Abstract: The invention relates to new inclusion complexes of piperonyl butoxide formed with cyclodextrin.The new complex of the invention can be prepared by reacting cyclodextrin or a solution thereof formed with water and/or an organic solvent having 1-4 carbon atoms, preferably ethanol with piperonyl butoxide or a solution thereof formed with an organic solvent having 1-4 carbon atoms, preferably ethanol at a temperature between 20.degree. C. and 90.degree. C., whereby the piperonyl butoxide is used in an amount of 0.6-1.5 moles related to 1 mole of cyclodextrin.The complexes of the present invention synergize the pesticidal effect of known insecticides and fungicides to a much higher extent of known insecticides and fungicides to a much higher extent than piperonyl butoxide used per se.

Abstract: The invention relates to a method of combatting phytopathogenic fungi, primarily powdery mildew. The method involves administering compositions according to the invention which contain as active principle at least one compound of the formula (I), ##STR1## wherein R.sup.1 is a C.sub.1-12 alkyl or a chloroethyl group,R.sup.2 is hydrogen, halogen, a C.sub.1-4 alkyl, a C.sub.1-4 alkoxy or nitro group,R.sup.3 is hydrogen, halogen, a C.sub.1-4 alkyl or nitro group, andR.sup.4 is hydrogen, halogen, a C.sub.1-4 alkyl or nitro group, or an acid addition salt thereof.