Rats are wild animals that are often found in various habitats and become a nuisance in human life. Rats can

cause damage and losses to crops, one of which is oil palm plantation. Therefore, control efforts are needed, one

of which is chemical control using rodenticides. This study aimed to determine the level of attractiveness of

Malayan field rats to various formulations of coumatetralyl-based rodenticides with cereal-based baits and with

vegetable and animal flavorings. Study also conducted to measure the durability and effectiveness of these

rodenticides after being exposed in the oil palm crop. The types of rodenticides used were coumatetralyl

rodenticides in rice bait and rice plus wheat baits, with chocolate, pandanus, strawberry, and mealworm

flavorings. This study consisted of three tests: Palatability, durability, and mealworm tests, each method lasts for

mealworms were more preferred by Malayan field rats than others. Further research is aimed at testing the

coumatetralyl rodenticide with the best type of bait and flavoring agent for application in oil palm plantations to

kill pest rats and reduce the damage they cause to oil palm fruit.

Keywords: Effectiveness, chocolate, choice test, mealworm, pandanus, rice bait

Rats are wild mammals commonly found in various habitats and are known as pests in human life. These animals

are pests because they cause damage in various sectors, from agriculture, plantation, forestry, to health

(Priyambodo 2009, Purbaningsih and Widyanto 2018). In agriculture and plantations, rats cause damage to

almost all types of crops, including oil palm (Ngidha et al. 2016). Oil palm (Elaeis guineensis Jaqc.) is a

plantation commodity that plays a vital role in building the Indonesian economy. Therefore, in oil palm

species pest in oil palm plantations in Indonesia. A single of R. tiomanicus can consume 5.94–13.7 g of oil palm

mesocarp per day (Gunawan et al. 2024).

Based on the damage and losses caused by rat infestations in the plantation, control efforts are necessary. Rat

pest control commonly employed by humans includes: Sanitation (clean cultivation), technical culture

(agronomic methods), physical-mechanical methods, the use of natural enemies (biological control), and

chemical methods. Chemical rat control using rodenticides is the most effective strategy for suppressing the rat

populations (Priyambodo 2006, Saipullah and Iskarlia 2018). Chemical control using poison bait (rodenticides)

in the field typically involves only one type of active ingredients and baits in rodenticide with standard flavoring.

The use of rodenticides with standard flavorings is often ineffective because rats are less attracted to the

rodenticides. To improve the effectiveness in chemical control, rodenticide trials with various types of bait and

The tools and materials used in this study were scales, bowls or small containers, glasses, spoons, bamboo tubes,

trays, coconut milk strainers, mortars and pestles. Include experimental cages measuring 90 cm x 90 cm x 90 cm

and 60 cm x 40 cm x 20 cm, test animals (R. tiomanicus), rice as feed, ready to use coumatetralyl rodenticide

with various baits and flavorings, meal worm (larvae of beetle, Tenebrio molitor), and water.

The anticoagulant rodenticide, coumatetralyl, was tested on Malayan field rats (R. tiomanicus) using the choice

test method. This rodenticide test involved three tests using the same method: Palatability, durability, and meal

worms test. All test conducted sequentially.

The ready-to-use coumatetralyl rodenticide used in the palatability and durability tests consisted of eight (8)

types of bait and flavoring: Coumatetralyl rodenticide in rice bait with chocolate (A), pandanus (B), and

strawberry flavoring (C). Coumatetralyl rodenticide in rice and wheat bait with chocolate (D), pandanus (E),

and strawberry flavoring (F). Coumatetralyl rodenticide negative control without additional bait and flavoring

(G). Coumatetralyl rodenticide positive control (H) (Figure 1).

Durability testing was conducted after all of the rodenticides were exposed under oil palm crops for fourteen (14)

consecutive days (Figure 2). The rodenticides used in the meal worm test were: The positive control

coumatetralyl rodenticide with meal worm (A) and without meal worm (B). Rodenticide A in the meal worm

test was obtained from a mixture of 144 g of coarsely ground coumatetralyl rodenticide and 16 g of finely ground

meal worm. Rodenticide B was the positive control coumatetralyl rodenticide in the coarsely ground form. The

rodenticides prepared for testing were each weighed at 20 g per rat per day in separate bowls.

Figure 2. Exposure to the rodenticide coumateralyl bait and flavoring under an oil palm crops for fourteen days

in the durability test.

The Malayan field rats were placed in experimental cages containing water cups and bamboo tubes. They were

kept for three (3) consecutive days and fed rice. After three days, the rodenticide bait and flavoring treatments

were administered. The rodenticides used in the palatability, durability, and meal worm tests were placed in

random locations within the experimental cages for three (3) consecutive days. If the Malayan field rats

consumed the poisoned bait, resulting in decreasing their weight below 20 g per container, the poisoned bait was

added.

Afterward, the rats were fed rice again until the rats died within fourteen (14) days, calculated from the first day

rats were weighed to determine their body weight, which was used to determine the final weight of the Malayan

field rats.

Bait or rodenticide conversion (g/100 g body weight) = Bait or rodenticide

consumed (g) x 100 divided by average rat’s body weight

Average rat body weight (g) = (Initial weight + final weight) divided by 2

The data were analyzed using a Randomized Block Design (RBD) using one rat species (R. tiomanicus) with

eleven (11) replications for palatability test, twelve (12) replications for durability test, and eight (8) replications

for meal worm test. Further testing was performed using R Studio Programme with Tukey's test at the α level of

5%.

The consumption of Malayan field rat on the rodenticides in this test did not show a significant difference with

a Pr (F) value of 0.143. The consumption value ranged from 1.20 to 3.30 g with an average of 1.97 g. Malayan

field rat consumption to coumatetralyl with rice bait and with pandanus flavoring was the highest among the

others (3.30 g). Pandanus contains essential oils that produce a distinctive aroma or eugenol (Kurniati 2017).

This aroma can increase the attraction of Malayan field rats to the poison bait. In addition to poison consumption,

calculations were also carried out on the consumption to rice, before and after poison treatment (Table 2).

palatability test with various baits and flavorings

The average rice consumption of Malayan field rat before treatment was 4.026 g and after treatment was 2.149

g. After the poison treatment, the test rats consumed small amounts of rice because the rats experienced a

decreased appetite due to consuming rodenticide (Natawigena et al. 2021). Rats No. 3 and 4 had zero rice

consumption because they died during the poison treatment. Rats No. 6 and 7 had higher rice consumption after

treatment because they survived 14 days of rice administration.

The Malayan field rats died starting at the sixth day on the palatability test, at the first day on the durability test,

and at the third day on the mealworm test (Table 7).

Table 7. The mortality of Malayan field rat in the palatability, durability, and mealworm tests

function, to eliminate the substance from the rats' bodies, is approximately 71 hours, or three days (Natawigena

et al. 2021). All Malayan field rats died in the palatability test. However, in the durability test, two rats remained

undead and one escaped from the experimental cage. Three Malayan field rats remained undead in the mealworm

test. The rats that did not die in the durability test are suspected to have degraded the poison, thus reducing its

effectiveness. In the melworm test, the rats allegedly consumed a small amount of poison and possessed

resistance genes. Furthermore, feeding after the poison treatment affected the mortality of rats, as rats can recover

from the effects of rodenticide poisoning by consuming more food. The dead rats were found lethargic in their

cages (Figure 6). This lethargy, due to chronic poisoning, does not cause pain, but causes fatigue and lethargy,

and will not leave the nest (Natawigena et al. 2021).

Figure 7. Symptoms of poisoning include blood stains on the legs (a), anal (b), mouth (c), and nose (d)

Malayan field rats (Rattus tiomanicus) prefer the rodenticide coumatetralyl flavored with rice bait and pandanus

flavoring. After being exposed under oil palm crops, coumatetralyl rice and wheat bait with chocolate flavoring

is preferred by Malayan field rats. This evidence because the rodenticides with pandanus and chocolate flavoring

have a distinctive aroma that is attractive to the Malayan field rats. The positive control of rodenticide

coumatetralyl mixed with mealworm (animal protein) is also preferred by Malayan field rats compared to the

positive control of rodenticide coumatetralyl without mealworm. This fact because mealworm are one of the

animals favored by rats. Further research is aimed at testing the coumatetralyl rodenticide with the best type of