A 0.12-ha plot containing high-yielding rice plants (IR-26) 3-4 weeks
from harvest, and with a potential for heavy rat damage, was selected
near Lumban, Laguna. A barrier was installed by placing stakes at 1-m
intervals along the inside, top of dikes surrounding the plot, and
stretching a plastic fishnet (5 mm mesh) from ground level to about
0.5 m above the ground from stake to stake around the plot. At the
base of the barrier, the netting was curled under for several centi-
meters, and topped with soil and cut weeds. At the top, the netting
was curled outward and loose, so that rats attempting to climb the
fence would fall back to the ground. A series of three electrodes
(35-gauge wire) were arranged along the top of the dike, outside and
parallel to the fence. The outermost wire was 5 cm above ground, the
innermost about 2.5 cm. The electrodes were affixed to small wooden
spikes driven into the dike, and insulated with plastic or varnish.
The barrier was electrified with a Gallagher Model E 12 fence charger
set at a medium pulse rate. The outermost and innermost electrodes
were energized and the center electrode was grounded. The barrier
operated continuously until harvest (approximately 3 weeks).

Tracking tiles and traps were placed uniformly around the fence, ten
outside and ten inside, during the first 3 days of operation. A
similar procedure was followed on an unfenced reference plot about 90
m away. Damage appraisals (percent damage on 100 randomly selected
rice plants) were conducted in both plots during the first 2 days of
operation and again at harvest. In addition, damage appraisals were
conducted at harvest on three fields surrounding and separated by 30
m from both the treated and reference plots.

The barrier held a 5-kV or better charge during most of the 3-week
study. The first battery, a new 12 V d.c. car battery, was defective
and was replaced after 8 days. The used replacement battery was
recharged once during the remaining 2 weeks.

Statistical analysis of the data revealed that the barrier was effec-
tive in reducing rat damage. Damage in the plot bounded by the
barrier averaged 1.9 percent and damage in the fields surrounding the
test plot averaged 8.6 percent. The reference plot suffered 18.8 per-
cent damage while the three fields surrounding it had an average of
11.9 percent damage.

Training

Several staff members continued their pursuit of advanced degrees.
One completed the requirements for the Ph. D. degree and another has
completed the required course work, passed the comprehensive examina-
tion, and is currently finishing the thesis work. Four of six
Master's candidates completed requirements for their degrees.