Localization of A. citrulli in infested watermelon seeds. To
compare the effect of invasion pathway on A. citrulli location,
seeds from pericarp- and pistil-inoculated fruits were studied.
Seed samples (n = 50 seeds) from each lot were dissected into
testa, PE layer, and embryo tissues and assayed for A. citrulli. To
separate seed sections, testae were first removed from dry seeds
using a sterile scalpel. Each decoated seed was soaked in distilled
water for 3 h at 25°C in the dark and then the PE layer was
removed using sterile forceps (DR Instruments, Palos Hills, IL).
Soaking in distilled water was required to facilitate the complete
removal of PE layers from seeds.