TOXICITY OF INSECTICIDES TO FIRST-INSTAR LARVAE OF THE SPRUCE BUDMOTH, ZEIRAPHERA CANADENSIS MUT. AND FREE. (LEPIDOPTERA: TORTRICIDAE): LABORATORY AND FIELD STUDIES

1989 ◽  
Vol 121 (1) ◽  
pp. 81-91 ◽  
Author(s):  
B.V. Helson ◽  
P. de Groot ◽  
J.J. Turgeon ◽  
E.G. Kettela
Keyword(s):  
Residual Activity ◽  
Field Studies ◽  
Field Trials ◽  
Contact Toxicity ◽  
Pyrethroid Insecticides ◽  
First Instar ◽  
Azinphos Methyl ◽  
Population Reduction ◽  
Newly Hatched Larvae ◽  
Residual Effectiveness

AbstractLaboratory tests with selected carbamate, organophosphorus, and pyrethroid insecticides demonstrated that the pyrethroid permethrin has the best potential for controlling newly hatched larvae of Zeiraphera canadensis Mut. and Free. Permethrin possessed high crawling contact toxicity (toxicity of insecticide deposits on foliage when contacted by crawling larvae) and direct contact toxicity to first-instar larvae and exhibited long residual effectiveness on potted, white spruce trees. Chlorpyrifos, fenitrothion, mexacarbate, and methomyl had high crawling contact toxicity but short residual activity. Azinphos-methyl appeared to possess long residual effectiveness but relatively low crawling contact toxicity. Aminocarb and thiodicarb exhibited short residual effectiveness and relatively low toxicity. In field trials, an aerial application of permethrin (70 g/ha) at egg hatch resulted in an 81% population reduction and limited the destruction of tree leaders to 9%. Leader destruction was greater than 19% after treatments of permethrin at 35 g AI/ha or aminocarb at 180 g AI/ha or aminocarb twice at 90 g AI/ha. Leader destruction in an untreated plantation was 51%.

A STRAIN OF FRUITTREE LEAFROLLER, ARCHIPS ARGYROSPILUS (LEPIDOPTERA: TORTRICIDAE), TOLERANT TO AZINPHOS-METHYL IN AN APPLE ORCHARD REGION OF THE OKANAGAN VALLEY OF BRITISH COLUMBIA

1984 ◽  
Vol 116 (1) ◽  
pp. 69-73 ◽  
Author(s):  
J. M. Vakenti ◽  
C. J. Campbell ◽  
H. F. Madsen
Keyword(s):  
British Columbia ◽  
Bacillus Thuringiensis ◽  
Resistant Strain ◽  
Field Trials ◽  
Probit Analysis ◽  
Apple Orchard ◽  
Control Material ◽  
First Instar ◽  
Azinphos Methyl ◽  
Archips Argyrospilus

AbstractProbit analysis of the dosage response of first instar, fruittree leafroller larvae to azinphos-methyl indicated that a strain from a commercial orchard in East Kelowna, B.C. was 7.8 times more tolerant than a susceptible strain. Azinphos-methyl applied to experimental apple blocks in the same area did not provide satisfactory control. Leafroller damage as high as 10.5% was found in several orchards which had received multiple azinphos-methyl and other organophosphorous insecticide treatments. The development of an organophosphorous resistant strain of fruittree leafroller in this orchard area is strongly suggested. Bacillus thuringiensis applied at the pink stage of apple blossom development gave adequate control of fruittree leafroller in East Kelowna field trials and will be suggested as the control material for commercial orchards in this area.

Comparative toxicity of foliar and systemic applications of acetamiprid and imidacloprid against the cotton whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)

1998 ◽  
Vol 88 (4) ◽  
pp. 437-442 ◽  
Author(s):  
A.R. Horowitz ◽  
Z. Mendelson ◽  
P.G. Weintraub ◽  
I. Ishaaya
Keyword(s):  
Bemisia Tabaci ◽  
Residual Activity ◽  
Field Trials ◽  
Adult Mortality ◽  
Cotton Field ◽  
Ovicidal Activity ◽  
Laboratory Conditions ◽  
Controlled Conditions ◽  
Comparative Toxicity ◽  
Cotton Whitefly

AbstractComparative bioassays of two chloronicotinyl insecticides, acetamiprid and imidacloprid, against the whitefly Bemisia tabaci (Gennadius), using foliar and systemic applications, were conducted under laboratory conditions and in field trials. Under controlled conditions, the ovicidal activity of foliar applications of acetamiprid on cotton seedlings was much higher than that of imidacloprid. According to LC50 and LC90 values, acetamiprid was 10- and 18-fold more potent than imidacloprid. Both compounds were effective when applied to soil against whitefly adults; however, the potency of imidacloprid was somewhat higher than that of acetamiprid 2, 7 and 14 days after application; resulting (with the concentration of 25 ml a.i./l) in adult mortality of 90, 93, and 96% and 76, 84, and 76% respectively. In an experimental cotton field, the efficacy of foliar applications of 60 g a.i./ha acetamiprid and 210 g a.i./ha imidacloprid was compared. Field residual activity of acetamiprid to whitefly adults lasted for approximately ten days, compared with three days for imidacloprid.

Chemical control of potato tuber moth, Phthorimaea operculella (Zell.), in Rhodesia

1967 ◽  
Vol 57 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Margaret E. Richardson ◽  
D. J. W. Rose
Keyword(s):  
Chemical Control ◽  
Good Control ◽  
Field Trials ◽  
Phthorimaea Operculella ◽  
Macrosiphum Euphorbiae ◽  
Control Field ◽  
Azinphos Methyl ◽  
History Of ◽  
New Compounds ◽  
Made In

An account is given of the history of chemical control Phthorimaea operculella (Zell.) in potato fields in Rhodesia since the introduction of DDt prior to 1952. The failure of DDT and endrin, in routine spraying, to control field infestations is reproted, and some evidence that this is due to insecticide resistance is given. The results of critical field trials made in 1961, 1964 and 1965 to evaluate a range of insecticides for control of P. operculella and for their effects on populations of Macrosiphum euphorbiae (Thos.) are presented, together with the results of some laboratory tests. Good control of P. operculella in the field was obtained with sprays of azinphos-methyl at the rate of 0.5 lb active ingredient in 20 gal. water per acre, and two new compounds, methidathion and chlorfenvinphos, showed promise for the future.

CHAETOPHLEPSIS NASELLENSIS, A DIPTEROUS PARASITOID OF THE WESTERN HEMLOCK LOOPER (LEPIDOPTERA: GEOMETRIDAE)

1977 ◽  
Vol 109 (8) ◽  
pp. 1121-1128
Author(s):  
Richard D. Medley ◽  
V. M. Carolin
Keyword(s):  
Body Length ◽  
Field Studies ◽  
Instar Larva ◽  
Western Hemlock ◽  
Larval Instars ◽  
First Instar ◽  
Western Hemlock Looper ◽  
Lambdina Fiscellaria Lugubrosa ◽  
Hemlock Looper

AbstractPreserved material from 1962 field studies provided information on the habits and morphology of the tachinid parasitoid Chaetophlepsis nasellensis Reinhard. Parasitization of the larvae of the western hemlock looper, Lambdina fiscellaria lugubrosa (Hulst), continues over a 30- to 40-day period. Maggots issue from the host larvae and drop to the ground to pupate. The pupae normally overwinter, with adults emerging the following spring or summer. The early first-instar larva differs markedly from the late first-instar. The three instars can be distinguished on the basis of body length and the structure and form of the buccopharyngeal apparatus. The first and third larval instars and the puparium are distinctive enough to permit easy identification during studies of the western hemlock looper and associated loopers.

EFFECTS OF RESIDUES OF CHITIN-SYNTHESIS INHIBITORS ON EGG HATCH AND SUBSEQUENT LARVAL ENTRY OF THE CODLING MOTH, CYDIA POMONELLA (LEPIDOPTERA: OLETHREUTIDAE)

1984 ◽  
Vol 116 (8) ◽  
pp. 1057-1062 ◽  
Author(s):  
H. R. Moffitt ◽  
K. D. Mantey ◽  
G. Tamaki
Keyword(s):  
Cydia Pomonella ◽  
Residual Activity ◽  
Codling Moth ◽  
Field Studies ◽  
Ring Stage ◽  
Chitin Synthesis ◽  
Egg Hatch ◽  
Chitin Synthesis Inhibitors ◽  
Stage Of Development ◽  
Previously Treated

AbstractIn laboratory and field studies with the codling moth, Cydia pomonella (L.), TH 6043 and TH 6044, experimental benzoylphenyl urea chitin-synthesis inhibitors, were as effective as diflubenzuron in reducing egg hatch and subsequent larval entry when eggs were deposited on previously treated fruits or foliage. All three compounds exhibited extended residual activity, with significant reductions in egg hatch occurring over a 19-week period. TH 6045 exhibited little activity against codling moth. All compounds tested were relatively ineffective in reducing egg hatch or subsequent larval entry when they were applied topically to deposited eggs, except for the red ring stage of development which was slightly affected.

scholarly journals Managing Bees for Delivering Biological Control Agents and Improved Pollination in Berry and Fruit Cultivation

2015 ◽  
Vol 4 (3) ◽  
pp. 89 ◽  
Author(s):  
Heikki M. T. Hokkanen ◽  
Ingeborg Menzler-Hokkanen ◽  
Marja-Leena Lahdenpera
Keyword(s):  
Crop Protection ◽  
Field Tests ◽  
Weather Conditions ◽  
Field Studies ◽  
Field Trials ◽  
Marketable Yield ◽  
Dissemination Activity ◽  
Grey Mold ◽  
Commercial Farms ◽  
Disease Pressure

<p>Targeted precision biocontrol and improved pollination were studied Europe-wide in the EU ERA-NET CORE ORGANIC 2 project BICOPOLL (Biocontrol and Pollination). A case study was conducted on the management of strawberry grey mold <em>Botrytis cinerea</em>, with the biocontrol fungus, <em>Gliocladium catenulatum</em>, vectored by honey bees or bumble bees. A joint field trial carried out in five countries targeted strawberry cultivations in open field, and included four treatments: untreated control, chemical fungicide, entomovectored biocontrol, and chemical and biocontrol combined. In organic fields, no pesticide treatments were included. The proportion of moldy berries, and/or the marketable yield of healthy berries were recorded from each treatment, along with other parameters of local interest. A pilot study was started in Finland in 2006, and, by 2012, large commercial farms were using entomovectoring. In 2012, field trials were started in Estonia and in Italy, and in 2013-14, these experiments were expanded to Slovenia and Turkey. In total, 26 field tests were conducted using entomovectoring and <em>Gliocladium catenulatum</em> (Prestop<sup>®</sup> Mix) on strawberry, with five additional trials on raspberry. Efficacy results have been excellent throughout the field studies. The results show crop protection equalling or exceeding that provided by a full chemical fungicide program, under all weather conditions, and over a wide geographical range (from Finland to Turkey). Under heavy disease pressure, entomovectoring provided on average a 47% disease reduction, which was the same as multiple fungicide sprays. Under light disease pressure, biocontrol decreased grey mold by an average of 66%, which was greater than fungicide sprays. The concept has proven to be effective on strawberries, raspberries, pears, apples, blueberries, cherries, and grapes. A conservative estimate for Finland is that over 500 ha of strawberry cultivation currently use the technique (≈15% of the strawberry growing area). To make full use of the entomovectoring technique, organic berry and fruit growers are encouraged to (i) keep bees, or to hire the service from local beekeepers for entomovectoring; and (ii) manage vegetation within and around the target crop to support the activity of bees and other pollinators, which can help to disseminate the beneficial microbial populations within the crop. Beekeepers are encouraged to (i) market pollination and biocontrol services to fruit and berry growers, and (ii) ensure that all operations are effective in mananging bees and their microbe dissemination activity. Biocontrol product manufacturers are encouraged to further develop products and their formulations specifically for entomovectoring, because current formulations are suboptimal as they are initially optimized for other uses (e.g., mixing into the soil).</p>

scholarly journals Optimizing Sowing Depth of Tef for Irrigated Mediterranean Conditions: From Laboratory to Field Studies

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1983
Author(s):  
Shiran Ben-Zeev ◽  
Shane Kerzner ◽  
Onn Rabinovitz ◽  
Yehoshua Saranga
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Field Trials ◽  
Eragrostis Tef ◽  
Sowing Depth ◽  
New Crops ◽  
Different Depths ◽  
Plant Emergence ◽  
Increasing Demand ◽  
Mediterranean Conditions

Developing new crops adapted to arid conditions is a promising approach to meet the increasing demand for food production under expanding aridity. Tef [Eragrostis tef (Zucc.) Trotter] is a C4 cereal crop cultivated mainly in Ethiopia and the Horn of Africa, and known for its high resilience to stressful environments. Due to their tiny size, tef seeds are traditionally sown by broadcasting and lightly covering with soil. Under semiarid Mediterranean conditions, a deeper sowing may guarantee seedling establishment while saving on irrigation water. The objective of this study was, therefore, to determine the effects of sowing depth on tef emergence, development, lodging, and productivity. Tef seeds were sown at different depths in test tubes and pots, and in two field experiments. In tubes and pots, time from sowing to emergence increased about twofold and emergence rate decreased in the deepest sowing (3 cm) treatment compared to controls (0 cm). In the pot and field trials, deep sowing (3 cm) significantly reduced plant height, shoot and root biomass, and lodging. Sowing depths of 1–2 cm allowed successful plant establishment while not exacting penalties on plant emergence or development; hence this range appears to be optimal for sowing irrigated tef.

Reliability of Singing Bird Surveys: Changes in Observer Efficiency with Avian Density

The Auk ◽  
1984 ◽  
Vol 101 (2) ◽  
pp. 307-318 ◽  
Author(s):  
Jonathan Bart ◽  
James D. Schoultz
Keyword(s):  
Measurement Error ◽  
General Procedure ◽  
Field Studies ◽  
Abundant Species ◽  
Common Species ◽  
Field Trials ◽  
Bird Songs ◽  
Auditory Cues ◽  
Basic Assumptions ◽  
Maximum Estimate

Abstract Field trials in which paired observers were used and indoor simulations in which recorded bird songs were used indicated that, as the number of singing birds audible from a listening station increased from 1 to 4, the fraction of them recorded by observers declined by up to 50%. This reduction in efficiency violates one of the basic assumptions of any index-that the proportion of animals detected remains constant-and could cause surveyors who rely primarily on auditory cues to underestimate changes in population density by up to 25% for common species and 33% for abundant species. The change in efficiency, which is best regarded as measurement error, cannot be detected by a statistical examination of the data and thus may pass undetected in many field studies. It seems unlikely that any general procedure for "correcting" the error would be reliable. The results indicate that singing bird surveys of common species should be supplemented by other methods if accurate estimates of changes in density are needed. A general conclusion of the study is that whenever animals "compete" for a place in the survey, for example by filling up traps or suppressing one another's songs, then the index tends to underestimate a change in density. If efficiency increases with density, then the survey tends to overestimate a change in density. If the sign of the bias can be determined, the survey can be used to provide a minimum or maximum estimate of a change in density even if the magnitude of the bias cannot be estimated.

scholarly journals Influence of soil pH, rainfall, dosage, and application timing of herbicide Merlin 750 WG (isoxaflutole) on phytotoxicity level in maize (Zea mays L.)

2011 ◽  
Vol 50 (No. 2) ◽  
pp. 88-94 ◽  
Author(s):  
J. Soukup ◽  
M. Jursík ◽  
P. Hamouz ◽  
J. Holec ◽  
J. Krupka
Keyword(s):  
Soil Ph ◽  
Weight Reduction ◽  
Zea Mays L ◽  
Field Studies ◽  
Field Trials ◽  
Early Growth ◽  
Application Timing ◽  
Pot Trials ◽  
Phytotoxic Effect ◽  
Shoot Weight

Pot trials and field studies were carried out to describe the influence of soil pH and rainfall on the phytotoxic effect of the herbicide Merlin 750 WG (isoxaflutole) in maize. Symptoms as bleaching, and root and shoot weight reduction in early growth of maize were found. In pot trials, a statistically significant crop injury in early growth of maize was found only at the herbicide dose of 100 and 130 g/ha followed by 30 mm precipitation directly after herbicide application in soils with pH 6.5 and 7.2. Bleaching and significant weight reduction of maize up to growth stage BBCH 13 were observed in field trials at treatments with early post-emergence application of Merlin and 20 mm precipitations. Bleaching symptoms recovered up to BBCH 19. Significant differences were found in maize shoot weight and cob yield between treatments with and without watering (20 mm irrigation), and between pre- and post-emergence application of Merlin under field conditions. No significant differences were found between herbicide doses tested.

scholarly journals Competition Between Fusarium pseudograminearum and Cochliobolus sativus Observed in Field and Greenhouse Studies

2018 ◽  
Vol 108 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Erin E. Gunnink Troth ◽  
Jeffrey A. Johnston ◽  
Alan T. Dyer
Keyword(s):  
Wheat Plant ◽  
Field Studies ◽  
Field Trials ◽  
Cochliobolus Sativus ◽  
Fusarium Spp ◽  
Fusarium Pseudograminearum ◽  
Population Sizes ◽  
Polymerase Chain ◽  
Pathogen Populations ◽  
Respective Species

Among root pathogens, one of the most documented antagonisms is the suppression of Cochliobolus sativus by Fusarium (roseum) species. Unfortunately, previous studies involved single isolates of each pathogen and thus, provided no indication of the spectrum of responses that occur across the respective species. To investigate the variability in interactions between Cochliobolus sativus and Fusarium pseudograminearum, field and greenhouse trials were conducted that included monitoring of spring wheat plant health and monitoring of pathogen populations via quantitative real-time polymerase chain reaction. The interactions between two isolates of C. sativus and four isolates of F. pseudograminearum were explored in three geographically distinct wheat fields. To complement field trials and to limit potentially confounding environmental variables that are often associated with field studies, greenhouse trials were performed that investigated the interactions among and between three isolates of C. sativus and four isolates of F. pseudograminearum. Across field locations, C. sativus isolate Cs2344 consistently and significantly reduced Fusarium populations by an average of 20.1%. Similarly, F. pseudograminearum isolate Fp2228 consistently and significantly reduced C. sativus field populations by an average of 30.9%. No interaction was detected in the field between pathogen species with regards to disease or crop losses. Greenhouse results confirmed a powerful (>99%), broadly effective suppression of Fusarium populations by isolate Cs2344. Among greenhouse trials, additional isolate–isolate interactions were observed affecting Fusarium populations. Due to lower C. sativus population sizes in greenhouse trials, significant Fusarium suppression of C. sativus was only detected in one isolate–isolate interaction. This study is the first to demonstrate suppression of Fusarium spp. by C. sativus in field and greenhouse settings. These findings also reveal a complex competitive interaction between these two pathogen species that was previously unknown.

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