cabbage fly, and seedcorn maggot. On average over the research period (2008—2022), the largest areas of radish crops were infested by the diamondback moth, crucifer flea beetles, and striped flea beetle, cabbage white butterfly, winter and owlet moths, cabbage shield bug, and cabbage aphid, ranging from 5% to 80%, reaching a maximum in some years up to 60—100% of the area.

Electrophysiological and Behavioral Responses of Cabbage Aphid (Brevicoryne brassicae) to Rosemary (Rosmarinus officinalis) Volatiles, a Potential push Plant for Vegetable push-pull Cropping System.

The cabbage aphid (Brevicoryne brassicae) is a major pest of kale (Brassica oleraceae var. acephala), an important vegetable that is grown worldwide due to its high nutritional and economic value. Brevicoryne brassicae poses a great challenge to B. oleraceae var. acephala production, causing significant direct and indirect yield losses. Farmers overly rely on synthetic insecticides to manage the pest with limited success owing to its high reproductive behavior and development of resistance. This necessitates a search for sustainable alternatives to mitigate these challenges. This study assessed behavioral responses of B. brassicae to odors from rosemary (Rosmarinus officinalis) and B. oleraceae var. acephala headspace volatiles in a Perspex four-arm olfactometer. We identified and quantified volatiles emitted by each of the two plants and those eliciting antennal response using coupled gas chromatography-mass spectrometry (GC-MS) and GC-electroantennograhic detection(GC-EAD), respectively. Our findings revealed that B. brassicae spent more time in the arms of the olfactometer that contained B. oleraceae var. acephala volatiles compared to the arm that held R. officinalis volatiles. Additionally, B. brassicae spent more time in the olfactometer arms with B. oleracea var. acephala compared to the arms holding B. oleracea var. acephala and R. officinalis enclosed together and clean air. GC-MS analysis revealed diverse and higher quantities of volatile compounds in R. officinalis compared to B. oleraceae var. acephala. GC-EAD analysis showed that antennae of B. brassicae detected Linalool, α-Terpineol, Verbenone, Geraniol, Camphor, and Borneol from the volatiles of R. officinalis, and Sabinene, γ-Terpinene, and β-Caryophyllene from B. oleraceae var. acephala volatiles.Our findings demonstrate the potential of R. officinalis as a repellent plant against B. brassicae and could be utilized as a 'push' plant in an intercropping strategy against this pest.

Insect herbivory but not plant pathogen infection drive floral volatile‐mediated indirect effects on pollinators and plant fitness in Brassica rapa

Abstract Plant enemies can indirectly affect pollinators by modifying plant traits, but simultaneous tests of herbivore and pathogen effects are lacking, and the role of floral volatiles has seldom been assessed. In this study, we tested for indirect effects of insect herbivores and pathogens on pollinator attraction via altered floral volatile emissions, and its consequences for plant fitness in Brassica rapa. Plants in the field were exposed to either no damage or damage by caterpillars (Mamestra brassicae), aphids (Brevicoryne brassicae), a leaf fungus (Sclerotinia sclerotiorum), or a bacterium (Xanthomonas campestris pv. campestris). We then recorded pollinator visits and measured floral traits (flower number, volatiles) and plant fitness‐correlates. We additionally performed a greenhouse experiment with artificial floral emitters to test for effects of target volatiles on pollinator attraction. In the field experiments, relative to controls, plants subjected to herbivory by the aphid B. brassicae (but not those exposed to the other enemies) exhibited a marked reduction in the emission of two volatile organic compounds (nonanal and 2‐butyl‐1‐octanol), experienced lower pollinator visits and produced seeds of lower quality in terms of seed biomass and germination rate, while flower output itself was not affected. Consistently, artificial emitters with reduced amounts of these volatile organic compounds were less attractive to pollinators under greenhouse conditions. Synthesis. These results provide strong evidence for volatile‐mediated indirect interactions between plant enemies and pollinators ultimately impacting plant fitness, and further point at enemy and compound specificity in such effects.

Chloride, glutathiones, and insect-derived elicitors introduced into the xylem trigger electrical signaling.

Ricca assays allow the direct introduction of compounds extracted from plants or the organisms that attack them into the leaf vasculature. Using chromatographic fractionation of Arabidopsis (Arabidopsis thaliana) leaf extracts, we found glutamate was the most active low mass elicitor of membrane depolarization. However, other known elicitors of membrane depolarization are generated in the wound response. These include unstable aglycones generated by glucosinolate (GSL) breakdown. None of the aglycone-derived GSL-breakdown products, including nitriles and isothiocyanates, that we tested using Ricca assays triggered electrical activity. Instead, we found that glutathione and the GSL-derived compound sulforaphane glutathione triggered membrane depolarizations. These findings identify a potential link between GSL breakdown and glutathione in the generation of membrane depolarizing signals. Noting that the chromatographic fractionation of plant extracts can dilute or exchange ions, we found that Cl- caused glutamate receptor-like3.3-dependent membrane depolarizations. In summary, we show that, in addition to glutamate, glutathione derivatives as well as chloride ions will need to be considered as potential elicitors of wound-response membrane potential change. Finally, by introducing aphid (Brevicoryne brassicae) extracts or the flagellin-derived peptide flg22 into the leaf vasculature we extend the use of Ricca assays for the exploration of insect/plant and bacteria/plant interactions.

Dominant species of radish (Raphanus sativus (L.) convar. radicula (Pers) Sazon.) pests in the Right Bank Forest Steppe of Ukraine

Based on the results of phytosanitary monitoring (2008–2022), the species composition of pests in agroecosystems of radish (Raphanus sativus (L.) convar. radicula (Pers) Sazon.) in the central part of the Right-Bank Forest-Steppe of Ukraine has been specified. In radish crops, 59 species of phytophagous insects, two species of nematodes, and one species of slugs were identified. The harmful entomocomplex structure includes insects from 20 families of 8 orders. Representatives of the orders Coleoptera (17 species), Lepidoptera (16 species), and Homoptera (9 species) dominate the taxonomic structure, collectively occupying 71% in the structure of the harmful entomocomplex. Representatives of the orders Diptera and Orthoptera were presented by species from 6 and 5 families, respectively, and in the entomocomplex structure, they occupied 10% and 8%, respectively. The least species diversity was found for the order Thysanoptera, Hemiptera, and Hymenoptera, which collectively occupied 10% in the structure of the harmful entomocomplex. Sixteen constant species were identified (Plutella maculipennis Curt., Phyllotreta cruciferae Goeze, Phyllotreta undulata Kutsch., Pieris brassicae L., Agrotis segetum Denis&Schiff., Lacanobia oleracea L., Eurydema ventralis Kol., Brevicoryne brassicae L., Delia brassicae Bouche, Athalia rosae L., Delia platura Mg., Ceutorrhynchus quadridens Panz., Delia floralis Fallen, Thrips tabaci Lindeman, Entomoscelis adonidis Pallas, Evergestis extimalis Scop.), which caused significant damage to radish plants throughout the vegetation period. These species were trophically specialized, with 75% being oligophagous and 81% being phytophagous. Flea beetles such as Phyllotreta cruciferae Goeze, Phyllotreta undulata Kutsch., diamondback moth (Plutella maculipennis Curt.), cabbage aphid (Brevicoryne brassicae L.), turnip moth (Agrotis segetum Denis&Schiff.), and armyworm (Lacanobia oleracea L.) were found with high and medium frequencies in the studied agroecosystems, with population densities reaching maximum levels of 60–100% in some years.

Species composition and aphid population seasonal dynamics in vegetable agrocenoses of St. Petersburg and Leningrad region

The purpose of this work was to study the species composition, the dynamics of aphid abundance in vegetable agrocenoses of the Pushkin district of St. Petersburg, as well as Tosnensky and Gatchina districts of the Leningrad region in the conditions of 2021-2022, significantly differing in weather conditions. The catching of insects was carried out using a Malaise trap. In total, during the two-year monitoring period, 40 species of aphids were registrated in the three studied agrocenoses, of which 28 are pests of agricultural crops. The total number of identified species in 2021 was 9 in each of the three research areas; the total number of captured insects was 99. At the end of May – beginning of June, the migration potential of aphids was high, active migration to secondary hosts was observed, however, abnormally high daytime temperatures in June – July with minimal precipitation had a detrimental effect on phytophages. In the weather conditions favorable for the development of aphids during the growing season of 2022, 11 species of aphids were caught in the Pushkinsky district of St. Petersburg, 12 in the Gatchina district, 20 in the Tosnensky district, that is, an increase in the species composition of phytophages was 2.2 times compared to 2021. In 2022, 279 individuals were registered; the largest number of insects was noted in the Tosnensky district – 171. In all the studied agrocenoses, the most numerous of the harmful species was the gray svidin-cereal aphid Anoecia corni F., damaging the roots of perennial grasses (the maximum number of 128 individuals in the Tosnensky district in 2022). A significant number in the same year was observed in the pea Acyrthosiphon pisum Harr., as well as in the cabbage aphid Brevicoryne brassicae L. Quite rare species of aphids for the North-Western region were recorded in the agrocenosis of the Pushkin district: Oxton and maple aphids. The pink tansy aphid was registered only in the Tosno agrocenosis in June 2022. The Malaise trap proved to be convenient to work with, since it is not stationary, can be installed anywhere in any agrocenosis. It can be recommended to use it, first of all, to assess the species diversity of insects, and secondly, to estimate the number.

Integrated Management of Cabbage Aphid (Brevicoryne brassicae L.)

The present investigation entitled “Integrated Management of Cabbage Aphid (Brevicoryne brassicae L.)” was carried out at Department of Entomology as well as field of Vegetable Research and Demonstration Block, College of Horticulture, VCSG Uttarakhand University of Horticulture and Forestry, Bharsar, Pauri Garhwal during 2022. Seasonal incidence of Cabbage aphid (Brevicoryne brassicae) revealed that the maximum numbers of aphid, (784.05 nymphs/plants and 506.32 adults/plants) were recorded during 23rd SMW viz., 2nd week of June. Correlation studies indicated that aphid population exhibited highly significant positive correlation with maximum temperature and minimum temperature and significant negative correlation with morning and evening relative humidity. While rainfall showed non-significant positive correlation with aphid population. Efficacy of different treatments (Cultural practices (Weeding) + Yellow sticky trap), (Garlic extract + Red pepper extract), (Onion extract + Yellow sticky trap), (Neem leaf extract + Cow urine), (Thiamethoxam 25 WG + Beauveria bassiana), (L-cyhalothrin 5 EC + Beauveria bassiana) and (Biological control + Mechanical control) were evaluated by two sprays at 3, 5 and 7 days interval against aphid (B. brassicae) during year 2022. After 1st and 2nd application highest reduction in aphid population (77.37 and 93.57) and maximum yield (5.85 kg/plot and 541.66 q/ha) over pre treatment was recorded in L-cyhalothrin 5 EC incorporated with Beauveria bassiana.

Metabolism of plant-derived toxins from its insect host increases the success of the entomopathogenic fungus Beauveria bassiana

Beauveria bassiana is a soil fungus that parasitizes a large number of arthropod species, including numerous crop pests, causing white muscardine disease and is therefore used as a biological insecticide. However, some insects, such as the cabbage aphid (Brevicoryne brassicae), defend themselves chemically by sequestering dietary pro-toxins (glucosinolates) from their Brassicales host plants. Glucosinolates are accumulated by cabbage aphids and activated to form toxic isothiocyanates when under attack. While isothiocyanate formation protects aphids against most attackers, B. bassiana is still able to infect the cabbage aphid under natural conditions. We therefore investigated how this fungus is able to circumvent the chemical defense system of the cabbage aphid. Here, we describe how B. bassiana infection activates the cabbage aphid defense system, but the resulting toxins are metabolized by B. bassiana via the mercapturic acid pathway, of which the first step is catalyzed by glutathione-S-transferases of low substrate specificity. This detoxification pathway enhances B. bassiana growth when isothiocyanates are present in natural concentrations, and so appears to be an important factor in fungal parasitization of these chemically defended aphids.

Aphids on Aphid-Susceptible Cultivars Have Easy Access to Turnip Mosaic Virus, and Effective Inoculation on Aphid-Resistant Cultivars of Oilseed Rape (Brassica napus).

Plant viruses improve transmission efficiency by directly and indirectly influencing vector behavior, but the impact of plant cultivars on these modifications is rarely studied. Using electropenetrography (EPG) technology, a comparative study of the effects of turnip mosaic virus (TuMV) infection on quantitative probing behaviors of the cabbage aphid (Brevicoryne brassicae) was conducted on two oilseed rape cultivars ('Deleyou6' and 'Zhongshuang11'). Compared to mock-inoculated plants, cabbage aphids on infected plants increased the frequency of brief probing, cell penetration, and salivation. Additionally, aphids on infected 'Deleyou6' prolonged cell penetration time and decreased ingestion, but not on infected 'Zhongshuang11', suggesting that aphids were more likely to acquire and vector TuMV on the aphid-susceptible cultivar 'Deleyou6' than on resistant cultivars. TuMV also affected aphid probing behavior directly. Viruliferous aphids reduced the pathway duration, secreted more saliva, and ingested less sap than non-viruliferous aphids. In comparison with non-viruliferous aphids, viruliferous aphids started the first probe earlier and increased brief probing and cell penetration frequencies on the aphid-resistant cultivar 'Zhongshuang11'. Based on these observations, viruliferous aphids can be inoculated with TuMV more efficiently on 'Zhongshuang11' than on 'Deleyou6'. Although aphid resistance and TuMV infection may influence aphid probing behavior, oilseed rape resistance to aphids does not impede TuMV transmission effectively.

A Field Survey of Syrphid Species and Adult Densities on Annual Flowering Plants in the Northeastern United States.

With the long-term goal of exploring the viability of conservation biological control of cabbage aphid Brevicoryne brassicae (L.) (Hemiptera: Aphididae) in the northeastern United States, adult syrphid flies (Diptera: Syrphidae) were observed on several species of annual insectary plants at farm sites in Connecticut, Massachusetts, and New Hampshire. Insectary plant species included alyssum, Lobularia maritima (L.) (Brassicales: Brassicaceae), buckwheat, Fagopyrum esculentum (Moench) (Caryophyllales: Polygonaceae), phacelia, Phacelia tanacetifolia (Bentham) (Boraginales: Hydrophyllaceae), calendula, Calendula officinalis (L.) (Asterales: Asteraceae) and ammi, Ammi majus (L.) (Apiales: Apiaceae). Among these insectary plants, alyssum had the longest bloom period and attracted the most syrphids. We identified 21 species of syrphid flies from insectary plants. The three most prevalent species collected were the aphidophagous Toxomerus marginatus (Say) (Diptera: Syrphidae) (70.1% of samples) and T. geminatus (Say) (Diptera: Syrphidae) (8.8% of samples), as well as the non-aphidophagous Syritta pipiens (L.) (Diptera: Syrphidae) (13.1% of samples). The benefits of including these insectary plant species as a companion to Brassica (L.) (Brassicales: Brassicaceae) cropping systems are discussed.

Assessment of sublethal and transgenerational effects of spirotetramat, on population growth of cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae).

The cabbage aphid (Brevicoryne brassicae L.) is a devastating pest of cruciferous crops causing economic damage worldwide and notably owing to its increasing resistance to commonly used pesticides. Such resistance prompts the development of integrated pest management (IPM) programs that include novel pesticides being effective against the aphids. Spirotetramat is a novel insecticide used against sap-sucking insect pests, particularly aphids. This study evaluated the toxicity of spirotetramat to adult apterous B. brassicae after 72h using the leaf dipping method. According to the toxicity bioassay results, the LC50 value of spirotetramat to B. brassicae was 1.304mgL-1. However, the sublethal concentrations (LC5 and LC15) and transgenerational effects of this novel insecticide on population growth parameters were estimated using the age-stage, two-sex life table theory method. The sublethal concentrations (LC5; 0.125mgL-1 and LC15; 0.298mgL-1) of spirotetramat reduced the adult longevity and fecundity of the parent generation (F0). These concentrations prolonged the preadult developmental duration while decreasing preadult survival, adult longevity and reproduction of the F1 generation. The adult pre-reproductive period was also extended by spirotetramat treatment groups. Subsequently, the population growth parameters such as the intrinsic rate of increase r, finite rate of increase λ and net reproductive rate R 0 of the F1 generation were decreased in spirotetramat treatment groups whereas, the mean generation time T of the F1 generation was not affected when compared to the control. These results indicated the negative effect of sublethal concentrations of spirotetramat on the performance of B. brassicae by reducing its nymphal survival, extending the duration of some immature stages and suppressing the population growth of B. brassicae. Overall, we demonstrated that spirotetramat is a pesticide showing both sublethal activities, and transgenerational effects on cabbage aphid; it may be useful for implementation in IPM programs against this aphid pest.

Amending soil with insect exuviae improves herbivore tolerance, pollinator attraction and seed yield of Brassica nigra plants

To promote circularity in agriculture, the residual –streams from the production of insects as feed and food, such as insect exuviae (moulted skins), can be a sustainable novel organic soil amendment for crop production. Organic soil amendments can influence soil composition by providing nutrients and stimulating the growth of beneficial microorganisms. Soil composition significantly impacts plant growth and resistance against herbivores. However, little is known about the effect of soil composition on flower visitors and seed production. Here, black soldier fly (BSF; Hermetia illucens) exuviae was added to soil to investigate the effects on plant growth, plant resistance against two insect herbivores, and the consequences for attraction of pollinators and seed yield. Brassica nigra seeds were sown in field soil or in field soil mixed with powdered BSF exuviae. Three-week-old plants and the soil of each pot were planted in a common garden. The effects on vegetative and flower traits, interactions with flower visitors and seed yield were quantified. In addition, the performance of the leaf-chewing larvae of Pieris brassicae and the piercing-sucking aphid Brevicoryne brassicae were assessed. Brassica nigra plants grown on soil amended with BSF exuviae showed increased growth, had more flowers and flower visitors, and higher seed production. Herbivory neither affected number of flowers nor seed production, suggesting tolerance and compensatory growth responses to herbivory compared to plants growing in soil without the addition of BSF exuviae. After five weeks fewer aphids were found on plants growing in amended soil. Our findings show that BSF exuviae added to soil can positively affect tolerance to herbivory and seed production of B. nigra, an insect-pollinated plant species. Moreover, adding insect exuviae as soil amendment in the field benefits plant-pollinator mutualism and seed yield even during herbivore attack in the field. Use of by-products from insect production as soil amendment can contribute to sustainable agricultural practices along with the conservation of ecosystem services.

Mortality, Enzymatic Antioxidant Activity and Gene Expression of Cabbage Aphid (Brevicoryne brassicae L.) in Response to Trichoderma longibrachiatum T6.

Aphids are one of the most common insect pests in greenhouse and field crops worldwide, causing significant crop yields and economic losses. The objective of this study was to determine the mortality, enzymatic antioxidant activity and gene expression of cabbage aphids (Brevicoryne brassicae L.) in response to Trichoderma longibrachiatum T6 (T6) at different time points from Day 1 to 7 after inoculation. Our results showed that the highest mortality of B. brassicae was observed on Day 7 at a concentration of 1 × 108 spores ml−1 (73.31%) after inoculation with T6 compared with the control on Day 7 (11.51%). The activities of the enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX) and glutathione S-transferase (GST) were increased by 52.98%, 44.77%, 48.26%, 49.39%, 45.13% and 39.67%, respectively on Day 3 after inoculation with T6 compared to the control. Howerver increased days post treatment (dpt) decreased the activities of SOD, POD, CAT, APX, GPX and GST enzymes by 20.79%, 21.05%, 13.75%, 20.45%, 25.38%, and 19.76% repectively on Day 7 compared to control. The transcript levels of SOD, POD, CAT, GPX, and GST genes were increased by 10.87, 9.87, 12.77, 6.22 and 4.07 respectively at Day 3 after inoculation with T6 in comparison to the control. However, the SOD, POD, CAT, GPX, and GST transcription levels decreased by 0.43, 0.44, 0.35, 0.52 and 0.47 respectively, compared to control at Day 7. Our results suggest that the T6 strain has a potential effect on the antioxidant activity and mortality of B. brassicae and therefore could be used as a natural biocontrol agent against B. brassicae in the future.

Specialist root herbivore modulates plant transcriptome and downregulates defensive secondary metabolites in a brassicaceous plant.

Summary Plants face attackers aboveground and belowground. Insect root herbivores can lead to severe crop losses, yet the underlying transcriptomic responses have rarely been studied.We studied the dynamics of the transcriptomic response of Brussels sprouts (Brassica oleracea var. gemmifera) primary roots to feeding damage by cabbage root fly larvae (Delia radicum), alone or in combination with aboveground herbivory by cabbage aphids (Brevicoryne brassicae) or diamondback moth caterpillars (Plutella xylostella). This was supplemented with analyses of phytohormones and the main classes of secondary metabolites; aromatic, indole and aliphatic glucosinolates.Root herbivory leads to major transcriptomic rearrangement that is modulated by aboveground feeding caterpillars, but not aphids, through priming soon after root feeding starts. The root herbivore downregulates aliphatic glucosinolates. Knocking out aliphatic glucosinolate biosynthesis with CRISPR‐Cas9 results in enhanced performance of the specialist root herbivore, indicating that the herbivore downregulates an effective defence.This study advances our understanding of how plants cope with root herbivory and highlights several novel aspects of insect–plant interactions for future research. Further, our findings may help breeders develop a sustainable solution to a devastating root pest.