Penetration and development of Chalara elegans in peanuts (Arachis hypogaea).
Phialospores of C. elegans [Thielaviopsis basicola] germinated on groundnut roots and pods in 2 to 8 h and penetrated directly through cell walls within 12 h. Only one penetration per phialospore was observed. Secondary phialospores were produced by hyphae on the surface in 28-30 h. The pathogen advanced more rapidly through sclerenchyma cells of mesocarpic extensions than through exocarpic parenchyma cells. Passage through sclerenchyma cells was through pits and lumina. An abundance of aleuriospores were formed in the infected testa but the cotyledons were not infected. The pathogen traversed the hull and entered the testa in 5 days.