Evaluation of insecticide applications to reduce corn leafhopper populations and corn stunt disease

Corn stunt disease, caused by Spiroplasma kunkelii and vectored by the corn leafhopper (Dalbulus maidis), has become a significant problem in silage corn production in the southern portion of the San Joaquin Valley. California, since 1996. In large, replicated field trials, systemic seed treatments...

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Bibliographic Details
Published in:Phytopathology 2004-06, Vol.94 (6)
Main Authors: Frate, CA, Summers, C, Mueller, S M, Collar, C, Newton, A
Format: Article
Language:English
Subjects:
Dalbulus maidis
Spiroplasma kunkelii
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Summary:Corn stunt disease, caused by Spiroplasma kunkelii and vectored by the corn leafhopper (Dalbulus maidis), has become a significant problem in silage corn production in the southern portion of the San Joaquin Valley. California, since 1996. In large, replicated field trials, systemic seed treatments (imidaclopid in 2002 and elothianidin in 2003) reduced leafhopper numbers by about 50% compared to control plots. Disease incidence, based on symptom expression, was significantly reduced in each trial but not as much as leafhopper populations. Yields in the seed treatments were not significantly higher than the control treatment. In three large-scale replicated field trials in 2003, foliar pyrethroid insecticides applied after leafhopper populations were established were more effective than organophosphates in reducing leafhopper counts. Disease incidence was not significantly reduced in any of these foliar trials. However in two of the trials, insecticide treatments as a group had higher yields (P = 0.02 and P = 0.06) than the control with increases of 1.0 and 0.6 tons per acre (30% dry matter basis) respectively.
ISSN:0031-949X