THE RESPONSE OF FLAX TO DIFFERENT POPULATION DENSITIES OF THE RED-BACKED CUTWORM, EUXOA OCHROGASTER (GN.) (LEPIDOPTERA: NOCTUIDAE)

1990 ◽  
Vol 122 (1) ◽  
pp. 21-28 ◽  
Author(s):  
G.L. Ayre
Keyword(s):  
Plant Growth ◽  
Soil Surface ◽  
Field Studies ◽  
Crop Loss ◽  
Population Densities ◽  
Larval Population ◽  
Plant Yield ◽  
Stable Relationship ◽  
Euxoa Ochrogaster ◽  
Lepidoptera Noctuidae

AbstractControlled field studies carried out in plots within a field of NorMan flax, Linum usitatissum L., showed that the loss of flax plants caused by the red-backed cutworm was proportional to the number of cutworm larvae present. A density of 16 larvae per 0.5 m2 destroyed most plants by severing the plant stems at the soil surface. The loss of only some plants at larval densities lower than 16 larvae per 0.5 m2 resulted in a small but significant increase in per plant yield but the increase did not completely compensate for the yield reductions caused by plant loss. The larvae removed plants in blocks with the result that the density of the remaining plants was unchanged and the opportunity for compensating plant growth was limited. An equation defining this relationship between larval densities and yield is presented. Ancillary experiments in which the population of cutworm larvae was sequentially sampled showed that, after an initial loss of about 20% when the plots were established in the field, the larval population remained constant. The proportion of the larvae found around damaged plants also remained constant until the larvae became immobile through preparation for pupation. Because of this stable relationship, reliable estimates of potential crop loss from cutworm larvae in flax should be possible by sampling for cutworms only around damaged plants within a specified row length.

Tolerance of southern highbush and rabbiteye blueberry cultivars to saflufenacil

2019 ◽  
Vol 33 (03) ◽  
pp. 475-480
Author(s):  
Ryan B. Aldridge ◽  
Katherine M. Jennings ◽  
Sushila Chaudhari ◽  
David W. Monks ◽  
Wesley J. Everman ◽  
...  
Keyword(s):  
Plant Growth ◽  
Soil Surface ◽  
Field Studies ◽  
Highbush Blueberry ◽  
Plant Analysis ◽  
Negative Effects ◽  
Visible Injury ◽  
Whole Plant ◽  
Growth Change ◽  
Southern Highbush

AbstractGreenhouse and field studies were conducted to determine tolerance of blueberry to saflufenacil. Greenhouse studies included five saflufenacil rates (0, 50, 100, 200, and 400 g ai ha−1) and three southern highbush blueberry cultivars (‘Legacy’, ‘New Hanover’, and ‘O’Neal’) and one rabbiteye blueberry cultivar (‘Columbus’). Saflufenacil treatments were soil applied into each pot when blueberry plants were approximately 30-cm tall. Visible injury (purpling/reddening of foliage and leaf abscission) ranged from 3% to 12%, 3% to 42%, 0% to 43%, and 0% to 29% with saflufenacil from 50 to 400 g ha−1 in Columbus, Legacy, New Hanover, and O’Neal, respectively, at 28 d after treatment. Regardless of injury, plant growth (change in height), soil plant analysis development, and whole-plant dry biomass of all cultivars did not differ among saflufenacil rates. Field studies were conducted in Burgaw, NC, to determine the tolerance of nonbearing (<3-yr-old and not mature enough to produce fruit) and bearing (>3-yr-old and mature enough to produce fruit) southern highbush blueberry (‘Duke’) to saflufenacil application at pre-budbreak or during the vegetative growth stage. Treatments included three rates of saflufenacil (50, 100, and 200 g ha−1), glyphosate (870 g ae ha−1), glufosinate (1096 g ai ha−1), glyphosate (870 g ha−1) + saflufenacil (50 g ha−1), glufosinate (1096 g ha−1) + saflufenacil (50 g ha−1), and hexazinone (1,120 g ai ha−1), applied POST-directed to the soil surface beneath blueberry plants in a 76-cm band on both sides of the blueberry planting row. The maximum injury from treatments containing saflufenacil was ≤11% in both nonbearing and bearing blueberry. No negative effects on plant growth or fruit yield were observed from any treatments. Results from both greenhouse and field studies suggest that saflufenacil applied at 50 (1X commercial use rate) and 100 g ha−1 is safe to use in blueberry.

scholarly journals Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface

2021 ◽  
Vol 11 (7) ◽  
pp. 2979
Author(s):  
Maxime Fortin Faubert ◽  
Dominic Desjardins ◽  
Mohamed Hijri ◽  
Michel Labrecque
Keyword(s):  
Soil Surface ◽  
Field Work ◽  
Field Studies ◽  
Soil Hydrology ◽  
Intensive Culture ◽  
Shrub Species ◽  
Short Rotation ◽  
Pollutant Concentrations ◽  
Polycyclic Aromatic ◽  
Made In

The Salix genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (Salix miyabeana ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided.

scholarly journals Protists as main indicators and determinants of plant performance

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Sai Guo ◽  
Wu Xiong ◽  
Xinnan Hang ◽  
Zhilei Gao ◽  
Zixuan Jiao ◽  
...  
Keyword(s):  
Plant Growth ◽  
Organic Fertilizer ◽  
Agricultural Practices ◽  
Plant Performance ◽  
Organic Fertilization ◽  
Plant Yield ◽  
Growing Seasons ◽  
Beneficial Microorganisms ◽  
Plant Growth Promoting ◽  
Plant Growth Promoting Microbes

Abstract Background Microbiomes play vital roles in plant health and performance, and the development of plant beneficial microbiomes can be steered by organic fertilizer inputs. Especially well-studied are fertilizer-induced changes on bacteria and fungi and how changes in these groups alter plant performance. However, impacts on protist communities, including their trophic interactions within the microbiome and consequences on plant performance remain largely unknown. Here, we tracked the entire microbiome, including bacteria, fungi, and protists, over six growing seasons of cucumber under different fertilization regimes (conventional, organic, and Trichoderma bio-organic fertilization) and linked microbial data to plant yield to identify plant growth-promoting microbes. Results Yields were higher in the (bio-)organic fertilization treatments. Soil abiotic conditions were altered by the fertilization regime, with the prominent effects coming from the (bio-)organic fertilization treatments. Those treatments also led to the pronounced shifts in protistan communities, especially microbivorous cercozoan protists. We found positive correlations of these protists with plant yield and the density of potentially plant-beneficial microorganisms. We further explored the mechanistic ramifications of these relationships via greenhouse experiments, showing that cercozoan protists can positively impact plant growth, potentially via interactions with plant-beneficial microorganisms including Trichoderma, the biological agent delivered by the bio-fertilizer. Conclusions We show that protists may play central roles in stimulating plant performance through microbiome interactions. Future agricultural practices might aim to specifically enhance plant beneficial protists or apply those protists as novel, sustainable biofertilizers.

Incidence of Helicoverpa armigera (Lepidoptera: Noctuidae) and its natural enemies on smallholder crops in Kenya

1993 ◽  
Vol 83 (3) ◽  
pp. 321-328 ◽  
Author(s):  
H. van den Berg ◽  
M. J. W. Cock ◽  
G. I. Oduor ◽  
E. K. Onsongo
Keyword(s):  
Helicoverpa Armigera ◽  
Heliothis Armigera ◽  
Population Densities ◽  
Parasitoid Species ◽  
Larval Parasitoid ◽  
Total Percentage ◽  
Four Seasons ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Experimental Plots

AbstractSmallholder crops (sunflower, maize, sorghum and cotton) were grown in experimental plots at seven sites, representing different agricultural zones of Kenya, over four seasons. Helicoverpa armigera (Hübner) (formerly Heliothis armigera) only occasionally achieved population densities sufficient to cause obvious damage to the crops, and was virtually absent from the coastal sites. At the inland sites, infestation and mortality levels varied greatly. Information is presented on the incidence of H. armigera, and the identity, distribution and frequency of its common parasitoids and (potential) predators, sampled in the experimental plots. Trichogrammatoidea spp., egg parasitoids, and Linnaemya longirostris (Macquart), a tachinid late-larval parasitoid, were the most common parasitoid species, but total percentage parasitism was rather low. Of the large complex of predators, only anthocorids and ants (predominantly Pheidole spp., Myrmicaria spp. and Camponotus spp.) were sufficiently common and widespread to be of importance in suppressing H. armigera. The abundance of predators fluctuated widely between sites, but anthocorids were most abundant at the western sites.

scholarly journals The role of new stress protectors in the formation of production process of oat culture during cultivation in anthropogenically polluted areas

2020 ◽  
Vol 23 ◽  
pp. 03011
Author(s):  
Yuliya M. Andriyanova ◽  
Irina V. Sergeyeva ◽  
Nataliya N. Gusakova ◽  
Yuliya M. Mokhonko
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Negative Impact ◽  
Field Studies ◽  
Amylolytic Enzymes ◽  
Cereal Products ◽  
Oat Seeds ◽  
Lead Zinc

Stress protectors (adaptogens) are among the most important factors that regulate growth processes at all stages of plant development. This article presents results of field studies of the effect of new synthetic plant growth regulators of stress protectors (adaptogens) on the elements of productivity and yield of spring oats of the Skakun variety. The obtained results during the research showed that all the studied derivatives of peredazinones are adaptogens and they contribute to an increased productivity and increased yield of spring oats. We studied the effect of pre-sowing treatment of seeds with new synthetic plant growth regulators of stress protectors on the quality indicators of cereal production of Skakun oats (protein, starch and amylolytic enzymes content in the cereal). Pre-sowing treatment of oat seeds increases the amount of protein in the cereal up to 15%, starch – up to 25%, amylase – up to 20%. We proved the ability of stress protectors to minimize the negative impact of heavy metals (lead, zinc) on agrophytocenoses, which will make it possible to obtain environmentally friendly cereal products when cultivating oats in anthropogenically polluted areas of the Saratov Oblast.

Growth, seed production and effect of defoliation in an early flowering perennial grass, Alloteropsis semialata (Poaceae), on Cape York Peninsula, Australia

2001 ◽  
Vol 49 (6) ◽  
pp. 735 ◽  
Author(s):  
Gabriel M. Crowley ◽  
Stephen T. Garnett
Keyword(s):  
Plant Growth ◽  
Seed Production ◽  
Perennial Grass ◽  
Soil Surface ◽  
Plant Size ◽  
Perennial Grasses ◽  
Wet Season ◽  
Cape York ◽  
Seed Dynamics

Alloteropsis semialata (R.Br.) A.Hitchc. is one of the first perennial grasses in monsoonal Australia to produce seed at the start of the wet season. Patterns of growth and seed production and seed dynamics of Alloteropsis semialata were examined in this study, along with the effects of partial defoliation. Growth of Alloteropsis semialata tussocks started with the first pre-wet-season rains, and was then interrupted during a period with little rain. Growth ceased before the end of the wet season, indicating that factors other than moisture availability were limiting. Seeds of Alloteropsis semialata were germinable on production, but did not remain viable or persist on the soil surface through the dry season. Most seeds and young seedlings were harvested and no seedlings were recruited. Inflorescence production increased with plant size. Moderate defoliation in the early wet season had no impact on plant growth, but reduced inflorescence and seed production for at least 2 years. Absence of a seed bank and early wet-season flowering mean that Alloteropsis semialata is likely to be sensitive to long-term over-grazing.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

Ethylene: A Witchweed Seed Germination Stimulant

Weed Science ◽  
1975 ◽  
Vol 23 (5) ◽  
pp. 433-436 ◽  
Author(s):  
Robert E. Eplee
Keyword(s):  
United States ◽  
Seed Germination ◽  
Clay Soil ◽  
Soil Surface ◽  
Field Studies ◽  
The United States ◽  
Major Contributor ◽  
Single Treatment ◽  
Striga Asiatica ◽  
Heavy Clay

Ethylene gas (C2H4) was found to stimulate the germination of witchweed [Striga asiatica(L.) O. Kuntze] seeds. Ethylene diffuses greater than 120 cm horizontally from point of injection and more than 90 cm below the soil surface. Rates of 0.42 kg/ha induced germination of witchweed seeds in sandy soil; but 1.1 kg/ha is required on a heavy clay soil. Witchweed seeds respond to ethylene after a period of preconditioning that is necessary to break dormancy. Under field conditions in the Carolinas, maximum response of seeds to ethylene occurs between late April and late July. Field studies indicate a 90% reduction in viable witchweed seeds occurs where a single treatment with ethylene has been applied. The use of ethylene appears now to be a major contributor toward the eventual eradication of witchweed from the United States.

scholarly journals Field efficacy of Helicoverpa armigera nucleopolyhedro-virus isolates against H. armigera (Hübner) (Lepidoptera: Noctuidae) on cotton and chickpea in Tamil Nadu

2010 ◽  
Vol 46 (No. 3) ◽  
pp. 116-122 ◽  
Author(s):  
S. Jeyarani ◽  
N. Sathiah ◽  
P. Karuppuchamy
Keyword(s):  
Helicoverpa Armigera ◽  
Tamil Nadu ◽  
Cost Benefit ◽  
Larval Population ◽  
Coimbatore District ◽  
Field Efficacy ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Virus Isolates ◽  
Insecticide Control

Field efficacy of seven geographical isolates of Helicoverpa armigera nucleopolyhedrovirus (HaNPV) along with an insecticide control was evaluated against H. armigera on cotton and chickpea in the Coimbatore district of Tamil Nadu, India. Among the HaNPV isolates, CBE I (Coimbatore) and NEG (Negamum) applied at 3.0 &times; 10<sup>12</sup> POB/ha to cotton and 1.5 &times; 10<sup>12</sup> POB/ha to chickpea with an adjuvant, crude sugar, significantly reduced the H. armigera larval population and increased the yield. CBE I and NEG recorded the highest yield of 2038 kg/ha and 2033 kg/ha, which was on a par with endosulfan (2026.7 kg/ha) with cost/benefit ratios of 1:2.32, 1:2.48, and 1:1.12, respectively, on cotton. In chickpea grain yields of 980, 983, and 973.3 kg/ha and cost/benefit ratios of 1:1.36, 1:1.48 and 1:0.87, respectively, in CBE I, NEG and endosulfan treated plots were obtained. The isolate RAJ (Rajasthan) recorded the lowest yield comparable to that of the untreated control in both crops.

scholarly journals CONTROL OF CUTWORMS IN ASPARAGUS FIELDS IN THE INTERIOR OF BRITISH COLUMBIA

1957 ◽  
Vol 37 (2) ◽  
pp. 108-112
Author(s):  
F. L. Banham ◽  
R. H. Handford
Keyword(s):  
British Columbia ◽  
Soil Surface ◽  
Moist Soil ◽  
Highly Effective ◽  
Euxoa Ochrogaster ◽  
Dry Soil

Emulsions of dieldrin, aldrin, isodrin, toxaphene and chlordane applied to the soil surface and incorporated to a depth of about 4 inches proved highly effective in controlling the red-back cutworm, Euxoa ochrogaster (Guen.) when tested in asparagus fields in the interior of British Columbia in the summer of 1953 and 1954. In 1953 aldrin emulsion mixed with the soil was much more effective than when it was left on the soil surface, Bran bait containing paris green, although giving fairly satisfactory control, was less effective and slower in action than the emulsions. In 1952, dieldrin, aldrin, and isodrin dusts, applied to the soil surface, were superior to and faster in action than bran baits containing aldrin or endrin; all of the 1952 treatments were apparently slower in action in dry soil than in relatively moist soil. A survey of asparagus fields treated by growers in 1953 but not in 1954 indicated that aldrin emulsion, mixed with the soil at about 4 lb. of toxicant per acre, protects asparagus for at least two years.

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