Geographical distribution, population density, and fruit damage due to pest, Silba adipata McAlpine (Diptera: Lochaeidae) on cayenne pepper in Bali, Indonesia

Cayenne pepper (Capsicum frutescens L). is one of the leading vegetable plants in Bali. The black fruit fly is a new pest species that strips fruit before it is ripe. Initially, the symptoms of fruit dropping were caused by fruit flies of the Bactrocera dorsalis (Tephritidae), however, preliminary survey results showed that the type of pest that attacked was the black fruit fly Silba adipata from the Lonchaidae family. This study aims to determine distribution, population density, and fruit damage caused by Silba sp. in Bali. Field research was carried out in nine districts/city in Bali. Meanwhile, laboratory research was carried out at the Integrated Pest Management Laboratory, Faculty of Agriculture, Udayana University. The results showed that the S. adipata pest has spread evenly throughout all districts/city in Bali. The highest population was found in the Bangli district, with 22.09 individuals per plant, and the lowest population was found in Denpasar city, with 1.92 individuals per plant. Altiduinally, the highest population density was in altitude areas between 500-750 m above sea level. The highest percentage of attack and damage to small chilies due to fly attack was in Bangli at 41.33%, and the lowest was found in Denpasar City.


I. Introduction
Cayenne pepper Capsicum frutescens L. is a mainstay horticultural commodity in Bali, which is generally widely cultivated in the lowlands to highlands.Cayenne pepper production fluctuates.From 2010 to 2015, production was 521.7 thousand tons to 869.95 thousand tons [1].However, it is only sometimes possible to achieve the expected results.The decline in cayenne pepper production is influenced by several factors, including the presence of plant-disrupting organisms (OPT).Some pests associated with chili plants include peach aphids Myzus persicae, whitefly Bemisia tabaci, Thrips parvispinus Karny, and fruit fly Bactrocera Sp.Especially for fruit flies, chili plants are generally known to be attacked by fruit flies of the type Bactrocera dorsalis (Diptera: Tephritidae) [2].MacGowan and Rauf [3] reported that another pest was also found attacking chili fruit in Bogor, West Java, namely the Silba capsicarum fly.Silba sp. is a member of the family Lonchaeidae (spear flies) shiny black.Larvae are usually saprophagous or frugivorous [4].Silba 1346 (2024) 012016 IOP Publishing doi:10.1088/1755-1315/1346/1/012016 2 sp. is a pest previously only found in the Mediterranean and Middle Eastern regions such as Egypt, Spain, and Israel [5].It was also found in Iraq [6], Japan [7], and Turkey [8].In 2007, Silba sp. was reported to attack fruit (Ficus arica L.) in South Africa [9].
Merta [10] reported for the first time that a new type of pest, Silba adipata, was found attacking cayenne pepper plants in Banua Village, Kintamani District, Bangli Regency, Bali.The symptoms of Silba sp.attack in Bali are similar to those of S. capsicarum attack found in Bogor on cayenne pepper plants.Female Silba sp.flies infest cayenne pepper fruits by poking their ovipositor into the fruit skin for egg laying.Female fly ovipositor punctures are characterized by stains or dots on immature fruits.After the larvae hatch, they immediately feed on the fruit flesh so that puncture marks around the ovipositor turn brownish.The discovery that Silba sp. has attacked cayenne pepper plants in Bali needs further research to determine the distribution, population density, the effect of altitude on the population of Silba sp., and yield loss caused by Silba sp.Various abiotic and biotic factors influence the spread and development of pest populations.Abiotic factors that influence include temperature, humidity, and rainfall.It is necessary to know the distribution and population of Silba sp.pests in the lowlands to highlands in Bali.
One crucial factor that must be known in determining or choosing a pest control method is knowing the population density of the pest.Population density is the relationship between the number per unit area or volume of space occupied at a particular time.Two things affect the population density of an organism, namely 1.Some individuals come from other places 2. Some individuals go to other places, or the individual experiences death.The study aims to find the distribution, population density of Silba sp., the effect of altitude on Silba sp.population, and yield loss due to Silba sp. in cayenne pepper plantations in Bali.In Bali, it is essential to know as a basis for protecting chili plants.The data obtained in this study will provide a basis for decision-making in determining the control method to be selected.

Time and Place of Research
The research was carried out for 6 months, namely from April to September 2021.Research (sampling) was carried out in nine districts /cities in Bali.The next observation was carried out in the Integrated Pest Management Laboratory Faculty of Agriculture Udayana University.

Tools and Materials
Tools and materials used in research include a pocket plastic weighning 1 kg, label paper, writing tools, a camera, altimeter, thermohygrometer, GPS, plastic glass (d=8, t=10.5 cm), gauze cloth, rubber bracelet, cotton, scissors, petri dish, brush, raffia rope, microscope, and collection bottle.The materials used consist of Silba sp.pests, cayenne chilli fruits that have been attacked, sand, 10% honey solution, and 75% alcohol.

Research Implementation
The survey was conducted in all regencies/city in Bali, Indonesia.The selected land is the land that has chili plants.The number of experimental plots in this study was 13 plots.Each experimental plot measured 1 m x 18 m with a distance of 1 m between plots, 11 experimental sample plots.Plant spacing was 50 cm x 60 cm so the plant population amounted to 64 per plot.Sampling was carried out systematically with a U shape, each experimental plot was taken 10 clumps of plants as samples numbered sequentially from 1 to 10.The total number of sample plants was 110 plants.
Observations of population density were made by taking all infested chili fruits on each sample plant, putting them into a 1 kg clear plastic bag, and then bringing them to the laboratory for breeding.Infested fruits obtained from the field were maintained in the IPM laboratory by preparing plastic cups (diameter=8, height=10.5cm).Plastic cups were filled with 20 g of sand, the sand was kept moist using water, and one plastic cup was inserted with one infested chili fruit covered with gauze and labeled with the date of sampling.Maintained until adult flies appear.Observations of yield loss were made by counting the infested fruits divided by the total number of fruits per plant multiplied by 100%.

Data Analysis
Distribution data are presented in maps to make it easier for readers to know the distribution of Silba sp. in Bali.Density, altitude, and yield loss observations were tabulated to obtain averages and then displayed in tables and histograms.

Distribution of the Pest Silba sp. in Bali
The results showed that Silba sp. was found in almost all districts/city in Bali, Indonesia spreading evenly (Figure 1).Silba sp. was first found in chili plantations in Kintamani District, Bangli Regency, Bali Province in 2020 [10].The spread of the pest is also followed by a number of parasitoid species that act as natural enemies of the pest in the field [11]; [12].Factors that influence the spread of the population are the encouragement of individual insects to carry out the process of foraging and the habit of finding mating partners.In addition, the distribution also aims to take action to avoid predators.In addition, the distribution is also influenced by vectorial factors such as wind direction, water carried, and other physical factors [13].Therefore, the population abundance of Silba sp.varies between districts/city in Bali, Indonesia (Figure 1).Karangasem Regency with 5613 heads, Klungkung Regency with 3524 heads, Jembrana Regency with 1544 heads, Badung Regency with 1106 heads, Denpasar City with 422 heads.The abundance of Silba sp.population in Gianyar Regency is caused by the availability of small cayenne pepper host plants, and the opposite occurs in Denpasar City.The availability of host plants is a key factor influencing the presence of pests in a given location.This incident supports the findings of previousresearch [15] emphasizing that the high population or abundance of insect populations in a habitat is supported by the availability of resources of both type, quantity, and quality, serving as food for the insect pests concerned.

Population Density of Silba sp. on cayenne pepper plantations in districts/city in Bali Indonesia
The results showed that the population density of Silba sp. was highest in Bangli Regency, with 22.09 heads per plant with an average attack of 7.42 fruits per plant; Gianyar Regency, with 20.69 heads per plant with an average attack of 7.06 fruits per plant; Karangasem Regency, with 17.01 heads per plant with an average attack of 5.15 fruits per plant; Tabanan Regency, with 12.53 heads per plant with an average attack of 3.66 fruits per plant; Buleleng Regency, with 12, 10 heads per plant with an average attack of 3.79 fruits per plant; Klungkung Regency, as many as 8.01 heads per plant with an average attack of 2.80 fruits per plant; Jembrana Regency as many as 4.68 heads per plant with an average attack of 3.24 fruits per plant; Badung Regency, as many as 2.90 heads per plant with an average attack of 1.44 fruits per plant; Denpasar City, as many as 1.92 heads per plant with an average attack of 0.96 fruits per plant (figure 2).

Figure 2. Silba Population Density sp. in each of the central districts for cayenne pepper in Bali
Population density and infestation of Silba sp. are influenced by internal factors (male: female ratio, migration, and mortality) and external factors (temperature, humidity, rainfall, wind, host plants, pesticide use, and natural enemies).Their natural enemies influence the population density of insect pests [14].According to Giliomee et al. [16], the main host plant of Silba sp. is fruit.At the same time, Silba sp. in Bali was found to attack cayenne pepper plants [10].The high population of Silba sp. in Bangli Regency is due to the continuous and overlapping planting of small cayenne peppers throughout the growing season.According to Price [17], continuously and overlapping in large quantities, herbivorous insects that obtain food sources in monoculture cropscan support the life of these insects to reproduce and survive.

Influence Height Place to population Silba sp. in Bali
The results show that the highest average population of Silba sp.Pests was found at an altitude of >500-750 masl, with 32.10 heads per plant, followed by an altitude of >750-1000 masl, with 19.36 heads per plant, followed by an altitude of >1000 masl, with16.94heads per plant, followed by an altitude of >250-500 masl, with 9.51 heads per plant, and at an altitude of 0-250 masl, there were 4.70 heads per plant.The population of Silba sp.pests is highest at altitudes >500-750 (figure 3).One of the factors affecting the highest population of Silba sp.pests at altitudes >500-750 is closely related to abundant plant vegetation so that these pests can develop quickly.This statement is supported by [15], indicating that the diversity and abundance of food sources and other resources in a habitat determine insect population in nature.The planting system (monoculture and polyculture) around the agroecosystem can create micro-habitats that can strongly influence the number of pest populations [18].Another factor that causes the high population of Silba sp. at altitudes >500-750 is caused by temperature and humidity factors.According to Susanto and Khaliq [19,20], the spread and diversity of fruit flies are influenced by abiotic factors such as temperature, rainfall, humidity, and light.Optimal temperature and humidity for growth and development of fruit flies are + 26 o C with 70% relative humidity [21].The results show that at an altitude of >500-750 the average temperature of 27.67 o C with a relative humidity of 70%, is suitable for the growth of Silba sp.

Conclusion
The spatial distribution of Silba sp. is evenly spread across all regencies/city in Bali, Indonesia with varying population abundance between regencies/city in Bali, Indonesia.While its altitudinal distribution is clustered in the medium-highlands (>500-750 masl

Figure 1 .
Figure 1.Map of the distribution of Silba sp. in Bali

Figure 3 .
Figure 3. Influence Height Place to population Silba sp. in Bali

Figure 4 .
Figure 4. Yield loss by Silba sp. in cayenne pepper crops in districts in Bali, Indonesia.
[26]a sp. in cayenne pepper crops in districts in Bali, Indonesia.The results showed that yield loss by Silba sp. was highest in Bangli Regency at 41.33% per plant, Gianyar Regency at 38.59% per plant, Karangasem Regency at 33.61% per plant, Tabanan Regency at 27.83% per plant, Buleleng Regency at 26.90% per plant, Klungkung Regency at 18.18% per plant, Jembrana Regency Drouet[23]reported fig fruit damage of 12 to 88%, and Abbes et al.[24]reported that S. adipata attacked all fig plantations in Tunisia with 88.17% infestation.S. adipata is a new pest attacking cayenne pepper fruit and is capable of causing significant yield losses.This proves that S. adipata can develop well on cayenne pepper plants in Bali.This research can strengthen the research of Supartha et al.,[25]which states that the newcomer pest Spodoptera frugiperda can cause yield losses reaching 82% in corn plants in Karo North Sumatra.The high yield loss by Silba sp. in Bangli Regency is partly due to the continuous planting of small cayenne peppers throughout the growing season.According to Price[17], continuously and overlapping in large quantities, herbivorous insects that obtain food sources in monoculture crops, can support the life of these insects to reproduce and survive.The high yield loss by Silba sp. in Bangli Regency is also influenced by the high population of S. adipata in chili plants in Bangli Regency.According to Nofiardi et al.[26], if the population is relatively small, the damage caused is economically insignificant.Otherwise if the population is high, it will cause economic damage.
). High population density is distributed successively in Bangli, Gianyar, Karangasem and Tabanan regencies.Crop damage caused by Silba sp.caused the highest yield loss (41.33% per plant) in Bangli District and the lowest (10.53% per plant) in Denpasar City. 75.Acknowledgment