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In this work, we have studied the benzofurans of <i>Pericallis echinata</i> (aerial parts and transformed roots), <i>P. steetzii</i> (aerial parts and transformed roots), <i>P. lanata</i> (aerial parts), and <i>P. murrayi</i> (aerial parts and roots). This work has permitted the isolation of the new benzofurans 10-ethoxy-11-hydroxy-10,11-dihydroeuparin (<b>10</b>), (-)-eupachinin A ethyl ether (<b>12</b>), 11,15-didehydro-eupachinin A (<b>13</b>), 10,12-dihydroxy-11-angelyloxy-10,11-dihydroeuparin (<b>14</b>), 2,4-dihydroxy-5-formyl-acetophenone (<b>15</b>) isolated for the first time as a natural product, 11-angelyloxy-10,11-dihydroeuparin (<b>16</b>), and 12-angelyloxyeuparone (<b>17</b>), along with several known ones (<b>1</b>–<b>9, 11</b>). In addition, the incubation of the abundant component, 6-hydroxytremetone (<b>1</b>), with the fungus <i>Mucor plumbeus</i> has been studied. Benzofurans in the tremetone series (<b>1</b>, <b>1a</b>, <b>2</b>–<b>5</b>, <b>18</b>, <b>18a</b>), the euparin series (<b>6</b>, <b>7</b>, <b>7a</b>, <b>8</b>–<b>10</b>, <b>14</b>, <b>16</b>), and the eupachinin-type (<b>11</b>, <b>12</b>) were tested for antifeedant effects against the insect <i>Spodoptera littoralis</i>. The antifeedant compounds (<b>1</b>, <b>4</b>, <b>6</b>, <b>11</b>, <b>12</b>) were further tested for postingestive effects on <i>S. littoralis</i> larvae. The most antifeedant compounds were among the tremetone series, with 3-ethoxy-hydroxy-tremetone (<b>4</b>) being the strongest antifeedant. Glucosylation of <b>1</b> by its biotransformation with <i>Mucor plumbeus</i> gave inactive products. Among the euparin series, the dihydroxyangelate <b>14</b> was the most active, followed by euparin (<b>6</b>). The eupachinin-type compounds (<b>11</b>, <b>12</b>) were both antifeedants. Compounds <b>4, 11,</b> and <b>12</b> showed antifeedant effects without postingestive toxicity to orally dosed <i>S. littoralis</i> larvae. Euparin (<b>6)</b> had postingestive toxicity that was enhanced by the synergist piperonyl butoxide.