No abstract

Effective control disease measures require a great deal of knowledge about the pathogen, which is also applied to dieback disease of the nutmeg tree in Aceh Selatan District, Province of Aceh, Indonesia. The objectives of this study were to identify the causal agent of dieback disease on a nutmeg plantation and to assess the effect of drought stress on the development of dieback disease. Pathogen identification was carried out by observing the symptoms of infected plants, morphological characters of the isolated pathogens, Koch’s postulates, and molecular analysis and pure pathogen cultures. The samples were taken from an infected part of the nutmeg plant (twigs, stems, and roots) in 6 subdistricts at the center of the nutmeg plantation in Aceh Selatan. Koch's postulates were performed by using the mycelia of pathogens on 1-year-old nutmeg seedlings. Drought stress was simulated everyday, and then once every 2 weeks, to study the effect of drought stress on dieback. The results showed that there were 4 genera of fungal pathogens (Botryodiplodia theobromae, Fusarium solani, Graphium euwallaceae, and Rigidoporus microporus) out of 6 fungi associated with dieback disease. However, B. theobromae Pat. turned out to be the dominant fungi associated with dieback on the nutmeg tree in Aceh Selatan. Drought stress was proven to be a predisposing factor for explaining this problem epidemic in Aceh Selatan.

Actually, chemistry learning is very fun, but it takes a high motivation, passion and confident. Based on that, the teacher's effort in developing student's learning activity is very important, because the students' learning activity becomes the determinant of the success of learning that is done. The use of an appropriate learning methods was an alternative to overcome the problem of low absorption of students to the lesson. The arm of this research was to know how the applying of cooperative learning model Teams Games Tournament (TGT) was type through domino card media to affected the learning chemistry achievement of XI-MIA student in MAN 4 Aceh Besar. Instruments used i.e. research instruments and data instruments. Data collection techniques are observation, test results, and questionnaires. Based on the objectives and the results of data analysis in this study, shown that the teacher activity in managing learning for each cycle was in very good category. Student activity at the time of applying the cooperative learning model Teams Games Tournament (TGT) type through domino card media on petroleum material was active. Students' learning achievement after the implementation of Cycle I, cycle II and final test respectively was about 61.29%, 90.32% and 93.55%. Student response to the application of cooperative learning model type Teams Games Tournament (TGT) through domino card media on petroleum material was positive.

The low teaching ability of teachers is one of the factors that cause low student learning outcomes. The purpose of this research is to examine and analyze the ability of teachers to teach and students' learning completeness. This research is classroom action research. Collecting data using student learning outcomes tests and observation sheets of teacher teaching abilities. Analysis of student learning outcomes test data was carried out using percentage statistics, and observational data on teachers' teaching abilities were analyzed using descriptive assessment scores. The results showed that the teacher's ability to manage to learn has increased in each cycle. In cycle 1, it was included in the poor category, then increased in cycle 2 to be good and increased again in cycle 3 to be better. Student learning outcomes increase in each cycle. Individually in cycle 1,.35% complete their learning. Cycle 2 is 60.00% and cycle 3 is 92.00%. Classical completeness in cycle 1 is 42.00%, cycle 2 is 65.00% and cycle 3 is 85.00%.

This research aims to find out the application of discovery learning models in increasing students' interest and learning outcomes in harmonic vibrational materials in MAN 4 Aceh Besar. The method in this study is quasi-experimentation with the design of a pretest-posttest control group. The instruments used are questionnaires and problems. The results showed that the average N-gain of student learning interest in the experimental class was 0.79 high category and control class 0.28 low category. The results of each experimental class indicator included a very positive category while the category control class was positive. Based on the results of the analysis of both classes, it can be concluded that the average interest in student learning in the experimental class is more increased than in the control class, especially on indicators of student engagement. The average N-gain result of student learning outcomes in the experimental class obtained a score of 0.61 moderate categories, then in the control class obtained a score of 0.35 medium category. Based on the test results, the average of the two classes obtained significance scores of 0.000 < 0.05, meaning that there was a difference in the average learning outcome of students in experimental classes and control classes. This proves that the discovery learning model's application can improve students' learning outcomes higher than the discovery learning model in the control class. This study concludes that the application of discovery learning models can increase students' interest and learning outcomes in harmonic vibrational materials in MAN 4 Aceh Besar