POPULATION DYNAMICS OF THE CABBAGE APHID, BREVICORYNE BRASSICAE (HOMOPTERA: APHIDIDAE) AT VANCOUVER, BRITISH COLUMBIA: III. DEVELOPMENT, FECUNDITY, AND MORPH DETERMINATION VS. APHID DENSITY AND PLANT QUALITY

1984 ◽  
Vol 116 (6) ◽  
pp. 879-888 ◽  
Author(s):  
D. A. Raworth ◽  
S. McFarlane ◽  
N. Gilbert ◽  
B. D. Frazer
Keyword(s):  
Leaf Area ◽  
Age Distribution ◽  
Dry Weight ◽  
Developmental Time ◽  
Brevicoryne Brassicae ◽  
Plant Quality ◽  
Medium Density ◽  
Field Cage ◽  
Adult Weight ◽  
Aphid Density

AbstractDevelopmental time, fecundity, adult weight, numbers, and age distribution of Brevicoryne brassicae (L.) and leaf area and plant quality of Maris Kestrel kale, Brassica oleracea L., were determined at three aphid densities and two watering rates in a factorial field-cage experiment. The watering treatment had no effect on the aphid or plant response variates. The aphid density treatment significantly affected final aphid numbers (low < medium = high density), leaf area (high < low = medium density), average adult weight measured at the end of the experiment (high < low < medium density), and weight of the adults in the developmental time measurement (high < low = medium density). The results suggested a strong aphid–plant interaction, but at densities which rarely occur in the field. Leaf water/dry weight was used to assess plant quality, but it was not a good predictor of any of the aphid response variates. Developmental time decreased, and fecundity increased as adult aphid weight increased. Production of fourth-instar apterae decreased logarithmically as aphid density increased.

POPULATION DYNAMICS OF THE CABBAGE APHID, BREVICORYNE BRASSICAE (HOMOPTERA: APHIDIDAE) AT VANCOUVER, BRITISH COLUMBIA: IV. PREDATION BY APHIDOLETES APHIDIMYZA (DIPTERA: CECIDOMYIIDAE)

1984 ◽  
Vol 116 (6) ◽  
pp. 889-893 ◽  
Author(s):  
D. A. Raworth
Keyword(s):  
Larval Development ◽  
Age Distribution ◽  
Predation Rate ◽  
Brevicoryne Brassicae ◽  
Temperature Threshold ◽  
Aphidoletes Aphidimyza ◽  
Cabbage Aphid ◽  
Complete Life Cycle ◽  
Aphid Density ◽  
Field Plots

AbstractPredation of the cabbage aphid, Brevicoryne brassicae (L.), by the cecidomyiid Aphidoletes aphidimyza (Rond.) was studied in the laboratory and the field. Predation was random with respect to aphid instar, and predation rate was constant with respect to aphid density. A. aphidimyza consumed 1.7 times more aphids in the laboratory than in the field during larval development. When aphid weight and age distribution were accounted for, it was found that the same biomass, 2.14 mg, was eaten in both cases.The pupal developmental temperature threshold for A. aphidimyza was 9.2 °C. The developmental times of the egg, larval and pupal stages, and complete life cycle were 32°, 66°, 171°, and 283°D9.2. In the field, there was at least 5 times more food available on individual leaves than was necessary for larval development, suggesting that female A. aphidimyza took care to place their eggs where there was sufficient food for larval development.The numerical response of A. aphidimyza to aphid density was calculated using sample data from three field plots. The response between plots was not statistically different.The implications of using prey weight rather than number to measure predator consumption, and biological control of aphids by A. aphidimyza, are discussed.

scholarly journals Modeling Poinsettia Plant Quality in Response to the Ratio of Radiant to Thermal Energy

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 501A-501
Author(s):  
Bin Liu ◽  
Royal D. Heins
Keyword(s):  
Quality Control ◽  
Plant Growth ◽  
Leaf Area ◽  
Thermal Energy ◽  
Crop Production ◽  
Mechanistic Model ◽  
Computer Software ◽  
Dry Weight ◽  
Plant Quality ◽  
Area Index

The objectives of this study were to quantify the effects of the radiant-to-thermal energy ratio (RRT) on poinsettia plant growth and development during the vegetative stage and develop a simple, mechanistic model for poinsettia quality control. Based on greenhouse experiments conducted with 27 treatment combinations; i.e., factorial combinations of three levels of constant temperature (19, 23, or 27°C), three levels of daily light integral (5, 10, or 20 mol/m2 per day), and three plant spacings (15 × 15, 22 × 22, or 30 × 30 cm), from pinch to the onset of short-day flower induction, the relationship between plant growth/development and light/temperature has been established. A model for poinsettia quality control was constructed using the computer software program STELLA II. The t-test shows that there were no significant differences between model predictions and actual observations for all considered plant characteristics; i.e., total, leaf and stem dry weight, leaf unfolding number, leaf area index, and leaf area. The simulation results confirm that RRT is an important parameter to describe potential plant quality in floral crop production.

scholarly journals Fertilizer Concentration Affects Growth and Foliar Elemental Concentration of Strobilanthes dyerianus

HortScience ◽  
2006 ◽  
Vol 41 (1) ◽  
pp. 231-234
Author(s):  
Erin E. Gamrod ◽  
Holly L. Scoggins
Keyword(s):  
Leaf Area ◽  
Tissue Concentration ◽  
Leaf Tissue ◽  
Dry Weight ◽  
The United States ◽  
Linear Increase ◽  
Plant Quality ◽  
Superior Performance ◽  
Total N ◽  
Shoot Dry Weight

Grown as an annual in most of the United States, Strobilanthes dyerianus Mast. has become increasingly popular in summer landscapes partially due to its superior performance in hot and humid conditions. At present, there is no published research on the nutritional requirements of S. dyerianus. Our study examined growth and foliar elemental response to different levels of fertilizer. Rooted cuttings were transplanted and grown with 0, 100, 200, 300, and 400 mg·L–1 N from 5N–2.2 P–12.4 K fertilizer as constant liquid feed. Plants were irrigated whenever the volumetric water content of the substrate was <20% as determined with a Theta Probe moisture meter. Weekly pH and electrical conductivity (EC) were monitored using the pour through method. Eight weeks after initiation of treatment, dry weight and leaf area was measured. Recently mature leaf tissue was analyzed for total N, P, K, Ca, Mg, S, Fe, Mn, B, Cu, Zn, and Mo. There were no significant differences in plant quality under the 100, 200, 300, or 400 mg·L–1 N treatments. The largest plants, based on leaf area and shoot dry weight, were produced with 200 mg·L–1 N. Compared to recommended EC levels for bedding plants, the treatments receiving 300 and 400 mg·L–1 N had excessively high levels of substrate soluble salts though overall plant quality was not reduced. The increase in fertilizer concentration yielded a linear increase in tissue concentration of N, P, and K and a linear decrease in tissue concentration of Ca and Mg.

IMPACT OF FERTILIZERS APPLICATION ON SEED GERMINATION AND SEEDLING GROWTH OF VIGNA RADIATA

2018 ◽  
Vol 24 (2) ◽  
Author(s):  
SUPRIYA DIXIT ◽  
R. K. GUPTA
Keyword(s):  
Seed Germination ◽  
Leaf Area ◽  
Seedling Growth ◽  
Vigna Radiata ◽  
Agricultural Research ◽  
Dry Weight ◽  
Fertilizer Application ◽  
Research Field ◽  
Chemical Fertilizer ◽  
Seedling Length

Currently, a real challenge for the workers in the agricultural research field is to stop or reduce the use of expensive agrochemicals/ chemical fertilizers which are hazardous to the environment as well as human health. Present study was aimed to improve the growth and obtain optimum yield of Vigna crop with eco-friendly, non-toxic way and to reduce the use of agrochemical/chemical fertilizer application in agricultural activities. A pot experiment was conducted to study the effect of chemical fertilizer (DAP) and biofertilizer ( Rhizobium strain) separately and in combination on seed germination and seedling growth (at 30 days) based on morphological parameters such as seedling length (cm), fresh weight (g), dry weight (g) and leaf area (cm)2 of Vigna radiata (L.) Wilczek. After one month (30 Days) observations, it was found that seedling length, fresh and dry weights and leaf area were maximum in T4 and minimum in T15, T7 and T8 favored improved seedling length and leaf area whereas T7, T8, and T9 favored improved fresh and dry weights as compared to control.

Impact of an Open Trellis on Canopy Growth, Light Interception, Yield, and Leaf Physiology of Red Raspberry (Rubus idaeus)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 468b-468
Author(s):  
Stephen F. Klauer ◽  
J. Scott Cameron ◽  
Chuhe Chen
Keyword(s):  
Leaf Area ◽  
Total Nitrogen ◽  
Dry Weight ◽  
Light Interception ◽  
Rubus Idaeus ◽  
Above Ground Biomass ◽  
Red Raspberry ◽  
Leaf Physiology ◽  
Total Dry Weight ◽  
Upper Third

After promising results were obtained with an open-style split trellis (two top wires) in its initial year, two new trials were established in 1997 in northwest (Lynden) and southwest (Woodland) Washington. For the split trellis, actual yields were 33% (machine-picked 1/2 season) and 17% (hand-picked) greater, respectively, for the two locations compared to the conventional trellis (one top wire). In Woodland, canes from the split trellis had 33% more berries, 55% more laterals, 69% more leaves, and 25% greater leaf area compared with the conventional trellis. Greatest enhancement of these components was in the upper third of the canopy. Laterals were also shorter in this area of the split canopy, but there was no difference in average total length of lateral/cane between trellis types. Total dry weight/cane was 22% greater in the split trellis, but component partitioning/cane was consistent between the two systems with fruit + laterals (43%) having the greatest above-ground biomass, followed by the stem (30% to 33%) and the leaves (21% to 22%). Measurement of canopy width, circumference, and light interception showed that the split-trellis canopy filled in more quickly, and was larger from preanthesis through postharvest. Light interception near the top of the split canopy was 30% greater 1 month before harvest with 98% interception near the top and middle of that canopy. There was no difference between the trellis types in leaf CO2 assimilation, spectra, or fluorescence through the fruiting season, or in total nitrogen of postharvest primocane leaves.

Irrigation of Geraniums with an Automatic Controlled Water Table System

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 522d-522 ◽  
Author(s):  
J.W. Buxton ◽  
D.L. Ingram ◽  
Wenwei Jia
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Water Table ◽  
Nutrient Solution ◽  
Irrigation System ◽  
Central Area ◽  
Dry Weight ◽  
Trickle Irrigation ◽  
Run Off ◽  
Optimum Water

Geraniums in 15-cm pots were irrigated automatically for 8 weeks with a Controlled Water Table (CWT) irrigation system. Plants were irrigated with a nutrient solution supplied by a capillary mat with one end of the mat suspended in a trough below the bottom of the pot. The nutrient solution remained at a constant level in the trough. Nutrient solution removed from the trough was immediately replaced from a larger reservoir. The vertical distance from the surface of the nutrient solution and the bottom of the pot determined the water/air ratio and water potential in the growing media. Treatments consisted of placing pots at 0, 2, 4, and 6 cm above the nutrient solution. Control plants were irrigated as needed with a trickle irrigation system. Geraniums grown at 0,2 and 4 CWT were ≈25% larger than the control plants and those grown at 6 CWT as measured by dry weight and leaf area. Roots of plants grown at 0 CWT were concentrated in the central area of the root ball; whereas roots of plants in other treatments were located more near the bottom of the pot. Advantages of the CWT system include: Plant controlled automatic irrigation; no run off; optimum water/air ratio.

scholarly journals Field Cage Assessment of Feeding Damage by Riptortus pedestris on Soybeans in China

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 255
Author(s):  
Wenjing Li ◽  
Yu Gao ◽  
Yinglu Hu ◽  
Juhong Chen ◽  
Jinping Zhang ◽  
...  
Keyword(s):  
Lipid Content ◽  
Transfer Rate ◽  
Soybean Seed ◽  
Dry Weight ◽  
Nutrient Transfer ◽  
Field Cage ◽  
Stay Green ◽  
Riptortus Pedestris ◽  
Green Leaves ◽  
Pest Density

The bean bug, Riptortus pedestris, is a major pest of soybeans. In order to assess the critical stages of soybean damage by R. pedestris, we tested the damage to soybeans at different growth stages (R2, R4, and R6) caused by five densities of R. pedestris (1, 2, 3, 4, and 5) through a field cage experiment. The results show that the R4 stage was the most sensitive stage in terms of suffering R. pedestris injury damage, followed by the R6 stage and then the R2 stage. The number of stay green leaves was 7.04 per plant, the abortive pod rate of the soybeans was 56.36%, and the abortive seed rate of the soybeans was 46.69%. The dry weight of the soybeans was 14.20 g at the R4 stage; these values of R4 were significantly higher than at the R2 and R6 stages. However, the dry weight of soybean seed was 4.27 g and the nutrient transfer rate was 27.01% in the R4 stage; these values were significantly lower than in the R2 and R6 stages. The number of stay green leaves, abortive pod rates, and abortive seed rates were all increased significantly with increasing pest density at each stage of soybean growth. However, the nutrient transfer rate was significantly decreased with the increase in the pest density. Soybean nutrition factors changed after they suffered R. pedestris injury; the lipid content of the soybean seed decreased and the lipid content of the soybean plant increased compared to controls, when tested with a density of five R. pedestris in the R4 stage. These results will be beneficial to the future management of R. pedestris in soybean fields.

scholarly journals EFFECT OF MINERAL DEFICIENCY ON MORPHOLOGICAL AND PHYSIOLOGICAL PARAMETERS AND ON SHOOT AND ROOT MINERAL PARTITIONING IN THREE SUNFLOWER VARIETIES / EFECTO DE LA FALTA DE ELEMENTOS MINERALAS SOBRE LOS PARAMENTROS MORFOLOGICOS Y FISIOLOGICOS Y REPARTICION DE ELEMENTOS MINERALES DE LA PARTE SOBRE EL SUELO Y DE LA RAIZ EN TRES VARIEDADES / INFLUENCE DE LA CARENCE D’ÉLÉMENTS MINÉRAUX SUR LES PARAMÈTRES MORPHOLOGIQUES ET PHYSIOLOGIQUES ET SUR LA DISTRIBUTION DES ÉLÉMENTS MINÉRAUX ENTRE LA PARTIE AÉRIENNE ET LA RACINE POUR TROIS SORTES DE TOURNESOL

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 135-148
Author(s):  
Mohammed El Midaoui ◽  
Ahmed Talouizte ◽  
Benbella Mohamed ◽  
Serieys Hervé ◽  
Ait Houssa Abdelhadi ◽  
...  
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Growth Parameters ◽  
Dry Weight ◽  
Mineral Deficiency ◽  
P Deficiency ◽  
Plant Parts ◽  
Shoot Dry Weight ◽  
K Deficiency ◽  
Matter Effect

SUMMARYAn experiment has been carried out in order to study the behaviour under mineral deficiency of three sunflower genotypes, a population variety (Oro 9) and two hybrids (Mirasol and Albena). Sunflower seedlings were submitted to five treatments: N deficiency (N0), P deficiency (P0), K deficiency (K0), N and K deficiency (N0K0) and a control. Plants were harvested when they reached 3-4 true pairs of leaves. Growth parameters measured (height, total leaf area, root length, root and shoot dry mater) were all significantly reduced by mineral deficiency. Leaf area was most reduced by N0 (-61%) and P0 (-56%). Total dry matter was most affected by N0 (-63%) and by N0K0 (-66%). Genotype comparisons showed that Oro 9 had the highest shoot dry matter while Albena had the lowest root dry matter. Effect of mineral deficiency on content and partitioning of N, P, K, Ca and Na was significant and varied according to treatments and among plant parts. Shoot dry weight was significantly correlated with root N content (r2=0.81) and root K content (r2=-0.61) for N0 and K0.

scholarly journals Effect of Organic Manures on Growth, Rhizome Yield and Quality Attributes of Turmeric (Curcuma longa L.)

2012 ◽  
Vol 10 (1) ◽  
pp. 16-22 ◽  
Author(s):  
M. Z. U. Kamal ◽  
M. N. Yousuf
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Curcuma Longa ◽  
Dry Weight ◽  
Fresh Weight ◽  
Area Index ◽  
Yield Attributes ◽  
Organic Manures ◽  
Neem Cake ◽  
Yield And Quality

The investigation was carried out to evaluate the effect of different organic manures on turmeric with reference to vegetative growth, biomass production, rhizome yield and its attributes of turmeric (Curcuma longa L.). Turmeric showed better response to the application of organic manures. Plant with neem cake application had the taller plant (79.30 cm), maximum number of tillers per plant (5.40), leaf number (5.40), leaf area (44.09) leaf area index (0.429), fresh weight of halum ( 190.05g), fresh weight of root (49.13 g), fresh weight of rhizome per plant (256.21 g) and dry weight of halum (15.21g), dry weight of root (7.32 g), dry weight of rhizome per plant (40.35 g), total dry matter yield (6.85 t ha-1) than those received other types of manures. Moreover, yield attributes such as number of mother rhizomes per plant-1 (1.75), more number of primary rhizomes per plant-1 (5.19), secondary rhizomes per plant-1 (18.03) and tertiary rhizomes per plant (7.69) were also highly accelerated by neem cake application. Similarly, the same treatment expressed the best in terms of size of mother rhizome (7.69 cm), primary rhizome (21.86 cm) and secondary rhizomes (7.05 cm).All these parameters in cumulative contributed to  produce the highest estimated fresh rhizomes yield & cured rhizomes yield (29.48 t ha-1, 5.59 t ha-1 respectively). The highest curing percentage (20.28) was observed in T3 treatment having mustard cake@ 2.0 t/ha. Thus, organic manure like neem cake was best fitted natural fertilizer for turmeric cultivation.DOI: http://dx.doi.org/10.3329/agric.v10i1.11060The Agriculturists 2012; 10(1): 16-22

scholarly journals Evaluation of the Susceptibility of Some Eggplant Cultivars to Green Peach Aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Zienab Raeyat ◽  
Jabraiel Razmjou ◽  
Bahram Naseri ◽  
Asgar Ebadollahi ◽  
Patcharin Krutmuang
Keyword(s):  
Insect Pests ◽  
Growth Parameters ◽  
Green Peach Aphid ◽  
Integrated Management ◽  
Resistance Index ◽  
Dry Weight ◽  
Developmental Time ◽  
Resistance Mechanisms ◽  
Screening Tests ◽  
Population Increase

Due to the detrimental side-effects of synthetic pesticides, the use of nonchemical strategies in the management of insect pests is necessary. In the present study, the susceptibility of fourteen eggplant cultivars to green peach aphid (M. persicae) were investigated. According to preliminary screening tests, ‘Long-Green’, ‘Ravaya’ and ‘Red-Round’ as relatively resistant, and ‘White-Casper’ and ‘Pearl-Round’ as susceptible cultivars were recognized. In the antixenosis tests, the highest hosting preference was documented for ‘White-Casper’. Population growth parameters were used for evaluation of antibiosis. The highest and lowest developmental time (d) was observed on ‘Long-Green’ (4.33 d) and ‘White-Casper’ (3.26 d), respectively. The highest and lowest intrinsic rates of population increase (rm) were on ‘White-Casper’ (0.384 d−1) and ‘Long-Green’ (0.265 d−1), respectively. Significant differences were observed in the height and fresh and dry weight of infested and noninfected plants. Plant resistance index (PRI), as a simplified way to assess all resistance mechanisms, provides a particular value to determine the proper resistant cultivar. The greatest PRI value was observed on ‘Long-Green’. In general, the ‘Long-Green’ showed the least, and the ‘White-Casper’ displayed the most susceptibility among tested cultivars infested by M. persicae, which might be useful in integrated management of this pest.

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