Traces of Imidacloprid Induce Hormesis as a Stimulatory Conditioned Response of Sweetpotato Whitefly (Hemiptera: Aleyrodidae)

2019 ◽  
Author(s):  
M Rakotondravelo ◽  
D Smitley ◽  
E Calabrese ◽  
M Ladoni

Abstract Our purpose is to determine whether extremely low concentrations of imidacloprid (2–8 ppb) typically found in field soil 1–3 yr after a crop is grown using seed with a standard imidacloprid seed-coating could impact the fitness of whiteflies, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). Results of our experiments indicate that imidacloprid-resistant whitefly larvae feeding on cotton seedlings growing in soil with 8.0 ppb imidacloprid are conditioned so that when the same individuals feed on plants treated with imidacloprid as adults their fitness, measured as fecundity, increases 30–70% compared with individuals that were not primed as larvae. This conditioning hormesis stimulates resistant whiteflies more than susceptible whiteflies, which may contribute to the selection of resistant populations.

2010 ◽  
Vol 41 (No. 1) ◽  
pp. 8-13 ◽  
Author(s):  
K. Karut ◽  
C. Chu C ◽  
T.J. Henneberry ◽  
C. Kazak

The flight activities of adult sweetpotato whitefly, Bemisia tabaci, and leafhoppers were monitored by plastic cup traps at Boğalı, Taşçı, Hacıali, Doğankent and Balcalı in the Çukurova Plain, Turkey, in 2001 and 2003. Activity of B. tabaci, expressed as numbers of adults caught in traps, was low from May to early July in both years. Numbers of B. tabaci caught at Tasçı were higher than at Boğalı from 10 July and 21 August in 2001. Its numbers were also higher at Doğankent than at Hacıali and Balcalı during August of 2003. The numbers of leafhopper adults caught fluctuated greatly in both years. Numbers remained low until late June, followed by gradual increases in July and August at Boğalı and Taşçı in 2001. In contrast, numbers of adults caught were higher at Hacıali, Doğankent and Balcalı from May through July in 2003, followed by lower catches during the remainder of the season. Daily minimum temperatures in July and August were positively correlated with higher trap catches of both B. tabaci and leafhoppers.


2010 ◽  
Vol 6 ◽  
pp. 1079-1088 ◽  
Author(s):  
Peter C Griffiths ◽  
David W Knight ◽  
Ian R Morgan ◽  
Amy Ford ◽  
James Brown ◽  
...  

Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5–50 mg ml−1, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration). A range of neutron techniques – in particular small-angle neutron scattering (SANS) – have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester) motif, with SANS demonstrating the presence of regular structures in the 30–40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS) indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS) studies demonstrated that the solvent is largely unaffected by gelation, but does reveal insights into the thermal history of the samples. Further neutron studies of this kind (particularly SESANS and INS) are warranted, and it is hoped that this work will stimulate others to pursue this line of research.


PLoS ONE ◽  
2013 ◽  
Vol 8 (5) ◽  
pp. e61820 ◽  
Author(s):  
Nina Yang ◽  
Wen Xie ◽  
Xin Yang ◽  
Shaoli Wang ◽  
Qingjun Wu ◽  
...  

EDIS ◽  
1969 ◽  
Vol 2002 (8) ◽  
Author(s):  
Heather J. McAuslane

This document is EENY-129, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: April 2000. Revised: November 2002. https://edis.ifas.ufl.edu/in286


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