Kovács I. Endre szerk.: Rovartani Közlemények (Folia Entomologica Hungarica 16/22-30. Budapest, 1963)
of monotonous biocoenosea, poor in species numbers but the more rioh in individuals .If this state of affairs is further aided and abetted by regular artificial fertilization, intensive tillage, and the use of chemical herbicides and insecticides, there will evolve communltiea of on exceedingly instable equilibrium, concomitant with unexpected gradations and sudden damages. Prom a qualitative point of view, the disappearance, together with the balks, of quantitatively not copious but very important species, e.g. wild bees /Bombua/, is a significant gap in the community,aa. their absence involves a considerable decline in the aeed-production of certain leguminous plants. In orchards, as was also mentioned earlier, there appears some times, due to extensive culture and mechanized plant protections harmful upset of the biologic equilibrium. These two instances clearly show that „conveyor-belt" agriculture will occasionally create entirely new problems, - to be solved successfully only by plant protection experts with an eye on biocoenology , Just so,modern agriculture presents us with the problem of insect forecast, the prediction of the appearance of insect pesta. It reed not be discussed in details before the members of the Hungarian Entomological Society that a succèsfui pest forecast cannot be imagined without a profound knowledge of the habits and coenological relatione of the insects. On the basis of estimations of the injuries caused by agricultural insect peats, we now know that, on the average, more than ten per cent of the nationwide annual yield is annihilated by pests. If Hungarian plant-protection entomologists avert but a fraction of this appalling demage, they have refunded many times over to national economy all expenses - the costs of the whole Hungarian entomology, theoretical and applied experts ,staffe,salaries „Investmente, etc It is my profound belief that the future projects of plant protection will gradually ahift over to control by in-
