Efficacy of Entomopathogenic Nematodes Against Western Flower Thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), Under Laboratory Conditions

2019 ◽  
Vol 27 (2) ◽  
pp. 322 ◽  
Author(s):  
T.M. Dlamini ◽  
E. Allsopp ◽  
A.P. Malan
Keyword(s):  
Entomopathogenic Nematodes ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Laboratory Conditions ◽  
Flower 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.

Laboratory bioassays of virulence of entomopathogenic nematodes against soil-inhabiting stages of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)

Nematology ◽  
2003 ◽  
Vol 5 (4) ◽  
pp. 539-547 ◽  
Author(s):  
Dammini Premachandra ◽  
Christian Borgemeister ◽  
Oliver Berndt ◽  
Ralf-Udo Ehlers ◽  
Hans-Michael Poehling
Keyword(s):  
Entomopathogenic Nematodes ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Steinernema Carpocapsae ◽  
Steinernema Feltiae ◽  
Flower Thrips ◽  
Laboratory Trial ◽  
Dose Response Study ◽  
First Time ◽  
Laboratory Bioassays

Abstract The efficacy of entomopathogenic nematodes (EPN) was evaluated in a laboratory trial against soil-dwelling stages, late second instar larvae and pupal stages of western flower thrips (WFT), Frankliniella occidentalis Pergande. Among the six EPN strains assessed for the first time, Steinernema feltiae (Nemaplus®) and Heterorhabditis bacteriophora (HD01) caused 65 and 59% mortality, respectively. Steinernema carpocapsae (Agriotos) and S. arenarium (Anomali) caused moderate mortality (40-45%) while Steinernema spp. (Morocco) and H. bacteriophora (Nematop®) had little effect. In a dose response study with concentrations of 100, 400 and 800 infective juveniles (IJ) per cm2 soil of H. bacteriophora (HK3), S. feltiae (Nemaplus®) and H. bacteriophora (HD01), mortality increased only up to 400 IJ cm-2. The rate of infectivity of H. bacteriophora (HK3) and S. feltiae (Nemaplus®) indicated that both strains could survive at least 6 days in the soil and infect WFT immature stages.

Efficacy of entomopathogenic nematodes against western flower thrips Frankliniella occidentalis at different pupation depths

Nematology ◽  
2004 ◽  
Vol 6 (4) ◽  
pp. 495-505 ◽  
Author(s):  
Lemma Ebssa ◽  
Christian Borgemeister ◽  
Jörg Semrau ◽  
Hans-Michael Poehling
Keyword(s):  
Entomopathogenic Nematodes ◽  
Frankliniella Occidentalis ◽  
Soil Depth ◽  
Western Flower Thrips ◽  
High Concentration ◽  
Heterorhabditis Indica ◽  
Dose Rates ◽  
Flower Thrips ◽  
Different Depths

Abstract To study the effects of the pupation depth of western flower thrips (WFT), Frankliniella occidentalis (Pergande), on the efficacy of entomopathogenic nematodes (EPN), Heterorhabditis indica strain LN2 and Steinernema bicornutum were applied at dose rates of 100 and 400 infective juveniles (IJ) cm–2to WFT that had pupated at different depths. Additionally, the effects of EPN concentrations and thrips densities were tested on the pupation depth of WFT. A higher concentration of H. indica was required when the thrips pupated deeper. Yet applications of S. bicornutum even at a high concentration resulted in a significantly lower WFT mortality at greater rather than at shallower depths. Generally, WFT control levels of 5-57% were obtained depending on depth of pupation, EPN species, and concentrations. The results clearly indicate that WFT at high EPN concentrations seem to remain at a certain soil depth in order to avoid EPN attraction by moving around. Without or at low EPN concentrations, up to 80% of WFT pupated at the deepest depth of 3-5 cm. However, at higher thrips densities and EPN concentrations, 45-48% of WFT pupated in the medium depth of 1-3 cm. Thus, depth of pupation is an important factor in WFT control using EPN.

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