Elson J. Shields (state rep to NCR-148) & G. C. Bergstrom
Cornell University
Ithaca, NY 

Fusarium graminearum in corn

Aerial spore traps were built from the combination of a 3 L soda bottle and a 2 L soda bottle

Two spore traps were mounted beneath the wing of an 8 ft radio controlled model airplane and carried aloft to altitudes ranging from 75 ft to 400 ft depending on the sampling location.

In each spore trap, a standard sized petri plate was completely filled with selective culture media and mounted vertically inside the trap in the airstream entering the trap from the front. A remotely controlled door on the front of the trap prevented the plate from being exposed to the airstream before the airplane reached the desired altitude. Upon reaching the desired altitude, the door on the front of the trap was opened and the sample was exposed to the airstream for 30 minutes. Plane speed remained between 50 & 55 mph for the entire sampling period. At this speed, each trap sampled approximately 250 cubic meters of air during the 30 minute exposure period. During the sampling runs, air speed and altitude was monitored using an airborne telemetry system carried in the airplane. Data was transmitted to a lap top computer in real time.

A total of 11-30 min sampling flights on 5 different days in May were flown over corn stubble. Sampling times ranged from noon to dark and sampling altitude ranged between 75 and 150 ft. Viable F. graminearum spores were collected on 8 of the 11 sampling flights. Viable spores ranged from 1 to 5 spores per sample. A total of 16-30 min sampling flights on 3 different days in early June were flown over mixed hardwood forest, removed from corn stubble by approximately 1 mile. Sampling altitude ranged between 250 and 400 ft. Viable F. graminearum spores were collected on 8 of the 16 sampling flights. Viable spores ranged from 1 to 3 spores per sample. In mid-June, a total of 9 - 30 min flights were flown over a grass/hardwood forest hill top overlooking a agricultural valley with corn stubble on the valley floor. Sampling altitude ranged between 250 and 400 ft above the hill top and exceeded an altitude of 1000 ft above the valley floor. The hill top was located at a bend in the valley which directed the prevailing valley wind to impact on the hill side. The only corn stubble present in the area was located on the valley floor. Viable F. graminearum spores were collected on 2 of the 9 flights and the remoteness of the site suggested that the source of spores was the corn stubble on the valley floor, several miles distant and more than 1000 ft lower in altitude.

Return Migration of Potato Leafhopper (E. J. Shields)

The 1997 spring migration of potato leafhopper was the largest migration in recent years. Field studies focused on the return migration of potato leafhopper were initiated on August 15. Field observations included daily suction trap samples, sweep samples taken 3 times a week, continuous recording of weather conditions including barometric pressure, daily collection of the weather maps and aerial collections over leafhopper infested alfalfa fields when ever possible. Field and aerial samples were frozen for examination and tabulation during winter months. Data collection continued for approximately 60 days until daily temperatures remained the flight threshold of potato leafhopper (50°F) in mid October. Data will be analyzed during the winter months and reported at the 1998 meeting.

 

Aerial Sampling of Potato Leafhopper and Other Arthropods (E. J. Shields).

The goal of sampling 10,000 cubic meters during a 30 minute sampling flight has become a bit elusive with the current 8 ft sampling platform. Wing loading limitations restrict engine size to ca. 1.2 cu inch producing ca. 3 hp and fuel load to 40 ozs. As a result, the RC airplane is restricted to 16 inch square net which is pulled through the air at ca. 35 mph. This net samples ca. 5,000 cubic meters of air during a 30 minute sampling run. Captures of leafhoppers range from 0-6 individuals per 30 min. sample. Entomologically speaking, a sample containing 0-15 leafhoppers collected during 30 minutes aloft would be more meaningful and would allow the flexibility of both dissection and biological studies in the laboratory. At the collection speed of ca 40 mph, the vast majority of the insect specimens come down alive and intact.

At my low level of "rocket science", the following logic prevails. To achieve 10,000 cubic meters in 30 minutes while maintaining a favorable entomological sampling speed (pre-splat speed), twice as much air needs to be sampled per second. Therefore, the sampling platform needs to be bigger to carry more weight while maintaining a reasonable wing loading and the sampling platform needs to be more powerful to drag a bigger net through the air. This winter will be spent in two directions. This first project will be to optimize the current 8 ft sampling platform for use during the 1998 sampling season. The second project will be to explore the options of going to a bigger sampling vehicle.

[ 1997 Research Index ]