|Zhang, Jiuxu - TEXAS A&M UNIVERSITY|
|Starr, J - TEXAS A&M UNIVERSITY|
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 1995
Publication Date: N/A
Interpretive Summary: Cotton seed treatment with strains of the biocontrol agents Gliocladium virens or Bacillus subtilis resulted in less infection of cotton roots by Fusarium species. It also lessened the incidence and severity of Fusarium wilt disease caused by Fusarium oxysporum and the root knot nematode. However, these treatments had no effect on the reproduction of root knot nematodes on the cotton root. The roots of the cotton plant were heavily colonized by the biocontrol agents put on the seed. These results may help to explain why seed treatment with biocontrol agents often result in more vigorous and higher yielding plants.
Technical Abstract: In growth chamber at 25 C, fungal antagonist Gliocladium virens colonized taproots and secondary roots of cotton in nonsterile soil after seed treatment with preparations of G. virens. Colonization of taproots by G. virens increased over time, and decreased with root depth. Seed treatments with G. virens strains G-4 and G-6 and with Bacillus subtilis strains GB03 and GB07 reduced the colonization of taproots and secondary roots of cotton seedlings by Fusarium spp. Under greenhouse conditions, the same seed treatments suppressed the incidence and severity of Fusarium wilt of cotton in soil infested with Fusarium oxysporum f. sp. vasinfectum and Meloidogyne incognita. Gliotoxin, produced by 'Q'-group strains of G. virens, inhibited F. o. vasinfectum in vitro. The seed treatments with G. virens strain G-6 and B. subtilis strains GB03 and GB07 did not affect the reproduction of root-knot nematodes. The results of this study may help to explain why treatment of cotton seed with biocontrol agents often results in more vigorous and higher yielding plants, and indicate that there is potential for using G. virens and B. subtilis as seed treatments to control Fusarium wilt of cotton.