Location: Crop Genetics and Breeding Research
Title: Influence of brown stink bug feeding, planting date and sampling time on common smut infection of maize Authors
|Toews, Michael -|
|Buntin, G. David -|
Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2014
Publication Date: N/A
Interpretive Summary: Common smut infection has been considered one of the important diseases that can significantly reduce corn yield. Because of the steady increase of the brown stink bug population, and common smut infection in the corn fields in the southeastern coastal plain region, the effect of brown stink bug feeding, planting date and sampling time on common smut infection in corn plants was examined. The brown stink bug feeding did not affect the smut infection percentage in the experiments conducted in 2005 and 2006, although the smut infection percentage differed in the two years. The effect of planting date and sampling time on smut infection percentage of the eight corn inbred lines differed between 2010 and 2011. Two of the eight corn inbred lines showed the lowest smut infection percentage in 2010, while there is no difference among the inbred lines in 2011. There was no difference in smut infection percentage among the three planting dates. The post-flowering sampling showed higher smut infection percentage than the pre-flowering sampling in both 2010 and 2011. The two ear-colonizing fungal (such as, common smut and Aspergillus flavus) infections in relation to other environmental factors (such as, rainfall, and temperature) and insect damage could be further examined in detail.
Technical Abstract: Phytopathogen infections are frequently influenced by both biotic and abiotic factors in a crop field. The effect of brown stink bug, Euschistus servus (Hemiptera: Pentatomidae), feeding and planting date and sampling time on common smut (Ustilago maydis) infection percentage of maize plants was examined in 2005 and 2006, and 2010 and 2011, respectively. Brown stink bug adult feeding on maize hybrid ‘DKC6971’ at flowering in 2005 and 2006 did not influence smut infection percentage when examined using three treatments (i.e., 0 adult, 5 adults, and 5 adults mixed with the smut spores). The smut infection percentages were < 3% (n = 12) in the three treatments. The smut infection percentage among the four weekly samplings was the same, so was natural aflatoxin contamination at harvest among the treatments. The second experiment showed that planting date did not affect the smut infection percentage in either 2010 or 2011. But, the smut infection percentage from the post-flowering sampling was greater than pre-flowering sampling in both years. The smut infection percentage varied among the germplasm lines in 2010, but not in 2011. This study demonstrated that brown stink bug feeding at flowering had no effect on smut infection in maize, and the best time for smut evaluation would be after flowering. The temperature and precipitation might have also influenced the percentage of smut infected maize plants during the four years when the experiments were conducted. The similarity between ear-colonizing U. maydis and Aspergillus flavus infections and genotype × environment interaction were also discussed.