Consumption of Eggplant Foliage by Colorado Potato Beetle (Coleoptera: Chrysomelidae)

1996 ◽  
Vol 31 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Salvatore Arpaia ◽  
James Lashomb ◽  
George C. Hamilton ◽  
Karen Vail

Feeding of second- to fourth-instar Colorado potato beetle, Leptinotarsa decemlineata Say, on eggplant was monitored at constant temperatures of 20, 26, 29, 32 and 35° C, and at 16, 20, 27, 29, and 33° C for adults to determine the effects of temperature on consumption. For comparison, consumption by each stage relative to fourth instars was standardized to feeding equivalants. A significant non-linear relationship was found between temperature and consumption for each life stage tested. Placement of each life stage on an equivalent feeding basis showed second instars consume on average 21.5% as much foliage as fourth instars, third instars 51.2% the amount of fourth instars, and adults 39.0% the level of fourth instars. These feeding equivalents can be used to develop field sampling plans and toxicant bioassays.

1998 ◽  
Vol 130 (2) ◽  
pp. 187-194 ◽  
Author(s):  
S.A. Hilton ◽  
J.H. Tolman ◽  
D.C. MacArthur ◽  
C.R. Harris

AbstractResidual and contact toxicities of several insecticides to larvae and adults of insecticide-susceptible (four insecticides) and insecticide-resistant (three insecticides) Colorado potato beetle, Leptinotarsa decemlineata (Say), were measured in laboratory studies. For both methods of exposure, azinphosmethyl was the least toxic to all life stages tested. The residual toxicity of deltamethrin was at least 4.4-fold higher than either cypermethrin or endosulfan. With the insecticide-susceptible strain, residual toxicities of azinphosmethyl, endosulfan, and deltamethrin were, respectively, 3.5, 5.9, and 4.1 times higher to first instars than to adults and 1.2, 8.1, and 1.6 times higher to third instars than to adults. Contact toxicities of azinphosmethyl, endosulfan, and deltamethrin were, respectively, 3.3, 2.9, and 1.4 times higher to insecticide-susceptible third instars than to adults. In most comparisons, susceptibilities of fourth and third instars were similar. With the insecticide-resistant strain, azinphosmethyl, endosulfan, and deltamethrin were, respectively, 3.2, 1.6, and 8.0 times more toxic to third instars than to adults. The importance of differential life stage toxicity to current control recommendations for Colorado potato beetle is discussed.


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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