DETERRING AND INHIBITING EFFECTS OF QUINOLIZIDINE ALKALOIDS ON SPRUCEBUDWORM (LEPIDOPTERA, TORTRICIDAE) OVIPOSITION

Although alkaloids are known feeding deterrents for lepidopteran larva e, including the spruce budworm, Choristoneura fumiferana (Clemens), f ew studies have investigated their effects on lepidopteran oviposition . Quinolizidine-containing alkaloid extracts and isolated quinolizidin e alkaloids were obtained from 2 Chinese plants, Sophora alopecuroides L. and Thermopsis lanceolata Robert Brown, to evaluate their effects on spruce budworm oviposition. Application of extracts from either pla nt on Parafilm substrate significantly deterred oviposition at dosages as low as 4.7 and 7.9 mu g/cm(2), respectively, in dual-choice bioass ays. Of 9 quinolizidine alkaloids produced by these plants. 6 deterred oviposition on Parafilm substrate treated at 7.9 mu g/cm(2) or less. The most effective compounds were aloperine (0.3 mu g/cm(2) = 1.3 nmol /cm(2)). sparteine (1.6 mu g/cm(2) = 6.8 nmol/cm(2) ), and cytisine (1 .6 mu g/cm(2) = 8.4 nmol/cm(2)). Oviposition was deterred also on fres h host foliage, 8-cm twigs of balsam fir, Abies balsamea (L.) Miller, which had been sprayed with either a I-mi aliquot of alkaloid extract (10 mg/ml) of S. alopecuroides or 1 mi of an aloperine solution (I mg/ ml). There was no effect ori longevity of males or females continuousl y exposed to artificial substrate treated with aloperine or alkaloid e xtract from S, alopecuroides in no-choice bioassays, nor was the abili ty of males to inseminate females affected. However, female production of egg masses was inhibited. although clutch size (eggs per egg mass) was not affected. These results are the Ist demonstration of the beha viorally deterring and physiologically inhibiting effects of quinolizi dine alkaloids on lepidopteran oviposition.