Field Performance of Clavibacter xyli subsp. cynodontis Expressing the Insecticidal Protein Gene cryIA(c) of Bacillus thuringiensis against European Corn Borer in Field Corn

• Published in: Biological control Vol. 5; no. 3; pp. 442 - 448
• Main Authors: Tomasino, S.F., Leister, R.T., Dimock, M.B., Beach, R.M., Kelly, J.L.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.09.1995
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1006/bcon.1995.1053

The field efficacy of the endophytic bacterium Clavibacter xyli subsp. cynodontis (Cxc) expressing the cry-IA( c) insecticidal protein gene of Bacillus thuringiensis (Bt) was evaluated against European corn borer ( Ostrinia nubilalis) (ECB) in field corn during 1990 in Maryland and during 1991-1993 in Nebraska. The engineered strains, referred to as Cxc/Bt, were introduced into corn seedlings using a would inoculation technique or into corn seed via a pressure infiltration technique. Two Cxc/Bt strains (MDR1.586, MDR1.1413) were evaluated in the pedigree LH119 × LH82. Plants were artificially infested near pollen shed with neonate ECB larvae and later dissected to determine the amount of ECB tunneling. In 1993, plots were machine-harvested to obtain yield data. Both Cxc/Bt strains significantly reduced ECB damage compared with plants colonized by wild-type Cxc and/or uncolonized control plants. In 1990, strain MDR1.586 reduced the number of tunnels by 64.0%. Field efficacy of strain MDR1.586 was further demonstrated in 1991 and 1992 as treated plants exhibited 57.1 and 65.0% fewer tunnels, respectively. Strain MDR1.1413 reduced the number of tunnels by 79.0% in 1992 and by 68.7% in 1993. Despite the significant control of ECB by strain MDR1.1413 in 1993, grain yield from Cxc/Bt-inoculated plants was not significantly different from the uninoculated control.