Jurnal Proteksi Tanaman (Journal of Plant Protection)

Resistance of Local Rice Varieties from South Pesisir Regency to Brown Planthopper, Nilaparvata lugens Stal

Dea Safitri — 2025-12-31

The use of resistant rice varieties remains a key component in managing the brown planthopper (BPH), Nilaparvata lugens Stål (Hemiptera: Delphacidae). However, information on the resistance of indigenous rice varieties from South Pesisir Regency, West Sumatra Province, Indonesia, is still limited. This study aimed to evaluate the resistance levels of several local rice varieties from South Pesisir Regency to BPH. The experiment was conducted under laboratory conditions using a completely randomized design with seven treatments and four replications. The treatments consisted of five local rice varieties (Sarai Sarumpun, Kutu, Bakwan, Banang Salai, and Bujang Marantau), with TN1 and IR74 used as susceptible and resistant controls, respectively. Seven-day-old rice seedlings were infested with second–third instar BPH nymphs. Variables observed included BPH attack symptoms, mortality, attack percentage, and attack intensity. The results showed significant variation in resistance among the tested varieties. Banang Salai exhibited the highest resistance, with 83.13% BPH mortality, 68.75% attack percentage, and 50.34% attack intensity, indicating a resistant response. In contrast, Sarai Sarumpun showed the lowest resistance, with only 25.94% BPH mortality and the highest attack intensity (90.52%), and was classified as highly susceptible. These findings demonstrate that Banang Salai is a promising local genetic resource for BPH resistance, highlighting the potential of indigenous rice varieties to support sustainable pest management.

Community Structure and Spatial Distribution of Mealybugs on Cassava Plants in Bali, Indonesia

Made Mika Mega Astuthi — 2025-12-31

Mealybugs (Hemiptera: Pseudococcidae) are important pests that threaten cassava in Bali; however, detailed information on their community structure and spatial distribution remains limited. This study aimed to analyze the community structure and spatial distribution patterns of mealybugs infesting cassava across Bali Province, Indonesia. Field sampling was conducted in nine regencies—Jembrana, Tabanan, Buleleng, Badung, Denpasar, Gianyar, Bangli, Klungkung, and Karangasem—using a diagonal sampling method. In each regency, five sampling units were established, with five cassava plants observed per unit. On each plant, three upper, middle, and lower leaves were examined. The results of the study showed four mealybug species: Phenacoccus manihoti, Paracoccus marginatus, Ferrisia virgata, and Pseudococcus jackbeardsleyi, with species richness index values ranging from 0.368 to 0.388. All species were recorded in all surveyed regencies and exhibited a predominantly random spatial distribution pattern, as indicated by a variance-to-mean ratio (S²/X ≈ 1). Overall dominance was highest for P. marginatus (46.23%), particularly in Karangasem, followed by P. manihoti (45.72%) in Denpasar. The mealybug community structure was characterized by a diversity index (H′) ranging from 0.73 to 1.22, an evenness index (E) ranging from 0.16 to 0.24, and a dominance index (C) ranging from 0.32 to 0.54, indicating spatially variable communities that ranged from relatively stable to less stable conditions. These findings provide the baseline data on the community structure and spatial distribution of mealybugs on cassava in Bali, offering important insights for developing targeted monitoring and sustainable pest management strategies

Biological Control of Aphis gossypii on Red Chili Pepper using Locally Isolated Beauveria bassiana and Metarhizium anisopliae

Dang Khoa Bui — 2025-12-31

Red chili pepper (Capsicum annuum) is a high-value horticultural crop in Indonesia, but its production is severely constrained by Aphis gossypii, which can cause yield losses of up to 65%. This study aimed to evaluate the biological characteristics, virulence, and lethal-sublethal effects of local isolates of Beauveria bassiana and Metarhizium anisopliae against A. gossypii. Fungal viability and growth were assessed through spore germination and radial growth assays, while pathogenicity was evaluated using four conidial concentrations (10⁴–10¹⁰ conidia mL⁻¹). Aphid mortality, lethal concentration (LC), lethal time (LT), and reproductive performance were recorded, and the data were analyzed using factorial and probit analyses. The results showed that both fungi exhibited high spore viability (>96%) and stable mycelial growth rates (3.71–3.74 mm day⁻¹). Aphid mortality increased significantly with increasing conidial concentration, reaching 100% at 10¹⁰ conidia mL⁻¹, whereas mortality at 10⁴ conidia mL⁻¹ ranged from 26.67% to 40.00%. Probit analysis revealed comparable virulence, with LC₉₅ values of 8.09 for M. anisopliae and 8.29 for B. bassiana. Lethal time analysis showed a concentration-dependent killing pattern, with B. bassiana acting more rapidly at lower concentrations (10⁴–10⁶ conidia mL⁻¹) and M. anisopliae exhibiting shorter LT₅₀ values at higher concentrations (10⁸–10¹⁰ conidia mL⁻¹). In addition to lethal effects, both fungi significantly suppressed aphid reproduction, particularly at higher conidial concentrations. These findings demonstrate that B. bassiana and M. anisopliae possess strong and complementary bioefficacy against A. gossypii, supporting their potential application in integrated pest management programs.

First Detection of Major Viruses Causing Mixed Infections in Melon (Cucumis melo L.) in Bengkulu Province, Indonesia

Mimi Sutrawati — 2025-12-31

Melon cultivation has increased rapidly in recent years and is frequently associated with widespread virus-like symptoms in Bengkulu Province, Indonesia; however, thereis no formal documentation of the mixed viral infections has been available. Therefore, this study aimed to detect major viruses infecting melon crops in Bengkulu Province and to evaluate their occurrence based on field symptoms and serological detection. Field surveys were conducted at three melon cultivation sites: Kandang Limun Village (Bengkulu City), Air Sebakul Village (Central Bengkulu Regency), and Tawang Rejo Village (Seluma Regency). Symptomatic leaf samples were collected purposively. Virus detection was performed using the Dot Immunobinding Assay (DIBA) with antisera specific to Cucumber mosaic virus (CMV), Tobacco mosaic virus (TMV), and Papaya ringspot virus (PRSV). The results showed that the dominant symptoms of viral infection in melon plants included mosaic, vein banding, chlorosis, leaf curling, and stunted growth in both Snow & Rock and Merlin F1 varieties. Disease incidence varied among varieties and locations, with the highest incidence recorded in Snow & Rock (73.3%). Serological detection revealed that 100% of symptomatic samples tested positive for CMV, TMV, and PRSV, confirming that all infections occurred as mixed infections. This study represents the first report of mixed viral infections in melon crops in Bengkulu Province. These findings demonstrate that overlapping and variable field symptoms cannot be attributed to a single virus and cannot be reliably distinguished through visual diagnosis alone, highlighting the importance of laboratory-based diagnostic approaches for accurate virus identification.

Physiological Interference of Nanoemulsion-Formulated Botanical Insecticide Para-Menthane-3,8-Diol on Spodoptera frugiperda

Rayhan Fadhlurrahman — 2025-12-31

Para-menthane-3,8-diol (PMD), derived from citronellal of citronella plants, has potential as an eco-friendly botanical insecticide for controlling Spodoptera frugiperda. This study aimed to evaluate the physiological interference caused by a PMD nanoemulsion formulation on S. frugiperda. Bioassays were conducted using the leaf-dip method. Data were analyzed using analysis of variance (ANOVA), followed by the Least Significant Difference (LSD) test with Statistix 8 and Duncan’s multiple range test at a 5% significance level using SPSS version 25. Probit analysis with POLO PLUS was performed to determine LC₂₅ and LC₅₀ values. The results showed that PMD nanoemulsion induced significant physiological interference in S. frugiperda, as indicated by increased mortality with LC₂₅ and LC₅₀ values of 0.15% and 0.48%, respectively. At a concentration of 0.75%, the treatment disrupted development by reducing pupation and adult emergence to 30% and altering the sex ratio to 1 male: 0.22 female. Sublethal interference was evident through strong antifeedant activity (62.88%) and pronounced changes in physiological parameters, including consumption rate (0.0328 mg/day), growth rate (0.0023 mg/day), and efficiency of ingested food (6.0029 mg/day). Overall, the PMD nanoemulsion formulation interfered with survival, feeding behavior, growth, and developmental physiology of S. frugiperda, highlighting its potential as an eco-friendly botanical insecticide.

Dynamics of Fusarium Wilt Severity in Banana as Affected by Different Nitrogen Fertilizer Rates

Zulfahri Arifandi — 2025-12-31

Fusarium wilt disease caused by Fusarium oxysporum f. sp. cubense (Foc) is a major constraint in banana cultivation, and its development in the field is frequently associated with improper nitrogen fertilization. However, information on how different nitrogen fertilizer rates influence Fusarium wilt severity remains limited. This study aimed to evaluate the effect of varying nitrogen doses on Fusarium wilt and growth of banana. The experiment was conducted under laboratory and field conditions at the Horticulture Research Center of BRIN, Solok, Indonesia, using a randomized block design with nine treatments and four replications. The treatments were nitrogen with different rates (control, 100, 250, 400, and 550 kg ha⁻¹ year⁻¹), applied with and without Foc inoculation. The results demonstrated that nitrogen fertilization enhanced vegetative growth of banana plants under pathogen-free conditions. However, in Foc-infected plants, increasing nitrogen rates—particularly at high levels—exacerbated disease development. High nitrogen rates (400–550 kg ha⁻¹ year⁻¹) accelerated symptom appearance, indicated by shorter incubation periods, and increased disease severity. In contrast, a moderate nitrogen rate (250 kg ha⁻¹ year⁻¹) delayed symptom development and reduced disease severity, although it did not prevent infection. These findings suggest that excessive nitrogen fertilization increases Fusarium wilt severity, while moderate nitrogen application may help suppress disease progression. Therefore, nitrogen management in Fusarium wilt–endemic banana production areas should prioritize moderate nitrogen rates and avoid excessive fertilization as part of an integrated and sustainable disease management strategy.