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Effects of crop type on Bacillus thuringiensis toxicity and residual activity against Trichoplusia ni in greenhouses
Author(s) -
Janmaat A. F.,
Ware J.,
Myers J.
Publication year - 2007
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/j.1439-0418.2007.01181.x
Subject(s) - trichoplusia , cabbage looper , bacillus thuringiensis , biology , noctuidae , bruton's tyrosine kinase , pepper , crop , biopesticide , horticulture , greenhouse , agronomy , pest analysis , pesticide , genetics , bacteria , signal transduction , biochemistry , tyrosine kinase
We assessed the efficacy and persistence of a Bacillus thuringiensis kurstaki ( Btk ) formulation (Dipel) against Trichoplusia ni (Hubner) (Lep., Noctuidae), the cabbage looper, on three greenhouse vegetable crops (tomato, bell pepper and cucumber). First, T. ni larvae were fed leaf discs treated with Btk to assess how Btk toxicity varies with host plant. Secondly, T. ni larvae were fed leaf discs harvested from plants that had been sprayed with Btk 1, 5 and 9 days previously to assess the residual activity of Btk toxicity in greenhouse environments. Mortality of T. ni larvae fed tomato leaf discs was significantly higher than T. ni fed cucumber or pepper leaf discs. The toxicity of Btk had declined by less than 50% after 9 days, which suggests that Btk persistence is lengthy in greenhouse environments. No crop effects on the residual activity of Btk were found. These results demonstrate that the greenhouse environment and the crop should be considered when using Btk for insect management on greenhouse crops.