Six populations of hard endosperm opaque maize were evaluated with 2 local normal maize populations at Lajas and Isabela, Puerto Rico, from March to May 1983. Corn entries were either i) inoculated with pink mold at 7 to 10 days after anthesis, ii) sprayed with benomyl at the same date and 14 days thereafter, or iii) not treated. Insect damage, caused mostly by corn earworm (Heliothis zea), and visible mold were assayed on cobs before shelling. Shelled seeds were surface-disinfected and planted on potato dextrose agar for assay of germination and internally seed-borne mycoflora. At Lajas 6.3% of the cob area showed earworm damage, and 3.8 kernels/cob had visible mold. Natural infection with pink mold was high (53.8%), and seed germination was low (68.6%). At Isabela, 0.1% and 8.3 kernels/cob were damaged by earworm and molds, respectively. Seed germination was high (93.9%) at Isabela and incidence of internally seed-borne pink mold was low (17.2%). The dominant fungus at Isabela was Cephalosporium acremonium (32.8%). Seeds infected with this species were exceptionally vigorous and lacked root discoloration typical of seedlings infected by the other fungi. Ear-silk inoculations increased seed-borne pink mold infection by 25% at Lajas and over 100% in Isabela. Incidence of moldy kernels was also increased by inoculation. Ear-silk application of benomyl in field plants did not reduce seed-borne infections by fungi. The same treatment increased earworm damage. Percentage earworm damage over both sites was 4.4, 3.0, and 2.1% for the benomyl, nontreated, and pink mold inoculated treatments, respectively. Benomyl applied directly to corn seed controlled all major corn-seed molds except Curvularia lunata, a benomyl-tolerant species. Higher visible seed mold was found in modified opaque corn (cv. White H. E.) than in the other entries. A local flint corn (cv. Mayorbela) suffered the least damage from both visible mold and insects. Among the hard endosperm opaque populations, Amarillo Dentado QPM-2 showed the best visible seed quality.