UNH LIBRARY 



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ABSTRACT 



The construction and operation of battery-operated field instru- 

 mentation for plant disease management programs and epidemio- 

 logical studies are described and illustrated^ The major components 

 are a digital rain gauge and leaf wetness indicator coupled to pen 

 arms added to a hygrothermograph which also monitors and 

 records temperature and relative humidity. The instrumentation 

 has several characteristics considered essential for the programs 

 being developed in New Hampshire: low-cost, low-maintenance, 

 simplified design and technology, durability, reliability, and flexi- 

 bility (adaptable to orchard and field crop conditions). Temperature 

 (°F or °C), relative humidity, duration (hrs) of leaf wetness, rainfall 

 (0.25 mm), and rain-intensity (occurrence of each 0.25 mm of rain) 

 are monitored and recorded. In addition, the instrumentation can be 

 wired to activate a spore trap or other device during periods of leaf 

 wetness. An important feature is a visual record of the temperature, 

 relative humidity, duration of leaf wetness, and rain-intensity and 

 distribution on one chart. This allows these weather variables to be 

 readily examined and assessed in the field either individually or as 

 they interrelate. 



KEY WORDS: Integrated Pest Management, Disease Management, Leaf Wetness 

 Indicator, Field Instrumentation, Weather*Variables. 



