. Continuous mass rearing of the European corn borer in the laboratory. European corn borer. carefully placed on the water surface, the leaf floated; it remained fresh for about a week. Some first instar corn borer larvae transferred to a leaf tended to wander around and to come in contact with the water surround- ing the leaf. In order to prevent the water from being drawn onto the surface of the leaf following contact with the water by the larvae, a thin film of petroleum jelly was applied around the edges of the leaf and around the hole in the center of the leaf. It was found advisable to t
. Continuous mass rearing of the European corn borer in the laboratory. European corn borer. carefully placed on the water surface, the leaf floated; it remained fresh for about a week. Some first instar corn borer larvae transferred to a leaf tended to wander around and to come in contact with the water surround- ing the leaf. In order to prevent the water from being drawn onto the surface of the leaf following contact with the water by the larvae, a thin film of petroleum jelly was applied around the edges of the leaf and around the hole in the center of the leaf. It was found advisable to treat the leaf on the underside as well. In order to prevent flooding of the upper surface of the leaf when it had been treated with wetting agents, the gutter formed by the midrib was closed at both ends with bees- wax. If it was necessary to increase the bouyancy of the leaf, a piece of wax paper of somewhat smaller size was floated beneath the leaf. The leaf was placed in a crystallizing dish of such size that there would be clear- ance of at least an inch between the leaf and the wall of the dish. The floating leaf was held in the center of the dish by a simple, triangle-shaped anchor made of a bent glass rod. Around this anchor the leaf could turn freely, provided the hole was made large enough. With the help of this anchor the leaf could be lifted out from the water for examination and replaced at any time. It was sometimes necessary to cover the dish in order to reduce the evaporation of water. Class or other. Fig. 7. — Airangemenl HosigneH to approximate the conditions prevailing in the whorl of a young corn plant. A 20 x 90 mm. double strength extraction thimble. A, is reinforced with a band of lacquer around the lip and two vertical strips of lacquer on opposite sides; also, it is provided with a cork that has been softened and wrapped in tinfoil. A coil of wire, B, about 2-1/4 inches long, narrow enough to fit easily in the extraction thimble, and with the lower end
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Keywords: ., bookauthorillinoisnaturalhistorysurveydivision, bookcentury1900
