Chromone fungicides

A method of combating phytopathogenic fungi at a locus infested or liable to be infested therewith which comprises applying to the locus a compound of formula ##STR28## where one of Z and Y is CO and the other is C--W--R.sup.2 :

• the dotted line indicates a double bond is present in the appropriate position to meet valency requirements;
• W is O, S(O).sub.n, N(R.sup.3), N(R.sup.3)N(R.sup.4), N(R.sup.3)O or ON(R.sup.3);
• R.sup.1 is an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, phenyl, or heterocyclyl group;
• R.sup.2 is an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, phenyl or heterocyclyl group;
• R.sup.3 and R.sup.4, which may be the same or different, are as defined above for R.sup.1, or are hydrogen or acyl, or
• R.sup.2 and R.sup.3 or R.sup.2 and R.sup.4 or R.sup.3 and R.sup.4 together with the nitrogen or oxygen to which they are attached form an optionally substituted ring which may contain other hetero atoms:
• each X, which may be the same as or different from any other X, is halogen, CN, NO.sub.2, SF.sub.5, B(OH).sub.2, triakylsilyl or a group E, OE or S(O).sub.n,E where E is a group as defined hereinbefore for R.sup.2 or is optionally substituted amino;
• or two adjacent groups X together with the atoms to which they are attached form an optionally substituted carbocyclic or heterocyclic ring;
• n is 0, 1 or 2;
• and
• p is 0 to 4;
• with the proviso when W is O, R.sup.2 is not o-substituted benzyl.