scholarly journals Flower Quality, Flower Number, and Western Flower Thrips Density on Transvaal Daisy Treated with Granular Insecticides

1998 ◽  
Vol 8 (4) ◽  
pp. 567-570 ◽  
Author(s):  
Raymond A. Cloyd ◽  
Clifford S. Sadof
Keyword(s):  
Frankliniella Occidentalis ◽  
Block Design ◽  
Western Flower Thrips ◽  
Gerbera Jamesonii ◽  
Flower Number ◽  
Flower Thrips ◽  
Randomized Complete Block Design ◽  
Flower Tissue ◽  
Four Blocks ◽  
Flower Quality

Greenhouse studies were conducted to determine the efficacy of two granular systemic insecticides, acephate (Pinpoint 15G) and imidacloprid (Marathon 1G), against western flower thrips (Frankliniella occidentalis Pergande) on Transvaal daisy (Gerbera jamesonii H. Bolus ex. Hook. f). These studies were arranged in a randomized complete-block design with four blocks and four treatments per block. Two rates of acephate (0.75 g/16.5-cm pot and 1.0 g/16.5-cm pot) and one rate of imidacloprid (1.3 g/16.5-cm pot) were used in two studies. Plants were artificially inoculated with five adult western flower thrips at the prebloom stage. Plants were evaluated each week for flower quality (1 = complete injury or flower distortion to 5 = no injury), thrips density per flower, and number of plants flowering in each plot. Both studies showed that the acephate treated plants had the best flower quality, lowest numbers of thrips, and greatest number of plants flowering compared to imidacloprid and the check. These studies demonstrate that granulated acephate exhibits some activity in flower tissue and may assist growers in managing western flower thrips in floricultural crops.

scholarly journals Effects of Spinosad and Acephate on Western Flower Thrips Inside and Outside a Greenhouse

2000 ◽  
Vol 10 (2) ◽  
pp. 359-362 ◽  
Author(s):  
Raymond A. Cloyd ◽  
Clifford S. Sadof
Keyword(s):  
Natural Enemies ◽  
Frankliniella Occidentalis ◽  
Block Design ◽  
Western Flower Thrips ◽  
Gerbera Jamesonii ◽  
Flower Thrips ◽  
Randomized Complete Block Design ◽  
Four Blocks

Greenhouse studies were conducted from 1996 to 1998 to determine the efficacy of spinosad, and acephate, against western flower thrips (Frankliniella occidentalis Pergande) on transvaal daisy (Gerbera jamesonii H. Bolus ex. Hook f). In addition, the number of natural enemies inside and outside the greenhouse was determined. Studies were arranged in a randomized complete-block design with four blocks and four treatments per block. Three rates of spinosad, 50, 100, and 200 mg·L-1 (ppm), and one rate of acephate, 600 mg·L-1 were used in all three studies. Plants were artificially inoculated at bloom with 10 adult western flower thrips. The number of live and dead thrips was counted from each plant. In all three studies, both spinosad and acephate controlled thrips. However, there was more variation in the average number of live thrips for acephate than spinosad across years. In all treatments fewer live thrips and more natural enemies were found on plants outside the greenhouse than inside the greenhouse. This suggests that placing plants outdoors allows the natural enemies of thrips to colonize plants and provide supplemental control.

scholarly journals Comparisons of Chemical Controls for Thrips (Frankliniella occidentalis) on Greenhouse-grown Gerbera (Gerbera jamesonii L.)

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 677a-677
Author(s):  
Julie A. McIntyre ◽  
Douglas A. Hopper ◽  
W.S. Cranshaw
Keyword(s):  
Diatomaceous Earth ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Gerbera Jamesonii ◽  
Saccharopolyspora Spinosa ◽  
Physical Methods ◽  
Chemical Treatments ◽  
Flower Thrips ◽  
Soil Actinomycete ◽  
Over Time

Chemical and physical methods were tested to determine their effectiveness in controlling Western Flower Thrips, Frankliniella occidentalis (Pergande), in greenhouses. Comparisons were made between abamectin (Avid); Spinosyn A and D, formulated from the soil Actinomycete, Saccharopolyspora spinosa (Spinosad); azadirachtin (Margosan-O); and diatomaceous earth, a physical control aimed at deterring pupation. Results based on the number of thrips counted in gerbera (Gerbera jamesonii L.) flowers indicate that the chemical treatments were significantly more effective in reducing populations than the diatomaceous earth. Over time, the population of thrips in both the Avid and Spinosad treatments was reduced to zero. Diatomaceous earth treatments reduced populations almost 50% as compared to the control, while reductions from Margosan-O ranged 50-90%.

scholarly journals Morphological and Chemical Factors Related to Western Flower Thrips Resistance in the Ornamental Gladiolus

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1384
Author(s):  
Dinar S. C. Wahyuni ◽  
Young Hae Choi ◽  
Kirsten A. Leiss ◽  
Peter G. L. Klinkhamer
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Resistance Breeding ◽  
Breeding Programs ◽  
Triterpenoid Saponins ◽  
Flower Thrips ◽  
Highly Correlated

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the 1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.

Stability of spinosad resistance inFrankliniella occidentalis(Pergande) under laboratory conditions

2008 ◽  
Vol 98 (4) ◽  
pp. 355-359 ◽  
Author(s):  
P. Bielza ◽  
V. Quinto ◽  
C. Grávalos ◽  
E. Fernández ◽  
J. Abellán ◽  
...  
Keyword(s):  
Resistant Strain ◽  
Selection Pressure ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Laboratory Conditions ◽  
Flower Thrips ◽  
Factors Influencing ◽  
Stability Of Resistance ◽  
The Stability ◽  
Successive Generations

AbstractThe stability of spinosad resistance in western flower thrips (WFT),Frankliniella occidentalis(Pergande), populations with differing initial frequencies of resistance was studied in laboratory conditions. The stability of resistance was assessed in bimonthly residual bioassays in five populations with initial frequencies of 100, 75, 50, 25 and 0% of resistant individuals. There were no consistent changes in susceptibility of the susceptible strain after eight months without insecticide pressure. In the resistant strain, very highly resistant to spinosad (RF50>23,000-fold), resistance was maintained up to eight months without further exposure to spinosad. In the absence of any immigration of susceptible genes into the population, resistance was stable. In the case of the population with different initial frequency of resistant thrips, spinosad resistance declined significantly two months later in the absence of selection pressure. With successive generations, these strains did not change significantly in sensitivity. Spinosad resistance inF. occidentalisdeclined significantly in the absence of selection pressure and the presence of susceptible WFT. These results suggest that spinosad resistance probably is unstable under field conditions, primarily due to the immigration of susceptible WFT. Factors influencing stability or reversion of spinosad resistance are discussed.

scholarly journals Generation Mean Analysis in Cowpea [Vigna unguiculata (L.) Walp.] under Flower Thrips infestation

2018 ◽  
Vol 10 (4) ◽  
pp. 86 ◽  
Author(s):  
Gonné Sobda ◽  
Fonji Maureen Atemkeng ◽  
Ousmane Boukar ◽  
Chistian Fatokun ◽  
Pangirayi Bernard Tongoona ◽  
...  
Keyword(s):  
Block Design ◽  
Generation Mean Analysis ◽  
Flower Number ◽  
Narrow Sense Heritability ◽  
Gene Effects ◽  
Flower Thrips ◽  
Randomized Block Design ◽  
Cowpea Resistance ◽  
Predominant Type ◽  
Screen House

Two sets of six generations (P1, P2, F1, F2, BC1P1, BC1P2) of cowpea were developed from crosses of contrasting inbred lines VYA (susceptible) × SANZI (resistant) and LORI (susceptible) × SANZI (resistant). The aim of this study was to determine the inheritance and elucidate the genetic control of cowpea resistance to thrips. The first set (VYA × SANZI) was evaluated under natural thrips infestation in the field in a completely randomized block design with three replications. The second set (LORI × SANZI) was screened using artificial thrips infestation in the screen house. In each trial, data were recorded on 150 individual plants. These included the score of thrips damages using the scale of one to nine, number of thrips per flower, number of pods per plant, pod weight per plant and grain weight per plant. The generation mean analysis revealed that both additive and non-additive types of gene effects were significant. Dominance × dominance was the most predominant type of gene effects for thrips resistance, suggesting that breeders should delay selection to late generations to allow advancement of as many high-potential recombinants as possible during hybridization. The number of genes that control the expression of number of thrips per flower was three and ranged from three to four, for score of thrips damages. High broad sense and moderate narrow sense heritability were observed ranging from 0.53 to 0.65 and 0.14 to 0.36, respectively for all of the traits measured. 

Virus Decline of Strawberry in California and the Role of Insect Vectors and Associated Viruses

2015 ◽  
Vol 16 (4) ◽  
pp. 211-215 ◽  
Author(s):  
Surendra K. Dara
Keyword(s):  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Trialeurodes Vaporariorum ◽  
Current Status ◽  
Insect Vectors ◽  
The Past ◽  
Disease Vector ◽  
Flower Thrips ◽  
Purple Coloration

Greenhouse white fly, Trialeurodes vaporariorum (Westwood); western flower thrips, Frankliniella occidentalis (Pergande); and strawberry aphid, Chaetosiphon fragaefolii (Cockerell), are common pests of strawberries in California and are vectors of one or more viruses. Most of the viruses transmitted by these vectors do not cause symptoms on strawberry when the infection occurs individually. However, when one of the viruses (Beet pseudoyellows virus or Strawberry pallidosis-associated virus) transmitted by T. vaporariorum is present along with one of the viruses transmitted by F. occidentalis, C. fragaefolii, or other sources, it results in a virus decline of strawberry, which can cause significant crop losses. Stunted root and plant growth, purple coloration of foliage, and dieback of the plant are some of the symptoms associated with virus decline. Increases in T. vaporariorum infestations during the past few years significantly elevated the risk of whitefly as a crop pest and a disease vector. This article reviews virus decline of strawberry, symptoms of infection, and the current status of insect vectors in California strawberries. Accepted for publication 17 November 2015. Published 20 November 2015.

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