Journal de pathologie végétale et de microbiologie

Abstrait

Induction of Systemic Resistance in Sugar- Beet against Root-Knot Nematode with Commercial Products

Mostafa Fatma AM, Khalil AE, Nour El Deen AH, Ibrahim and Dina S

The potentials of Bio-arc (a commercial formulation of the Bacillus megaterium) at the rate of 5, 10, 15 and 20 ml and Nemastrol (a commercial formulation of active ingredients) at the rate of 0.25 ml, for induction of systemic resistance to sugar-beet var. Negma infected with M. incognita were conducted in two soil types. Results revealed that all treatments with tested rates were found to have nematicidal activity against nematode infection and improved plant growth parameters of sugar-beet with various levels of success. The dual application of Bio-arc+Nemastrol at the rate of 20 ml +0.25 ml proved to be the best and showed significant improvement in plant growth parameters in terms of shoot length (92.6,127.5%) and total plant fresh weight (91.7, 370.4) of sugar-beet grown either in clayey or sandy soil, respectively. Among all treatments Nemastrol ranked next to oxamyl and performed the best and significantly suppressed total nematode population (Rf=1.9, 2.2), root galling (RGI=3.0, 3.0), number of egg masses (EI=3.0, 3.0) and number of eggs / egg mass (Red. %=76.5, 74.5) in clayey and sandy soil, respectively. However, concomitant treatment showed better results than did Bio-arc alone at four tested rates. The greatest suppression in total nematode population was recorded with clayey and sandy soil receiving the dual application of Nemastrol (0.25 ml) and Bio-arc (20 ml) with reproduction factor 2.2, 2.6 and reduction percentages reached 92.8, 92.6% respectively. Leaves of sugar-beet were assayed for their biochemical profiles with respect to NPK, total cholorophyll, total carbohydrates, proteins, and phenols. Moreover, remarkable induction in such chemical constituents except phenol content was recorded with the application of Bio- arc+Nemastrol (20 ml+0.25 ml). On the other hand, activities of related enzymes i.e. Peroxidase (PO) and Polyphenol Oxidase (PPO) were evaluated in roots of sugar-beet infected with M. incognita. The enzymes accumulation was much greatest in Bio-arc+Nemastrol (20+0.25 ml) treated plants compared to control as they reached their peak at day 9th from nematode inoculation