Cereal Leaf Beetle Research Articles

Evaluating locally sourced inert dusts as insecticides against the cereal leaf beetle ( Oulema melanopus [L.]; Coleoptera: Chrysomelidae): a combined laboratory and field study

Evaluating locally sourced inert dusts as insecticides against the cereal leaf beetle ( <i>Oulema melanopus</i> [L.]; Coleoptera: Chrysomelidae): a combined laboratory and field study

Plant growth promotion of crops using phosphate solubilizing bacterial strains derived from insects

The aim of this study was to investigate insect derived bacteria for the ability to dissolve insoluble soil phosphate to release soluble phosphorus compounds, available to plants. Bacterial isolates were obtained from Diabrotica virgifera, Hermetia illucens, Oulema melanopus, and Ostrinia nubilalis. An in vitro evaluation of phosphate solubilization ability on Pikovskaya’s medium was done and the phosphate solubilizing index (PSI) was calculated for each isolate. Bacteria were tested in a greenhouse experiment on seeds of oats, wheat, triticale, barley and soybeans. After incubation, the weight and length of their aerial plant parts were measured. The highest increase in the weight of aerial parts was recorded for oats after using strain Om046 for inoculation (88.98%), then, wheat (Dv097, 31.43%), soybean (strain 96, 53.79%), and triticale (bacterial consortium, 36.9%). Bacteria used were identified as Lactococcus lactis (strains Om030 and Om046), Acinetobacter sp. (Dv123), Lactococcus garvieae (Dv097) and Rothia kristinae (strains 90 and 96). We showed that a successful application of insect derived bacteria for phosphate solubilization in soil, to promote plant growth, is possible. Innovative agriculture requires constant improvements in increasing crop growth. Thus, new sources of bacterial strains effectively promoting plant growth, are needed. We described a new source of plant growth-promoting bacteria that can be used in agriculture.

Cereal leaf beetle (Oulema spp.) damage reduces yield and is more severe when natural enemy action is prevented

Insect pests pose a global threat to crop yield. Biological control by natural enemies aims to reduce pest damage in a sustainable way. Cereal leaf beetles (CLB; Oulema spp.) are major pests in small-grain cereals. We studied the effect of natural enemies on CLB damage and its consequences on yield within its native distribution area in Europe. In exclusion cage experiments and by documenting a naturally occurring CLB damage gradient, we found that CLB damage reduced yield, but natural enemy action reduced the damage by CLB. Comparing exclusion and open treatments on artificially CLB-infested plants, plants accessible to natural enemies had 30% less leaf damage. CLB damage significantly affected yield parameters. Thousand grain weight was 22–29% less in maximum leaf damage scenarios. In the damage gradient field, maximal infestation reduced grain yield by 52%. However, maximal damage occurred only on a few plants and over small areas. In natural infestation cases, the number of CLB larvae per plant had a median of zero; nevertheless, there were more than 35 larvae on 10% of the plants. Patchiness explained 40% of CLB damage variance. Damage was unevenly distributed; as a result, thousand grain weight decreased only by 1.6% for 75% of the plants but by 18% for 10% of the plants. In the natural damage gradient, the estimated yield loss for the entire field was 16% due to CLB. Skewed CLB distribution may lead to perceptible yield losses locally, but natural enemies may limit overall damage to the crop.

Natural plant disease suppressiveness in soils extends to insect pest control

BackgroundSince the 1980s, soils in a 22-km2 area near Lake Neuchâtel in Switzerland have been recognized for their innate ability to suppress the black root rot plant disease caused by the fungal pathogen Thielaviopsis basicola. However, the efficacy of natural disease suppressive soils against insect pests has not been studied.ResultsWe demonstrate that natural soil suppressiveness also protects plants from the leaf-feeding pest insect Oulema melanopus. Plants grown in the most suppressive soil have a reduced stress response to Oulema feeding, reflected by dampened levels of herbivore defense-related phytohormones and benzoxazinoids. Enhanced salicylate levels in insect-free plants indicate defense-priming operating in this soil. The rhizosphere microbiome of suppressive soils contained a higher proportion of plant-beneficial bacteria, coinciding with their microbiome networks being highly tolerant to the destabilizing impact of insect exposure observed in the rhizosphere of plants grown in the conducive soils. We suggest that presence of plant-beneficial bacteria in the suppressive soils along with priming, conferred plant resistance to the insect pest, manifesting also in the onset of insect microbiome dysbiosis by the displacement of the insect endosymbionts.ConclusionsOur results show that an intricate soil–plant-insect feedback, relying on a stress tolerant microbiome network with the presence of plant-beneficial bacteria and plant priming, extends natural soil suppressiveness from soilborne diseases to insect pests.4oEYADM9UCsv5obDEsLZQ_Video

Comparative Efficacy of Bio Active Plant Extracts and Insecticides against Cereal Leaf Beetle (Oulema melanopus L.) Infesting Oats in North Kashmir, India

Experiment was carried out at farmers field near the Faculty of Agriculture, Wadura, Kashmir, India during 2021-22 to evaluate efficacy of various insecticides and botanicals against cereal leaf beetle Oulema melanopus (L.) (Coleoptera: Chrysomelidae) infesting Rabi Oats (Avena sativa L.) in North Kashmir. Among plant extracts and insecticides evaluated against O. melanopus, Abamectin proved to be most effective in causing huge mortality to grub population with decreasing number of grub were recorded as (24, 21.3, 8.3, 1.6 and 1 %) after 2,4,6,8 and 10 days of spray, respectively during 2021 followed by Thiamethoxam (32.6, 15.3, 8, 0.3%) after 2, 4, 6, 8 ad 10 days of spray. Same trend of results was observed in 2022 and the pooled data. Among tested botanicals viz. neem and Artimesia; Artimesia was effective in declining the grub population with (44, 42, 41, 39 and 37%) after 2, 4, 6,8 and 10 days after spray. Severe infestation has been observed at maturity of crop and keeping in view the use as fodder to cattle it is necessary to inculcate the use of locally available botanicals for better health of cattle during the dearth period of fodder in Kashmir valley. Overall, the marginal farmers might be saved from any untoward by utilization of the bioactive plant extracts in management of this notorious pest.

Cereal leaf beetle-associated bacteria enhance the survival of their host upon insecticide treatments and respond differently to insecticides with different modes of action.

The cereal leaf beetle (CLB, Oulema melanopus) is one of the major cereal pests. The effect of insecticides belonging to different chemical classes, with different mechanisms of action and the active substances' concentrations on the CLB bacterial microbiome, was investigated. Targeted metagenomic analysis of the V3-V4 regions of the 16S ribosomal gene was used to determine the composition of the CLB bacterial microbiome. Each of the insecticides caused a decrease in the abundance of bacteria of the genus Pantoea, and an increase in the abundance of bacteria of the genus Stenotrophomonas, Acinetobacter, compared to untreated insects. After cypermethrin application, a decrease in the relative abundance of bacteria of the genus Pseudomonas was noted. The dominant bacterial genera in cypermethrin-treated larvae were Lactococcus, Pantoea, while in insects exposed to chlorpyrifos or flonicamid it was Pseudomonas. Insecticide-treated larvae were characterized, on average, by higher biodiversity and richness of bacterial genera, compared to untreated insects. The depletion of CLB-associated bacteria resulted in a decrease in larval survival, especially after cypermethrin and chlorpyrifos treatments. The use of a metagenome-based functional prediction approach revealed a higher predicted function of bacterial acetyl-CoA C-acetyltransferase in flonicamid and chlorpyrifos-treated larvae and tRNA dimethyltransferase in cypermethrin-treated insects than in untreated insects.

Antioxidant and Secondary Metabolite Responses in Wheat under Cereal Leaf Beetle (Oulema melanopus L.) Infestation

AbstractWheat is one of the most important cereal crops grown in the Western Himalayas of India but its production is challenged by the insect “cereal leaf beetle (CLB)”. This study explores the impact of domestication and modern crop improvement on wheat's defense mechanisms against the CLB, a global threat to wheat cultivation. Sixteen diverse wheat genotypes having different ploidy levels were investigated, including wild wheat, landraces, mutants, advanced breeding lines, commercial varieties, and a Rye grass genotype. Genotypes with resistance genes, landraces, and wild wheat exhibited the lowest CLB infestation and oxidative damage. These genotypes displayed enhanced antioxidant enzyme activity, such as peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), and polyphenol oxidase (PPO), reduced reactive oxygen species (ROS) production, and increased plant secondary metabolite (phenol and tannin) production upon CLB infestation. Resistant durum wheat demonstrated moderate responses and exhibited higher levels of flavonoid production. On the other hand, susceptible durum wheat genotypes, commercial variety Shalimar Wheat‐02 (SW‐2), showed high CLB infestation, ROS production, reduced antioxidant enzyme and secondary metabolite production. This may be because modern varieties like SW‐2 were not selected for insect resistance. These findings emphasize the significance of preserving genetic diversity from wild wheat and landraces to bolster wheat breeding programs against pests such as CLB. This study underscores the need to harness ancestral wheat lines to enhance insect pest resistance in modern wheat cultivars.

Life history and host preferences of Tetrastichus julis (Walker) (Hymenoptera: Eulophidae), the principal parasitoid of the cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae)

Tetrastichus julis is the key larval endoparasitoid of the cereal leaf beetle, Oulema melanopus. The beetle has recently invaded cereal growing regions of western Canada, and classical biological control with T. julis is a viable management option. Although the general biology of T. julis is known, several knowledge gaps on life history traits still remain particularly in relation to host preferences and their consequences for parasitoid-beetle interactions. We investigated life history parameters and host preferences of T. julis with reference to a number of developmental parameters including survivorship, clutch size, ovipositional preferences for larval stages and their influences on realized clutch size of the parasitoid. Salient features of T. julis biology observed in this study were a short developmental time, a female-biased sex ratio, which is slightly more pronounced in larger instars, extended longevity of females, sibling mating, and more importantly, the capacity of females to live longer in the absence of hosts. The seasonal trend in parasitism rate of T. julis indicated a peak in activity in mid-June. This investigation revealed that T. julis females can discriminate among host instars and can adjust clutch size accordingly and to some extent increase production of females more than males in larger instars. In laboratory and field trials, given a choice, females laid more eggs in fourth instars than in first instars. The sex ratio was female biased and was positively correlated with clutch size. At least one male emerged from most clutches (>2) and sibling mating was common. Parasitism rates were higher after an exposure period of 48 h than 24 h. Mass rearing of T. julis can be enhanced by exposing mated T. julis females for at least 48 h to fourth-instar larvae of O. melanopus. Understanding T. julis biology can enhance mass rearing to relocate parasitoids and improve sustainable management of the cereal leaf beetle as it expands its geographic range.

Screening of Oats (Avena sativa) against Cereal Leaf Beetle within the Ranges of Himalayas of Kashmir

Cereal leaf beetle (Oulema melanopus L.) Chrysomelidae: Coleoptera is one of the devastating pests of wheat, oat and barley in Kashmir valley. Freezing temperatures of Kashmir valley are not suitable for double cropping in a single year. In these harsh winters, farmers are not able to feed their cattle fresh greens, to overcome the problem oats serve as best green fodder not only for cattle but now a days oats are preferred as dietary meal for people. Oats is encountered by various limiting factors, among which cereal leaf beetle has posed a threat in both quality and quantity as well. Hence, an experiment was laid to study the screening of four available varieties of Oats. Investigations were carried out at the farmers field near the Faculty of Agriculture, Wadura, Kashmir, India during 2021-22 under free choice conditions to evaluate the results. Among the evaluated varieties SKO-90 registered least damage of 17% followed by SABZAR (19%), however highest damage of (35%) was found on the cultivar KENT, it was closely followed by SKO-96 with leaf damage of (33%). It is advisable that, farmers should go through the two least damaged varieties of the oats and the chemical constituents responsible for the less damage need to identified through biochemical analysis.

Weak evidence for biocontrol spillover from both flower strips and grassy field margins in conventional cereals

Agri-environment measures such as flower strips are considered fundamental instruments to reduce farmland biodiversity loss. Their effect on associated ecosystem services, such as biocontrol of crop pests, has received increased attention in recent discussions on the ecological intensification of agriculture, to create a win-win situation for biodiversity and production. However, studies of flower strips are rarely compared to the status quo, namely permanent field margins. We assessed the impact of two different field margin types (pre-existing grassy field margins vs. perennial flower strips) and distance decay effects from the field margins towards field centres on two major cereal pests (cereal leaf beetles and cereal aphids), their natural enemies (predators and aphid parasitoids) and crop yield on five conventional farms in Germany. Proximity to both types of field margin enhanced the enemy-to-pest ratio for cereal leaf beetles but not for aphids. However, the parasitism rate for aphids was higher next to grassy strips than next to flower strips. Yield also tended to be higher adjacent to flower strips (although not significantly) and showed no variation with distance to the field margin. Our findings paint a more nuanced picture than most previous studies: whilst field margins generally had a positive impact on one of the studied biocontrol agents, flower strips do not outperform the standard grassy margins currently in place. To promote biocontrol services, we recommend protecting existing, permanent grassy strips through the EU Common Agricultural Policy as a cost-effective alternative to flower strips.

The Weather as an Indicator for Decision-Making Support Systems Regarding the Control of Cutworms in Beets and Cereal Leaf Beetles in Cereals and Their Adoption in Farming Practice

The requirements of integrated control clearly indicate the need to use all available non-chemical methods to protect crop plantations, before deciding on a chemical method. In addition, there is also a provision in the integrated protection guidelines about the need for monitoring and signalling of pests and the recommendation to use available decision support systems (DSS) in chemical protection. The decision-support system facilitates and assists the agricultural producer in fulfilling the above principles and guidelines. The Institute of Plant Protection-National Research Institute (IPP–NRI) has conducted a six-year research program to develop a scientific basis for supporting decisions to control cutworms (Agrotis segetum Schiff et. Den., and Agrotis exclamationis L.) in sugar beets and cereal leaf beetles (Oulema spp.) in cereals. Validation tests in field experiments have demonstrated their effectiveness and their suitability for agricultural practice. Thanks to the obtained results, farmers have access to knowledge supported by solid research and field tests. Based on the obtained results, applications have been developed that will be usable by producers. The applications will assist in deciding the need for chemical protection of sugar beet against cutworms and cereals against cereal leaf beetles, thus recommending treatment only when necessary.

Rows make the field: Winter wheat fields with manipulated crop architecture show potential for ecological intensification based on higher natural pest and weed seed control

Ecological intensification aims to reduce environmental costs of agricultural production by increasing biodiversity and using the associated ecosystem services instead of, or in combination with, external inputs, so that yields are maintained at high levels or increased. However, to date there are few measures available for which such benefits have already been demonstrated in the field.In this study, the seeding pattern in winter wheat fields was manipulated to create a diversified crop architecture consisting of ‘unsown-rows’ and ‘densely-sown-rows’ in treatment fields in comparison to ‘conventionally-sown-rows’ in control fields to assess whether (i) in-field structural and microclimatic conditions are more heterogeneous in fields with manipulated crop architecture compared to conventionally managed fields, (ii) a change in crop architecture is related to higher species richness, activity density and altered body size distribution of carabid communities, (iii) this in turn increases natural pest and weed seed control, but (iv) does not lead to yield loss.In-field structural and microclimatic conditions were more heterogeneous in treatment fields compared to control fields, which was associated with significantly increased body sizes of predatory carabids and a trend for increased predatory carabid species richness (in the ‘unsown-rows’ of treatment fields). These changes were related to significantly stronger pest suppression in the ‘densely-sown-rows’ of treatment fields compared to ‘conventionally-sown-rows’ in control fields, with 10 % higher experimental pest predation rates and 56 % reduced crop damage caused by cereal leaf beetles. Moreover, carabids known to consume weed seeds showed significantly higher activity densities in ‘unsown-rows’ compared to ‘conventionally-sown-rows’, which was related to significantly higher experimental weed seed predation in ‘densely-sown-rows’. Wheat yields were not significantly different in fields with or without manipulated crop architecture.The results suggest that the simple measure of manipulating the seeding pattern in winter wheat fields creates a diversified crop architecture, thereby promoting carabid diversity and altering their community composition and activity density such that important ecosystem services are increased without yield losses. Thus, beyond fostering biodiversity, this measure has, although not directly tested here, the potential for being used for ecological replacement of pesticides through enhanced ecosystem services without entailing agronomic and economic disadvantages such as land opportunity costs or increased workload.

Genetic analysis reveals conspecificity of two nominal species of Anaphes fairyflies (Hymenoptera: Mymaridae), egg parasitoids of Oulema leaf beetle (Coleoptera: Chrysomelidae) pests of cereal crops in Europe and of rice in East Asia.

Anaphes (Anaphes) flavipes (Foerster), a fairyfly (Hymenoptera: Mymaridae) native of Europe, is an economically important egg parasitoid for the natural control of Oulema spp. leaf beetle (Coleoptera: Chrysomelidae) pests of cereal crops such as barley, oats, rye, and wheat in Europe, and for the classical biological control of the invasive Oulema melanopus (L.) in North America. A morphologically very similar Anaphes (Anaphes) nipponicus Kuwayama, known from mainland China, Japan, Republic of Korea, Far East of Russia and Taiwan, is an egg parasitoid of Oulema oryzae (Kuwayama), a pest of rice mainly in temperate parts of East Asia. The nuclear 28S-D2 and ITS2 and the mitochondrial COI genes were used as markers to compare specimens of A. (Anaphes) flavipes reared from eggs of an Oulema sp. on barley in Germany with those of A. (Anaphes) nipponicus reared from eggs of O. oryzae on rice in Honshu Island, Japan. Because the resulting sequences are practically identical, within an expected intraspecific genetic variability, conspecificity of these two nominal species has been confirmed, and consequently A. (Anaphes) nipponicus Kuwayama, 1932, syn. n. is synonymized with A. (Anaphes) flavipes (Foerster, 1841). Taxonomic notes and illustrations are provided for the specimens of both sexes of A. (Anaphes) flavipes from Japan to facilitate their recognition.

Evaluation of two artificial defoliation methods to simulate damage by the cereal leaf beetle (Oulema melanopus) larvae in winter wheat

AbstractDefoliation reduces photosynthetic area, negatively effecting overall plant vitality, which at the end, severely impacts seed quality and production. The economic importance of the loss in winter wheat (Triticum aestivum L.) due to larvae of the cereal leaf beetle (Oulema melanopus, CLB) generated studies investigating the significance of the flag leaf. Simultaneously, the role of other leaves remains rather undiscovered. We simulated herbivory caused by CLB larvae in a two-year study between 2017 and 2018. We removed different amounts of leaf material from two winter wheat cultivars, either from the flag leaves only, or from all leaves. The impact of artificial defoliation was measured in grain production per ear, and related to natural CLB larval herbivory. Removing all leaves simulated CLB larval herbivory more closely than the artificial defoliation of flag leaves only. Our results suggest that the relative importance of flag leaves in seed production may be lower than previously assumed. Further studies involving various cultivars are invited to enhance the knowledge on the significance of the damage done by CLB larvae.

Insect Gut Bacteria Promoting the Growth of Tomato Plants (Solanum lycopersicum L.).

We investigated gut bacteria from three insect species for the presence of plant growth properties (PGP). Out of 146 bacterial strains obtained from 20 adult specimens of Scolytidae sp., 50 specimens of Oulema melanopus, and 150 specimens of Diabrotica virgifera, we selected 11 strains displaying the following: PGP, phosphate solubility, production of cellulase, siderophore, lipase, protease, and hydrogen cyanide. The strains were tested for growth promotion ability on tomato (Lycopersicon esculentum) plants. Each strain was tested individually, and all strains were tested together as a bacterial consortium. Tomato fruit yield was compared with the negative control. The plants treated with bacterial consortium showed a significant increase in fruit yield, in both number of fruits (+41%) and weight of fruits (+44%). The second highest yield was obtained for treatment with Serratia liquefaciens Dv032 strain, where the number and weight of yielded fruits increased by 35% and 30%, respectively. All selected 11 strains were obtained from Western Corn Rootworm (WCR), Diabrotica virgifera. The consortium comprised: Ewingella americana, Lactococcus garvieae, L. lactis, Pseudomonas putida, Serratia liquefaciens, and S. plymuthica. To our knowledge, this is the first successful application of D. virgifera gut bacteria for tomato plant growth stimulation that has been described.

TREATMENT OF CEREALS AND THEIR SEEDS WITH ACETAMIPRID BASED PREPARATIONS – AN EFFECTIVE METHOD OF PROTECTION FROM PESTS

The paper presents the results of evaluating the efficiency of insecticides for 2016–2021 containing acetamiprid as an active ingredient (a.i.) and its combination with compounds from other chemical groups in protecting cereals from dominant pests. It’s established that pre-sowing treatment of seeds with an insecticidal preparation contributed to a decrease in the damage caused by wireworm and cereal flies to winter wheat up to 87,0 % and up to 69,9 %, to spring barley – up to 91,5 % and up to 80,9 %, respectively; insecticidal and fungicidal preparation used in winter cereals – up to 93,1 % and in spring cereals – up to 91,4 %. The results of production experiments on winter wheat and triticale demonstrated a high efficiency of King Combi, SC in reducing the damage caused by larvae of ground beetle (by 85,9–90,2 %) and cutworm (by 80,9–84,1 %) and the number of phytophages – by 73,3 % and 90,0 % respectively.&#x0D; When vegetating plants are treated with two-component insecticides containing acetamiprid, the damage caused by corn flies to spring cereals stems decreased up to 93,3 %, the number of fleas – up to 93,8 %. The biological effect in reducing the number of cereal leaf beetle larvae in winter crops with the use of the studied toxicants was 80,3–100 %, in spring crops – 81,0–100 %, the number of plant lice amounted to 98,8 % in spring barley and up to 99, 4 % – in spring wheat.

Creation of the initial breeding material of soft winter wheat with a complex of economically valuable traits

Purpose. Creation of new breeding material of soft winter wheat, highly resistant to diseases of the ear and pest colonization for use in the breeding process. Methods. The studies were carried out in 2017–2020 under conditions of artificial inoculation of wheat plants with pathogens of common bunt and fusariosis of the ear in field infectious nurseries of the Department of Plant Protection of the V. M. Remeslo Institute of Wheat of NAAS. An artificial infectious background of common bunt was created according to the method of A. I. Borggard-Anpilogov, which consists in contamination of seed material with spores several days before sowing. An artificial infectious background of fusarium ear blight was created by spraying soft winter wheat plants in the flowering phase with a suspension of spores isolated from the local pathogen population. Results. According to the results of the conducted research, highly resistant (up to 5% ear dama­ge) combinations of hybrids of the fourth generation of soft wheat were selected against the causative agent of fusarium: ‘Berehynia Myronivska’ / ‘Nobeoka bozu’ had a thrips population of 5.2 ind./ear, and cereal leaf beetle – 35,0 ind./m2 and ‘Horly­tsia myronivska’ / ‘C-Lokia’, the thrips population of which was 5.0 ind./ear, cereal leaf beetle – 2.0 ind./m2. On an artificial infectious background of fourth-generation hybrids, in terms of resistance to common bunt, the crossing combinations ‘Berehynia Myronivska’ / ‘Horianka’, ‘Lehenda Myronivska’ / ‘Nana’ were selected, which were affected by common bunt from 15 to 20%, and thrips population was 2.8–8.6 ind./ear, cereal leaf beetle – 5.0–6.0 ind./m2. The highest indicators of the length of the ear, the number of grains in the ear and the mass of grain from the ear were obtained in the combinations of ‘Oberih Myronivskyi’ / ‘Maris Templer’ and ‘Berehynia Myronivska’ / ‘Horianka’, which were created in accordance with the breeding programs of soft winter wheat for resistance against fusarium head blight and common bunt. Conclusions. The constant lines of soft winter wheat, isolated by complex resistance against diseases and pests, are used in the breeding process of the V. M. Remeslo Institute of Wheat of NAAS and the National Center of Plant Genetic Resources of Ukraine (The Plant Production Institute named after V. Ya. Yuriev, Kharkiv).

The Impact of Oulema melanopus—Associated Bacteria on the Wheat Defense Response to the Feeding of Their Insect Hosts

Wheat production is threatened by the destructive effects of numerous pests, including Oulema melanopus (cereal leaf beetle, CLB). Both adults and larvae of CLB damage grain crops, but the target of insecticide treatments are the larvae. Insect-associated bacteria are important for many of the insects’ life processes and may also modulate plant defense responses to feeding of their insect host. The aim of our study was to elucidate the early wheat plants’ reaction to this herbivore feeding and to disclose the CLB-associated bacteria modulation of the wheat-insect interactions. Transcriptome analyses were performed for the leaves wounded mechanically and by feeding of the CLB larvae as well as for the distal leaves to study both, the plant’s local and systemic response. Comparative transcriptome analysis indicated that 24 h after the plant treatment, a much larger number of up-regulated DEGs in damaged leaves was noted, especially those on which larvae were fed. It may suggest that at the analysed time point, the local response was stronger than the systemic one. In the leaves on which larvae with natural bacterial flora were fed (local response), the number of up- and down-regulated differentially expressed genes (DEGs) was 7136 and 7411, respectively, in comparison to the dataset obtained for the leaves wounded by larvae with a reduced number of bacteria. In the distal leaves, 3015 up- and 2372 down-regulated DEGs were noted. CLB-associated bacteria were found to affect many aspects of the physiology of wheat plants, especially in wounded leaves, including the expression of genes related to primary metabolism, phytohormone signaling and photosynthesis. We also observed that CLB-associated bacteria mitigated numerous anti-herbivore processes and pathways associated with the synthesis of metabolites and proteins, potentially harmful to the insects. The bacteria also reversed the expression of some genes involved, inter alia, in the phosphorylation of proteins, oxidative stress, cell wall organization, and biogenesis. Understanding the role of CLB-associated bacteria in the plant’s defense response will be important to the fields of pest control and herbivore and its host ecology and evolution.

Physiological Responses Manifested by Some Conventional Stress Parameters and Biophoton Emission in Winter Wheat as a Consequence of Cereal Leaf Beetle Infestation.

Oulema melanopus L. (Coleoptera: Chrysomelidae) is one of the most serious pests of winter wheat that causes peeling of the epidermis and tissue loss. The complex mapping of the physiological responses triggered by O. melanopus as a biotic stressor in winter wheat has not been fully explored with the help of non-invasive imaging and analytical assays, yet. The aim of the present work was to study the effect of O. melanopus on the physiological processes of winter wheat, especially on the extent of lipid peroxidation and antioxidant activity derived from tissue destruction, as well as photosynthetic ability. The results of the measurements enabled the identification of the antioxidant and lipid-oxidation–related physiological reactions, and they were reflected in the dynamics of non-invasive biophoton emissions. Our non-invasive approach pointed out that in the case of O. melanopus infestation the damage is manifested in tissue loss and the systemic signaling of the biotic stress may have reached other plant parts as well, which was confirmed by the results of antioxidant capacity measurements. These results indicate that the plant reacts to the biotic stress at a whole organizational level. We identified that the antioxidant and lipid-oxidation–related physiological reactions were reflected in the dynamics of two aspects of biophoton emission: delayed fluorescence and ultra-weak bioluminescence. Our research further supported that the non-invasive approach to stress assessment may complete and detail the traditional stress indicators.

Crop diversity increases predator abundance but not predation on cereal leaf beetles in agricultural landscapes

Crop diversity increases predator abundance but not predation on cereal leaf beetles in agricultural landscapes