Effect of Nosema fumiferanae (Microsporida) on Fecundity, Fertility, and Progeny Performance of Choristoneura fumiferana (Lepidoptera: Tortricidae)

Abstract

Female eastern spruce budworm, Chor_toneura fumiferana (Clemens), in-. oculated sublethally as fourth or fifth instals with Nosema fumiferanae (Thomson), exhibited significant reductions in size, fecundity, and total egg complement. Mating success and egg fertility were similar for treated and control insects. The presence of disease improved the positive correlation between fecundity or total egg complement and female pupal weight without significantly reducing the slope. Total egg complement was negatively correlated with disease load. A subsample of progeny reared from each fertile mating indicates 100% • transovarial transmission efficiency at the spore dosages provided. Diseased progeny expe-• rienced twice the larval mortality, and surviving individuals were approximately 25% smaller and took 17% longer to complete development than healthy progeny. Maternal disease load • was a significant, positive factor in percentage progeny mortality and male pupal weight.