THE EFFECT OF WATER STRESS AND LEAFLET SIZE ON THE DENSITY OF TRICHOMES AND THE RESISTANCE TO COLORADO POTATO BEETLE LARVAE (LEPTINOTARSA DECEMLINEATA [SAY]) IN SOLANUM BERTHAULTII HAWKES

1990 ◽  
Vol 122 (6) ◽  
pp. 1141-1147 ◽  
Author(s):  
Yvan Pelletier
Keyword(s):  
Water Stress ◽  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Solanum Berthaultii ◽  
Abaxial Surface ◽  
First Instar ◽  
Potato Beetle ◽  
Resistance To Insects ◽  
Leptinotarsa Decemlineata Say ◽  
Growing Conditions

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.

scholarly journals Screening test for detection of Leptinotarsa decemlineata (Say) sensitivity to insecticides

2012 ◽  
Vol 27 (1) ◽  
pp. 59-67
Author(s):  
Dusanka Indjic ◽  
Slavica Vukovic ◽  
Snezana Tanaskovic ◽  
Mila Grahovac ◽  
Tatjana Keresi ◽  
...  
Keyword(s):  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Screening Test ◽  
Rapid Assessment ◽  
Potato Beetle ◽  
Highly Sensitive ◽  
Leptinotarsa Decemlineata Say ◽  
Two Populations ◽  
Insight Into

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.

scholarly journals Virulence of Beauveria bassiana Strains Isolated from Cadavers of Colorado Potato Beetle, Leptinotarsa decemlineata

Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1077
Author(s):  
Rostislav Zemek ◽  
Jana Konopická ◽  
Eva Jozová ◽  
Oxana Skoková Habuštová
Keyword(s):  
Beauveria Bassiana ◽  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Reference Strain ◽  
The Czech Republic ◽  
Potato Beetle ◽  
Leptinotarsa Decemlineata Say ◽  
Native Strains ◽  
Chemical Pesticides ◽  
Fungus Beauveria Bassiana

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious, widely distributed pest of potato and other crops. This pest is able to defoliate the host plant and cause severe yield loss. Moreover, the pest quickly becomes resistant to many chemical pesticides. Therefore, the development of novel biopesticides targeting this pest is urgently needed. The purpose of this study was to obtain new strains of the entomopathogenic fungus Beauveria bassiana and assess their efficacy against L. decemlineata adults under laboratory conditions. Twelve strains were isolated from cadavers of Colorado potato beetles collected in potato fields in the Czech Republic. Test beetles were treated by suspensions of conidia at the concentration of 1 × 107 spores per milliliter and their survival was recorded daily for three weeks. The results of the bioassays revealed that all new native strains were pathogenic to L. decemlineata adults and caused mortality up to 100% at the end of the trial period with an LT50 of about 7 days. These strains were more virulent than a reference strain GHA and some of them can be recommended for the development of a new mycoinsecticide against L. decemlineata. Our findings also highlight the importance of searching for perspective strains of entomopathogenic fungi among naturally infected hosts.

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