Plant Infestation Research Articles

Screening and efficacy evaluation of antagonistic fungi against Phytophthora infestans and combination with arbuscular mycorrhizal fungi for biocontrol of late blight in potato

Late blight caused by Phytophthora infestans is the most devastating disease of potato crops worldwide. Control practices mostly rely on synthetic fungicides or copper-based products. In recent years, biological control agents have generated significant enthusiasm as eco-friendly sustainable alternatives. Here, the filtrates of 149 filamentous fungi and yeasts were tested in vitro against P. infestans MUCL 54981. The most effective filtrates were then combined in alginate beads with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis MUCL 41833 and tested in vitro for their compatibility, and finally in the greenhouse for their efficacy against P. infestans. The filtrates of Penicillium aurantiogriseum MUCL 47586, Penicillium griseofulvum MUCL 29201, Trichoderma virens MUCL 18139, and Verticillium psalliotae MUCL 18310 totally suppressed conidial germination and growth of P. infestans in vitro. In whole potato plants in vitro, only the filtrate of T. virens significantly suppressed P. infestans plant infestation. With the exception of P. griseofulvum, none of the selected filtrates affected the germination, root colonization, and spore production of R. irregularis following their combined entrapment in alginate beads. According to these results, the filtrate of T. virens was selected for the greenhouse experiment with the potato variety Annabelle. The filtrate was used as leaf spray and/or as root treatment in combination with R. irregularis entrapped in alginate beads. Root treatments with AMF alone as well as with the AMF entrapped with the filtrate of T. virens significantly reduced the area under disease progress curve compared to the non-treated plants. LC-MS analyses of the filtrate showed the production of koninginin D, gliotoxin, and koningic acid, three antifungal compounds, which could have impacted P. infestans. Conversely, foliar application of the filtrate, whether the plant was colonized by the AMF or not, did not reduce symptoms of the disease, possibly because of the greenhouse growth conditions making the potato plants more susceptible to P. infestans and counterbalancing the positive effects of the antimicrobial secondary metabolites or AMF. Our results demonstrated the potential of R. irregularis MUCL 41833 combined or not with a filtrate of T. virens MUCL 18139 into alginate beads as a biological control strategy against P. infestans.

Preliminary Survey of Parasitism of Leaf Roller, Sylepta derogata (Fabricius) (Lepidoptera: Pyralidae) in Roselle (Hibiscus sabdariffa L. (Malvales: Malvaceae) in Maiduguri, Nigeria

This study was carried out in Maiduguri in north eastern Nigeria during the cropping seasons of 2018 and 2019 to determine the seasonal infestation rate, larval abundance and parasitism of Syleptaderogata (Fabricius) (Lepidoptera: Pyralidae) in roselle, Hibiscus sabdariffaL. Data collection was from 30 farmer fields planted with roselle plants. Data on plant infestation, pest abundance and parasitism were analyzed using Kruskal-Wallis test. Mean percent plant infestation by S. derogataper farmers’ field ranged from 84% in 2019 to 88% in 2018, and was not significantly different between years. Mean number of S. derogata larvae per farmers’ field was significantly higher in 2018 (83) than in 2019 (69). In both years, parasitization by microgastrinae was high (97%-98%), whilst that by Bracon sp. was low (2%-3%). Mean total larval parasitism per farmers’ field significantly varied between years, and was particularly higher (18%) in 2018 than in 2019 (5%). In conclusion, results indicate that S. derogata is seasonally responsible for heavy infestation of roselle plants in parts of north eastern Nigeria. Microgastrinae accounts for a high proportion of host parasitization, whilst that by Bracon sp. is negligible. Total larval parasitism is seasonally low, and insufficient to control this pest in roselle grown in this locality.

Field evaluation of promising mutants of mungbean against Fela Beetle, Aphid and POD Borer

Experiment was conducted at the Agricultural Farm of Patuakhali Science and Technology University to know the morphological characteristics of different mutants of mungbean and to find out tolerant/least susceptible mutant(s) against flea beetle, aphid and pod borer based on the reaction of insect pests to promising mutants of mungbean during the period from April to June, 2015. The mutant MBM-07(S)-2 was found to be the tallest (32.57 cm) with highest number of branches/plant (5.03), highest number of leaves/plant (11.06) among all mutants and check variety while MBM-07-Y-2 (23.40 cm) was the shortest plant height, MBM-656-51-2 had the lowest number of branches/plant (3.73), MBM-347-13 (7.03) had the lowest number of leaves/plant. The mutant MBM-427-87-3 had the highest number of pods (5.00) compared to other mutants but MBM-656-51-2 had the lowest number of pods/plant (3.09). Significantly the highest pod length and the highest number of seeds/pod were recorded in the mutant MBM-07-Y-1 (6.37 cm) while the lowest pod length (5.19 cm) was in MBM-80(LCAL) and lowest number of seeds/pod was in the mutant MBM-390-94-Y (5.34). Mutant MBM-347-13 had the lowest population of flea beetle (18.00) and pod borer (2.00) compared to all other mutants while the lowest number of aphid/plant was observed in mutant MBM-07-Y-1 (1.00). In case of infestation, the mutant MBM-347-13 had the lowest percentage of infestation (20.69%) by flea beetle, (3.18%) by pod borer but the lowest infestation by aphid (3.33%) was recorded in the mutant MBM-390-94-Y while the mutant MBM-427-87-3 had the highest percentage of plant infestation (37.80%) by flea beetle, pod damage (9.69%) by pod borer and variety BARI moog-6 had the highest percentage (34.45%) of plant infestation by aphid. Mutant MBM-347-13 was least susceptible to flea beetle and pod borer while mutant MBM-427-87-3 was highly susceptible to flea beetle and pod borer. However, mutant MBM-390-94-Yand MBM-07-Y-2 were less susceptible to aphid while BARI moog-6 and mutant MBM-427-87-3 were highly susceptible to aphid. SAARC J. Agric., 20(1): 97-106 (2022)

Genetic variability and correlation analysis in F2 segregating population in brinjal (Solanum melongena L.)

Genetic advance denotes the improvement in the mean genotypic values of selected families over the base population. Thus, it helps the breeder select the progenies in the earlier generation. The objective of the study was to analyse the heritability, genetic advance and genetic variability for ten traits in brinjal contributing to fruit yield were studied in the F2 population obtained from the cross of Sevathampatti local x Seetipulam local. The study examined the subsistence of a significant extent of genetic variability for the traits considered. The characteristics of brinjal exhibited higher values of genotypic variation (GCV), viz., the height of the plant (20.93), yield per plant (17.42), number of branches (22.73) and shoot infestation (56.39) and phenotypic coefficient of variation (PCV) viz., the height of the plant (21.10), yield per plant (22.32), number of branches (23.42) and shoot infestation (57.24). However, the number of branches (45.44 %), height of the plant (42.76%), number of fruits (38.58%), fruit yield (28.02%) and shoot infestation (114.4%) exhibited high estimates of genetic advance and heritability for plant height (98.36), number of branches per plant (94.19) and shoot infestation (97.06). These characteristics can be effectively improved through selection. Association analysis mentioned that the yield of the fruit was significantly and positively correlated with the number of fruits, number of branches, individual fruits per plant and fruit girth. Direct selection may be executed because of these characteristics as the key choice of criteria to minimize the indirect result of additional traits throughout the improvement of high yielding varieties.

Determination of spider mite abundance in soil of field-grown cucumbers and in plants under predatory mite pressure in invasive infestations using HRM real-time PCR assay

The two spotted spider mite, Tetranychus urticae Koch L. (Acari: Tetranychidae), is a plant pest that can lead to severe economic losses in open field cucumber cultivation. Between 2017 and 2019 we studied the abundance of spider mites in the soil to estimate the potential infestation pressure of soil colonizing spider mites. The spider mites were heterogeneously distributed in small concentrations in the soil. Soil colonizing spider mites did not affect spider mite abundance on plants and reversed. We observed that spider mite migration occurred primarily from the edge of the field adjacent to the weed strip. In 2020 and 2021, we investigated the efficacy of the predatory mite Neoseiulus californicus (McGregor) for suppressing spider mite hotspots in the cropland. We compared untreated spider mite hotspots with N. californicus treated hotspots and showed that a single release of predatory mites could result in a high level of control when spider mite infestation density was initially high. With this study, soil can be ruled out as a habitat for spider mites, and attention to spider mite pest control can be directed to plant infestations. The highly sensitive HRM real-time PCR assay was used for the quantification of the spider mites.

Infestation of soft spring wheat by leaf diseases depending on nitrogen nutrition

Infestation of soft spring wheat plants depends on the growth stage and weather conditions of the growing season. Plants have the highest resistance to brown rust in the tillering stage. Brown rust developed in 2014 throughout the growing season. The lowest infestation intensity was during tillering – booting stage, which did not change from the experiment variant – 5.0 %. The lowest spread of brown rust was in the tillering stage – 10 %, in the booting stage – 40 %. The resistance was assessed 8 points. In the earing stage, the infestation intensity increased in no fertilizer variants and P30K30 to 8.0–8.2 % or by 60 % with a resistance of 7 points. This indicator in the variants with nitrogen fertilizers was 4.1–4.3 % with a resistance of 8 points, but all stems were infected (100 % spread). Affected leaves were in the middle layer, as their resistance by E. E. Saari and J. M. Prescott scale was at 5 points. Plants had the least resistance to brown rust in the milk stage of soft spring wheat grain. The intensity increased to 15.2–18.7 % or 2.1–4.7 times compared to the earing stage. The lowest resistance was assessed 6 points. All leaves were affected (resistance by E. E. Saari and J. M. Prescott scale – 1 point). In 2015, brown rust appeared in the milk stage of soft spring wheat grain. However, the infestation intensity was insignifcant – 5.0–6.5 % depending on the experiment variant. The prevalence of brown rust decreased from 60 % in unfertilized areas to 30 % on phosphorus–potassium background and up to 10 % with nitrogen fertilizers. Plant resistance was high – 7–8 points depending on the experiment variant. Powdery mildew develops throughout the growing season of both research years. In 2014, the infestation intensity is the lowest in the tillering stage – 7.7–8.0 % with 50 % spread, with the resistance of 7 points. In the booting stage of plants, the infestation intensity increased to 44.1–46.8 % or 5.8–5.9 times compared to the tillering stage. All plants were affected, and the resistance was 3 points. In subsequent stages of growth, the intensity of powdery mildew increased. Thus, in the earing stage this indicator increased to 65.1–69.2 % or 8.5–8.7 times, and in the milk stage – 9.5–9.7 times compared to tillering depending on the fertilizer. The stems of soft spring wheat were all affected, and the resistance was 2 points. Key words: brown leaf rust, powdery mildew, infestation intensity, spread, resistance.

Fast improvement of macrofauna communities and soil quality in plantain crops converted to agroecological practices

Plantain (Musa paradisiaca AAB) is one of the main staple food crops in tropical areas, particularly in the Caribbean region. Therefore, supporting a sustainable production of plantain in this zone is crucial to secure food and to provide income to millions of people. We hypothesized that agroecological practices based on multi-functionality and biodiversity and that preserve soil should i) increase macrofauna abundance, ii) enhance soil chemical fertility, iii) improve soil physical structure, iv) reduce plant infestation by parasitic nematodes, and v) immediately achieve similar yield as in conventional systems. For this purpose, we compared plantain conventional and agroecological systems at the farm scale. The agroecological system consisted in a combination of three innovations: i) inputs of vermicompost to replace mineral fertilizers, ii) use of healthy planting material and iii) use of a mulching of living crop to control weeds. Ten months after the plantation, soil macrofauna abundance had doubled and taxonomic richness had increased by 45% in the agroecological system. In addition, soil structure was improved in the agroecological system (52% of biogenic aggregates in the agroecological system vs. 21 % in conventional systems), as well as the abundance of free-living nematodes associated to plantain roots increased by 73 % in the agroecological system. The abundance of Radopholus similis, one of main plant parasitic nematodes, decreased in the agroecological system. Moreover, the agroecological system achieved similar crop yield level than conventional systems. Agroecological practices are thus an efficient option to allow a fast transition from conventional to environmentally friendly cropping systems.

IMPROVING POTATO PRODUCTION TECHNOLOGY BY OPTIMISING THE USE OF ORGANOMINERAL GROWTH STIMULANTS IN THE FOREST-STEPPE ZONE OF WESTERN SIBERIA

In the article experience of application of various organomineral growth stimulants on potatoes in the conditions of forest-steppe of Western Siberia is stated. In the course of work, the authors used new perspective preparations whose application has an essential influence on growth, development, the structure of a crop, and potato productivity. As a result of work, it has been established, that organomineral growth stimulants slightly influence the duration of the vegetation period of potatoes (1-3 days). The authors found that the infestation and spread of diseases in potato crops depended to a greater extent on the conditions of the year and the preparations used, and to a lesser extent on the variety. On average, the overall degree of plant infestation on the treated background was 2-8 % lower compared to the control. The use of organomineral growth regulators has a positive effect on potato yields. The Epin-Extra preparation was the most effective, application of which provided up to 8.3 t/ha yield increase at tubers treatment, and up to 7.2 t/ha at vegetative plants treatment. The use of organomineral growth regulators does not have a significant impact on quality indicators of potatoes, as the difference between the variants was not more than 1 %.

Impacts of zebra chip disease and irrigation on leaf physiological traits in potato

Zebra chip disease (ZC) is caused by the fastidious, phloem-limited, bacterial pathogen ‘Candidatus Liberibacter solanacearum (Lso), which is transmitted from plant to plant by the potato psyllid (Bactericera cockerelli (Sulc)). Understanding how ZC impacts potato (Solanum tuberosum L.) physiology, could help growers in making more informed crop management decisions. Measurements of instantaneous leaf physiological responses, such as photosynthetic CO2 uptake and transpiration on the leaf surface, can be used not only for fast screening of affected plants in the field but also for optimizing irrigation management. Over the 2019 and 2020 field seasons, we characterized time-course photosynthetic physiological responses of potato plants infested by potato psyllids (B. cockerelli (Sulc)) carrying the Lso haplotypes A+B. Potato plants were subjected to different variable-rate irrigation (VRI) treatments (100%, 80%, and 60% of field capacity of the soil) through a center-pivot sprinkler system to examine the impact of the disease on key physiological parameters of photosynthesis and transpiration. Leaf and air temperatures, and hyperspectral profiles of the canopy were also measured and compared. The measurements were made during midday weekly from 25 to 50 days after plant infestation (DAI) with bacteriliferous psyllids. The results showed that many of the measured variables, including stomatal conductance, photosynthesis rate, transpiration rate, quantum yields, and normalized difference in vegetation index started to decrease beginning approximately 28–35 DAI, gradually worsening until 50 DAI, in both 2019 and 2020, as the infection proceeded. The decreases in stomatal conductance in infected plants led to decreases in photosynthesis and transpiration. In turn, reduced transpiration resulted in increased leaf temperature due to decrease in evaporative cooling on the leaf surface. Higher leaf temperatures under hot and dry conditions with high light intensity during the daytime would further reduce photosynthetic light harvesting, which is supported by our data, indicating the damage to the photosynthetic pigment formation and machinery. These findings support the previous report that increased leaf temperature in infected plants may have been derived from the closure of stomata in hypersensitive reactions to infection. These stomatal responses were detected within 28 DAI, a week earlier than the differences in hyperspectral profiles observed 35 DAI, and could be implemented in early disease detection strategiesusing measurements of leaf temperature.

Pratylenchus brachyurus Suppression by Organic Fertilizers and the Development of Soybean Plants

The root lesion nematode, Pratylenchus brachyurus (Godfrey) Filipjev & Schuurmans Stekhoven, has been caused significant losses in soybean crops in Brazil. The addition of organic fertilizers may suppress the population of these plant-parasitic nematodes. The aim of this work was to evaluate the action of cattle manure, cattle vermicompost, cattle compost, and slaughterhouse swine compost on the reduction of P. brachyurus population and the development in soybean plants (cv. NR 5909). The experiment was conducted for 90 days after P. brachyurus inoculation (DAI) in the pots, in greenhouse. At 90 DAI, shoots, roots and soil were collected from all experimental units to determine shoot dry matter, root fresh mass and nematodes quantification present in roots and soil. All the organic fertilizers promoted the increase of shoot dry matter and root fresh mass in relation to control, even under nematode infestation in soybean plants (cv. NR 5909). However, organic fertilizers did not promote a suppressive effect on P. brachyurus population in soybean plants.

THE EFFECTIVENESS OF THE USE OF BIOLOGICAL PRODUCTS IN WINTER WHEAT CROPS IN THE CONDITIONS OF THE RIGHT-BANK FOREST-STEPPE

This article presents the results of studies of the effectiveness of the use of biological products in winter wheat crops. The positive effect of pre-sowing seed inoculation with biological products Azotofit and Help Growth on the germination capacity of winter wheat seeds of the Skagen variety has been established which was 3-4% higher than the control and contributed to an increase in the number of nodal roots by 56% and 50%, respectively, the plant density was 13-9 pcs / m2 more than in the control. In the variants Azotofit and Help Growth, productive tillering was higher by 0.3-0.2 stems / plant. compared with the control, and the infestation of plants by root rot was 6.6-4.7%, respectively. It was established that an increase in winter hardiness as a result of pre-sowing inoculation of winter wheat seeds, which was 93.2-94.5%, respectively, which was 2.7-4% higher than the control indicator and overwintering of plants, which was 546-521 pcs / m2, which 111-85 pieces / m2 more compared to the control. The combination of pre-sowing inoculation with biological products Azotofit, Help Growth and feeding with Organic Balance (during spring tillering) had a positive effect on the bushiness of plants and their productivity, which, in the variant providing for pre-sowing inoculation of seeds with the biological product Azotofit and feeding with Organic Balance, was 580 which is 102 pcs / m2 higher than the control indicator. The use of the studied preparations contributed to the better spring tillering of winter wheat plants and the number of productive stems, in particular, the combination of pre-sowing inoculation, respectively, with the biological products Azotofit and Help. Growth and feeding Organic balance (during the spring tillering period), the number of productive stems is 535-540 pcs / m2, which is 112-117 pcs / m2 more than in the control. The use of the studied biological products had a positive effect on the elements of the structure of the crop, in particular, an increase in the number of grains per spike, the mass of grain per spike and the mass of 1000 grains was noted, which ultimately contributed to obtaining the highest yield of winter wheat, which in the application of Azotofit and Help Growth was 5.64-5.82 t / ha, respectively, which is 0.48-0.66 t / ha more than in the control. When feeding in the tillering phase with Organic, the yield balance was 5.63 t / ha, which is 0.47 t / ha higher than in the control. With a combination of presowing inoculation, respectively, with the biological products Azotofit and Help Growth and feeding Organic balance (during the spring tillering period), the yield was 6.21-6.38 g, which is 1.09-1.22 t / ha more than in the control.

Effectiveness of insecticides against pests of white cabbage grown using seedling technology

Among the two methods of growing white cabbage, the seedling technology is more widely used in North-Western Russia. Watering seedlings in cassettes with a systemic formulation of neonicotinoid insecticide Actara, WDG (250 g/kg thiamethoxam) prior to planting has been developed to protect white cabbage from early spring pests: flea beetles of the genus of Phyllotreta and the cabbage root fly. This approach is widely used by commercial growers and its efficacy requires monitoring under current conditions because of a possibility of resistance development. Testing Actara, WDG in 2019 and 2021 at the experimental field of All-Russian Institute of Plant Protection didn’t show any significant decrease of biological effectiveness of seedling treatment. Testing biological effectiveness of systemic insecticides belonging to the chemical class of carbamates Lannate, WSP (250 g/kg metomil) and the new class isoxazolines isocycloseram was carried out in parallel. Biological effectiveness of the latter insecticide was higher compared to Actara against the flea beetles and the cabbage root fly during a 21-day period. In addition, plant infestation with diamondback moth decreased. Efficacy indices of Lannate were significantly lower. Isocycloseram shows a good potential for inclusion into the Index of Registered Formulations of the Russian Federation to protect cabbage against a complex of insect pests. Having an additional active ingredient available to farmers will be begenicial for developing rotation schemes to combat pest resistance.

Stem solidness as an important factor for wheat protection from European wheat stem sawfly (Cephus pygmaeus L.) in Altai

Background. European wheat stem sawfly (Cephus pygmaeus L.) is the main pest of wheat in Altai Territory, Russia. Resistance of host plants to this insect is based on a solid stem. The effect of a solid stem on the infestation of wheat stem sawfly larvae and on agronomic traits of spring bread wheat under the conditions of Altai Territory has not been studied.Materials and methods. The study was conducted on the experimental field of the Federal Altai Scientific Centre of Agro-BioTechnologies, Barnaul, Russia, in 2019–2021. The index of stem solidness was assessed according to a 20 point scale. The interplay between stem solidness and wheat stem sawfly larvae infestation of wheat plants was studied on 12 genotypes. The effect of stem solidness on agronomic traits was studied on 6 pairs of sister lines. One hundred cultivars were studied for the stem solidness index and 184 cultivars were tested for their resistance to wheat stem sawfly.Results. Stem solidness negatively correlated with wheat stem sawfly infestation (Spearman’s rank correlation coefficient was rs = –0.77 in 2019 and rs = –0.80 in 2020). Sister lines with a solid stem had significantly shorter plant height (–5 cm), less kernels per spikelet (–0.11 kernels), 1000 grain weight (–1.7 g) and grain weight per spike (–0.08 g), but higher grain weight per tiller spike (+0.11 g), compared to sister lines with a hollow stem averaged over two years. Stem solidness had no negative effect on yield or grain quality. Eleven cultivars with a solid stem index higher than 15 points were identified (‘Ershovskaya 33’, ‘Izera’, ‘Kvintus’, ‘KWS Akvilon’, ‘Tybalt’, ‘Cunningham’, ‘KW 240-3-13’, ‘KWS 3.13’, ‘Lillian’, ‘Sparrow’, ‘WW-4’).Conclusion. Stem solidness significantly decreases the damage from wheat stem sawfly and has no negative effect on yield or gluten and protein content in grain. The abovementioned cultivars with a solid stem are recommended for use in breeding for resistance to wheat stem sawfly.

Effectiveness of combining bioacaricides with sprinkler irrigation to control the red spider mite, <em>Tetranychus evansi</em> Baker and Pritchard (Acari: Tetranychidae), in irrigated tomato crops in Burkina Faso, West Africa

Tomato production plays an important role in Burkina Faso by contributing to food security and increasing farmers’ income. However, this crop is susceptible to several pests among which Tetranychus evansi Baker and Pritchard is of economic importance. The present study carried out in the commune of Yako, an important tomato production area in northern Burkina Faso, aims to evaluate the outcome of combining a bioacaricide (Biopiq) from plant origin with sprinkler irrigation in the view of an integrated control of T. evansi in tomato irrigated crops. The experimental design consisted of six treatments in four replications including sprinkler irrigation, gravity irrigation, Acarius (abamectin-based commercial acaricide used as positive control) and Biopiq (plant-based acaricide) sprayings and the combination of each acaricide with both irrigation techniques. Observations made from tomato transplanting to harvest included T. evansi density/ leaf, plant infestation levels, leaf damage index, plant production parameters such as numbers of leaves, flowers and fruits and yield assessment. Results showed that the combination of Acarius and Biopiq with sprinkler irrigation significantly reduced density and damage caused by T. evansi. These treatments also produced similar and significantly higher yields (14,875±1,982 kg/ha; 14,687±924kg/ha respectively) compared to other treatments. These results lead to promising prospects for the control of T. evansi in irrigated tomato crops in West Africa. The strategies for an optimal use of these findings on a large scale through an integrated management approach remain to be defined.

Infestation and host specificity of mistletoe parasitic plants in Purwodadi Botanic Garden

Mistletoes are aerial hemiparasitic plant that infesting and parasitizing on wild and cultivated plants. They are can be categorized as generalist and specialist mistletoes according to their host plants diversity. Shannon index of the host plants diversity can be used to determine host specificity of mistletoes. Study aimed to know and determine host plants and host specificity of mistletoes in Purwodadi Botanic Garden was conducted in 2013, 2017 and 2021. Data of mistletoes and their hosts species was collected by explorative and descriptive methods in 2013, 2017, and 2021. Recorded data by observation in the fields were species and species number of mistletoes and their hosts. Observation of the misteltoes used binoculars to ditermine the species of the mistletoes. Identification of the mistletoes species and their hosts was conducted directly in the garden and undirectly by making herbarium specimens and taking photographs. The results showed that there were five species of mistletoes infested 142 species, 82 genera and 36 families of host plants namely Dendrophthoe pentandra, Macrosolen tetragonus, Scurrula atropurpurea, Viscum articulatum, and Viscum ovalifolium. There were significantly different between the mistletoe species and their Shannon index of host plants . D. pentandra was the most generalist or the least specialist to host plants with the highest Shannon index value of 2.20±0.10, whereas S. atropurpurea was the least generalist or the most specialist with Shannon index value of 0.16±0.09.

Efectiveness of Huminatrin application on grain crops in the foreststeppe of Novosibirsk Priobye region

At present, it is of particular importance to further increase the yield and quality of grain crops under experimental conditions in Western Siberia. Of special meaning is finding new effective growth regulators and bio-fertilizers that promote ecological plasticity, resistance to environmental stressors and pests. The work aims to study the influence of the new biofertilizer Huminatrin on growth and development features, yield and quality of grain crops under conditions of increasing crop productivity in the northern forest-steppe of the Novosibirsk Priobye region. Experimental field was on the fields of JSC “Irmen” livestock breeding farm in Ordynsky district of Novosibirsk region. The authors determined that Huminatrin (a mixture of micronutrients and bacteria) provides an increase in leaf surface parameters in two varieties of wheat by 23% and in spring barley by 34%. The authors treated soil with Huminatrin before sowing in a dose of 2 l/t at operating-liquid flow rate of 10 l/t and during the growing season in the phases of tillering and earing in a dose of 1.5 l/ha (300 l/ha). It was shown that both wheat varieties and spring barley variety “Biom” significantly increased the yield on the background of Huminatrin. On average, the yield increased by 22%. When using Huminatrin, the authors observed an increase in the number of productive stems (up to 408 mg/m2), the number of grains in the ear (up to 32 pcs), weight of 1000 grains (up to 40.86 g). There was also an increase in gluten content - up to 34%; gluten deformation index was about 96. In addition, the authors note the reduction of plant infestation by brown rust to 28% against 47% in the control (water). Indicators such as weight of 1000 grains, weight of grains per plant, the number of grains in the ear form the quality of the crop. Application of Huminatrin allows to achieve high yield quality of two varieties: spring soft wheat and spring barley

Biotic stress caused by Tetranychus urticae mites elevates the quantity of secondary metabolites, cannabinoids and terpenes, in Cannabis sativa L.

Secondary metabolites are known to play a role in the plant's defense system, which can be triggered by biotic or abiotic stress. Cannabis (Cannabis sativa L.) plants and mainly their female flowers, have a variety of bioactive metabolites, predominantly cannabinoids and terpenes, which are synthesized and secreted by the trichomes. Many studies have examined their chemistry and bioactive effects; however, there is insufficient information on the effect of biotic stress on the presence of secondary metabolites in cannabis. The present study examined the effect of a well-known cannabis pest, Tetranychus urticae, on the occurrence and concentration of cannabinoids and terpenes in cannabis leaves and flowers. Six cannabis plants were infested with T. urticae mites (treatment group), and six plants were used as the control group. Cannabinoids and terpenes were analyzed and quantified by liquid chromatograph mass spectrometer and gas chromatograph mass spectrometer, respectively. The contents of several cannabinoids and terpenes increased significantly in the leaves of the treatment group of plants in their late vegetative phase as the mite population increased, compared with the control group. Significantly increased content of almost all terpenes, and the cannabinoids; Δ9-tetrahydrocannabinol, cannabichromene, and cannabigerol, was also seen in mature flowers of the treatment group plants, compared with the control group. Thus, cannabis plant infestation has an impact on its secondary metabolites, cannabinoids and terpenes, reflected by an overall increase in these compounds.

Change in the Physiological and Biochemical Aspects of Tomato Caused by Infestation by Cryptic Species of Bemisia tabaci MED and MEAM1.

Simple SummaryBemisia tabaci is a polyphagous pest with cryptic species that infest various agricultural crops worldwide. Among the cryptic species, MED and MEAM1 are the most invasive, causing large production losses due to the feeding and transmission of the virus. We aimed to analyze the influence of these insects on the physiology and biochemistry of tomato. We found that the cryptic species MED caused considerable reduction in CO2 assimilation rates, stomatal conductance, and instantaneous carboxylation efficiency. Furthermore, plants infested with MED showed high activity of the enzymes peroxidase and polyphenol oxidase, which are considered expressions of plant defense. In contrast, plants infested with MEAM1 showed low peroxidase activity, which may result in a less lignified feeding place.Infestation by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes damage to tomatoes with production losses of up to 100%, affecting the physiological and biochemical aspects of host plants. The objective of this study was to analyze the influence of infestation of cryptic species of B. tabaci MED and MEAM1 on the physiological and biochemical aspects of tomato. Tomato plants ‘Santa Adélia Super’ infested with B. tabaci (MED and MEAM1), and non-infested plants were evaluated for differences in gas exchange, chlorophyll - a fluorescence of photosystem II (PSII), and biochemical factors (total phenols, total flavonoids, superoxide dismutase—SOD, peroxidase—POD, and polyphenol oxidase—PPO). Plants infested with B. tabaci MED showed low rates of CO2 assimilation and stomatal conductance of 55% and 52%, respectively. The instantaneous carboxylation efficiency was reduced by 40% in MED and by 60% in MEAM1 compared to the control. Regarding biochemical aspects, plants infested by MED cryptic species showed high activity of POD and PPO enzymes and total phenol content during the second and third instars when compared to control plants. Our results indicate that B. tabaci MED infestation in tomato plants had a greater influence than B. tabaci MEAM1 infestation on physiological parameters (CO2 assimilation rate (A), stomatal conductance (gs), and apparent carboxylation efficiency (A/Ci)) and caused increased activity of POD and PPO enzymes, indicating plant resistance to attack. In contrast, B. tabaci MEAM1 caused a reduction in POD enzyme activity, favoring offspring performance.

Population Dynamics of Fall Armyworm, Spodoptera frugiperda (J. E. Smith) on Sorghum

The study on seasonal incidence of fall armyworm was carried out during kharif, 2019 at Agricultural college farm, Bapatla. The oviposition of fall armyworm was observed from 34th SMW (Standard Meterological Week) and reached its peak during 40th SMW (0.03 egg masses plant-1). The larval population of fall armyworm was commenced during 35th SMW and increased gradually to a peak of 1.67 larvae plant-1 during 41st SMW. The maximum plant infestation (60.00%) and leaf damage severity rating (3.13) of fall armyworm was observed during 41st SMW. The peak activity of natural enemies was observed during 41st SMW which coincides with the larval population of fall armyworm. The correlation analysis indicated that eggmasses of fall armyworm was positively correlated with minimum temperature(r= 0.668) and wind speed (r= 0.529) while, the larval population showed significant positive correlation with maximum temperature (r= 0.029). The plant infestation caused by fall armyworm had shown significant negative correlation with maximum temperature (r= -0.633) and positive correlation with morning relative humidity (r= 0.678) and evening relative humidity (r= 0.664) whereas, the leaf damage severity rating exhibited significant positive correlation with evening relative humidity (r= 0.691). The multiple regression analysis revealed that the influence of weather parameters on the incidence of fall armyworm and natural enemies in sorghum ecosystem was more than 65% and 40%, respectively.

Influence of prevailing weather parameters on population dynamics of spotted stem borer, Chilo partellus (Swinhoe) and its natural enemies on maize in Haryana


 The experiment was conducted at CCS Haryana Agricultural University Regional Research Station, Karnal to ascertain the influence of prevailing meteorological parameters on population dynamics of Chilo partellus and its natural enemies on maize during Kharif, 2017. Maximum oviposition (0.75 egg masses per plant) was recorded during 28th standard meteorological week (SMW) whereas larval population was at peak during 31st SMW (3.8 larvae per plant). Cumulative (47.5%) and fresh plant infestation (11.5%) were maximum during 34th and 28th SMW, respectively. Maximum egg parasitisation (6.53%) by Trichogramma sp. and larval parasitisation (31.64%) by Cotesia flavipes was recorded during 28th and 33rd SMW, respectively. Changes in pest population were correlated and regressed with weather parameters. Egg and larval populations of C. partellus and parasitisation by Trichogramma sp. exhibited significant positive correlation with average minimum temperature whereas C. flavipes exhibited significant negative correlation with average maximum temperature (r = -0.741) and highly significant positive correlation with evening relative humidity (r = 0.695). Plant infestation and dead heart formation were significantly correlated with average minimum temperature and non-significantly correlated with all other weather parameters. The multiple linear regression analysis explained the variability due to various weather parameters. This information can be utilised while formulating integrated management tactics against this pest.