5.6.10
THE EFFICIENCY OF THE COMBINED TREATMENT OF MAIZE AND WHEAT SEEDS WITH FUNGICIDES AND A STEROID GLYCOSIDE MOLDSTIM

P KINTIA and G LUPASHKU

Institute of Genetics, Academy of Sciences, Padurilor str., 20, Chisinau 2002 MD, Republic of Moldova

Background and objectives
Undesirable ecological consequences and low efficiency of fungicides have recently demanded special attention to the utilization of natural bioregulators in plant protection from pathogens. Steroid glycosides isolated from different plant parts are among them [1]. We have noted earlier that some steroid glycosides exhibit a fungitoxic effect on pure cultures of the Fusarium fungi and have a regulatory action on membrane permeability and synthesis of photosynthetic pigments in wheat and triticale plants infected with F. graminearum [2]. The goal of our research was to study the influence of combined treatment of maize seeds with cytoxal (fungicide) and moldstim (steroid glycoside) and wheat seeds with Baytan (fungicide) and moldstim on the resistance to Fusarium disease and some parameters of productivity.

Results and conclusions
Our studies have shown that under field conditions combined treatment of maize seeds with cytoxal (4.5 kg/t) and moldstim (0.1-10.0 g/t) has a higher effect in the inhibition of the Fusarium disease in the earcorn as compared with the control (cytoxal). Simultaneously, an increase in some parameters of productivity as observed, i.e. kernel number per earcorn (+14 +15%) and kernel weight per earcorn (+12 +17%).

It has been established that upon infection of wheat seeds with F. graminearum under laboratory conditions, the addition of moldstim (0.1 g/l) into the baytan solution leads to a 3-4-fold reduction of the amount of the latter (30 g/I). At the same time, its toxic effect decreases and the positive effects such as seed emergence (+14.5%), germination energy (+33.0), dry biomass accumulation in roots (+1 8.4%) and stem (+144.8%) of plants increase. Thus the addition of moldstim into the fungicide composition may increase their positive effect, decreasing the pesticide pressure which is of a special importance from the economic and ecological viewpoints.

References
1. Kintia PK, Lazuryevskiy GV, Balashova NN et al., 1980. The structure and biological activity of steroid glicosides of spirostan and furostan series. Kishinev, Shtiintsa (in Russian).
2. Kintea PK, Lupashku GA, 1996. Saponins Used in Food and Agriculture. Plenum, New York, pp. 75-82.