JURNAL AGRONOMI TANAMAN TROPIKA (JUATIKA)

Analysis of the Effect of Sunlight Intensity on Leaf Spot Disease (Cercospora sp) in Edamame Plants (Glycine max (L.) Merrill) in Oil Palm Intercropping Systems

Muhammad Akbar Maulana — 2026-09-01

Edamame (Glycine max (L.) Merr.) is an important agricultural commodity in Indonesia, with increasing market demand both domestically and for export. One of the major biotic constraints in edamame cultivation is leaf spot disease caused by Cercospora sp. Environmental factors, particularly sunlight intensity and temperature, significantly influence the development of this disease. High sunlight intensity can reduce uredospore viability and limit fungal infection, while shaded or low-light conditions promote pathogen development due to increased humidity. This research aims to analyze the effect of sunlight intensity on the development of leaf spot disease caused by Cercospora sp. in edamame plants. The study was conducted at the experimental field of the Indonesian Palm Oil Institute, Medan, from March to May 2026. Parameters observed include disease incidence, disease intensity using a scoring scale, sunlight intensity measured with a lux meter, and temperature. The data were analyzed using ANOVA in SPSS. Results showed that disease intensity increased progressively from 0.02 to 0.60, and disease incidence reached 100% by early May 2026. Conidium count correlated positively and significantly with disease intensity (r = 0.747, p < 0.05), while sunlight intensity showed a weak, non-significant negative correlation (r = -0.143, p = 0.347). Multiple regression analysis (F = 30.083, p = 0.000) confirmed the significant simultaneous effect of both variables, with conidia count being the dominant factor in disease development.

Earthworm (Lumbricus) Feeding on Rubellus and Cabbage Waste on Purple Eggplant (Solanum melongena L.)

Gusmawartati — 2026-09-01

Eggplant (Solanum melongena L.) is a widely consumed vegetable in Indonesia, both as a fresh salad and in various prepared dishes. This vegetable is rich in nutrients, particularly vitamin A and phosphorus, and can help improve the nutritional diversity of the population. In Riau Province, average eggplant productivity has declined, necessitating improvements to the production system to meet steadily rising demand. This study aims to investigate the interaction between earthworm application and cabbage residue and to identify the combination that produces the best eggplant plants. The experiment used a factorial Completely Randomized Design (CRD) with two factors. The first factor was earthworm application (0, 20, and 30 earthworms per polybag). The second factor was cabbage residue application (0, 420 g, and 630 g per polybag). The observed parameters included plant height, days to flowering, days to first harvest, fruit length, fruit diameter, and fruit weight. The data were statistically analyzed using analysis of variance (ANOVA); if the calculated F-value exceeded the table F-value, the analysis continued with Duncan's New Multiple Range Test (DNMRT) at the 5% significance level. The results showed that there was no significant interaction between the two factors for any of the observed parameters. However, individually, the application of 30 earthworms and 630 g of cabbage waste tended to produce the best growth and yield. Based on the research results, it is recommended to use a combination of 30 earthworms and 630 g of cabbage waste.

Analysis of N, P, K Content in Soil Planted with Edamame Beans (Glycine max (L.) Merr.) As an Intercrop on Land Where Oil Palm Plants Have Not Yet Produced

Raisya Nazwa Auliandri — 2026-09-01

Edamame beans (Glycine max (L.) Merrill) are legumes with potential as intercrops because they can help improve soil fertility through their effects on nitrogen (N), phosphorus (P), and potassium (K) content. This study aims to determine the changes in soil nutrient content—specifically nitrogen, phosphorus, and potassium—before and after planting edamame beans as intercrops on oil palm immature plants (TBM). The research was conducted on smallholder oil palm TBM land in Bukit Lawang Bahorok, Langkat Regency, from May 2025 to May 2026, using descriptive statistical methods. Edamame was planted on five beds measuring 1 m × 10 m, with 1,500 seeds of the Japanese variety Ryoko 75. During the study, no fertilizer or mulch was applied, but weeding was carried out periodically to maintain plant growth. Laboratory analysis of soil samples assessed the nutrient content of N, P, and K before and after planting. The results showed that nitrogen content decreased from 0.07% to 0.06%, while phosphorus content decreased from 19.78 ppm to 11.87 ppm. These decreases likely occurred because plants absorbed high levels of nutrients during vegetative and generative growth. Meanwhile, potassium content increased from 0.06 me/100 g to 0.15 me/100 g. The primary advantage of this system is its high productivity, yielding 3,068 kg of edamame without any fertilizer or mulch application, demonstrating excellent cost-efficiency. Based on these findings, it can be concluded that planting edamame beans as an intercrop on oil palm TBM land affects soil nutrient dynamics—particularly by increasing potassium content—though it did not significantly increase nitrogen and phosphorus levels during the study period. Therefore, it is highly recommended that farmers adopt this intercropping system to optimize land use and generate early income during the oil palm immature phase. However, a low-dose supplementary application of N and P fertilizers is advised to prevent soil nutrient depletion.

Population Census of Fire Caterpillars (Setora Nitens Walker) in Oil Palm Plantations (Elaeis Guineensis Jacq.) in the Begerpang Plantation of PT PP London Sumatera Indonesia TBK

Nurmala Aqsa — 2026-09-01

The fire caterpillar Setora nitens Walker (Lepidoptera: Limacodidae) is a major pest of oil palm (Elaeis guineensis Jacq.) and causes significant economic losses through defoliation. This study aimed to analyze the population of S. nitens in two front observation schemes, PE1 (fronts 9, 17, 25) and PE2 (fronts 8, 16, 24), and to identify the dominant positions of larvae and the attack level as a basis for control. The study was conducted at Division 03 Naga Timbul, Begerpang Plantation of PT PP London Sumatra Indonesia Tbk., Deli Serdang Regency, North Sumatra Province, from February to April 2026. Sample trees were determined using purposive sampling based on classifications of light, moderate, and heavy attacks, with parameters including the number of eggs, live larvae, dead larvae, and pupae on the sample tree and six surrounding trees. The highest population of live larvae was found in the heavy attack category, with 469 individuals (PE1) and 177 individuals (PE2), averaging 21.4 individuals per tree. The highest number of pupae reached 394 individuals in the same category, indicating a potential risk of population explosion in the next generation. The dominant larvae were found in positions 1A and 1B at the tips of the 9th and 17th leaf sheaths, on the underside of the leaf, while no eggs were observed during the study. This is the first empirical comparison of the effectiveness of PE1 and PE2 in the field, as well as the establishment of the most representative anatomical positions of the leaf sheaths as a reference for standardizing pest censuses. It is recommended that control measures be prioritized in blocks with severe infestations, with monitoring focused on the 9th and 17th leaf sheaths at the tips of the underside of the leaf.

Causing Pathogens and Level of Attack of Leaf Spot Disease in The Main Palm Oil (Elaeis guineensis Jacq.) Nursery in North Labuhanbatu

Aycel Ginting — 2026-09-01

Leaf spot disease is of constraint in oil palm nurseries because it can reduce quality and inhibit seedling growth of seedlings. This study aims to identify the pathogen causing leaf spot disease and determine the percentage and intensity of attacks in the main oil palm nurseries owned by the community in North Labuhanbatu Regency. The study used survey methods and purposive sampling in Kualuh Hulu, Kualuh Selatan, and NA IX-X districts. Symptomatic leaf samples were isolated on Potato Dextrose Agar (PDA) media and identified based on macroscopic and microscopic morphological characteristics. The results showed that Curvularia sp. is the pathogen causing leaf spot disease, while Alternaria sp. and Aureobasidium sp. are associated fungi. The percentage of attacks increased in the three districts, respectively, from 19.30% to 26.31%, 17.33% to 23.66%, and 29.57% to 35.94%. Attack intensity increased from 8.21% to 11.15%, 7.46% to 10.60%, and 13.68% to 16.46%. NA IX-X showed the highest attack rate. The results can serve as a basis for monitoring leaf spot disease in oil palm nurseries.

Morphological Characterization of Coelogyne asperata Lindl. in Kuantan Singingi Regency, Riau Province, Indonesia

Pebra Heriansyah — 2026-09-01

Coelogyne asperata Lindl. is a tropical orchid with distinctive vegetative and reproductive characteristics and considerable potential for ornamental cultivation and conservation. However, detailed morphological information on this species remains limited, particularly for populations in Riau Province, Indonesia. This study aimed to characterize the morphological traits of C. asperata based on quantitative characteristics of vegetative and reproductive organs. The study was conducted in Kuantan Singingi Regency, Riau Province, Indonesia, using a descriptive observational approach. Six healthy and mature individuals were selected through purposive sampling, with three measurement replicates. Morphological observations included roots, pseudobulbs, leaves, inflorescences, and flowers, following standard orchid taxonomic descriptors. The results showed that C. asperata exhibited relatively large vegetative structures, with mean leaf length and width of 55.00 ± 2.00 and 13.00 ± 1.50 cm, respectively. Mean pseudobulb length and width were 14.00 ± 1.30 and 7.00 ± 0.50 cm, respectively. The root system comprised 31.00 ± 2.00 primary roots with a mean length of 25.00 ± 2.00 cm and 24.00 ± 2.00 secondary roots with a mean length of 9.00 ± 1.10 cm. The inflorescences produced an average of 10.00 ± 1.00 flowers per stalk. Overall, the observed morphological characteristics were consistent with the established descriptions of C. asperata and indicated well-developed vegetative and reproductive structures. These findings provide baseline morphological data supporting species identification, documentation, conservation, and future research on the cultivation and utilization of C. asperata.