The Chlorotic Leaf Distortion Pathogen, Fusarium lateritium, Cross Protects Sweetpotato against Fusarium Wilt Caused by Fusarium oxysporum f.sp. Batatas1

The chlorotic leaf distortion pathogen of sweetpotato, Fusarium lateritium, protected susceptible sweetpotato plants against Fusarium wilt caused by F. oxysporum f.sp. batatas. Protection could be effected by simultaneous inoculation with both fungi but required 1.0 × 106 propagules/ml of the protector to protect against similar inoculum density of the wilt pathogen. Although isolates of the protector and pathogen varied in effectiveness and sensitivity, all protector isolates showed some degree of protection. Fusarium lateritium did not cause significant repression of wilt on cotton, pepper, watermelon, or cabbage simultaneously inoculated with compatible formae speciales of F. oxysporum by root-dip inoculations in greenhouse tests. The significance of these findings in relation to screening for resistance to Fusarium wilt in sweetpotato is briefly discussed.