Aflatoxin in Arizona cottonseed: Lack of toxin formation following aspergillus flavus inoculation at sutures

Aflatoxin assays were conducted on seeds from cotton bolls inoculated withAspergillus flavus in commercial fields in Arizona. Inoculations were at sutures at the initiation of boll opening either in the morning or evening in August over a three-year period. One morning inoculation was followed by a water treatment that simulated rain. Fully fluffed bolls were harvested after two or four weeks, and lint and seed linters were examined for bright-green-yellow-fluorescence (BGYF). Ginned seed were assayed for aflatoxin. While BGYF of lint was detected, no seed linters exhibited BGYF and no seeds from the 140 bolls examined contained aflatoxin. Results imply that boll infection byA. flavus occurs before the initiation of boll opening, an observation that is in agreement with recent reports ofA. flavus infection but contrary to conclusions made in earlier reports.