Armstrong J, Armstrong W (2001 ) An overview of the effects of phytotoxins
on Phragmites australis in relation to die-back.
Mainly, the Deleterious Rhizobacteria (DRB) inter their harmful detriment (damage) by producing deleterious metabolites which absorb by root, without directly interfere the plant tissue,  These metabolites include: Hydrogen cyanide(HCN),plant hormones like indole-3 Acetic acid  and unknown phytotoxins
Rhizosphere organisms also contribute to the rhizosphere chemistry, releasing mineral nutrients from dead cells that can be taken up by roots, antibiotics and antifungal agents, phytotoxins
(Gerhardson et al.
The same held true for Argentinean coasts, where metal contamination, phytotoxins
, abnormal phytoplankton composition, and protozoan tissue-parasites were discarded as causative factors (Fiori & Cazzaniga 1999).
produced by fungi associated with grapevine trunk diseases.
These conditions lead to a large decrease in plant nutrient availability (Ernst, 1990) and to buildup of phytotoxins
produced by anaerbic soil mierobes or by anaerobie respiration in plant roots (Koch & Mendellsohn, 1989).
Apart from shading and keeping the soil moist, rye mulch also inhibits bothgermination and growth of weeds through release of phytotoxins
88] studied the effect of Helminthosporium phytotoxins
on cereal leaf protoplasts.
roots, suggesting a mechanism of detoxifying reduced phytotoxins