BIOLOGICAL CONTROL AND SEROLOGICAL STUDIES ON RALSTONIA SOLANACEARUMTHE CAUSAL AGENT OF POTATO BROWN ROT DISEASE IN EGYPT

Abstract

The present results included two big important subjects namely, biological control and serological studies of R. solanacearum.

6.1. Biological control of R. solanacearum:

The present results revealed the following:

1- Inoculation of potato tuber with B. subtilis (105 - 106 CFU/ml) at rate

100 ml/pot during planting resulted 90.96% and 90.79% reduction in wilt severity of C.V. Spunta and Diamont, respectively after 90 days in all the treatments. 2- Tubers drenched with B. subtilis (105 - 106 CFU/ml) for half an hour

and planting resulted 96% and 96.2% reduction in wilt severity of

C.V. Spunta and Diamont, respectively.

3- Inoculation of potato tuber with P. fluorescens (108 - 109 CFU/ml) at rate 100 ml/pot during planting resulted 37.07% and 48.02% reduction in wilt severity of c.v. Spunta and Diamont, respectively. 4- Tubers drenched with P. jluorescens (108 - 109 CFU/ml) for half an

hour and planting resulted 86.84% and 88.32% reduction in wilt severity of c.v. Spunta and Diamont, respectively. 5- Tubers drenched with Rhizo-N (8 gm/litre) for half an our and planting resulted 93.74% and 94.8% reduction in wilt severity ofC.v. Spunta and Diamont, respectively. 6- Tubers drenched with Rhizo-N (4 gm/litre) for half an hour and

planting resulted 95.92% and 96.27% reduction in wilt severity of c.v. Spunta and Diamont, respectively. 7- Rhiz'J-N as com: Prf'i3l prGdt and B. subtilis were the most

effective treatments and Pseudomonas jluorescens occupied the second rank in inhibitory effect against R. solanacearum.