@article {11006,
	title = {Partial characterization of glutathione S-transferases in pyrethroid-resistant and -susceptible populations of the maize weevil, Sitophilus zeamais},
	journal = {Journal of Stored Products Research},
	volume = {43},
	number = {2},
	year = {2007},
	month = {2007},
	pages = {167-170},
	abstract = {Glutathione S-transferases (GSTs) from a susceptible (Sete Lagoas) and two pyrethroid-resistant populations (Jacarezinho and Juiz de Fora) of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) were characterized through in vitro colorimetric assays. GSTs showed higher activity peaks at pH 9.0 and 30[degree]C. The Km-values for GSTs were similar among the populations except for the resistant population from Juiz de Fora, which was about two-fold higher than the susceptible population from Sete Lagoas when using 1-chloro-2,4-dinitrobenzene (CDNB) as substrate (and a fixed concentration of reduced glutathione-GSH). The Vmax of this same resistant population was also over two-fold higher than that of the pyrethroid-susceptible population when CDNB and GSH were used as substrates. The resistant population from Jacarezinho also had a slightly, but significantly, higher Vmax than the susceptible population when using these two substrates. However, there were no significant differences among the kinetic parameters of GSTs from the maize weevil populations when DCNB and GSH were used as substrates. These results provide evidence of the involvement of enhanced GST activity as an additional pyrethroid-resistant mechanism in at least some maize weevil populations from Brazil.},
	keywords = {Sitophilus zeamais},
	isbn = {0022-474X},
	author = {Fragoso, Daniel B. and Guedes, Raul Narciso C. and Oliveira, Maria Goreti A.}
}
@article {11000,
	title = {Detection of granary weevil Sitophilus granarius (L.) eggs and internal stages in wheat grain using soft X-ray and image analysis},
	journal = {Journal of Stored Products Research},
	volume = {43},
	number = {2},
	year = {2007},
	month = {2007},
	pages = {142-148},
	abstract = {In order to prevent grain mass and quality losses, rapid methods for early detection of insect infestation of cereal grain during trade and storage are urgently needed. Amongst many options, the soft X-ray method using roentgenograms is one of the most frequently applied. It has been shown that when some corrections for working parameters of the equipment used are made and some modification of the digital image analysis introduced, the soft X-ray method is suitable for accurate detection of granary weevil eggs laid in wheat kernels if at least 5 days after oviposition have elapsed.},
	isbn = {0022-474X},
	author = {Fornal, Jozef and Jelinski, Tomasz and Sadowska, Jadwiga and Grundas, Stanislaw and Nawrot, Jan and Niewiada, Anna and Warchalewski, Jerzy R. and Blaszczak, Wioletta}
}
@article {10990,
	title = {Comparative analysis of upper thermal tolerance and CO2 production rate during heat shock in two different European strains of Sitophilus zeamais (Coleoptera: Curculionidae)},
	journal = {Journal of Stored Products Research},
	volume = {46},
	number = {1},
	year = {2010},
	month = {Jan},
	pages = {20-27},
	abstract = {The maize weevil is a major pest of maize crops and post-harvest grain stocks in tropical countries that became established in western and southern European countries a few decades ago. The hypothesis that this species has adapted to the environmental conditions of temperate climates would be supported by significant adaptative changes in the responses to key ecological factors. Response to heat tolerance is one area likely to show such adaptive changes. In order to test the adaptation hypothesis, a comparative analysis of critical points of the kinetics of CO2 production rate during a heat treatment, using two Sitophilus zeamais strains originating in France (Sze_05) and in Portugal (Sze_19), was carried out by the "thermolimit respiration test" that allowed three critical temperature levels to be determined: 1) the spiracle closing point (SCP), 2) the heat stupor point (HSP) and 3) the death point (DP). The SCP was observed at 45.2 [degree]C and 44.3 [degree]C for Sze_05 and Sze_19 respectively. The HSP was observed at 46.9 [degree]C and 46.3 [degree]C and the DP was observed at 50.0 [degree]C and 48.6 [degree]C respectively for the two strains. The difference between the two strains was significant only for the DP temperature (P = 0.045). Comparison of adult and larval stages revealed a very different physiological response to a "fast" heat increase, with a spiracle closure phase much more marked for larvae than for adults. The understanding of the influence of environmental adaptation on physiological response to heat stress by the thermolimit respirometry test requires further study using fresh strains of S. zeamais originating from temperate countries. However, the methodology used in this trial can be useful for the rapid assessment of the "heat tolerance profile" for insect populations infesting cereal grain or food processing factories so that schedules for heat disinfestation of cereal processing plants can be optimised. [copyright] 2009 Elsevier Ltd. All rights reserved.},
	keywords = {Sitophilus zeamais},
	isbn = {0022-474X},
	author = {Fleurat-Lessard, Francis and Dupuis, Steve A.}
}
@article {10767,
	title = {Calorimetric evaluation of responses of Sitophilus oryzae and Tribolium confusum to elevated temperatures and controlled atmospheres},
	journal = {Journal of Stored Products Research},
	volume = {44},
	number = {3},
	year = {2008},
	month = {2008},
	pages = {295-303},
	type = {Article},
	abstract = {Metabolic heat rates, determined by microcalorimetry, were used to measure the effect of controlled atmospheres (CAs) and elevated temperatures on the stored-product insects Sitophilus oryzae (rice weevil) and Tribolium confusum (confused flour beetle). Results for larval and adult stages in air, and in a range of low O2 and/or high CO2 CAs, at temperatures from 15 to 45 [degree]C, showed the general effectiveness of such atmospheres in lowering the lethal temperatures relative to those in air. Effects on adult S. oryzae at 25 [degree]C were explored in more detail in experiments using the following conditions: exposure to anoxic CAs for extended times; exposure to hypoxic CAs; and simulated hermetic storage. A simple scanning calorimetric method was developed for determining lethal temperatures and a combined thermo-gravimetric and differential thermal-analysis method Was used to interpret the thermal events, due to loss of water, occurring at and above these temperatures. (C) 2008 Elsevier Ltd. All rights reserved.},
	keywords = {Sitophilus oryzae},
	isbn = {0022-474X},
	author = {Downes, C. J. and van Epenhuijsen, C. W. and Lill, R. E. and Downes, J. E. and Carpenter, A. and Brash, D.}
}
@article {10086,
	title = {Progress towards a multi-species lure: identification of components of food volatiles as attractants for three storage beetles},
	journal = {Journal of Stored Products Research},
	volume = {43},
	number = {1},
	year = {2007},
	month = {2007},
	pages = {53-63},
	abstract = {The objective of this study was to identify the attractive components of a carob-peanut extract which is known to be attractive to the three principal grain beetle pests in the UK (Oryzaephihis surinamensis, Sitophihis granarius and Cryptolestes ferruginelis). Coupled GCEAG was used to determine which components in the extract elicited an EAG response. The total number of GC peaks, which elicited an EAG response from O. surinamensis, S. granarius and C.fierrugineits was four, 10 and 12, respectively. The components responsible for these peaks were identified by GG-MS and the compounds tested for a behavioural response in pitfall bioassays along with some other potential attractants, identified from a literature review. Oryzaephilus surinamensis, S. granarius and C ferrugineus responded in bioassays to six, five and nine compounds, respectively. Two compounds (E-2-nonenal and 4-ethylacetophenone) elicited a positive behavioural response from all three species and three compounds (2-phenylethanol, hexanoic acid and E-3-octen-2-one) elicited a response from two of the species. This work has identified a number of compounds, which could form the basis for the formulation of a multi-species lure for the three principal grain beetle pests in the UK. Crown Copyright [copyright] 2005 Published by Elsevier Ltd. All rights reserved.},
	keywords = {Sitophilus granarius},
	isbn = {0022-474X},
	author = {Collins, L. E. and Bryning, G. P. and Wakefield, M. E. and Chambers, J. and Cox, P. D.}
}
@article {9948,
	title = {Insecticidal effect of spinosad dust, in combination with diatomaceous earth, against two stored-grain beetle species},
	journal = {Journal of Stored Products Research},
	volume = {44},
	number = {4},
	year = {2008},
	month = {2008},
	pages = {347-353},
	type = {Article},
	abstract = {Laboratory bioassays were carried out to determine the efficacy of spinosad applied alone or combined with the diatomaceous earth (DE) SilicoSec against adult rice weevils, Sitophilus oryzae and confused flour beetles, Tribolium confusum. Efficacy was assessed on wheat and maize at three dosages of spinosad dust formulation (corresponding to 0.0625, 0.1875 and 0.625 ppm of active ingredient [AI] for S. oryzae and to 0.1875, 0.625 and 1.25 ppm of AI for T. confusum), alone or combined with SilicoSec at 150 ppm for S. oryzae and 250 ppm for T. confusum. The mortality of S. oryzae exposed for 14 d on wheat treated with spinosad ranged between 83\% and 100\%. Conversely, the mortality of S. oryzae on maize treated with DE or on maize treated with lower doses of spinosad dust did not exceed 19\% and was only 59\% on maize with the highest spinosad dust treatment. Generally, the presence of SilicoSec combined with spinosad did not significantly increase S. oryzae mortality compared with spinosad alone. For T. confusum, mortality on both commodities was lower than for S. oryzae. After 14 d of exposure on wheat, mortality was 14\% at the highest dose of spinosad, but increased to 33\% in the presence of DE. Similar results were also obtained for T. confusum exposed on treated maize, which indicated a joint action between spinosad and DE. In the case of S. oryzae, the inclusion of DE reduced progeny production in comparison with spinosad alone. Progeny production of T. confusum was relatively low in all treatments, compared to progeny production of S. oryzae. The results of the study show the potential of combination treatments of spinosad dust and DE, but efficacy varies with the target insect species and commodity.},
	keywords = {Sitophilus oryzae},
	isbn = {0022-474X},
	author = {Chintzoglou, G. and Athanassiou, C. G. and Arthur, F. H.}
}
@article {9539,
	title = {Face or flee? Fenitrothion resistance and behavioral response in populations of the maize weevil, Sitophilus zeamais},
	journal = {Journal of Stored Products Research},
	volume = {47},
	number = {3},
	year = {2011},
	month = {Jul},
	pages = {161-167},
	abstract = {Insect survival in the presence of contact insecticides may be through physiological mechanisms or avoidance of contact with the compound. Curiously, although the first alternative is the object of frequent attention, the second is often neglected, but both may lead to insecticide resistance. Preliminary evidence for both physiological and behavioral resistance to pyrethroids has been obtained for a few strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). Here we carried out a more comprehensive survey using 15 populations of S. zeamais, by examining a long-used but relatively little studied organophosphate - fenitrothion, recording not only physiological resistance, but also the behavioral responses to exposure. Physiological resistance to fenitrothion among populations of S. zeamais reached low to moderate levels (ranging from 0.9 to 14.1 x at the LC50), an increase in resistance levels compared with previous studies. Fenitrothion-induced behavioral avoidance varied among populations, particularly regarding insecticide irritability (i.e., avoidance after contact with fenitrothion), but the behavioral responses observed were mainly stimulus-independent. However, there was no correlation between physiological and behavioral resistance to fenitrothion in S. zeamais populations. Both survival strategies to fenitrothion - facing or fleeing the insecticide exposure, were observed and may co-occur in a single population, emphasizing the need of assessing both responses and their relative importance in designing management programs against stored-product insects. [copyright] 2011 Elsevier Ltd. All rights reserved.},
	isbn = {0022-474X},
	author = {Braga, L. S. and Correa, A. S. and Pereira, E. J. G. and Guedes, R. N. C.}
}
@article {9048,
	title = {Enhanced proteolytic and cellulolytic activity in insecticide-resistant strains of the maize weevil, Sitophilus zeamais},
	journal = {Journal of Stored Products Research},
	volume = {44},
	number = {4},
	year = {2008},
	month = {2008},
	pages = {354-359},
	type = {Article},
	abstract = {Insecticide resistance is frequently associated with fitness costs in the absence of insecticides, but extended and intense past selection with these compounds may favor the evolution of fitness modifier genes that mitigate such costs. Insecticide resistance without fitness cost was associated with greater accumulation of total proteins and carbohydrates in a strain of the maize weevil (Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)). Increased energy reserves may be due to an accumulation of carbohydrates and proteins because of increased digestive efficiency. To test this hypothesis, proteases and enzymes (cellulase and the pectinases polygalacturonase and pectin lyase), which enable insects to access the nutrients, were used to compare digestive efficiency in insecticide-susceptible and -resistant strains of the maize weevil. A canonical variate analysis indicated significant differences among the strains in enzyme activities, and kinetic parameters were calculated. Serine- and cysteine-proteinases as well as cellulase activities were smaller in susceptible than resistant strains. In addition, the esterolytic activity of serine-proteinases was most increased in the insecticide-resistant strain exhibiting a fitness disadvantage associated with insecticide resistance. Overall, enzymes in the insecticide-resistant strains had increased serine- and cysteine-proteolytic and cellulolytic activity, and kinetic parameters suggested that cysteine-proteinase and cellulase activities were more important in mitigating the cost of insecticide resistance in maize weevil strains.},
	keywords = {Sitophilus zeamais},
	isbn = {0022-474X},
	author = {Araujo, R. A. and Guedes, R. N. C. and Oliveira, M. G. A. and Ferreira, G. H.}
}
