Author
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COSTA, HEATHER - UNIV OF CA, RIVERSIDE, CA |
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TOSCANO, NICK - UNIV OF CA, RIVERSIDE, CA |
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Hendrix, Donald |
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Henneberry, Thomas |
Submitted to: Silverleaf Whitefly: 1997 Supplement to the Five Year National Research and
Publication Type: Abstract Only Publication Acceptance Date: 8/1/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Whitefly honeydew droplets were collected on water sensitive paper strips. A plastic cylinder was glued to the face of an appliance timer that completed a full rotation every 24 hours. A water sensitive paper strip was attached around the perimeter of the cylinder and placed under feeding whiteflies such that the strip collected honeydew continuously over a 24 h period. Droplets appeared as a line of blue spots on the yellow paper. A periodic pattern of honeydew production by nymphs was observed. The pattern consisted of periods of droplet production followed by shorter periods where no honeydew droplets were produced. In most cases, late 4th instar produced honeydew continuously. Molts were indicated by an extended OFF period followed by a noticeable increase in droplet diameter. A significant positive relationship was found between nymphal body length and diameter of the droplet produced. The frequency of droplet production during ON periods decreased from first instar to fourth instar. The periodicity of 1st instar nymphs was more difficult to determine as few cycles per individual were measurable. There did appear to be a cyclic pattern of production, however the drops were much more scattered and inconsistently detected in 1st instars compared to later instars. In several cases the first instar did not produce detectable levels of honeydew. The physiological significance of the periodic pattern of honeydew production is unknown. |