Early detection of sweet potato weevil (Cylas formicarius) and scab diseases (Sphaceloma batatas) outbreak based on android application

Sweet potato weevil and scab disease are major pests and diseases that become obstacles for increasing sweet potato production in Indonesia. Recently, the incidence of both pest and disease attacks can be detected earlier by using an android-based mobile application. This study aims to assemble an android-based mobile application for early detection of the outbreak of sweet potato weevil and scab disease. This research was conducted in in Malang Regency, East Java, from September to December 2022. Research was carried out by survey, observation, literature studies, and interview with the leaders of farmer association, sweet potato farmers, and local agricultural extension staff. All basic data and supporting data as a trigger for the occurrence of the weevil and scab disease have been collected from the several sample areas. The information was arranged in clusters according to the priority of each variable then was entered into the android studio. The user must enter the supporting data based on the application program to find out the percentage of sweet potato weevil and scab disease. Understanding the predictive value of the incidence of major pests and diseases is required, so farmers can anticipate earlier and prepare appropriate, effective and efficient control technology. An-android mobile application version 1 for early detection of pest and disease which was successfully assembled was expected to be greatly assist sweet potato farmers for maintain their cultivation from yield losses due to C. formicarius and scab which can reduce the quantity and quality by up to 100%.


Introduction
The development of various tuber commodities (including sweet potatoes) in Indonesia needs to be focused on increasing the carrying capacity of the biotic and abiotic environment, which needs to be IOP Publishing doi:10.1088/1755-1315/1312/1/012044 2 integrated with the development of high quality, efficient and competitive multi-product industries.One of the main obstacles for increasing sweet potato productivity in various countries, both tropical and subtropical, is tuber borer, caused by Cylas formicarius Fabricius (Coleoptera: Curculionidae) [1][2].The life cycle of C. formicarius consists of egg, larval and imago.Larval, is the most damaging staged and this formed from the egg which hatches six days after being laid by the female at the base of the stem [3][4][5].Sweet potato yield losses due to C. formicarius larvae up to 100% in uncontrolled area [1], [2,6].Meanwhile, an important disease in sweet potatoes is scab, caused by Sphaceloma batatas Saw.(Anamorph).This patogen/disease can reduce sweet potatoes productivity by up to 30-50% if susceptible varieties are cultivated [7][8][9].The early symptom showed by S. batatas are brown spots or tiny lesions, circular to elliptical in leaves and stems.In favorable conditions, the symptoms may reach the top of leaves and the buds become twisted [10].
Integrated pest management (IPM) have been developed to improve the management of sweet potato weevil and scab disease, reducing the overall use of insecticides and focusing on more precise applications [11][12][13] However, the efficiency of the IPM depends on the accuracy of the chosen pest population monitoring method.As a result, it is important to study information technology systems to accurately, efficiently, quickly, and conveniently identify pests and diseases outbreak [14].
Currently, most of the farmers typically have an android or smartphone with a basic configuration.Technology based on an android system should be designed for real-time identification, be simple to install and use, and be appropriate for farmers' level of knowledge [14].This study aims to design and assemble an Android-based application that can help the process of reporting and monitoring the sweet potato weevil attack and scab disease incidence.The sweet potato weevil and scab disease outbreak reporting process was facilitated by the provided list of agroecology and cultivation technology stored in the system database.Thus, the pest and disease attacks can be reported to the system quickly.The farmers can take necessary action earlier based on the suggested control to avoid spreading of the infestation and experience in yield losses due to sweet potato weevil and scab disease.

Methods
Research for assembling an Android-based application for early detection of sweet potato weevil and scab disease outbreak were carried out through a survey and interviews with the sweet potato farmers and direct observation of sweet potato plant conditions in order to collect the supporting data on farmers' field, further supported by literature study.These activities were conducted from September to December 2022 in three villages of sweet potato production center which is an endemic area for C. formicarius dan S. batatas in Malang Regency, East Java (Suko Anyar, Pasir Kembar, and Sumber Keradenan).This research was a result of multi-disciplinary collaboration between Ecophysiology, Plant Breeders, Plant Protection, from Research Centre for Food Crop, IT staff from STIMATA Malang, and Lecturer from Plant Protection division from Andalas University, Padang, West Sumatra 2.1.Software requirement analysis At this stage, the requirement informations were gathered by studying the system and meeting session with all researchers from multidisciplinary area.This is necessary for specifying functional requirements and defining overall proposed system to assist users for monitoring and reporting the pest and disease outbreak [15].Analysis of supporting data for both C. formicarius and scab disease were carried out by entering all the collected data.All basic data and supporting data were clustered according to the priority of each variable, entered using Android apps into the Samsung Galaxy A03 4/128GB or other type of Android cell phone, then these data sent to the server.
The first step, compiled build first version, applications were created based on customer needs and explanations by involving users.The admin collected the data of sweet potato weevil existence dan scab disease incidence detected in the field area.The second, compile the modify unit of costumer satisfactions, Researcher and user evaluated the initial application that has been created including the risks of sweet potato field.At this stage, the user also provided comments if there is a difference of opinion regarding the application the user wants.Furthermore, if the user is not satisfied, the programmer will improve the application until it is fixed according to the user's expectations.The next step is maintenance if the application has experienced an error or damage.The final stage is retirement.Basic data and supporting data stored using a server that has been prepared to guarantee its security for a period of one year.The server delivered the information into a database to be reviewed and published the notification to the users.The notification sent to the users consisted of the existence of sweet potato weevil or scab incidence and the information about when the control should be carried out as well, as shown in Figure 1.Furthermore, data can be updated according to developments and can be saved again by extending the duration of server use (as needed).
The concept for managing C. formicarius was divided into four stages, (1) before planting, (2) planting phase, appearing of symptoms (holes) on the leaf surface, (3) growth phase, appearing symptoms of dirt marks of C. formicarius, and (4) harvesting, steps to handle the tubers that will be stored.The concept for scab disease consists of three stages, before planting, the planting phase, and the growth phase (after appearing scab symptoms)  [16][17] that was installed on the Android smartphone to detect sweet potato weevil and scab disease outbreak (Figure 2).Assembling this application required basic data and supporting data obtained through survey, interview, and direct observation on farmer's field.The number of sweet potato farmers used as replication were 20 peoples with different locations, both altitude and cultivation technology applied.The basic data collected consists of; (a) farmer information (name of location/village, age, gender, education, social status/economic level), (b) land (altitude, soil type, soil structure, land preparation, bund/stretch), (c) climate (temperature, rainfall, humidity, wind direction/speed), (d) seasons and planting patterns (rainy, dry, monoculture, intercropping), (e) varieties (local, VUB, cutting origin), (f) cultivation practices (treatment of cuttings, hilling, weeding, pest control), and (g) harvest (harvesting time, harvest method, processing).
Other supporting data collected as a trigger for the sweet potato weevil outbreak included; (1) the presence of imago C. formicarius on the plants surface at 1.5-2 weeks after planting, (2) the age of the plant which indicates the presence of C. formicarius larvae on the base of the plant stem, (3) the presence of holes due to imago bite marks on the leaves surface, and ( 4) sources of infestation as potential inoculum in the field, especially host plants and residues of previous plant.In order to detect the presence of the C. formicarius imago, arthropods were caught from the plant surface by using a sweep net in a five single swing, five points taken diagonally for each location.The arthropod obtained from each location (farmer's field) then were put into a plastic bag or test tube containing an ethanol/methanol/formalin and given an identity.Furthermore, the sample then taken to the laboratory to be observed and counted.To collect C. formicarius imago, apart from using a sweep net, we also observed visually for the presence of imago on the plant surface and the base of the sweet potato stem, if there were formed tubers.Observations on the plant surface was focused on the leaves with holes that indicated the presence of imago bite marks and at the base of the stem to detect the presence of larvae through the larval dirt.Plants that have formed the tubers and tuber that attacked by C. formicarius then were taken and placed in plastic jar.Further, we measured the diameter of the tuber by using a digital caliper and observed the number of C. formicarius per stage that found in the tuber.
Supported data for the incidence of scab disease consisted of; (a) plant organs infected with scab (leaves, leaf stalks/twigs, stems, plant shoots), (b) disease symptoms (spots, scab/scab become concave, twisted shoots/tips, dried or died plant shoots), (c) presence of inoculum sources around the field (sweet potatoes, weeds), (d) cutting (healthy/infected).In addition, to confirm the presence of the scab disease in field, visual observation was carried out, and we took samples of sweet potato plants that were identical/similar with scab disease symptoms from each location.Apart from that, observations and sampling were also carried out on plant surrounded that showed scab symptom, especially from the Convolvulaceae family.The plant samples from each location were put in a plastic bag and given an identity, then put in a container with ice cubes to maintain moisture and prevent plant samples from being damaged before being taken to the laboratory for preparation and observation.

Results and Discussion
Rapid development of sweet potato weevil and scab disease have caused heavy damage to the sweet potato production of many countries [8] [18].However, it is difficult for farmers to accurately identify their outbreak, further supported by high number of pesticides indiscriminately, causing insect resistance and resurgence as well as serious environmental pollution [19][20][21].Meanwhile, spraying pesticides required high cost, and thus developing a system to identify crop-damaging pests early will help farmers save a lot of money while also contributing to the development of sustainable agriculture [22] [23].
In this study, support data collection as the main component required to develop an Android-based application for early detection of C. formicarius and S. batatas were carried out on the field belonging to the leader of association of farmer groups and sweet potato farmers in Suko Anyar, Pasir Kembar, and Sumber Keradenan village, Pakis District, Malang Regency, East Java.Survey was carried out by researchers who are involved in this study through interviews with farmers and visual observations in the field to ensure that benchmarks for eliminating C. formicarius and S. batatas.Observations were carried out on sweet potato plants at 4 months after planting (MAP), 2.5 MAP and 5 MAP in Suko Anyar, Pasir Kembar and Sumber Keradenan, respectively.In Suko Anyar, in which sweet potato plants are 4 MAP, the symptoms appeared on the surface of the leaves were holes due to C. formicarius imago bites and dirt left by larvae at the base of the stem on the ground surface.The level of tuber damage in the field was proved with removing several stems, and from this act found that the level of tuber damage reached 50%.At 4 MAP, sweet potato should be ready to be harvested, if harvesting time delayed for 30 days then tuber damage can reach 90-100%.This occurred due to plants around sweet potato field are corn and rice, which are not host plants for C. formicarius.This condition will trigger the occurrence of sweet potato weevil and causing higher tuber damaged.
In Pasir Kembar, sweet potato plants aged 2.5 MAP, showed no indication of C. formicarius attack because the plants had not yet formed tubers.However, the remaining tuber from harvest from Sumber Keradenan could be the main source of infestation which can trigger the explosion of sweet potato weevil in Pasir Kembar.This is due to this remaining tuber was thrown away near a sweet potato plantation in Pasir Kembar and it was damaged by sweet potato weevil more than 35%.Meanwhile, the presence of scab disease in the field was not found in all sweet potato plants in the three villages that were surveyed.This is due to there were no source of inoculum in the field and no suited host plant.Moreover, the climatic condition in which dry season was not support the development of S. batatas, even though there was little rain.Another reason is that farmers applied some fungicide even though they did not know the active ingredient of the synthetic fungicide used.Furthermore, based on the interview, it might be suspected that the local varieties planted have high tolerance to scab disease.Basic data and supporting data obtained from survey, direct observations, interviews as mentions above, followed by literature studies arranged based on clusters according to the priority of each variable, then entered into the Android studio system.The Android-based application for early detection of sweet potato weevil (C.formicarius) and scab disease (S. batatas) could be used by various circles, including researchers, lecturers, students, practitioners, policy makers, agricultural extensions, observers of plant pest organisms, and sweet potato farmers.This application can also be used in various agroecosystems, both highlands and lowlands, endemic and non-endemic field, rainy season and dry season, and various other environmental conditions.This application is very useful for helping farmers to anticipate sweet potato weevil and scab disease early.Farmers can immediately develop and implement appropriate, effective, and efficient control technology strategies to avoid sweet potato yield losses.
Users should be downloaded first the application before using it in android or smartphone, register and login, after that the user can choose the application that they needed.In the system that we have assembled, there were two applications, sweet potato weevil and scab disease detection.User can input all information according to the form provided in the application to get notification about sweet potato weevil and/or scab incidence in their field.From that notification, user can quickly determine control

Load the information datashet
Processing the information to use Build the application using the android studio

App icon
Install the app in an android phone measures if there is any targeted pests and diseases (Figure 3, 4, 5).The results of the socialization and launching of the Android-based application for early detection of sweet potato weevil and scab disease at Agricultural Extension Centre, Pakis District, Malang, East Java, showed very high enthusiasm, especially from the sweet potato farmers and agricultural extensions who were present.These conditions indicated that the application created is very useful, especially for sweet potato farmers for defending cultivated crops from the outbreak of major pests and diseases that have not yet been resolved.One of the obstacles in the implementation or adoption of this Android-based application for early detection of pest and disease outbreaks by users is the availability of a server capable of storing data for a long time periods.Currently, the existence of the server will be accessible for one year until the end of 2023.To be able to access the application continuously, basic data and supporting data should be re-entered into the Android studio system.Therefore, a long-lasting server is required for reserving informations long period of time.Apart from that, signal provider was also really required for running run the Android-based application for early detection sweet potato weevil and scab disease smoothly.

Conclusion
Based on the results, it can be concluded that the Android-based application for early detection of the sweet potato weevil C. formicarius and scab disease S. batatas has been successfully installed on the server, so that, users can easily access the application via an Android to predict an outbreak by inputting supporting data as specified.The prediction level of C. formicarius and scab disease outbreaks was influenced by basic data and supporting data entered to the system, as well as differences in sweet potato growth locations.The speed of finding out the predicted results of pest and disease outbreaks from the supporting data that has been entered into the system depends on the user's cellphone capacity and the existence of a signal provider at the location.Research activities to determine early detection of sweet potato weevil and scab disease based an android application need to be carried out at endemic area in order to improve the application system version 1 which has been demonstrated in front of sweet potato farmers in Pakis District, Malang Regency, East Java.

Figure 1 .
Figure 1.System Flow Chart 2.2.Entering and updating basic data and supported data for early detection of C. formicarius and scab disease in the android application An Android Studio and SDK (software development kit) are used to develop the application (APP), and the completed APK (Android package) [16-17] that was installed on the Android smartphone to detect sweet potato weevil and scab disease outbreak (Figure 2).Assembling this application required basic data and supporting data obtained through survey, interview, and direct observation on farmer's field.The number of sweet potato farmers used as replication were 20 peoples with different locations, both altitude and cultivation technology applied.The basic data collected consists of; (a) farmer information (name of location/village, age, gender, education, social status/economic level), (b) land (altitude, soil

Figure 2 .
Figure 2. Android-based application system development method

Figure 3 .
Figure 3. How to register the early detection application for C. formicarius and scab disease (S.batatas) (version using Indonesian)

Figure 4 .Figure 5 .
Figure 4. Front page display of the early detection application