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The development of insecticide resistance in insect pests of crops is a growing threat to sustainable food production, and strategies that slow the development of resistance are therefore urgently required. The insecticide synergist piperonyl butoxide (PBO) inhibits certain insect detoxification systems and so may delay the evolution of metabolic resistance. In the current study we characterized resistance development in the silverleaf whitefly, Bemisia tabaci, after selection with either a neonicotinoid (thiacloprid) or pyrethroid ( alpha-cypermethrin) insecticide alone or in combination with PBO. Resistance development was significantly suppressed (> 60%) in the line selected with alpha-cypermethrin + PBO compared to the line selected with alpha-cypermethrin alone. RNA sequencing (RNAseq) analyses revealed an increase in frequency of a knock-down resistance mutation but no differentially expressed genes were identified that could explain the sensitivity shift. No significant difference was observed in the level of resistance between the thiacloprid and thiacloprid + PBO selected lines, and RNA sequencing (RNAseq) analyses revealed that the cytochrome P450 monooxygenase CYP6CM1, known to metabolize neonicotinoids, was significantly upregulated (>10-fold) in both lines. The findings of this study demonstrate that PBO used in combination with certain insecticides can suppress the development of resistance in a laboratory setting; however, the mechanism by which PBO supresses resistance development remains unclear. [ABSTRACT FROM AUTHOR]

During the spring of 2016, the aphid Myzus mumecola (Matsumura) (Hemiptera: Aphididae) was detected on its preferential host plant, Prunus armeniaca L. (Rosaceae), in Italy. This was the first record of the species in Europe. Several populations of the aphid have been collected in various apricot orchards in Emilia-Romagna, in the localities of Imola, Campiano, Cesena and Castiglione di Cervia. The species is considered to be an apricot pest in India and East Asia. Details on the morphology, biology and distribution of this aphid species and the damage it causes are given. [ABSTRACT FROM AUTHOR]

Chemical insecticides have been widely used to control insect pests, leading to the selection of resistant populations. To date, several single nucleotide polymorphisms (SNPs) have already been associated with insecticide resistance, causing reduced sensitivity to many classes of products. Monitoring and detection of target-site resistance is currently one of the most important factors for insect pest management strategies. Several methods are available for this purpose: automated and high-throughput techniques (i.e. TaqMan or pyrosequencing) are very costly; cheaper alternatives (i.e. RFLP or PASA–PCRs) are time-consuming and limited by the necessity of a final visualization step. This work presents a new approach (QSGG, Qualitative Sybr Green Genotyping) which combines the specificity of PASA–PCR with the rapidity of real-time PCR analysis. The specific real-time detection of Cq values of wild-type or mutant alleles (amplified used allele-specific primers) allows the calculation of ΔCqW–M values and the consequent identification of the genotypes of unknown samples, on the basis of ranges previously defined with reference clones. The methodology is applied here to characterize mutations described in Myzus persicae and Musca domestica and we demonstrate it represents a valid, rapid and cost-effective technique that can be adopted for monitoring target-site resistance in field populations of these and other insect species. [ABSTRACT FROM PUBLISHER]

Insecticides have played and still fulfil a very important role in sustainable production of food, animal feed and also as protection against disease vectors. They act to suppress insect populations and, as a consequence of their use, insecticide resistance has evolved. An overview of insecticide resistance mechanisms in insects is given, focusing on the metabolic systems involved in xenobiotic metabolism in the class Insecta. Several enzyme families (e.g., esterases, mixed function oxidases, glutathione S-transferases) are involved in insecticide detoxification, sequestration and excretion and have differing relative importance within the various taxonomic groups. A brief discussion of their impact on control strategies is given. [ABSTRACT FROM AUTHOR]

In this study, we present cytogenetic data regarding 66 Myzus persicae strains collected in different regions of Italy. Together with the most common 2n = 12 karyotype, the results showed different chromosomal rearrangements: 2n = 12 with A1–3 reciprocal translocation, 2n = 13 with A1–3 reciprocal translocation and A3 fission, 2n = 13 with A3 fission, 2n = 13 with A4 fission, 2n = 14 with X and A3 fissions. A 2n = 12–13 chromosomal mosaicism has also been observed. Chromosomal aberrations (and in particular all strains showing A1–3 reciprocal translocation) are especially frequent in strains collected on tobacco plants, and we suggest that a clastogenic effect of nicotine, further benefited by the holocentric nature of aphid chromosomes, could be at the basis of the observed phenomenon. [ABSTRACT FROM PUBLISHER]

The article explores the factors that contribute to differential levels of entrepreneurial performance, which is necessary to study the specific activities of the entrepreneurs and relate them to their environment and their social background in a comparative frame. The analysis pursued in this paper is based on fieldwork undertaken during the year 1973-74 at Faridabad. The major part of the fieldwork consisted of interviews held among fifty entrepreneurs engaged in the manufacture of engineering goods and components. Faridabad has enjoyed several unique advantages which have contributed to its rapid growth as a leading industrial center of north India. Besides, proximity to Delhi also implies accessibility to central government offices and the various ministries which play a crucial role in the industrial development of the country. The Faridabad industrial complex, especially its engineering goods sector, can be portrayed as a web of economic relationships linking various industrial units. This present analysis demonstrates that one's class background sets limits not only to growth but also to the extent to which one can overcome one's constraints by expanding one's skills.

The article presents a response by the author against criticism by P.N. Rastogi, professor, Indian Institute of technology, Kanpur, India, towards his book "The Nature and Dynamics of Factional Conflict: Some Clarifications." The author responds because the criticism raises some interesting methodological issues which enables to evaluate the use of sophisticated techniques of analysis in social sciences. Rastogi's "Corpus of Propositions" expounds his theory of factional conflict best. Some of his propositions are definitional; some restates to some extent proposition; whereas some refer to the development of the conflict over time. Rastogi points out that unresolved clash of interest between prominent persons reflects the impact of major changes in social, political and economic environment of the group. This unresolved clash of interests between prominent individuals develops over time into an overt phase of conflict between factions which may later involve strategic maneuvers to defeat each other. These propositions describe the development of factionalism rather than explain it. They are mere empirical generalizations.