Newly 4th instar larvae of Spodopetra littoralis were fed on lufenuron treated
leaves for two days and then on untreated leaves till the end of the experiment. Food
consumption and larvae were weighted every day. Data indicated that the weight
gained and foods consumed were decreased in the treated larvae compared with
untreated check at ali periods of the experiment. Data also indicated that lufenuron
decreased the values of consumption index (C.I.) and growth rate (G.R.) compared
with the untreated ones. The values of the efficiency of conversion of ingested food
(E.C.I.) explain the efficiency of conversion of food to weight gained. Data clearly
revealed the pronounced variations between the high values of average of (E.C.I.) in
untreated and the low levels in treated larvae. Data also indicated that the average of
the efficiency of conversion of ingested food was negatively propotional with the
increase of lufenuron concentration