Sublethal Effect of Six Insecticides on Predatory Activity and Survival of Coccinella Septempunctata (Coleoptera: Coccinellidae) Following Contact with Contaminated Prey and Residues

Abstract

Coccinella septempunctata L. is a dominant predator of herbivorous pest insects (e.g. aphids) in various crops in Pakistan. A series of bioassays were conducted to determine the sublethal and residual activities of six insecticides, which are commonly used in canola crop (Brassica napus L.) in Pakistan on adult and fourth instar larvae of Coccinella septempunctata L. in laboratory conditions. We measured the mortality, uncoordination and consumption rate of coccinellid beetle to identify the products with comparatively low toxicity or short duration effects. Six insecticides (imidacloprid, thiamethoxam, profenophos, chlorpyriphos, lambda-cyhalothrin and cypermethrin) were used to treat aphids and arenas at sublethal concentration (LC₃₀). Compared to control treatment, increased mortality and knockdown effects were observed following contact with residues and prey treated with all insecticides. While predatory efficiency of both adult and larval stages of C. septempunctata was significantly decreased after treatments. However, significantly lower mortality and high prey consumption were observed after treatment with imidacloprid and thiamethoxam (neonicotinoids) compared to other four insecticides. Results of choice and no-choice tests using field doses and ½ field doses also confirmed the significant difference in consumption of prey between imidacloprid, thiamethoxam and other four chemicals. Larvae and adult of C. septempunctata preferentially consumed untreated aphids than treated aphids with ½ and maximum field dose over the 5 h experimental period. This study provides information to guide canola growers in their selection of insecticides.

Erratum to: Effects of Chronic Dust Load On Leaf Pigments of the Landscape Plant Murraya Paniculata Erratum to: Gesunde Pflanzen 2019 https://doi.org/10.1007/s10343-019-00469-3 Unfortunately there was a technical problem with the conversion of the formulas in the PDF file of this article. The hyphen between chlorophyll‑a and chlorophyll‑b, as well as between pheophytin‑a and pheophytin‑b was not inserted …

The Effect of Air Pollution on Developmental Stages and Pollen Germination, Pollen Tube Growth and Fruit Set of the Apple Cultivars ‘Golden Delicious’ and ‘Golab’ Abstract In this study, the effect of industrial air pollution on developmental stages and pollen germination, pollen tube growth and fruit set of the apple cultivars ‘Golden Delicious’ and ‘Golab’ was studied. For this purpose, the flowers of the apple cultivars used were collected in early spring among the trees of the same age from Astaneh region as the non-polluted region, the region around the refinery as the semi-polluted region, and the Gavar region as the polluted region. The results of the variance analysis showed that the highest rate of pollen germination and pollen tube growth was associated with ‘Golden Delicious’ cultivar in Astaneh region; while, the lowest rate was related to the ‘Golab’ cultivar in Gavar region. The least amount of fruit set was related to pollen grains belonging to Gavar and refinery regions, whereas pollen grains from Astaneh region led to the highest amount of fruit set. Evaluation of the developmental stages of the anthers and pollen grains by light microscopy and SEM images of pollen grains showed that pollen grains from trees in polluted regions lost their normal forms and developed wrinkles. The results indicated that the effect of pollution on production of pollen grains with abnormal shape in the ‘Golab’ cultivar was more than the ‘Golden Delicious’ cultivar. Therefore, it is recommended for areas with air pollution to cultivate ‘Golden Delicious’ instead of ‘Golab’.

Suitability of High Doses of Phenolic Acids for Controlling Corchorus Olitorius and Phalaris Minor Weeds Abstract The herbicidal potential of nine phenolic acids including p-hydroxybenzoic acid, protocatechuic, syringic, vanillic, gallic, salicylic, ferulic, p-coumaric and caffeic acid were evaluated against Corchorus olitorius and Phalaris minor weeds at the concentrations of 5, 10 and 20 mM. The effectiveness of phenolic acids on germination depended on target seed, specific phenolic acid and concentration. The inhibitory effects varied between the two tested seeds, and P. minor was the more sensitive. With few exceptions, phenolic acids at all tested doses did not inhibit seed germination of C. olitorius, but the acids caused great inhibition effects on germination of P. minor. Salicylic acid nearly had a complete inhibition effect on germination of tested seeds when used at 20 mM. P-hydroxybenzoic, protocatechuic, salicylic, vanillic and ferulic acids appeared great inhibition effects on germination of P. minor and nearly had complete inhibition effects when used at high dose. In a greenhouse trial, we found that application of phenolic acids at 5–20 mM did not produce any significant effect on growth on 5‑weeks-old C. olitorius or P. minor plants, after seven days from treatments. The study concluded that phenolic acids had diverse activities on germination and growth of C. olitorius or P. minor weeds.

Comparative Efficacy of Leaf Extracts of Different Tobacco Varieties Against Mustard Aphid ( Lipaphis erysimi Kalt.) Abstract In this study, field and laboratory experiments were carried out in order to develop a biological control strategy against mustard aphid by using extracts of five tobacco varieties (Beeri wala, Balkhi, Pattay wala, Desi Tobacco and Hazropattar). Two extraction methods were used: extraction through boiling of leaves (ETBL) and extraction through overnight water soaking of leaves (ETOWSL). Mustard variety (Early Mustard) was cultivated with eleven treatments of three replicates each. Laboratory experiments were conducted to confirm the mortality due to the extract of tobacco varieties and the efficient type of extraction. All treatments were found to be effective in field against mustard aphid. Extracts of Pattay wala, Balkhi and Desi tobacco obtained through ETBL remained effective up to a week, whereas the extracts of Hazropattar, Balkhi, Pattay wala and Desi tobacco obtained through ETOWSL were found to be effective up to two weeks after treatment. The highest reduction in aphid population was noted by Pattay wala tobacco and the lowest reduction was seen by Desi tobacco. Almost the same trend of effectiveness was recorded during 2nd spray. In laboratory conditions 100% mortality of aphids was observed within three days under all treatments. The results of this study could be useful in an integrated pest management program for the management of mustard aphid Lipaphis erysimi.

Effects of Chronic Dust Load On Leaf Pigments of the Landscape Plant Murraya Paniculata Abstract In the past few years, a considerable decrease in growth and development of landscape plants was recorded, possibly due to chronic exposure to toxic pollutants, with dust probably playing a major role. In the current study, Murraya paniculata were grown in a greenhouse for a period of 4 months, during which roadside dust was sprinkled daily on the slightly damp leaves at different concentrations: T0 (0 g/plant-control), T1 (1 g/plant), T2 (3 g/plant) and T3 (5 g/plant). Roadside sediments were collected with a vacuum pump and passed through a filter to obtain a fine particle size (less than 800 μm). Phenotypic studies of leaves revealed that continuous addition of undesired dust effluents affects the foliar surface of the leaves and changes its morphology. Treatment with dust significantly increased the abscisic acid concentration of leaves and shoots and the effects were more severe in high level of dust treatments. Compared to control, chlorophyll, porphyrin, chlorophyllide and pheophytin contents were significantly decreased in the dust treated groups. In contrast, carotenoid and polar carotenoid contents were not influenced by dust (p > 0.05), while non-polar carotenoid contents were significantly reduced by different levels of dust treatments. This study concludes that roadside dust depositions have degradative effects on photosynthetic pigments, with extensive effects on growth and development of plants.

Wachstumsverhalten der Beifußblättrigen Ambrosie ( Ambrosia artemisiifolia  L.) auf landwirtschaftlichen Nutzflächen Brandenburgs – Schlussfolgerungen für die Bildverarbeitung kameragestützter Monitoring-Strategien Zusammenfassung Eine Voraussetzung für die Verhinderung der weiteren Ausbreitung des invasiven Neophyten Beifußblättrige Ambrosie (Ambrosia artemisiifolia L.) aus Nordamerika ist ein effektives Monitoring zum Auffinden von Nestern und Einzelpflanzen in den entsprechenden Naturräumen. Berührungslos arbeitende Kamerasensoren an landwirtschaftlichen, kommunalen und Luft-Fahrzeugen sind ein geeignetes Mittel, um große Landschaftsareale zu untersuchen. Die Vielzahl der dabei anfallenden Bilder muss mit geeigneten Bildverarbeitungsmethoden zeitnah, idealerweise in Echtzeit (real time, online) ausgewertet werden. In landwirtschaftlich genutzten Flächen ist es günstig, ein Monitoring mit den ohnehin anfallenden Feldarbeiten zu verbinden. Sich ändernde Aufnahmebedingungen für die Kameratechnik in Raum und Zeit sind daher die Folge. Das Erscheinungsbild der Ambrosie sowie der Begleitflora weisen spezifische Eigenschaften auf, die üblicherweise mit Hilfe von Metadaten beschrieben werden können. In der Bildverarbeitung gibt es eine Vielzahl von Methoden zur Objektklassifikation, die bei spezifischen Situationen Ihre Vor- und Nachteile haben. Eine Methode der Wahl zur Klassifikation von Ambrosie ist nach derzeitigem Kenntnisstand in naher Zukunft nicht zu erwarten. Im Beitrag werden Beispiele für das Erscheinungsbild der Ambrosie in verschiedenen Feldern zu verschiedenen Zeitpunkten im Jahr aufgezeigt. Entsprechend schließt sich eine Bildverarbeitung an, die Ambrosiengewebe im Bild klassifiziert. Vor- und Nachteile der ausgewählten Methoden werden diskutiert. Ein Ausblick für eine „Metadaten-angepasste Bildverarbeitung – metadata adapted image analysis“ wird aufgezeigt.

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Growth and Seed Production Response of Commelina Communis  L. to Water Stress Abstract A greenhouse-based in vitro investigation was carried out to determine the adaptation of Commelina communis L. to water stress and its deleterious influence on growth and seed production of C. communis. Plant height and number of leaves were regressed for two experiments (degree of water stress and durations of water stress) using three parameter sigmoid model. Different degree of water response for C. communis was 100%, 80%, 60%, 40% and 20% of field capacity (FC). Maximum plant height (85.58 cm) and number of leaves (92.96) with normal plant morphology, high seed and biomass production were recorded for 100 and 80% FC. However, a drastic decline was observed when water stress was increased (minimum plant height [20.83 cm] and number of leaves [21.87] was observed in 20% followed by 40% FC). Similarly, water duration responses were also considered for C. communis i.e. 2, 3, 4, and 6 days’ durations following 100% of field capacity. The results showed an inverse correlation between duration of water stress and C. communis performance. As the duration of water stress were reduced, the plant height, number of leaves, biomass and seed production were increased. This proves that C. communis growth and production increases with high water content, whereas water stress significantly decreases its growth and seed production. Results of these experiments showed that proper water management in cropping system could be an important component to deal with the management of C. communis.

Indole-3-Acetic Acid Rescues Plant Growth and Yield of Salinity Stressed Tomato ( Lycopersicon esculentum  L.) Abstract Soil is a medium for plant growth and provides support, minerals and water to the plant for survival. Soil salinity declines availability of water to the plant, affect microorganisms growth, and water drainage capacity of soil, which adversely affect plant growth and development. In the present work the effect of indole-3-acetic acid (IAA) on growth and yield of salinity stressed tomato (Lycopersicon esculentum L.) was studied. Salinity levels (0 [control, no NaCl], 30 and 60 mM of NaCl) were applied to the soil and IAA concentrations (0 [control, no IAA], 100 and 200 ppm) were sprayed on the plants after ten days of salinity treatment. The statistical analysis showed that salt stress conditions adversely affected plant height, branches per plant, stem diameter, fruits per plant, fruit diameter, fruit length, total chlorophyll content, root length, root fresh weight, roots dry weight, and yield per plant, while IAA application to salinity stressed tomato plants rescued the plants and had significantly positive effects on growth and yield of tomato plants. In the light of above results, it is concluded that foliar application of IAA may rescue the salinity stressed tomato plants.