A method for inhibiting hatching of soybean cyst nematode eggs is provided comprising contacting said eggs with an effective inhibitory amount of a compound of formula (I): ##STR1## wherein R.sup.1 is H or OH, R.sup.2 is H or OH, R.sup.3 is H or (C.sub.1 -C.sub.4)alkyl, R.sup.4 is H or (C.sub.1 -C.sub.4)alkyl, R.sup.5 and R.sup.6 are individually H, (C.sub.1 -C.sub.5)alkyl, C.sub.3 -C.sub.6 (cycloalkyl)alkyl, C.sub.5 -C.sub.7 (cycloalkenyl)alkyl, (C.sub.6 -C.sub.12)aryl, (C.sub.7 -C.sub.12)aralkyl, trans(C.sub.4 -C.sub.5)alkenyl, allyl or furan-2-ylalkyl or together are (C.sub.2 -C.sub.5)alkylene, or (C.sub.3 -C.sub.5)alkylidene or 1,2-phenylene, optionally substituted by OH, O(C.sub.1 -C.sub.3)alkyl, SH, phenyl or N(R.sup.7)(R.sup.8), wherein R.sup.7 and R.sup.8 are individually H, (C.sub.1 -C.sub.3)alkyl or phenyl; R.sup.9 =H or (C.sub.1 -C.sub.4)alkyl, n is 0 or 1 and wherein the bond represented by --- is present when n=0 or absent when n=1; or an agronomically-acceptable salt thereof.