Abstract: Although hatching of the arrowhead scale crawlers may occur anytime in a day, 69.7-76.9% of the hatching and 90.6* of the crawling-onto-citrus leaves were observed to take place during day time. Under illuminated laboratory conditions, the average crawling time of the scales (from, hatching to settle down) was 18.7 hr. for the males and 17.6 hr. for the females. This period was shortened under the dark. The crawlers showed positive phototaxis to various light sources. Stronger phototaxis by the crawlers was shown to ultraviolet light plus host plant than that to ultraviolet light alone, and the latter was yet stronger than that to fluorescent light. Survival rate of the scale was over 90% on either the indigenous squash or the Indian varieties. Thus, by manipulating the lighting conditions to attract the crawlers moving directly onto the squash and settling down, the dispersal and mortality of the young crawlers may be greatly reduced in the mass rearing of the scale.