scholarly journals 157 Susceptibility of Poinsettia Cultivars to Whiteflies

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 417A-417
Author(s):  
Robert P. Rice ◽  
Michael Crane
Keyword(s):  
Trialeurodes Vaporariorum ◽  
Natural Resistance ◽  
Euphorbia Pulcherrima ◽  
Silverleaf Whitefly ◽  
Bemisia Argentifolii ◽  
Immature Stages ◽  
Trichome Density ◽  
Greenhouse Whitefly ◽  
Wide Range ◽  
Leaf Trichome

Twenty-four poinsettia cultivars (Euphorbia pulcherrima) were exposed to a population of greenhouse whitefly (Trialeurodes vaporariorum) and silverleaf whitefly (Bemisia argentifolii) for 6 weeks. Evaluation was based on the number of immature whitefly present on each of the marked leaves. The poinsettias that produce white bracts were more heavily infested with immature stages of whitefly than those cultivars that produce red bracts, while those that produce pink bracts were intermediate. There was a wide range in degree of whitefly infestation among poinsettia cultivars. Leaf trichome density also explained a portion of the variance in whitefly oviposition rates among several of the cultivars. Cultivars with high trichome densities sustained less whitefly oviposition than did cultivars with low trichome densities. Certain cultivars tested showed an appreciable natural resistance to whitefly (`Freedom Red', `Freedom Bright Red', `Red Velvet', `Cranberry Punch', `Pepride').

scholarly journals 011 Reflective Mulches and Yellow Sticky Tape Control Whiteflies in Greenhouse Poinsettia (Euphorbia pulcherrima)

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 442E-442
Author(s):  
Robert P. Rice ◽  
Shelly Baird ◽  
Linzy Gatlin
Keyword(s):  
Insect Pests ◽  
Trialeurodes Vaporariorum ◽  
Euphorbia Pulcherrima ◽  
Silverleaf Whitefly ◽  
Bemisia Argentifolii ◽  
Greenhouse Whitefly ◽  
Subsequent Trial ◽  
Sticky Tape ◽  
Polyethylene Mulch ◽  
Better Than

Greenhouse Whitefly (Trialeurodes vaporariorum) and Silverleaf Whitefly (Bemisia argentifolii) are the most serious insect pests of poinsettia. Most growers rely on the use of foliar insecticide applications before bract coloring and an application of a single soil application of imidicloprid (Marathon) subsequently. This research was undertaken to investigate the use of reflective mulches or bench covers, which have been shown to be effective in outdoor applications for control of whitefly in the greenhouse. In an early trial, silver painted pot spacers and silver polyethylene mulch were placed between pots and both nymphs on leaves and adults caught on yellow sticky cards were monitored. Nymph populations were reduced by ≈35% and adults caught on sticky cards increased by ≈40% when compared with the control. In a subsequent trial, reflective bench covers were combined with the use of yellow sticky tape placed above the canopy of the crop and compared with sticky tape alone, reflective mulch alone, and no treatment. The combination of sticky tape and reflective mulch significantly reduced whitefly populations after 6 weeks and performed better than either of the other treatments alone.

scholarly journals Responses of Whitefly and Poinsettias to Insecticidal Controlled Atmospheres

2000 ◽  
Vol 125 (4) ◽  
pp. 513-517 ◽  
Author(s):  
Susan S. Han ◽  
Jennifer Konieczny
Keyword(s):  
Treatment Time ◽  
Treatment Temperature ◽  
Mortality Data ◽  
Euphorbia Pulcherrima ◽  
Silverleaf Whitefly ◽  
Bemisia Argentifolii ◽  
Complete Elimination ◽  
Greenhouse Whitefly ◽  
Controlled Atmospheres ◽  
Time Required

Eggs, larvae, pupae, and adult stages of greenhouse whitefly (Trialeurodes vaporarium Westwood) and silverleaf whitefly (Bemisia argentifolii Bellows & Perring) were exposed to insecticidal controlled atmospheres at 20 °C or 30 °C. Mortality data were calculated for each stage and results demonstrated that reduced-O2 atmospheres (an O2 level of <2 μL·L-1 balance in N2) resulted in faster and higher mortality than elevated-CO2 atmospheres (25% or 50% CO2). Responses, from the least to most tolerant stage was adult < larvae < eggs = pupae, regardless of the species of whitefly and treatment temperature. At 20 °C, treatment time required to kill >90% of adults, larvae, and eggs and pupae was 2, 4, and 8 hours, respectively. Increasing the treatment temperature from 20 to 30 °C reduced the treatment time to one-half that of 20 °C. Treatment time required to achieve complete elimination of the insects also caused phytotoxicity symptoms on poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch), thus, limiting use of insecticidal controlled atmospheres as the sole means for managing whitefly.

Evaluation of Selected Soybean Genotypes for Resistance to Two Whitefly Species (Homoptera: Aleyrodidae) in the Greenhouse

1995 ◽  
Vol 30 (4) ◽  
pp. 519-526 ◽  
Author(s):  
A. L. Lambert ◽  
R. M. McPherson ◽  
B. Sparks
Keyword(s):  
Growth Stage ◽  
Trialeurodes Vaporariorum ◽  
Leaf Damage ◽  
Silverleaf Whitefly ◽  
Bemisia Argentifolii ◽  
Greenhouse Whitefly ◽  
Breeding Lines ◽  
Varietal Response ◽  
Soybean Genotypes ◽  
Plant Injury

Fourteen soybean cultivars and breeding lines in Maturity Groups VII and VIII were monitored for silverleaf whitefly, Bemisia argentifolii Bellows and Perring, and greenhouse whitefly, Trialeurodes vaporariorum (Westwood), infestation levels in the greenhouse. Unifoliate leaves became infested with whitefly immatures and eggs 4 wks after planting. LA88-32 and F90-700 had significantly higher total whitefly populations than 11 and eight of the other entries, respectively, at growth stage V7. Whitefly populations were higher 6 wks after planting (growth stage V8–V9) when a unifoliate leaf and trifoliate leaves 1, 2, and 3 were sampled. G89-5180, Perrin, F90-988, G89-5066, N89-1, and N88-91 had significantly lower total numbers of whiteflies than F90-724, F90-700, and LA88-32. At 10 wks after planting (growth stage R2), G89-5180 and N88-91 had the lowest numbers of whiteflies, and total counts were significantly higher for F90-724 on trifoliolates 2, 4, and 6. Leaf damage ratings (% leaf burn) ranged from 1.3% (F90-724) to 74.0% (F90-1054). Sampling ceased after 10 wks because of excessive whitefly-induced plant injury to most soybean entries. This study reflected significant differences in soybean varietal response to whitefly population densities and demonstrated that the greenhouse can be used effectively to screen soybeans for resistance to whiteflies.

scholarly journals SCREENING OF SOMACLONAL VARIANTS IN VITRO TO PRODUCE INSECT RESISTANT PLANTS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1112e-1112
Author(s):  
Masood Hadi ◽  
Mark P. Bridgen
Keyword(s):  
Shoot Formation ◽  
Trialeurodes Vaporariorum ◽  
Callus Cultures ◽  
Ms Medium ◽  
Torenia Fournieri ◽  
Greenhouse Whitefly ◽  
Indolebutyric Acid ◽  
Wide Range ◽  
Tetranychus Urticae Koch

Callus cultures of Torenia fournieri `Compacta Blue' were initiated on a modified Murashige and Skoog salt medium (MS) with 2.26 uM 2,4-dichloro-phenoxy acetic acid. Shoots were regenerated from these cultures using the MS medium amended with 2.46 uM 3-indolebutyric acid and 8.88 uM 6-benzylaminopurine. These shoots were subjected to Tetranychus urticae Koch (twospotted spidermite) and Trialeurodes vaporariorum (Westwood) (greenhouse whitefly) in vitro. Pests were allowed to feed until such time that the pest population started to decrease due to lack of food. Remaining shoot tissue was placed on MS medium amended with 2.28 uM zeatin to -induce shoot formation. Shoots were acclimated to greenhouse conditions and evaluated for resistance to the pest to which they were subjected in vitro. Highly significant differences in pest numbers were found in somaclones when compared to control plants. A wide range of variability was observed within the somaclonal population.

scholarly journals Comparison of Biological and Chemical Control of Greenhouse Whitefly on Poinsettia Stock Plants

1992 ◽  
Vol 2 (4) ◽  
pp. 457-460 ◽  
Author(s):  
R.W. McMahon ◽  
R.K. Lindquist ◽  
M.L. Casey ◽  
A.C. Witt ◽  
S.H. Kinnamon
Keyword(s):  
Biological Control ◽  
Chemical Control ◽  
Trialeurodes Vaporariorum ◽  
Euphorbia Pulcherrima ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Wild Stock ◽  
Control Compartment

A demonstration study was conducted to compare the effectiveness of biological and chemical control treatments on the greenhouse whitefly (GHWF) (Trialeurodes vaporariorum, Westwood) using poinsettia (Euphorbia pulcherrima Wild.) stock plants. Two identical greenhouse compartments, each containing 84 stock plants, were used. In the biological control compartment, three biweekly releases of Encarsia formosa (EF) were made, while in the chemical control compartment eight weekly applications of resmethrin or acephate aerosol treatments were made. Results showed that overall greenhouse whitefly populations in the chemical control compartment were slightly lower than in the biological control compartment. Cuttings taken from stock plants in the biological control compartment at the end of the experiment were commercially acceptable with regard to the presence of GHWF adults. Chemical names used: O,S-dimethyl acetylphosphoramidothioate (acephate), [5-(phenylmethyl)-3-furanyl] methyl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropane-carboxylate (resmethrin).

scholarly journals First Report of Beet pseudo-yellows virus and Strawberry pallidosis associated virus in Strawberry in Peru

Plant Disease ◽  
2006 ◽  
Vol 90 (11) ◽  
pp. 1457-1457 ◽  
Author(s):  
W. M. Wintermantel ◽  
S. Fuentes ◽  
C. Chuquillanqui ◽  
L. F. Salazar
Keyword(s):  
Coat Protein ◽  
Pcr Amplification ◽  
Trialeurodes Vaporariorum ◽  
Rt Pcr ◽  
Greenhouse Whitefly ◽  
First Report ◽  
Wide Range ◽  
Pcr Products ◽  
Sequencing And Expression ◽  
Beet Pseudo Yellows Virus

During a 2006 survey for the presence of criniviruses in Peru, large numbers of greenhouse whitefly (Trialeurodes vaporariorum) were observed infesting strawberry (Fragaria × ananassa) fields near Huaral on the central coast of Peru. Plants exhibited a wide range of symptoms including stunting and reddening of leaves. These symptoms are characteristic of those induced by the presence of the criniviruses Beet pseudo-yellows virus (BPYV) and/or Strawberry pallidosis associated virus (SPaV) together with any of a number of different strawberry-infecting viruses (1,3). The virus complex causes older leaves to develop a red color, vein and petiole reddening, roots become stunted, and plants fail to develop. Leaf samples with varying symptoms were collected from 22 plants from 2 fields, each planted with a different cultivar. Total nucleic acid was extracted, spotted onto positively charged nylon membranes, and tested by hybridization with probes specific to the minor coat protein (CPm) gene of BPYV (2) and coat protein (CP) gene of SPaV (4). Results identified the presence of BPYV, SPaV, or both viruses in mixed infections in symptomatic strawberry, while control plants were infected with each virus individually. No signal was detected in virus-free strawberry. Secondary confirmation was obtained using probes specific to the RNA-dependent RNA polymerase (RdRp) genes of SPaV and BPYV. The SPaV probe corresponded to nucleotides 6116–6599 of SPaV RNA1 (GenBank Accession No. NC_005895), whereas the BPYV probe corresponded to nucleotides 6076–6447 of BPYV RNA1 (GenBank Accession No. NC_005209). All probes were generated by reverse-transcription polymerase chain reaction (RT-PCR) amplification using sequence-specific primers, cloning of RT-PCR products into pGEM-T Easy (Promega, Madison, WI), confirmation by sequencing, and expression as digoxygenin-labeled transcript probes (Roche, Indianapolis, IN). Field 1, containing cv. Fern Sancho, had the largest number of symptomatic and infected plants (5 of 12 BPYV, 6 of 12 SPaV, and 4 of 12 with both). Only 1 of 10 plants from field 2 containing cv. Tajo Holandesa was infected, but with both SPaV and BPYV. BPYV and SPaV are transmitted by the greenhouse whitefly (T. vaporariorum), although BPYV is transmitted much more efficiently and has a broader host range than SPaV (4). Movement of these viruses in Peru is likely a result of both propagation by runners and vector transmission. To our knowledge, this is the first report of either virus in Peru. References: R. R Martin and I. E. Tzanetakis. Plant Dis. 90:384, 2006. (2) I. E. Tzanetakis and R. R. Martin. Plant Dis. 88:223, 2004. (3) I. E. Tzanetakis et al. Plant Dis. 87:1398, 2003. (4) I. E. Tzanetakis et al. Plant Dis. 90:1343, 2006.

scholarly journals 549 Imidacloprid Applications for Whitefly Control on Poinsettia Using Ebb-and-flow Systems

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 540E-541
Author(s):  
Marc van Iersel ◽  
Ron Oetting
Keyword(s):  
Untreated Control ◽  
Leaf Tissue ◽  
Model System ◽  
Euphorbia Pulcherrima ◽  
Silverleaf Whitefly ◽  
Bemisia Argentifolii ◽  
Greenhouse Crops ◽  
Worker Exposure ◽  
Flow Systems ◽  
Ebb And Flow

Ebb-and-flow systems can be used to apply systemic pesticides to greenhouse crops without worker exposure or runoff. However, there is little information on the efficacy of pesticides applied with ebb-and-flow systems. We are using silverleaf whitefly (Bemisia argentifolii) control on poinsettia (Euphorbia pulcherrima) with imidacloprid as a model system to study pesticide efficacy in ebb-and-flow systems. The objective of this study was to determine the effect of the amount of insecticide taken up by the pot on the efficacy of whitefly control. Different amounts of imidacloprid uptake were obtained by not watering the plants for 0, 1, 2, or 4 days before the imidacloprid application. The imidacloprid (132 g·L–1) was applied once when the roots of the cuttings had reached the side of the pots. These treatments were compared to an untreated control on ebb-and-flow and a standard drench application (100 mL) to hand-watered plants. Pots in the different subirrigation treatments absorbed 12 to 175 mL of imidacloprid solution. Four days after the application, leaf tissue of the hand-watered plants contained 8 to 20 times more imidacloprid than the subirrigated plants. Efficacy was determined from the percentage of surviving mature whiteflies after 2 days on the plants and by counting the number of immatures after 2 weeks. Surprisingly, imidacloprid efficacy was better in the subirrigated imidacloprid treatments than in the hand-watered treatment. Whitefly control in all subirrigated imidacloprid treatments was excellent, irrespective of the amount of imidacloprid solution taken up by the pots.

Population Dynamics and Distribution of Trialeurodes vaporariorum and Bemisia tabaci (Homoptera: Aleyrodidae) on Poinsettia Following Applications of Three Chemical Insecticides

1993 ◽  
Vol 28 (1) ◽  
pp. 126-135 ◽  
Author(s):  
T. X. Liu ◽  
R. D. Oetting ◽  
G. D. Buntin
Keyword(s):  
Population Dynamics ◽  
Spatial Distribution ◽  
Bemisia Tabaci ◽  
Trialeurodes Vaporariorum ◽  
Immature Stages ◽  
Single Application ◽  
Sweetpotato Whitefly ◽  
Greenhouse Whitefly ◽  
Insecticide Application ◽  
The Third

The effects of three insecticides, bifenthrin, endosulfan and aldicarb, on the within- and between-plant distributions of both greenhouse whitefly (GHWF), Trialeurodes vaporariorum (Westwood), and sweetpotato whitefly (SPWF), Bemisia tabaci (Gennadius), were examined on greenhouse-grown poinsettia using Taylor's Power Law. Insecticide applications affected the spatial distribution of GHWF and SPWF. The populations of immatures of both species surviving an insecticide application on poinsettia were less aggregated within and between plants than untreated populations. Among the three insecticides, the efficacy against the two whiteflies was not significantly different at the end of the seventh week when multiple applications were conducted. Aldicarb caused higher mortality of immature stages than bifenthrin and endosulfan after four weeks following a single application. A single application of bifenthrin and endosulfan affected the distribution of all whitefly stages in the first and second weeks after treatment, whereas aldicarb did not affect the whitefly population until the third week. Insecticidal treatments had little effect on the stratification of whitefly stages within the plant.

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