To determine if baldcypress,Taxodium distichum(L.) Richard, could be a “most suitable host” for gypsy moth,Lymantria dispar(L.), we fed laboratory-reared larvae white oak,Quercus albaL. (a “most preferred host” species), baldcypress, or a mixed diet of baldcypress and white oak, and monitored survival, development, and fecundity for 2 developmental years. Criteria for most suitable host were>80% survival of 1st instars, development to pupation in350 full sized ova. Our 1990 and 1992 laboratory studies indicate that baldcypress generally met these critCl; a, and we consider baldcypress a most suitable host for gypsy moth. In 1990 and 1992, respectively, 69 and 83% of 1st instars survived after being reared on baldcypress, compared with 77 and 74% on white oak and 82 and 87% on mixed diet. In 1990 and 1992 61 % of larvae fed baldcypress completed larval development and pupated, as opposed to 7.3 and 56% on white oak and 80 and 83% on mixed diet. For 1990, mean days to pupation and adult emergence, respectively, were 50 and 63 d for baldcypress, 47 and 56 d for white oak, and 47 and 59 d for mixed diet. Mean days to pupation and adult emergence for 1992, respectively, were 48 and 61 d for baldcypress, 46 and 60 d on white oak, and 48 and 61 d on mixed diet. The percentage of pupae that emerged as adults in 1990 and 1992, respectively, were 74 and 98% on baldcypress, 96 and 100% on white oak, and 95 and 99% on mixed diet. Mean female pupal weights for 1992 were 1,100 mg (baldcypress), 1,350 mg (white oak) and 1,440 mg (mixed diet). Mean numbers of ova produced for 1990 and 1992, respectively, were 475 and 451 for baldcypress, 453 and 456 for white oak, and 508 and 519 for mixed diet.