standards) were the two reasons most frequently given by farmers for
not using improved rat control methods. The survey indicated lower
rat damage in rice where improved control measures, namely sustained
baiting with anticoagulants, were adopted. Mass media support and
improvement in the technical capability of agricultural technicians is
recommended.

 13. Work continued on a study aimed at developing a simple means
of detecting anticoagulant resistance in R. r. mindanensis and R.
argentiventer. Baseline data were established by treating large
numbers of each species with anticoagulant rodenticides and measuring
prothrombin clotting times. This information can be used to quantify
anticoagulant-resistant or susceptible animals. Bioassay tests of
several alternate control agents were completed. These would be used
as alternatives to anticoagulants if resistant populations do develop.
This study will be completed in 1979.

 14. Sugarcane yield losses due to rodents were determined on
Negros Island in the Philippines. Laboratory analysis of extracted
juice from damaged and undamaged stalks yielded an estimated total
sugar loss of 2.30 percent. Actual rat damage (percent of canes
attacked) ranged from 1.80 to 13.19 with a mean of 6.70. The rela-
tionship between percent total sugar loss (TSL) and the percentage of
rat damage (RD) is expressed by the equation TSL = -0.77803 + 0.5555
RD 0.01450 RDe. Yield loss can now be estimated from extensive
rat damage surveys.

 15. A study was conducted in Laguna, Philippines, to examine
variables that can influence the effectiveness of baiting programs.
Among the items examined were the relative acceptability of several
common baits, bait station design and placement, and discrimination
between fresh and moldy bait. Significantly greater amounts of rice
shorts were taken by R. r. mindanensis as compared to corn grits,
cornmeal, rice bran, and polished rice. R. r. mindanensis preferred
standard bamboo tube bait stations to the nipa baiting hut, coconut
husk, plastic quart oil can, narrow-gauge bamboo or plastic "floating
saucer" bait stations. During the vegetative stage, bait stations
located atop or alongside paddy dikes were preferred to in-paddy
locations. At booting stage, locations alongside or within the paddy
were preferred. Rats consumed significantly more fresh bait than
moldy bait.

 16. Methods to assess rat damage to corn were investigated in the
 Philippines. Damage occurred mostly at the periphery of the corn-
 fields, probably because of the proximity to adjacent uncultivated
 areas. Plants with rat damage were generally concentrated in
 restricted areas rather than being widely distributed. The relation-
 ship between corn loss (g) and the area (cm2) occupied on the corn ear
 was determined and used to obtain estimates of yield loss.