Assessment of pesticide effects on non-target soil microorganisms

Agricultural pesticides should be free of side effects that may cause a lasting disruption of microbial processes that are essential for continued soil fertility. A test program is described here for the assessment of the potential effects of newly-developed pesticides on non-target soil micro-organisms. The pesticides to be tested are applied at the equivalent of their recommended field application concentration and, for a margin of safety, also at the tenfold thereof. The measurement of pesticide effects on the microbial cycling of C, N and S constitute the core of the test program. These measurements are, in some cases, complemented by evaluation of pesticide effects on total and viable microbial numbers, on the abundance of specific components of the soil microbial community, and on the growth rates of selected soil microorganisms. The above test program was applied to evaluate the safety of the herbicides N-(1-ethylpropyl)-3,4-dimethyl-2,6-clinitrobenzeneamine(pendimethalin) l,2-dimethyl-3,5-diphenyl-1H pyrazolium (difenzoquat), S-(4-chlorophenyl)-N,N-diethyldithiocarbamate (thiobencarb), and the fungicides N-[(trichloromethyl) thio]-phthalimide (folpet) and cis-N-[(l,l,2,2-tetrachloroethyl) thio]-4-cyclohexene-1,2-dicarboximide (captafol). No detectable adverse effects were caused by any of the tested herbicides. The fungicides inhibited some of the C cycling activities, but the inhibition was temporary and was associated with their effect on soil fungi.     

DNA restriction enzyme analysis of a bovine herpesvirus 1 strain isolated from encephalitis in Hungary

The DNA of a bovine herpesvirus 1 (BHV-1) strain isolated from calf encephalitis in Hungary was analysed with restriction enzymes. The cleavage pattern of the encephalitis strain Na/67 differed from those of all the other Hungarian BHV-1 isolates investigated so far. The EcoRI and HindIII cleavage patterns of virus strain Na/67 were found to be similar to the patterns of two other encephalitis strains (N569 and A663 from Australia and Argentina, respectively) characterized earlier. Strain Na/67 is the first isolate in Europe which showed the restriction enzyme pattern of BHV-1.3 previously supposed to be characteristic of encephalitis strains.