scholarly journals Contact Toxicities of Oxygenated Monoterpenes to Different Populations of Colorado Potato Beetle, Leptinotarsa Decemlineata Say (Coleoptera: Chrysomelidae)

2011 ◽  
Vol 51 (3) ◽  
pp. 225-233 ◽  
Author(s):  
Safaei Mahdi ◽  
Jafarnia Sasan ◽  
Khosroshahi Sara

Contact Toxicities of Oxygenated Monoterpenes to Different Populations of Colorado Potato Beetle,Leptinotarsa DecemlineataSay (Coleoptera: Chrysomelidae)In the present study, 12 pure oxygenated monoterpenes at 2 different doses were tested for their toxicity against second and third instar larvae and adults of three different populations of Colorado potato beetle (Leptinotarsa decemlineataSay). Some of tested compounds were found to be toxic to larvae and adults, but the degree of toxicity was variable. The mortality range was 20-100%. In general, fenchone, linalool, citronella and menthone showed a strong toxicity against the tested developmental stages; camphor, carvone and linalyl acetate showed moderate toxicity against larvae and adults of Colorado potato beetle and some compounds like fenchol, isomenthol, menthol, nerol and neryl acetate showed the least or no toxicity against the tested developmental stages ofL. decemlineata.Another important result was that although the tested populations of Colorado potato beetle showed some resistance to Endosulfan (50% WP), there was no resistance to tested oxygenated monoterpenes. The present results indicate that some of these compounds can be used as potential control agents against both larvae and adults of Colorado potato beetle.

2020 ◽  
Vol 113 (3) ◽  
pp. 1445-1454
Author(s):  
K F Wiebe ◽  
O O Elebute ◽  
C M R LeMoine ◽  
B J Cassone

Abstract The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an important pest of the cultivated potato (Solanum tuberosum (L.) [Solanales: Solanaceae]). With its broad resistance toward commonly used insecticides, it is clear that more sophisticated control strategies are needed. Due to their importance in insect development, microRNAs (miRNAs) represent a potential tool to employ in insect control strategies. However, most studies conducted in this area have focused on model species with well-annotated genomes. In this study, next-generation sequencing was used to catalogue the miRNAs produced by L. decemlineata across all eight stages of its development, from eggs to adults. For most stages, the length of miRNAs peaked between 21 and 22 nt, though it was considerably longer for the egg stage (26 nt). Global profiling of miRNAs revealed three distinct developmental clusters: 1) egg stage; 2) early stage (first, second, and third instar); and 3) late stage (fourth instar, prepupae, pupae, and adult). We identified 86 conserved miRNAs and 33 bonafide novel miRNAs, including stage-specific miRNAs and those not previously identified in L. decemlineata. Most of the conserved miRNAs were found in multiple developmental stages, whereas the novel miRNAs were often stage specific with the bulk identified in the egg stage. The identified miRNAs have a myriad of putative functions, including growth, reproduction, and insecticide resistance. We discuss the putative roles of some of the most notable miRNAs in the regulation of L. decemlineata development, as well as the potential applications of this research in Colorado potato beetle management.


1990 ◽  
Vol 122 (6) ◽  
pp. 1141-1147 ◽  
Author(s):  
Yvan Pelletier

AbstractSolanum berthaultii Hawkes bears trichomes reportedly providing resistance to insects. Results indicated that the density of types A and B trichomes was linearly related to the inverse of the leaflet area. The number of trichomes on the adaxial and on the abaxial surface of terminal leaflets was not affected by two levels of water stress or by growing conditions in the greenhouse or the field. The leaflets of the water-stressed plants were generally smaller and, consequently, the density of trichomes higher.The survival of first-instar Colorado potato beetle larvae was similar on S. berthaultii grown under varying drought conditions and on leaves from field-grown plants bearing different densities of trichomes.


2012 ◽  
Vol 27 (1) ◽  
pp. 59-67
Author(s):  
Dusanka Indjic ◽  
Slavica Vukovic ◽  
Snezana Tanaskovic ◽  
Mila Grahovac ◽  
Tatjana Keresi ◽  
...  

In 2009, the sensitivity of 15 field populations of Colorado potato beetle (Leptinotarsa decemlineata Say.) - CPB was assessed to chlorpyrifos, cypermethrin, thiamethoxam and fipronil, four insecticides which are mostly used for its control in Serbia. Screening test that allows rapid assessment of sensitivity of overwintered adults to insecticides was performed. Insecticides were applied at label rates, and two, five and 10 fold higher rates by soaking method (5 sec). Mortality was assessed after 72h. From 15 monitored populations of CPB, two were sensitive to label rate of chlorpyrifos, one was slightly resistant, 11 were resistant and one population was highly resistant. Concerning cypermethrin, two populations were sensitive, two slightly resistant, five were resistant and six highly resistant. Highly sensitive to thiamethoxam label rate were 12 populations, while three were sensitive. In the case of fipronil applied at label rate, two populations were highly sensitive, six sensitive, one slightly resistant and six were resistant. The application of insecticides at higher rates (2, 5 and 10 fold), that is justified only in bioassays, provided a rapid insight into sensitivity of field populations of CPB to insecticides.


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