title: Evaluation of spatial and temporal patterns of insect damage and aflatoxin level in the pre-harvest corn fields to improve management tactics.
abstract: Spatial and temporal patterns of insect damage in relation to aflatoxin contamination in a corn field with plants of uniform genetic background are not well understood. After previous examination of spatial patterns of insect damage and aflatoxin in pre-harvest corn fields, we further examined both spatial and temporal patterns of cob- and kernel-feeding insect damage, and aflatoxin level with two samplings at pre-harvest in 2008 and 2009. The feeding damage by each of the ear/kernel-feeding insects (i.e., corn earworm/fall armyworm damage on the silk/cob, and discoloration of corn kernels by stink bugs) and maize weevil population were assessed at each grid point with five ears. Sampling data showed a field edge effect in both insect damage and aflatoxin contamination in both years. Maize weevils tended toward an aggregated distribution more frequently than either corn earworm or stink bug damage in both years. The frequency of detecting aggregated distribution for aflatoxin level was less than any of the insect damage assessments. Stink bug damage and maize weevil number were more closely associated with aflatoxin level than was corn earworm damage. In addition, the indices of spatial-temporal association (χ) demonstrated that the number of maize weevils was associated between the first (4 weeks pre-harvest) and second (1 week pre-harvest) samplings in both years on all fields. In contrast, corn earworm damage between the first and second samplings from the field on the Belflower Farm, and aflatoxin level and corn earworm damage from the field on the Lang Farm were dissociated in 2009.
authors: USDA-ARS, Crop Genetics and Breeding Research Unit.
authors: Xinzhi
authors: X
authors: Ni
authors: Jeffrey P
authors: JP
authors: Wilson
authors: Michael D
authors: MD
authors: Toews
authors: G David
authors: GD
authors: Buntin
authors: R Dewey
authors: RD
authors: Lee
authors: Xin
authors: X
authors: Li
authors: Zhongren
authors: Z
authors: Lei
authors: Kanglai
authors: K
authors: He
authors: Wenwei
authors: W
authors: Xu
authors: Xianchun
authors: X
authors: Li
authors: Alisa
authors: A
authors: Huffaker
authors: Eric A
authors: EA
authors: Schmelz
mesh_terms: D000348:Aflatoxins / Q000032:analysis*; D000818:Animals; D001231:Aspergillus flavus / Q000502:physiology; D005845:Georgia; D060434:Herbivory; D007313:Insecta / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D012621:Seasons; D062206:Spatial Analysis; D003313:Zea mays / Q000254:growth & development* / Q000382:microbiology*
chemical_list: D000348:Aflatoxins
keywords: SADIE analysis; aflatoxin level; corn earworm damage; maize weevil population; spatial pattern; spatio-temporal association; stink bug damage