Interrelations of Damage to Wheat and Feeding by the Pale Western Cutworm, Agrotis orthogonia Morrison (Lepidoptera: Noctuidae)

1965 ◽  
Vol 97 (2) ◽  
pp. 153-158 ◽  
Author(s):  
L. A. Jacobson ◽  
L. K. Peterson
Keyword(s):  
Soil Moisture ◽  
Crop Protection ◽  
Wheat Plant ◽  
Field Conditions ◽  
The Third ◽  
Potential Damage ◽  
Field Plots ◽  
Lepidoptera Noctuidae

AbstractLarvae of the pale western cutworm, Agrotis orthogonia Morrison, were fed on wheat in the laboratory, greenhouse, and in field plots. Larvae did not completely sever the plants until the third-instar. The rate and amount of damage varied directly with size and densities of larvae, temperatures above 15 °C., and soil moisture; and inversely with the age and size of the wheat plant. The findings were related to field conditions to appraise potential damage and the necessity of insecticides for crop protection. Possible procedures are discussed for evaluation of the efficiency of various chemicals in the laboratory and in field plots.

LIME AND DAIRY PRODUCTION

1982 ◽  
pp. 93-103
Author(s):  
N.A. Thomson
Keyword(s):  
Soil Moisture ◽  
Dairy Cows ◽  
Milk Production ◽  
Soil Ph ◽  
Dairy Production ◽  
Pasture Production ◽  
The Third ◽  
One Year ◽  
Plasma Magnesium

In a four year grazing trial with dairy cows the application of 5000 kg lime/ ha (applied in two applications of 2500 kg/ha in winter of the first two years) significantly increased annual pasture production in two of the four years and dairy production in one year. In three of the four years lime significantly increased pasture growth over summer/autumn with concurrent increases in milk production. In the last year of the trial lime had little effect on pasture growth but a relatively large increase in milkfat production resulted. A higher incidence of grass staggers was recorded on the limed farmlets in spring for each of the four years. In the second spring immediately following the second application of lime significant depressions in both pasture and plasma magnesium levels were recorded. By the third spring differences in plasma magnesium levels were negligible but small depressions in herbage magnesium resulting from lime continued to the end of the trial. Lime significantly raised soil pH, Ca and Mg levels but had no effect on either soil K or P. As pH levels of the unlimed paddocks were low (5.2-5.4) in each autumn and soil moisture levels were increased by liming, these factors may suggest possible causes for the seasonality of the pasture response to lime

A Multiscale Soil Moisture and Freeze–Thaw Monitoring Network on the Third Pole

2013 ◽  
Vol 94 (12) ◽  
pp. 1907-1916 ◽  
Author(s):  
Kun Yang ◽  
Jun Qin ◽  
Long Zhao ◽  
Yingying Chen ◽  
Wenjun Tang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Monitoring Network ◽  
Freeze Thaw ◽  
The Third

scholarly journals Influence of Flower Thrips on Fusarium Hardlock Severity

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1423-1429 ◽  
Author(s):  
D. J. Mailhot ◽  
J. J. Marois ◽  
D. L. Wright
Keyword(s):  
Gossypium Hirsutum ◽  
Untreated Control ◽  
Yield Loss ◽  
Fusarium Verticillioides ◽  
Field Conditions ◽  
Control Group ◽  
Flower Thrips ◽  
The Impact ◽  
Field Plots

Cotton (Gossypium hirsutum) fiber is sometimes affected by hardlock, which is characterized by a failure of the fiber to expand outward from the boll at maturity. Because affected fiber is inaccessible to mechanical harvesters, yield loss can be considerable. Hardlock has been linked to infection by Fusarium verticillioides. The involvement of flower thrips (Frankliniella spp.), which are commonly found in cotton flowers, was explored. At 1100 h, approximately 10% of cotton flowers contained thrips that were carrying F. verticillioides. The effect of thrips and/or Fusarium in flowers and bolls was explored under greenhouse conditions. Exposing flowers to Fusarium and thrips resulted in bolls with the most severe symptoms. Exposure to either Fusarium or thrips alone resulted in more hardlock than was noted in the control group. The impact of thrips was also evaluated under field conditions. Field plots were treated with insecticides, a fungicide, both, or left untreated. Insecticides reduced thrips numbers and reduced hardlock severity. The fungicide had no impact on thrips numbers and was less effective at reducing hardlock. Combining insecticide and fungicide applications was no more effective than using insecticides alone, although it more frequently increased yield. The untreated control plots generally had the most severe hardlock and lowest yields. Reducing hardlock severity resulted in higher yields, although not consistently. These studies suggest that thrips increase the severity of hardlock, and reducing their numbers may diminish hardlock severity.

Assessment and Error Analysis of Satellite Soil Moisture Products Over the Third Pole

2021 ◽  
pp. 1-18
Author(s):  
Jiangyuan Zeng ◽  
Pengfei Shi ◽  
Kun-Shan Chen ◽  
Hongliang Ma ◽  
Haiyun Bi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Error Analysis ◽  
The Third

Biology and Control of Black Nightshade (Solanum nigrum) in Cotton (Gossypium hirsutum)

1991 ◽  
Vol 5 (4) ◽  
pp. 713-722 ◽  
Author(s):  
Paul E. Keeley ◽  
Robert J. Thullen
Keyword(s):  
Soil Moisture ◽  
Sprinkler Irrigation ◽  
Yield Losses ◽  
Accelerated Degradation ◽  
Black Nightshade ◽  
Excellent Control ◽  
Late Application ◽  
And Control ◽  
Field Plots ◽  
Weed Resistance

A 4-yr study (1985, 1987, 1988, 1989) was conducted on the same field plots at Shafter, CA to evaluate the efficacy of prometryn in controlling black nightshade on planting beds of cotton. Two rates (1.7 and 2.2 kg ai ha–1) were applied at two times (mid March before the preplant irrigation and early April at cotton planting) each year. Incorporation of prometryn into moist planting beds with a powered rotary tiller operated at 10 cm deeper resulted in excellent control of black nightshade under low to moderate weed pressure in 1985 and 1987. Control of nightshade with early and late applications of 1.7 kg ha–1of prometryn under high weed pressure in 1988 was only 70% at harvest, and yield losses of cotton averaged 25%. Yields of cotton treated with 2.2 kg ha–1of prometryn in 1988 were not significantly different from weed-free plots. Only the late application of 2.2 kg ha–1of prometryn prevented significant cotton losses under extreme weed pressure in 1989. Cotton yield losses with the other prometryn treatments ranged from 78 to 100%. Losses of cotton in weedy-check plots that received only cultivation ranged from 22% in the absence of rain or irrigation at cotton planting in 1987 to as much as 100% when rain fell in 1988 or plots were irrigated at planting in 1989. Plots hoed one time 4 wk after cotton planting yielded an average of 84% as much seed cotton as weed-free plots. In an attempt to determine why the efficacy of prometryn declined between 1985 and 1989, several experiments were conducted in 1988 to 1990 to discover reasons for this poor control of nightshade. Because efforts failed to provide evidence for the movement of the herbicide with water, the development of weed resistance to prometryn, or accelerated degradation of this herbicide in soil, increasing weed seed populations in soil were believed to have contributed greatly to the declining nightshade control from prometryn. The fact that prometryn applied and incorporated into flat soil provided excellent control of nightshade in 1990 under sprinkler irrigation indicated that both soil moisture and incorporation techniques limited activity of prometryn in planting beds in 1988 and 1989. Incomplete control of nightshade plus good soil moisture at planting contributed to the high weed populations in 1988 and 1989.

scholarly journals Estimation of ascochytosis infection of samples and lines of chickpea sorts in natural field conditions in Uzbekistan

2020 ◽  
pp. 74-77
Author(s):  
J. T. Nakhalbaev ◽  
I. Kh. Khamdamov
Keyword(s):  
Field Conditions ◽  
Seed Infection ◽  
Natural Field ◽  
The Third ◽  
Experimental Station ◽  
Leguminous Crops ◽  
Sowing Period ◽  
Research Institute

Relevance and methods. The information on the influence of samples of chickpea sorts, time of planting the lines of chickpeas on seed infection with ascochytosis and on the weight of grain on one plant bush is presented in this article. Samples of chickpea sorts and lines were studied during the first sowing period — the first decade of March and the second sowing period — the third decade of March. Ascochytosis infection was evaluated in natural field conditions. The study was conducted at the Central Experimental Station of the Galaaral Research Institute of Grain and Leguminous Crops in 2015–2017 in Uzbekistan.Results. According to the three-year study, it was found that in the years when there was a lot of precipitation days, sorts Yulduz, ILC 263 and MП 2015/1 of the lines during the first sowing were determined to be infected with acochytosis up to 6 points. During the first sowing period of this cv., there was a decrease in the weight of grains on one plant bush compared to the second sowing period. Cv. ILC 3279, Umid and line 14442 were found to be virtually undamaged in natural field conditions with ascohitosis during both planting periods. It wasfound our that the weight of cv. Мustaqillik-20, line 14442 grain on one plant bush remained high during both planting periods.

scholarly journals AKTIVITAS EKSTRAK BIJI TANAMAN MINDI MELIA AZEDARACH (L.) TERHADAP SPODOPTERA LITURA (F.) (LEPIDOPTERA: NOCTUIDAE)

2005 ◽  
Vol 5 (1) ◽  
pp. 11-16
Author(s):  
Hamdani Hamdani
Keyword(s):  
Biological Activity ◽  
Insecticidal Activity ◽  
Spodoptera Litura ◽  
Developmental Time ◽  
Seed Extract ◽  
Melia Azedarach ◽  
The Third ◽  
First Instar ◽  
Lepidoptera Noctuidae

Activity of Melia azedarach (L.) seed extract against armyworm Spodoptera litura (F.) (Lepidoptera: Noctuidae). This study was conducted to evaluate the effectivenes and biological activity of Melia azedarach L. (Meliaceae) seed extract against armyworm, Spodoptera litura F. The first instar larvae were fed extract-treated cotton leaves for 2 days, then were maintained on untreated leaves until the third instar stage. Records were kept in regard to the larvae mortality and developmental time of surviving larvae from first instar to third instar. The result showed that Melia azedarach L. seed extract at consentration of 50 g of seeds/l of water (5%) exhibited moderate insecticidal activity against S. litura larvae (43.33 - 68.33% mortality). Addition of detergen at 0.2% to extract did not increase insecticidal activity of the extract. However, boiling seed extract at consentration of 50 g of seeds/l of water (5%) during 10 until 20 minutes increased insecticidal activity of extract (66.67 - 68.33% mortality). Generally, M. azedarach seed extract treatment did not affect  developmental time of  S. litura larvae.

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.

Sign in / Sign up

Export Citation Format

Share Document