TITRES OF PRECOCENE II AND ITS METABOLITES IN THE HAEMOLYMPH OF THE AFRICAN ARMYWORM SPODOPTERA EXEMPTA FOLLOWING TOPICAL TREATMENT WITH THE COMPOUND

摘要

No precocious metamorphosis or other morphogenetic effects were seen following topical treatment of Vth instar Spodoptera exempta with precocene II (6,7-dimethoxy-2,2-dimethylchromene). 3H-Precocene II penetrated the larvae rapidly following topical application. An uptake of 47% was recorded in the first hour and an average of 27% for the first 3 h. Radioactivity in the haemolymph reached a maximum 4 h after treatment at 6-8% of the applied dose. A maximum titre of precocene of 1.1 x 10~(-4) M was observed 2 h after treatment and a biological half-life of around 1 h was recorded for the first 6 h.