Search results for "PEST CONTROL"
showing 10 items of 221 documents
Development and Characterization of Diamondback Moth Resistance to Transgenic Broccoli Expressing High Levels of Cry1C
2000
ABSTRACT A field-collected colony of the diamondback moth, Plutella xylostella , had 31-fold resistance to Cry1C protoxin of Bacillus thuringiensis . After 24 generations of selection with Cry1C protoxin and transgenic broccoli expressing a Cry1C protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of Cry1C. After 26 generations of selection, the resistance ratios of this strain to Cry1C protoxin were 12,400- and 63,100-fold, respectively, for the neonates and second instars by a leaf dip assay. The resistance remained stable until generation 38 (G38) under continuous…
Toxicity and mode of action of Bacillus thuringiensis Cry proteins in the Mediterranean corn borer, Sesamia nonagrioides (Lefebvre)
2006
ABSTRACT Sesamia nonagrioides is one of the most damaging pests of corn in Spain and other Mediterranean countries. Bt corn expressing the Bacillus thuringiensis Cry1Ab toxin is being grown on about 58,000 ha in Spain. Here we studied the mode of action of this Cry protein on S. nonagrioides (binding to specific receptors, stability of binding, and pore formation) and the modes of action of other Cry proteins that were found to be active in this work (Cry1Ac, Cry1Ca, and Cry1Fa). Binding assays were performed with 125 I- or biotin-labeled toxins and larval brush border membrane vesicles (BBMV). Competition experiments indicated that these toxins bind specifically and that Cry1Aa, Cry1Ab, an…
Chemo-orientation responses in hymenopteran parasitoids induced by substrate-borne semiochemicals
2013
Hymenopteran parasitoids can utilize substrate-borne semiochemicals released by conspecifics or by their hosts, increasing the likelihood of successful mating and host location. According to the literature, two substrate-borne chemo-orientation patterns can occur: (1) biased random searching, a non-directional reaction toward the chemicals (kinesis), and (2) trailfollowing searching, a directional response toward the source emitting the chemical compounds (taxis). These two different strategies can be adopted by parasitoids to locate hosts and mates. In host location, random searching is induced by allelochemicals indirectly associated with the host, whereas trail-following behavior is indu…
Alteration of a Cry1A Shared Binding Site in a Cry1Ab-Selected Colony of Ostrinia furnacalis
2022
The Asian corn borer, Ostrinia furnacalis (Guenée, 1854), is a highly damaging pest in Asia and the Pacific islands, and larvae feed mainly from corn crops. To determine the suitability of Bt-corn technology for the future control of this pest, understanding the potential to develop resistance to Cry1Ab and the basis of cross-resistance to other Cry1 proteins is of great interest. Here, we have explored the binding of Cry1A proteins to brush border membrane vesicles from two O. furnacalis colonies, one susceptible (ACB-BtS) and one laboratory-selected with Cry1Ab (ACB-AbR). The insects developed resistance to Cry1Ab and showed cross-resistance to Cry1Aa, Cry1Ac, and Cry1F. Binding assays wi…
American cockroach control assays in the municipal sewerage system of Valencia (Spain)
2013
ABSTRACT Several insecticides (including different active substances and formulations) were applied to sewer shafts to control Periplaneta americana (LINNAEUS, 1758) populations in Valencia (eastern Spain). Results show that the best products for cockroach control were the paints (with and without insecticide), which provided an optimal reduction of P. americana populations for up to three months (P < 0.001). Therefore, it is important to note that the reduction of cockroach populations as well as the persistence of the insecticide effect in sewers was similar in both types of paints. A product combining two pyrethroids (Tetramethrin and Alfacipermetrin) and piperonyl butoxide also gave …
Applied Chemical Ecology to Enhance Insect Parasitoid Efficacy in the Biological Control of Crop Pests
2018
The field application of semiochemicals, used by parasitoids to find mates and to locate their hosts, is a promising environmentally sustainable and highly specific pest control strategy and an attractive alternative to the use of pesticides. In this chapter, we first examine research progress dealing with the effect of semiochemical cues on parasitoid foraging strategy. In the second part, we review the possible field applications of these chemical cues to enhance pest control strategies, either through direct pest control or by manipulating parasitoid behaviour. We then consider novel approaches, such as the “attract and reward” strategy, combining semiochemical application and habitat ma…
Is Bactra bactrana (Kennel, 1901) a novel pest of sweet peppers?
2015
AbstractThis is the first report of Bactra bactrana (Kennel, 1901) (Lepidoptera: Tortricidae) attacking a major solanaceous crop, sweet pepper Capsicum annuum L. The infestation was detected in two greenhouses at the area of Tympaki (Southern Crete, Greece). The moth larvae caused typical symptoms of a fruit borer with numerous small holes on the surface of the peppers and extensive damage on the inside of the fruit as a result of the feeding activity. Unknown factors facilitated this major shift in host range since B. bactrana is typically a stem borer of sedges. In addition, the pest status of B. bactrana is currently under question, as in both cases the infestations by the moth were asso…
Midgut microbiota and host immunocompetence underlie Bacillus thuringiensis killing mechanism
2016
Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced …
Gametic embryogenesis and haploid technology as valuable support to plant breeding
2011
Plant breeding is focused on continuously increasing crop production to meet the needs of an ever-growing world population, improving food quality to ensure a long and healthy life and address the problems of global warming and environment pollution, together with the challenges of developing novel sources of biofuels. The breeders' search for novel genetic combinations, with which to select plants with improved traits to satisfy both farmers and consumers, is endless. About half of the dramatic increase in crop yield obtained in the second half of the last century has been achieved thanks to the results of genetic improvement, while the residual advance has been due to the enhanced managem…
Improvement of baculovirus as protein expression vector and as biopesticide by CRISPR/Cas9 editing
2019
The clustered regularly interspaced short palindromic repeats (CRISPR) system?associated Cas9 endonuclease is a molecular tool that enables specific sequence editing with high efficiency. In this study, we have explored the use of CRISPR/Cas9 system for the engineering of baculovirus. We have shown that the delivering of Cas9-single guide RNA ribonucleoprotein (RNP) complex with or without DNA repair template into Sf21 insect cells through lipofection might be efficient to produce knockouts as well as knock-ins into the baculovirus. To evaluate potential application of our CRISPR/Cas9 method to improve baculovirus as protein expression vector and as biopesticide, we attempted to knockout se…