TIMING OF INSECTICIDE APPLICATIONS FOR THE CONTROL OF THE COLORADO POTATO BEETLE, LEPTINOTARSA DECEMLINEATA (SAY), (COLEOPTERA: CHRYSOMELIDAE), ON POTATOES IN NEW BRUNSWICK

1988 ◽  
Vol 120 (6) ◽  
pp. 587-591 ◽  
Author(s):  
G. Boiteau

AbstractDifferent insecticide spray regimes were tested in 1984, 1985, and 1986 to determine the optimal time to control the Colorado potato beetle, Leptinotarsa decemlineata (Say), on Russet Burbank potatoes in New Brunswick. Insecticides applied in mid-July at the peak of larval abundance when plants were entering into bloom had the greatest efficacy in controlling beetles and protecting the yield. A single insecticide application at 50% bloom was 12–17% and 82–95% more effective than one application at bloom and full growth, respectively.

1996 ◽  
Vol 128 (6) ◽  
pp. 1087-1099 ◽  
Author(s):  
Gilles Boiteau ◽  
Warren Coleman

AbstractThe seasonal change in the level of cold tolerance in a field population of Colorado potato beetle, Leptinotarsa decemlineata (Say), is described for a northern location. Survival of overwintering adult beetles is highest from September through January. After that it falls to a lower level that is maintained until beetle emergence in May or June. The seasonal change in the level of cold tolerance is parallel to the change in the intensity of diapause but not to the change in the low temperature exotherm. The value of the low temperature exotherm is variable but averages −8.8°C for active beetles on plants and −11.7°C for soil-collected overwintering beetles in their deep diapause phase. Experimental results suggest that reduction of the gut content and increase in the amount of body fat in diapausing beetles is sufficient to lower the low temperature exotherm by a few degrees. The diapausing state itself, without cold acclimation, is sufficient to increase cold tolerance. However, results suggest that it is not the level of cold tolerance of the Colorado potato beetle provided by the diapausing process that has allowed this species to extend its range northward into New Brunswick but its accompanying burrowing behaviour.


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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