A portable electronic apparatus was constructed to measure the quantity of moisture and its duration on citrus foliage. It consists of a sensor and recorder in a balanced circuit independently powered with direct current. Current flowing through the sensor was recorded as an impulse on a recording chart. The more moisture on the sensor, within limits, the lower the electrical resistance and the higher the scale deflection. Duration of moisture was determined as the time between the first and last impulses and from the chart speed. A single sensor situated beyond the tree canopy and elevated to about 4 ft above ground simulated overall leaf conditions most closely. Sensors performed adequately for 6 months, but generally were changed after 4 months.
Document Type: Research Article
Publication date: February 1, 1972
More about this publication?
Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.