. Commercial mass culture of the California red scale parasite : Aphytis lignanensis. Citrus; Scale insects. cluster on the tip of the squash nearest the light. Massed crawlers fall from the tip to a white card below, then move again toward the light until they reach the edge of the shadow cast by "V"- shaped shadow boards. The shadow col- lector is pictured in figure 1. The line of crawlers can be seen in the lower left center of the photograph. The light source is a 48-inch fluores- cent tube mounted vertically. The shadow cast by this light is not sharply defined, the edge being b
. Commercial mass culture of the California red scale parasite : Aphytis lignanensis. Citrus; Scale insects. cluster on the tip of the squash nearest the light. Massed crawlers fall from the tip to a white card below, then move again toward the light until they reach the edge of the shadow cast by "V"- shaped shadow boards. The shadow col- lector is pictured in figure 1. The line of crawlers can be seen in the lower left center of the photograph. The light source is a 48-inch fluores- cent tube mounted vertically. The shadow cast by this light is not sharply defined, the edge being broad and grading from very light shadow to dark shadow. Such gradation works well and may be su- perior to a sharply defined shadow in that the crawlers tend to distribute them- selves over a broader zone; this reduces the number of crawlers piling up at a sharp shadow line, and possibly thereby reduces injury to the crawlers involved. The mother-scale-infested squash are arranged on a circular rack as pictured in figure 1, with the crawler collection cards placed below in such a way as to receive crawlers falling from the tips of the squash nearest the light source. A rack constructed in a manner similar to the pictured one, but with three shelves, would accommodate 135 squash, or more than the 120 needed in a two-man opera- tion. The addition of one more shelf makes it possible to accommodate 180 squash, which under normal conditions represents the average number needed for a full-time three-man insectary opera- tion. A rack of this type is pictured in a later section (see "Mass-Culture Equip- ment," p. 36). A large collection of crawlers is shown at the shadow line in figure 2. From the card, the crawlers are transferred to a common kitchen-type metal salt shaker. This is done by lifting the ends of the card on which the crawlers have been col- lected until the ends of the card meet, grasping both ends in one hand with one finger inserted between the edges in order
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Keywords: ., book, bookcentury1900, booksubjectcitrus, booksubjectscaleinsects
