scholarly journals Evaluation of Medium-applied Insect Growth Regulators Against Fungus Gnats and Western Flower Thrips Populations on African Violets

2003 ◽  
Vol 13 (3) ◽  
pp. 515-517 ◽  
Author(s):  
Scott W. Ludwig ◽  
Kelli Hoover ◽  
Robert Berghage
Keyword(s):  
Growth Regulators ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Insect Growth Regulators ◽  
Experimental Conditions ◽  
Insect Growth ◽  
Flower Thrips ◽  
Fungus Gnats ◽  
Potting Medium ◽  
The Impact

In a previous study, three insect growth regulators, diflubenzuron, pyriproxyfen, and fenoxycarb, were shown to reduce the emergence of western flower thrips (Frankliniella occidentalis) from potting medium under experimental conditions. Our objective was to evaluate the impact of potting medium applications of fenoxycarb, diflubenzuron, and pyriproxyfen on western flower thrips and fungus gnats (Bradysia spp.) populations in conventionally grown african violets (Saintpaulia ionantha). In two trials conducted at a university greenhouse and one trial at a commercial flower grower's greenhouse, no reductions were observed in western flower thrips populations. In one university trial, all three insect growth regulators resulted in lower fungus gnat populations. In addition to medium treatment, results from the commercial greenhouse indicated that a pesticide application to the soil under the benches may also be needed to provide management of fungus gnats.

Spinetoram Is Compatible with the Key Natural Enemy of Frankliniella Species Thrips in Pepper

2008 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
Mrittunjai Srivastava ◽  
Lara Bosco ◽  
Joe Funderburk ◽  
Anthony Weiss
Keyword(s):  
Frankliniella Occidentalis ◽  
Field Experiments ◽  
Natural Populations ◽  
Western Flower Thrips ◽  
Central Florida ◽  
Flower Thrips ◽  
Natural Predator ◽  
Wilt Virus ◽  
The Impact ◽  
Reduced Risk

Feeding by the western flower thrips, Frankliniella occidentalis, causes damage to the fruits of pepper, and the species is the key vector of Tomato spotted wilt virus. Effective management integrates conservation of populations of the natural predator, Orius insidiosus, with the use of reduced-risk insecticides, namely spinosad. We conducted field experiments in northern Florida in 2005 and 2006 and in central Florida in 2006 to evaluate the new reduced-risk insecticide spinetoram for control of thrips and to determine the impact on natural populations of O. insidiosus. Spinetoram at 61 g ai/ha was as effective as spinosad at 140 g ai/ha against the western flower thrips and the other common thrips in Florida, Frankliniella tritici and Frankliniella bispinosa. The mean numbers of the predator were very high in all treatments in each experiment, and their numbers relative to the numbers of thrips indicated that predation was sufficient to suppress thrips populations in all treatments. Broad-spectrum insecticides when included in the experiments provided little or no control; sometimes, they flared thrips numbers compared to untreated pepper. Accepted for publication 25 October 2007. Published 18 January 2008.

scholarly journals Virus status of western flower thrips (Frankliniella occidentalis) does not affect their response to a thrips lure or host plant volatiles in a Ytube olfactometer

2012 ◽  
Vol 65 ◽  
pp. 120-125 ◽  
Author(s):  
M.M. Davidson ◽  
S.M. Skill ◽  
R.C. Butler ◽  
M-C. Nielsen ◽  
S. Keenan ◽  
...  
Keyword(s):  
Plant Volatiles ◽  
Tomato Spotted Wilt Virus ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Behavioural Response ◽  
Host Plant Volatiles ◽  
Flower Thrips ◽  
Tomato Spotted Wilt ◽  
Wilt Virus ◽  
The Impact

The impact of tospovirus infection on the behaviour of western flower thrips (Frankliniella occidentalis) was evaluated in a Ytube olfactometer The response of female western flower thrips with or without a tospovirus (Tomato spotted wilt virus TSWV) to a thrips lure (methyl isonicotinate MI) and chrysanthemum buds was recorded Compared to the blank arm significantly more thrips chose the odourladen arm of the Ytube when it contained MI (65 P016) increase the percentage of thrips that chose the odourladen arm over and above the cleanair arm but thrips (virusfree and infected) moved more quickly to the end of either arm when a bud was present The virus status of thrips was confirmed with RTPCR The presence of the virus in the vector did not substantially affect the behavioural response of the vector to a lure or hostplant material (P>04)

BIOLOGICAL CONTROL OF FUNGUS GNATS, BRADYSIA SPP. (DIPTERA: SCIARIDAE), AND WESTERN FLOWER THRIPS, FRANKLINIELLA OCCIDENTALS (PERGANDE) (THYSANOPTERA: THRIPIDAE), IN GREENHOUSES USING A SOIL-DWELLING PREDATORY MITE, GEOLAELAPS SP. NR. ACULEIFER (CANESTRINI) (ACARI: LAELAPIDAE)

1990 ◽  
Vol 122 (5) ◽  
pp. 975-983 ◽  
Author(s):  
David R. Gillespie ◽  
Donald M.J. Quiring
Keyword(s):  
Biological Control ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Predatory Mite ◽  
Flower Thrips ◽  
Fungus Gnats ◽  
Fungus Gnat ◽  
Greenhouse Cucumber ◽  
Crop Cycle ◽  
Hydroponically Grown

AbstractA soil-dwelling predatory mite, Geolaelaps sp. nr. aculeifer (Canestrini), introduced inundatively at a rate of 6000 mites per plant to the sawdust substrate of hydroponically grown, greenhouse cucumbers significantly reduced numbers of fungus gnat, Bradysia spp., larvae and adults over a 10-week period. Inundative introductions of 1600 mites per plant reduced emergence of western flower thrips, Frankliniella occidentalis (Pergande), adults to about 30% of that in the controls over a 40-day trial. An inoculative introduction of 125 mites per plant to cucumber plants in selected rows in a commercial greenhouse reduced peak fungus gnat numbers to about 20% of those in untreated rows. These results suggest that a single inoculative introduction of Geolaelaps sp. nr. aculeifer, early in the crop cycle, would maintain control of fungus gnat populations in greenhouse cucumber crops at an acceptable level. This predator would also contribute to biological control of western flower thrips by reducing emergence of adults.

Sublethal Effects of Insect Growth Regulators on Boll Weevil (Coleoptera: Curculionidae)

2019 ◽  
Vol 112 (5) ◽  
pp. 2222-2228 ◽  
Author(s):  
Guilherme G Rolim ◽  
Eduardo M Barros ◽  
Paulo R R Barbosa ◽  
Lucas S Arruda ◽  
Jorge B Torres
Keyword(s):  
Growth Regulators ◽  
Boll Weevil ◽  
Cotton Leaf ◽  
Anthonomus Grandis ◽  
Egg Viability ◽  
Insect Growth Regulators ◽  
Initial Exposure ◽  
Insect Growth ◽  
The Impact ◽  
Cotton Pest

Abstract Immature stages of the boll weevil, Anthonomus grandis grandis Boh. (Coleoptera: Curculionidae), develop protected inside cotton fruiting structures. Therefore, the adult beetles have become the main target of insecticide applications. The use of insect growth regulators (IGRs) is recommended against immatures, even though they may also affect the survival and reproductive traits of adult insects. The present study evaluated the impact of a juvenile hormone analog (pyriproxyfen), an ecdysteroid agonist (methoxyfenozide), and a chitin biosynthesis inhibitor (lufenuron) on adult cotton boll weevils, a key cotton pest. Mated and virgin beetles were treated by feeding them contaminated squares and cotton leaf discs that were previously immersed into pyriproxyfen, methoxyfenozide, and lufenuron solutions at field-rate concentrations. After exposure, treated couples were caged onto cotton plants, and survival, fecundity, and egg viability were evaluated. The IGRs neither affected the survival nor fecundity of adult boll weevils. On the other hand, egg viability was significantly reduced by lufenuron, regardless of whether the females were treated premating or postmating or whether their pairs were either treated or untreated. However, egg viability increased as the females aged since the initial exposure date to lufenuron, indicating a potential transovarial effect of this insecticide. Our results indicate that pyriproxyfen and methoxyfenozide do not affect adult boll weevils, whereas lufenuron temporarily reduces the egg viability of this key cotton pest.

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.

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