Insect-pest mobility can influence insect susceptibility to the insecticides used to control them. The objective of this work was to evaluate the flight activity of Sitophilus oryzae (L) and Sitophilus zeamais Motsch populations reared on corn and wheat grains, and its relationship with insecticide susceptibility. Unsexed adult insects with ages between 10 and 20 days were placed on a plastic t...

The spermiogenesis of Sitophilus zeamais and Sitophilus oryzae, the maize and the rice weevil, respectively, was studied by light microscopy and scanning and transmission electron microscopy. Sitophilus spp. is the most widespread and destructive primary pest of stored cereals in the world. The spermiogenesis occurs within cysts. There are approximately 256 germ line cells per cyst. Inside each...

Laboratory tests were carried out in order to examine competition among three congeneric species on rice and maize: the granary weevil, Sitophilus granarius, the rice weevil, Sitophilus oryzae and the maize weevil, Sitophilus zeamais. For this purpose, a total of 30 adults were placed in vials that contained 50 g or either rice or maize: 30 adults of S. granarius, 30 adults of S. oryzae, 30 adu...

The effects of exposure period and phosphine concentration were quantified in adults of representative strains of Sitophilus zeamais (Motsch.), Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) from China. All three species are major pests of stored grain in China. Although phosphine resistance is common in Chinese S. oryzae and R. dominica, with some very resistant populations, it is not pr...

Peas (Pisum sativum) are toxic to some stored-product insects. The repellent effect of fractions of pea seed to stored-product insects was evaluated in multiple-choice tests in which wheat kernels were dusted with fractions rich in either protein, fibre or starch at 0.001 to 10% (wt:wt). There was a negative correlation between pea protein concentration and the number of adults found in grain f...

Rice weevil (Sitophilus oryzae) and the lesser grain borer (Rhyzopertha dominica) are very important warehouse pests and, therefore, their control is crucial. At a key moment in life of adult Sitophilus spp., obligatory symbiotic nature Sodalis pierantonius bacterium opens up new perspective for natural antibiotics bactericides. In this study, we used nanopore sequencing 16S rRNA barcoding to e...

Cell physiology in the weevil Sitophilus oryzae is coordinated by three integrated genomes: nuclear, mitochondrial, and the "S. oryzae principal endosymbiont" (SOPE). SOPE, a cytoplasmic bacterium (2 x 10(3) bacteria per specialized bacteriocyte cell and 3 x 10(6) bacteria per weevil) that belongs to the proteobacteria gamma3-subgroup, is present in all weevils studied. We discovered a fourth p...

Studies were conducted to evaluate the effect of a protein-enriched pea (Pisum sativum var. Bonneville) flour extract against the rice weevil, Sitophilus oryzae in its repellency, toxicity, effect on fecundity, stability and sensory properties. Milled rice admixed with pea flour extract at 1% concentration significantly repelled S. oryzae. Mortality of S. oryzae was found to increase and fecund...

 Background: The rice weevil, Sitophilus oryzae and rice moth, Corcyra cephalonica are major and cosmopolitan insect. Adults of S. oryzae (male and female) and both larvae are insatiable feeders on a great variety of grains. Objective: This study was conducted to estimate the insecticidal effect of essential oils from peppermint, Mentha piperita L. and black pepper, Piper nigrum L. ag...