Indices of Plant Damage and Heritability of Tolerance to the Spotted Alfalfa Aphid in Alfalfa

Crop Science ◽  
1989 ◽  
Vol 29 (6) ◽  
pp. 1337-1340 ◽  
Author(s):  
H. O. Jimenez ◽  
J. L. Caddel ◽  
R. C. Berberet ◽  
R. W. McNew
Keyword(s):  
Plant Damage

Ethephon for American Ginseng (Panax quiquefolium L.) Inflorescence Removal

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 481b-481
Author(s):  
A.E. Fiebig ◽  
J.T.A. Proctor ◽  
D. Murr ◽  
R. Releeder
Keyword(s):  
Additive Concentration ◽  
Root Mass ◽  
Panax Quinquefolium ◽  
Fruit Removal ◽  
Plant Damage ◽  
Low Concentrations ◽  
Production Practice ◽  
Whole Plants ◽  
Mass Increase ◽  
Standard Production

Varying concentrations (500-4000 mg·L–1) of ethephon, an ethylene-releasing compound, were applied to 3-year-old ginseng (Panax quinquefolium L.) plants in fields of southern Ontario. The effects of this chemical on fruit removal, plant damage, infructescence morphology, and root mass were studied and compared to the normal practice of manual inflorescence removal. The highest concentrations had the highest rates of removal but also caused the greatest amount of damage to the whole plants when compared to the mid-range concentrations. The lowest concentrations showed less foliar damage but did not provide sufficient fruit removal to mimic hand removal. When individual inflorescences of the ethephon treatments were studied, the seed heads had fewer ripe berries and more unpollinated florets than the untreated controls. When root masses were compared, high and low concentrations showed lower masses than those of the standard production practice of hand removal. However, mid range concentrations showed similar root mass increase to manual removal. When all parameters were considered, the concentration range giving the best results was 1000-1500 mg·L–1. Multiple applications of ethephon, at weekly intervals, had an additive effect on flower removal and plant damage. Treatments having an additive concentration of over 2000 mg·L–1 had detrimental effects on all parameters. Those within the 1000–1500 mg·L–1 range showed the highest similarity to the hand removal benefits.

scholarly journals Flea Beetle Control in Lower Rainfall Se Washington, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 205-205
Author(s):  
D. E. Bragg ◽  
D. Mayer
Keyword(s):  
Flea Beetle ◽  
Plant Introduction ◽  
Plant Damage ◽  
Total Destruction ◽  
Cotyledon Stage ◽  
Untreated Check ◽  
Plant Stand

Abstract Plots were planted 9 June at the USDA-ARS Western Plant Introduction Center at Central Ferry, WA at a rate of 6 lb/acre in rows 7 inches apart. Plots were 15 x 3 ft replicated in a RCBD 4 times, and were situated with replicates perpendicular to a crested wheat grass field. Precounts (PrCt) of plant stand per 6.6 ft row, and damage on 20 randomly selected plants on a scale of 0 to 6, with 0 = no damage and 6 = total destruction, were made 21 Jun. A treatment consisting of Furadan CR-10 granules at a rate of 2.5 lb product per acre was applied at seeding. Four other insecticide treatments were made with a CO2 backpack sprayer at 20 gpa and 20 psi on 22 Jun. An untreated check was established. Conditions at treatment were 70°F with a 2 mph wind at 11 a.m. All plants were in the cotyledon stage with meristem visible. Evaluations of stand reduction and plant damage were made on 2, 5, 7, and 10 DAT. All surviving plants were in the rosette stage (5 to 7 leaf) at 10 DAT.

scholarly journals Acylsugars in tomato leaflets confer resistance to the South American tomato pinworm, Tuta absoluta Meyr

2006 ◽  
Vol 63 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Juliano Tadeu Vilela de Resende ◽  
Wilson Roberto Maluf ◽  
Marcos Ventura Faria ◽  
Alessandra Zawadzki Pfann ◽  
Ildon Rodrigues do Nascimento
Keyword(s):  
Tuta Absoluta ◽  
Wild Accession ◽  
South American ◽  
Resistance Level ◽  
Plant Damage ◽  
F2 Population ◽  
South American Tomato Pinworm ◽  
Lesion Type ◽  
Parental Lines ◽  
Interspecific Crossing

Acylsugars present in the accession 'LA716' of Lycopersicon pennellii play an important role in the resistance to Tuta absoluta. This paper investigates the possible association between the resistance to T. absoluta and the acylsugar contents in F2 and F2BC1 tomato plants derived from the interspecific crossing between L. esculentum 'TOM-584' and L. pennellii 'LA716'. From the F2 population, four high acylsugars and one low acylsugars plants were selected and tested for Tuta absoluta resistance along with parental lines TOM-584 and LA-716, and with the checks TOM-600 (high 2-tridecanone line with resistance to T. absoluta) and TOM-556 (low acylsugar line). The genotypes were tested under natural field infestation and were evaluated for overall plant damage, leaflet lesion type and percent of attacked leaflet. Four plants from F2BC1 [=(Lycopersicon esculentum 'TOM-584' <FONT FACE=Symbol>´</FONT> F2)] were selected for high acylsugars and two for low acylsugars, and tested in greenhouse cages infested with T. absoluta. These genotypes were evaluated with the parental lines and the checks for oviposition ten days after infestation, and for leaflet lesion type and overall plant damage at four different dates. The F2 genotypes BPX-370Bpl#25, BPX-370Bpl#30 and BPX-370Bpl#79, the F2BC1 genotypes BPX-370B pl#30-380 and BPX-370B pl#30-271 and the wild accession LA716 had good levels of resistance to Tuta absoluta. The resistance level increased with longer exposition time to the acylsugars, both in the field and in the cage tests. Acylsugar contents seemed to be highly and negatively correlated with the traits related to the pinworm resistance.

scholarly journals Digital imaging outperforms traditional scoring methods of spittlebug tolerance in Urochloa humidicola hybrids

2020 ◽  
Author(s):  
Luis M. Hernandez ◽  
Paula Espitia ◽  
Valheria Castiblanco ◽  
Juan A Cardoso
Keyword(s):  
Correlation Coefficient ◽  
Digital Imaging ◽  
Digital Images ◽  
Breeding Program ◽  
Alternative Methods ◽  
Screening Methods ◽  
Plant Tolerance ◽  
Scoring Method ◽  
Plant Damage ◽  
Visual Scoring

AbstractAmerican spittlebug complex (Hemiptera: Cercopidae) is a critical pest for existing Urochloa humidicola cultivars in the neotropical savannas. The U. humidicola breeding program of the International Center for Tropical Agriculture aims to increase tolerance to spittlebugs. To develop U. humidicola genotypes with superior tolerance to spittlebugs than existing cultivars, adequate screening methods ought to be deployed. Currently, visual scores of plant damage by spittlebugs is the standard method to screen for variation in plant tolerance. However, visual scoring is prone to human bias, is of medium throughput and relies of the expertise of well-trained personnel. In this study, we compared estimations of plant damage from two alternative methods (SPAD measurements and digital images) and visual scoring from an inexpert evaluator with the plant damage estimated from an expert. This information should instruct if different methods could be implemented in the U. humidicola breeding program. Time needed to evaluate damage was recorded for each method. Lin’s correlation coefficient, Pearson’s correlation coefficient and broad sense heritability values were also calculated. Overall, damage estimated from digital images showed the highest throughput (twice as fast as visual scoring from an expert); high correlations with visual scoring (r > 0.80, p < 0.0001); and heritability values for plant damage as good or better (> 0.7) than those obtained by visual scoring from an expert. Our results indicate that digital imaging is a phenotyping method that might improve the efficiency of breeding for increased tolerance to spittlebugs in U. humidicola.HighlightDigital imaging outperformed standard scoring method of spittlebug tolerance in Urochloa humidicola, suggesting that this method might improve the efficiency of breeding for such stress.

scholarly journals UJI EFEKTIVITAS NEMATODA ENTOMOPATOGEN (RHABDITIDA: Steinernema DAN Heterorhabditis) SEBAGAI MUSUH ALAMI NON-ENDEMIK PENGGEREK BATANG PADI KUNING (Scirpophaga incertulas)

2007 ◽  
Vol 7 (2) ◽  
pp. 71-79
Author(s):  
Chaerani Chaerani ◽  
Bebet Nurbaeti
Keyword(s):  
Entomopathogenic Nematodes ◽  
Insect Pests ◽  
Larval Mortality ◽  
Damage Threshold ◽  
Stem Borer ◽  
Leaf Sheath ◽  
Scirpophaga Incertulas ◽  
Potted Plants ◽  
Plant Damage ◽  
Rice Stem Borer

Efficacy Tests of Entomopathogenic Nematodes (Rhabditida:  Steinernema dan Heterorhabditis) as Non-endemic Natural Enemies of Yellow Rice stem Borer (Scirpophaga incertulas). Yellow rice stem borer (Scirpophaga incertulas) is a chronic insect pests of irrigated rice and difficult to control.  Entomopathogenic nematodes from the genus Steinernema and Heterorhabditis are promising biological control agents for this pest as their infective juveniles (IJs) are capable of seeking and infecting insect living in moist, cryptic habitat such as galleries created by stem borer larvae. Thirteen indigenous and exotic Steinernema and Heterorhabditis sprayed to rice seedlings in laboratory with nematodes at concentrations of 0.5 or 2.0×104 IJs ml-1 water caused larval mortality between 7–93%.  Further test in greenhouse on nematodes that had >50%  efficacy showed that an indigenous isolate, H. indicus INA H17, was the most effective among the tested nematodes in killing larvae or pupae (78%).  Reduction in plant damage caused by the insects could not be demonstrated as the trials was limited to potted plants. The survival ability of nematodes on rice plants was evaluated by using INA H4 as an example. A low percentage of INA H4 IJs (0.5%) persisted in inner leaf sheath until 7 days post application, while IJs on leaf surface and outer leaf sheath survived only until 2 and 48 hours post application, respectively. Improvement of application strategies including repeated spray, addition of antidessicant and adjusment of spray volume and application at damage threshold or plant critical period are deemed necessary to enhance nematode efficacy and reduce plant damage in the field.

scholarly journals AR37 endophyte effects on porina and root aphid populations and ryegrass damage in the field

2012 ◽  
pp. 165-169 ◽  
Author(s):  
A.J. Popay ◽  
B. Cotching ◽  
A. Moorhead ◽  
C.M. Ferguson
Keyword(s):  
Field Trials ◽  
Larval Survival ◽  
Italian Ryegrass ◽  
The Novel ◽  
Plant Damage ◽  
Pot Trials ◽  
Plant Densities ◽  
Aphid Populations

The novel endophyte, AR37, in ryegrass has reduced porina larval survival and plant damage in pot trials. To determine the effect of AR37 on larvae in the field, populations were estimated in two ryegrass field trials in Canterbury. Plant damage and plant densities were also scored in one trial. At Ceres Farm, no porina were found in Italian ryegrass 'Status' infected with AR37 whereas low populations (

scholarly journals Azalea Lace Bug, Stephanitis pyrioides (Scott) (Insecta: Hemiptera: Tingidae)

EDIS ◽  
2006 ◽  
Vol 2006 (20) ◽  
Author(s):  
Jamba Gyeltshen ◽  
Amanda Hodges
Keyword(s):  
Life History ◽  
Host Plant ◽  
Fact Sheet ◽  
Plant Damage ◽  
Lace Bug ◽  
Ornamental Trees ◽  
Trees And Shrubs

EENY-373, a 5-page illustrated fact sheet by Jamba Gyeltshen and Amanda Hodges, describes this pest of ornamental trees and shrubs. Part of the Featured Creatures series, this publication covers the distribution, description, life history, host plant, damage, management, and selected references. Published by the UF Department of Entomology and Nematology, May 2006. EENY-373/IN677: Azalea Lace Bug, Stephanitis pyrioides (Scott) (Insecta: Hemiptera: Tingidae) (ufl.edu)

The concentration of lamdacyhalothrin and its effect on the cutworm Agrotis segetum (Lepidoptera: Noctuidae)

1991 ◽  
Vol 81 (2) ◽  
pp. 143-145 ◽  
Author(s):  
B.W. Blair
Keyword(s):  
Fourth Instar ◽  
Synthetic Pyrethroid ◽  
Agrotis Segetum ◽  
Economic Plant ◽  
Initial Screening ◽  
Pest Damage ◽  
Plant Damage ◽  
Antifeedant Effect ◽  
Equivalent Rate ◽  
Lepidoptera Noctuidae

AbstractDuring initial screening of the synthetic pyrethroid lamdacyhalothrin (PP 321) at a concentration of 44 and 22 mg/l and applied as a 30 ml drench over each plant against third to fourth instar cutworms, Agrotis segetum (Denis & Schiffermüller) in microplots, few died but they did not damage the plants. Reducing the concentrations to 11 and 5.5 mg/l increased mortality and plant damage. When A. segetum were confined on soil treated with the insecticide at concentrations of 22, 11 and 5.5 mg/l and sprayed at an equivalent rate of 500 l/ha, they all died within one day. The higher concentrations appeared to have a repellent and/or antifeedant effect, and it has been possible to reduce the concentration of lamdacyhalothrin to 12.5 mg/l (≡5.6g a.i./ha) for the drench treatment without risking economic plant damage. For insecticides that have repellent and/or antifeedant properties, it should be possible to balance lower concentrations with adequate protection of plants from pest damage.

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