Post-harvest pest population based on observation method at bulog warehouse

Postharvest pests are the biggest problem during storage, so it is necessary to monitor for control measures. This study aims to monitor the population using two systems of monitoring methods. This research was conducted in three regencies where Bulogs rice was stored. The monitoring using namely direct and indirect method. Direct monitoring was carried out by determining five sample points diagonally, each sample point measuring 1×1 m and then directly monitoring all of the insects pest found. While indirect monitoring were carried out by taking samples using a probe with three times at each sample point and the collected rice was weighed as much as 300 grams and then count the population in the rice. Monitoring were made on comodities that had been fumigated for two months. The results showed that the highest population of postharvest pests was found in the direct visual monitoring method and the pests with the highest population was Cryptolestes, then Tribolium, and the lowest was Rhyzopertha.


Introduction
Rice is a source of staple food for the people of Indonesia.Rice is not only a food commodity but also a commodity that plays an important role in controlling the economy, social, politics and culture in Indonesia.Indonesian people consume rice as their main food with an average consumption of rice reaching 139.15 kg/person/year and increasing 95% from year to year [1].The need for paddy, which is the raw material for rice in 2050, is estimated to increase to 48,2 million tonnes [2].The need for rice has increased every year along with the increasing population in Indonesia.
The rice storage process is an important activity in the postharvest stage.Because rice is needed every day, rice harvested seasonally will be stored.Rice storage is also important as food availability to overcome the possibility of crop failure caused by drought and floods.During the storage process, rice experienced a decrease in quality and quantity [3].
Warehouses are an environment in which conditions can be controlled.However, various groups of pests and diseases can damage stored products in warehouses including insects, rats, birds, fungi and micro-organisms [2,3] Warehouse pest infestations begin occurs after grain is stored for more than three months or rice after being stored for one month [6].
During grain storage confirmed 10-30% of warehouse pest infestations are common in developing countries, it is estimated that the overall damage caused by pests is equivalent to 5% annually [7].Post-1230Post- (2023) ) 012118 IOP Publishing doi:10.1088/1755-1315/1230/1/012118 2 harvest food materials or materials that have been stored in a storage area cannot be separated from pests and diseases.This pest can damage crops in the form of pods or seeds in the storage area or in the field before harvest [8].This is in accordance with Singh [9] who said that post-harvest pests can cause severe damage to stored food grains.This event is because postharvest pests can reproduce quickly, easily spread, and induce the growth of fungi.Damage caused by postharvest pests such as decreased stored product weight, contamination of insects and reduced nutrient content.Sabier et al. [10] explained, there are 1,663 insect species in the world that have been recorded as damaging post-harvest agricultural commodities.Among the insects found were small grain borers (Bostrichidae; Rhyzopertha dominica; Coleoptera), rice beetles, (Curclionidae; Sitophilus oryzae; Coleoptera), red flour beetles, (Tenebrionidae; Tribolium; Coleoptera), and grain moths Angoumois, Sitotroga cerealella (Gelechidae; Lepidoptera) [4].
Various efforts to control stored products have been carried out, starting from the form of chemical control by using botanical materials, which have been intensively implemented.In addition, the form of Integrated Pest Management in food warehouse has become a basic provision in the management of stored products in the rice warehouse, such as the IPM concept implemented at the Perum BULOG storage warehouse, namely daily floor sanitation, fumigation/spraying applications once every three months and routine spraying in a month.The warehouse door opened in the morning and closed in the afternoon [11].
The basic thing in carrying out controls that is sometimes neglected is the determination of policies regarding the right time to carry out controls.This is of course inseparable from the results of monitoring the level of pest attack on stored materials in the warehouse.Monitoring of pests in warehouses plays a very important role, especially in making decisions related to pest control in warehouses.Monitoring results can provide information regarding the type and number of pest infestations that exist on food products in warehouses, because of this several monitoring methods are often found in warehouses.
At Perum BULOG there are two methods of monitoring the level of pest attack which are required to carry out control measures including direct observation and observation by sampling.Many observation methods have been used to determine the intensity of pest attacks in warehouses, including the use of attractant traps, the use of infrared, acoustic methods and electrical conductivity [12].The use of several of these methods has been widely developed, but the use of infrared, acoustics to the use of electrical conductivity requires considerable time and costs so that their use is rarely found.
The use of bait trap, which were previously considered very conventional, is currently being developed because of its easy combination with attractants from other formulations or materials.For example Sathiyaseelan et al. [13] explains that several formulations of food baits using starch based ingredients such as wheat and sorghum can be developed for monitoring and trapping post-harvest insects in warehouse.The combination of aggression pheromone 4,8 dimethyldecanal with vegetable oil can attract higher Tribolium castaneum because volatile compounds such as head oil or mee oil (mihua oil) are synergistic and show better attractant ability against T. castaneum than DMD 4.8 only [14].
Based on the description above, a study will be carried out to determine the number of post-harvest pest populations based on three different observation methods in pest monitoring in the warehouse of Perum BULOG, Bulukumba Branch Office.

Location
This research was carried out in three rice storage warehouse complexes of Perum BULOG, Jeneponto, Bantaeng and Bulukumba Branch Office which was carried out from October to December 2022.

Experimental design
This research was conducted on a field scale, namely in three warehouse complexes of Perum BULOG Bulukumba Branch Offices located in three different regencies, namely Bulukumba Regency, Bantaeng Regency and Jeneponto Regency.Determination of different locations to see differences in the influence of environmental factors on the intensity of pest attacks on rice in warehouses.This study used three methods of observing the level of pest infestation, including direct observation, samples and attractant traps.Observations will be made on rice with a shelf life of 3-5 months with two months after fumigation.

Direct Observation
In this method, observations are made by adopting the provisions of the monitoring implementation of Perum BULOG, namely by observing and calculating pests found on the sides of the surface of a pile of rice which has previously been determined to be five points diagonally.Each point on the side of the pile has been determined in size 1x1 meter.

Grain Sampling
Grain sampling at five location points that have been determined diagonally on the side of the pile surface.Sampling was carried out three times each at each point using a 156 cm probe then poured and put together in a plastic sample.The sample rice is then weighed using a digital scale as much as 300 grams, after which it is poured into a tray and begins to observe and calculate the pests found in the rice sample.The monitoring mechanism adopts the provisions for monitoring the implementation of Perum BULOG. 4

Attractant Traps
Attractant traps were used to trap pests by exploiting the attractiveness of insects to compounds contained in bait.The trap is a triangular shaped Delta trap made of self-adhesive paper which contains cotton that has been dripped with ginger oil and nutmeg oil in a ratio of 0.5:5 ml as a volatile odor attractant.The trap is hung on the side of the staple surface by determining the placement point diagonally.There were 20 sample points for placement, consisting of five sample points on each side of the rice staple surface.Observation and counting of trapped pests is carried out every three days until no additional pests are found in the tool.

Observation Parameters
The parameters of this study were to identify the pests that were obtained at the time of observation and calculate the number of pest found in the three warehouse complexes of Perum BULOG.

Data analysis
The observed data will be analyzed for the genus, population numbers of these pests in the Microsoft Office Excel 2012 software.

Direct Observation
The results of direct observation (Figur 3) found four insect pests namely Cryptolestes, Tribolium, Liposcelis and Rhyzopertha.The highest population level of Cryptolestes was in the BULOG warehouse in Jeneponto Regency (2 individuals), followed by storage warehouses in Bantaeng regency (1.8 individuals) and storage warehouses in Bulukumba regency (1.5 individuals).The second highest population in this observation was the Tribolium pest with the same population level in Bantaeng and Jeneponto regency 1 individual, while the Bulukumba regency warehouse had a lower population level of 0.6 individuals.However, the conditions were different from the Jeneponto and Bantaeng warehouses.In the storage warehouses in Bulukumba regency, Liposcelis were found with a population level of 0.4 individuals.This difference can be caused by the condition of the storage warehouses both from the condition of the warehouse building, the level of cleanliness of the warehouse and differences in temperature conditions and relative humidity levels of each of these storage warehouses.This was further supported by the fact that the shelf life of rice was found to be 3-4 months in storage with the same maintenance period, or 3 months after the last spraying treatment, in the three storage warehouses, which was found to be approximately the same.

Observation with Samples
In observation using a sample (probe) (Figur 4) there were four genus of insect pests, such as Cryptolestes, Tribolium, Liposcelis and Rhyzopertha.Figure 4 shows the population level of each of these pests, including the Cryptolestes pest with the highest population level in the Jeneponto regency storage warehouse (5 individuals) then in the Bantaeng and Bulukumba regencies warehouses showing the same population level (3 individuals).The second highest population is Rhyzopertha but is only found in the Bantaeng regency warehouse (2 Tribolium have the same population level in warehouses in Bantaeng and Jeneponto regencys (1 individual).While Liposcelis pests were found in warehouses in Bulukumba regency with a population level (1 individual).The existence of pests with different population levels in warehouses in each regency indicates that the life cycle of pests is very dependent on several conditions, including food factors, environmental conditions and the conditions of werehouse for these stored products.

Total of Pest in Three Regency
Figure 5 shows that the highest pest population was in Jeneponto regency, consist of 9 individuals, followed by Bantaeng regency with 8.8 individuals and Bulukumba regency with 6.6 individuals.Cryptolestes is a secondary pest whose existence with the highest population level in the BULOG storage warehouse can be caused by the condition of the storage period of the rice commodity which is 3-4 months old and the condition of the quality of the stored rice is the quality of rice with broken grains in the range of 17-20% as that is required by BULOG, namely a minimum degree of crushing of 95%, a maximum moisture content of 14%, a maximum of 20% broken grains and a maximum of 2% grain groats [15].This is in line with the results of research by Anggara [16] who identified 17 species of insects in rice that had been stored for 4 months of storage and were dominated by Sitophilus, Oryzaephilus and Cryptolestes.The existence of Cryptolestes and Tribolium pests with the highest population level indicates a fairly good level of treatment, however due to the shelf life factor which has a major effect on the presence of these insect pests.
The order Coleoptera is the most frequent post-harvest pest injurious to seeds [17].Common species of pest beetles in rice are Cryptolestes (Coleoptera: Laemophloeidae) (rusty grain beetle), Tribolium (Coleoptera: Tenebrionidae), and Rhyzopertha (Coleoptera: Tenebrionidae) (red flour beetle) [18].Combining primary and secondary pests in one commodity can increase rice pest attacks.For example, Rhyzopertha is primary pest in stored products in ability to attack whole grains [19].Cryptolestes, Tribolium and Liposcelis are secondary pests by attacking grains previously infested by primary pests and causing contamination of stored products [20].
Arthropods that act as secondary pests are larger or dominate, such as 94.94% [21].The existence of secondary pests that are so large indicates there is damage to stored products in the rice warehouse.These secondary pests attack seeds that are not intact or damaged [22].Damage to the seeds is possible attacks from the main pests and the condition of the seeds that are not intact at the time of rice procurement.The composition of Arthropods acting as primary pests was 8.19% [21].Even though the composition of the primary pests is smaller than the secondary pests, the presence of the primary pests can cause serious damage to the product stored in the rice warehouse.This damage causes the products to become damaged so as to increase the emergence of secondary pests in the warehouse.The existence of this primary pest is made possible by the low population of predators and parasitoids in storage so that they cannot suppress the population of this primary pest [21].

Conclusion
The highest pest population in BULOG warehouses was Cryptolestes, followed by Tribolium, Rhyzopertha and Liposcelis.The highest number of pest population is in Jeneponto Regency, followed by Bantaeng then Bulukumba Regencies.The highest pest population were found in samples with probes.

Figure 1 .
Figure 1.Illustration of observation points and rice sampling points on a pile of rice at the BULOG warehouse

Figure 2 .
Figure 2. Illustration of the Delta Attractant Trap

Figure 3 .
Figure 3. Population of direct observation of post-harvest pest in three regencys

Figure 4 .
Figure 4. Population of observation with samples of post-harvest pest in three regencys

Figure 5 .
Figure 5.Total population of insect pest in three regencys

Figure 6 .
Figure 6.Total population of insect pest