POPULATION DYNAMICS OF LEPTINOTARSA DECEMLINEATA (SAY) IN EASTERN ONTARIO: III. MAJOR POPULATION PROCESSES

1971 ◽  
Vol 103 (7) ◽  
pp. 1049-1061 ◽  
Author(s):  
D. G. Harcourt

AbstractAn appraisal of population processes in the Colorado potato beetle, Leptinotarsa decemlineata (Say), on its principal host plant showed that the insect has no natural agents that act in a manner that prevent it from overshooting its food supply. It is little affected by weather conditions or predators, and its only parasite, the tachinid Doryphorophaga doryphorae (Riley), is inversely density dependent in its action. Once the beetle has exploited its food resource, the larvae starve and the adults emigrate in quest of other hosts.The analysis of age interval survivals showed that populations are both regulated and disturbed by the principal key factor, adult migration, which is density dependent but overcompensating. A predictive model based on density relationships explained 94% of the variance in population trend.

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.


2021 ◽  
Vol 285 ◽  
pp. 03012
Author(s):  
Mariya Nefedova

The predator Podisus maculiventris Say is a representative of the order Hemiptera, family Pentatomidae. This insect is promising in the battle against the Colorado potato beetle Leptinotarsa decemlineata Say. For the successful use of P. maculiventris in the climatic conditions of the Russian Federation and other countries where this predator isn’t found, it is necessary to develop methods of its artificial reproduction. The paper provides information on the selection of food based on the use of phytophagous insects and pests. Among the subjects Galleria mellonella L. caterpillars, Tenebrio molitor L. larvae and pupae, Ephestia kuehniella Zll. caterpillars, as well as Zophobas morio Fabr larvae were used. As a result of the experiment, T. molitor was recognized as the most effective insect prey in terms of biological and economic indicators. When using Tenebrio molitor, the imago yield of P. maculiventris amounted to 81.0-90.5%, which was the best indicator in comparison with other options.


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