PARENT SESSION
Poster Session 24: Agro-Ecology
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Identification and field control effect of Aspergillus flavus in maize field.

Gao, Junxia^{1, 1}, Li, Guifang^*,, Liu, Zuoxin, ¹ Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China

ABSTRACT- Aspergillus flavus is a kind of soil-inhabiting fungi. From an agroecological perspective, A. flavus can infect crops and produce aflatoxin. Field management measures including crop rotation/continuous cultivation, irrigation/drought, nitrogen levels applied, crop varieties and sowing densities, were taken in maize field in northeastern China to identify and decrease the potential menace of A. flavus. Communities of A. flavus were isolated from field, which count varied from 10 to 10000 propagules per g of soil. A. parasiticus, however, had not been found yet. Nearly 2/3 of A. flavus isolates were L strain isolates assigned by sclerotial morphology which were more than S strain isolates in number. Differential adaptation and geographical divergence of species and strains to ecological niche maybe occur in the region. Except for 2 atoxigenic isolates, A. flavus isolates had a variable capacity to produce aflatoxin with less than 100 MISSING CHARACTER ENTITY: mug kg^-1. Aflatoxin-producing fungi to colonize crop were A. flavus strains with low toxigenic potential in the agroecosystem. The high probability of A. flavus was found in maize continuous cultivation field during sowing and growing stages. Other field management measures did not show significant effect to inhabit A. flavus propagation. Soil moisture content of the fields where A. flavus was isolated was less than 13%. The result suggested that cultivation and agronomic system to adapt aflatoxin management strategies should be considered. Rotation and irrigation should be applied and water supply is becoming important if the situation of soil moisture content lower than 13%. Higher sowing density can be considered to enhance yield without a decline in grain quality caused by A. flavus.

Key words: A. flavus, agroecosystem, identification, field control effect