Efforts to Support Sustainable Agriculture with The Understanding of Invasion and Colonization Egg Parasitoid of Yellow Rice Stemborer, Scirphopaga Incertulas Walker (Lepidoptera: Pyralidae) in Bali

The arrangement of sustainable agriculture in Bali which appropriate with Bali government’s mission: Bali Clean and Green "Go to Organic". The concept of modern agriculture looks like contradiction with the aspects of sustainable agriculture. The aspects of rice cultivation have been done by local agriculture community in Bali (call it SUBAK) for many years, but the attack of yellow rice stemborer still happen, which adverse farmer’s side, persist. The efforts control which has been done, still rely on insecticides because it can give quick effect, but it is not appropriate for sustainable agriculture. The other solution to solve that issue is with the integrated pest management (IPM), as the main component of which is the role of parasitoids. Therefore needed research to investigate the invasion and colonization of yellow rice stemborer parasitoids in Bali. The research was conducted in three districts centers of rice stemborer (Badung, Tabanan, Jembrana), since December 2013 to March 2014. This research using survey method with the rule is collecting the group of egg with purposive random sampling at 10 66 days after planting (dap), as many as 70 groups of eggs per week. The observed of variables include the percentage of infected eggs, diversity, dominance, similarity, abundance, attack level and ratio of female parasitoids. The result showed that invasion and colonization of the egg parasitoid of yellow rice stemborer in Bali vary in diversity, dominance, abundance, the percentage of infected eggs and attack level. Three types of parasitoids associated with rice plants, they are Trichogramma japonicum, Telenomus rowani and Tetrastichus schoenobii. The percentage of infected eggs, diversity, dominance of T. japonicum, T. rowani and T. schoenobii, similarity, abundance of T. japonicum, T. rowani and T. schoenobii, attack level of T. japonicum, T. rowani and T. schoenobii and ratio of female of T. japonicum, T. rowani and T. schoenobii found in Tabanan regency, were (90.14%; 0.32; 0.00; 0.06; 0.49; 100%; 96.16; 424.09; 1.193,54 tail; 1.30; 11.98; 85.13%; 77.36; 84.67; 79.51%), in Badung regency were found (83.68%; 0.42; 0.02; 0.12; 0.26; 100%; 199.94; 471.14; 708.83 tail; 5,22; 20,61; 64,25%; 76.48; 83.44; 77.63%) and at Jembrana regency were found (78.61%;0.39;0.02;0.35;0.07;100%;144,76;635,97; 293,15 tail; 4.79;39.43;50.20%;75.83;80.77; 75.30%). The above data’s as a basis for determining the measures to support sustainable agriculture. Keywords— sustainable agriculture, invasion, colonization, Scirphopaga incertulas


I. INTRODUCTION
The arrangement of sustainable agriculture in Bali which appropriate with Bali government's mission: Bali Clean and Green "Go to Organic". The concept of modern agriculture looks like contradiction with the aspects of sustainable agriculture. The aspects of rice cultivation have been done by local agriculture community in Bali (call it SUBAK) for many years, but the attack of yellow rice stemborer still happen, which adverse farmer's side, persist.
Yield losses caused by the pest's attacks reach 125.000 tons per one season. In 2001 -2011 the area infected by rice stemborer attack in Bali reach 1 Until now, efforts to control which has been done by the farmers still rely on insecticides, but improper handling might cause the target pest become resistant, natural enemies are killed and poisoned, and also cause environmental pollution [2]. To avoid of negative effect due to the use of insecticide in controlling of insect pest on rice should be use another method. One alternatives of control method of rice stemborer was used of integrated pest management (IPM) concept. IPM is ecological approach. Biological control is one of the most important of IPM component such as the role of parasitoids.
The understanding of the invasion and colonization of the parasitoid eggs as one component of efforts to control rice stemborer in paddy fields. That is very important in order to maintain the balance of natural enemies. The deeply understanding of the invasion and colonization that they have it as first step to determines the next steps to maintain a balanced population of parasitoids in sustainable agricultural systems. The information about the issue above were still limited, therefore research was conducted with the aim to understanding the invasion and colonization of the egg parasitoid of rice stemborer II. METHODOLOGY

A. Place and Time of Research
The experiment was conducted in three Regency of endemic centers of yellow rice stemborer (Badung, Tabanan and Jembrana with 5 subak each Regency), and in the Laboratory of Plant Pests and Diseases Faculty of Agriculture, Udayana University since December 2013 to March 2014.

B. Tools and Materials
Tools and materials were used in this research included a sample group of yellow rice stemborer eggs, KOH 10%, binocular microscope, preparat, the needle insects, spait, tweezers, paper, cotton, gauze, glass tube, tissue, Petridis, termohigrometer, loops, altimeter, camera and office stationery.

C. Sampling Method
The research was used survey method by taking a sample group of yellow rice stemborer eggs by purposive random sampling as many as 70 groups per week in an area of 2.5 acres at each Subak. Samples were taken at 10 -66 day plant age after planting by cutting leaves containing yellow rice rice stemborer eggs equal to 3 (three) cm, then put in a plastic tube, labeled the location and the date they were taken and brought to the laboratory to take care for further identification.

D. Methods of Observation
The observations began the day after sampling until the parasitoid does not appear anymore. The observations was included the number of eggs that infected group, type of parasitoids that emerged, the number of stemborer larvae and adults of parasitoids that emerged. The group of eggs that did not hatch, dissection under the microscope to determine the borer larvae and adults of parasitoids that are still left in the eggs.

E. Identification of Parasitoids
The identification of parasitoids was done in step by step according to the sample group of eggs taken from the field, using a key determination.

F. Observed Parameters
The observed parameter was included the percentage of infected eggs, diversity, similarity, dominance, abundance, attack level and ratio of female parasitoids. The parasitoid species diversity were analyzed using the Shannon-Wiener index [12], the similarity of the Sorensen index [15], dominance by dominance index [7] and attack level with the Rauf model [14].

G. Analysis of Data
The data were analyzed by using a randomized block design (RBD). If the components in the test showed significant differences then will continue to the LSD test level of 5%. The relationship between abundance population and parasitoid attack levels were analyzed by correlation analysis [4]. The results of the analysis are presented in tables, pictures and graphs.

III. RESULTS AND DISCUSSION
The result showed that the invasion and colonization of the egg parasitoid of yellow rice stemborer vary in Bali. The percentage of infected eggs, diversity, dominance, abundance population and attack levels of parasitoid were significantly different in the three Regency. The three types of parasitoids associated with rice plants, they are Trichogramma japonicum, Telenomus rowani and Tetrastichus schoenobii. More results are presented in the following table (Table 1- Table 2 shows that, the parasitoid species diversity index in the three Regency has same lower level but actually they are real differences. The highest species diversity index was found in Badung (0.42) 31.25% higher than the district of Tabanan (0.32) and 7.69% of Jembrana (0.39). Index of similarity of parasitoids in the three Regency have turned out to demonstrate the value that does not differences (100% was same), but the dominance index values has different. The highest parasitoid dominance index in Badung was T. schoenobii followed T. rowani and T. japonicum, as well as at Tabanan, but at Jembrana the highest dominance index obtained T. rowani followed T. schoenobii and T. japonicum (Figure 1).   Remarks: numbers followed by the same letter in the same column indicates no significantly difference at the 5% level LSD Table 5 shows that the average rate of the highest attack in Badung was T. schoenobii (64.25%) followed by T. japonicum (20.61%) and T. rowani (5.22%). Similarly, in Tabanan regency was (85.13%, 11.98% and 1.30%) and Jembrana regency was (50.20%, 39.43% and 4.79%).   (Table 5). Based on the analysis of correlation between abundance population and the parasitoid attack rate showed that the high abundance of the population has a very strong positive relationship (r =0.95; 0.99;0.99) for the high parasitoid attack T. japonicum, T. rowani and T. schoenobii respectively. The invasion and the colonization parasitoids of yellow rice stemborer in Bali is vary and differ on several variables were observed and shown as follows: the percentage of infected eggs, abundance population, attack rate, diversity and dominance of the parasitoid.
The highest percentage of developing eggs group found in Tabanan, followed by Badung and Jembrana regency ( Table  1). A similar incident also found in a variable abundance population and parasitoid attack rate (Tables 4 and 5). The high percentage of developing eggs group, abundance population and parasitoid attack rate in Tabanan regency closely related to agronomic acts as extrinsic factors. Following the agronomic question include seed treatment, planting young seedlings (21 days down), planting 3 plants in one hole, plant spacing, rotation varieties, cropping patterns, type of fertilizer, urea, irrigation and pesticide used (type, frequency and dose, with correlation value r = 0.79; 0.79; 0.77 each for rotation varieties, cropping patterns and types of pesticides ( Table 7). The Parasitoid abundance population is influenced by intrinsic factors such as individual adaptability of parasitoids to host and extrinsic factors (environmental support) such as nutritional quality of the host and the host plant biophysical constraints that affect the host-seeking behavior and nesting parasitoid on the host, besides farming practices such as spraying intensity and use of broad-spectrum pesticides by farmers also give a great influence on the lives of parasitoids in the field [17].
Parasitoid species diversity in the three study sites demonstrate the value of diversity is relatively low at<1.5 ( Table 2). The low value is due to the low number of species and number of individuals per species found during the study. In Bali only three species of parasitoids associated with rice plants. Actually 35 species of parasitoids associated with rice plants [9]. The low diversity is also closely related to the follow agronomic farmers, such as the use of pesticide. The low diversity of parasitoids also because the ecosystems are physically controlled by the actions of cultivation by the farmers [8]. Similarly, [11] stated that diversity tends to below when the ecosystem or physically controlled by the location of cultivation by farmers. Existence of human activity also gives the affect of diversity of species in an ecosystem [13].
The further of research analyze found that among the third of diversity low value index that have diversity index varian. The highest diversity index values obtained in Badung regency and the lowest one in Tabanan regency ( Table 2). The incident was caused by avariation in the number of individuals per species (Table 2). These events are also supported by the development of evenness variation parasitoids during the rice growth (age 10 -66 dap). The development of three types of parasitoids in Badung varied and turns during plant growth, while in Tabanan was was dominated by one type of parasitoid T.schoenobii. [11], when the diversity is low, the species parasitoid can become the dominant species and otherwise, when the high diversity the species can not be dominant. The value diversity will tend to be low if the community is dominated by a single species [6].
The results of the analysis of similarity type and ratio of female parasitoids in three locations showed no significantly differences (Tables 3 and 6), but the dominance of the parasitoid for each Regency has a dominant parasitoid. Figure 1 shown that T. schoenobii dominate in Tabanan  The abundance population of parasitoid has a strong correlation with the level of attack (Figure 2). The higher abundance caused the higher of population, but the lower abundance or vice versa the lower of attack level. Parasitoid attack rate is influenced by environmental factors.

V. CONCLUSIONS
The invasion and the colonization of the egg parasitoid of yellow rice stemborer in Bali is vary in diversity, dominance, abundance population, the percentage of infected eggs and attack level. This understanding is as a basis for determining the measures to support sustainable agriculture.