Exploration of allelochemicals with phytotoxic effects is intended to minimize a current dependency on synthetic herbicides in weed management. Several allelochemicals from the tropical tree <em>Cerbera manghas</em> (sea mango) have been reported as termiticides and bactericides. The present study investigated possible phytotoxic effects of <em>C. manghas</em> leaf extracts under laboratory conditions. Four monocots: barnyard grass (<em>Echinochloa crus-galli</em>), foxtail fescue (<em>Vulpia myuros</em>), Italian ryegrass (<em>Lolium multiflorum</em>), and timothy (<em>Phleum pratense</em>) and four dicots: alfalfa (<em>Medicago sativa</em>), garden cress (<em>Lepidium sativum</em>), lettuce (<em>Lactuca sativa</em>), and rapeseed (<em>Brassica napus</em>) were used as test species. Elongation of both shoots and roots of seedlings was measured to assess any phytotoxic effects. The results showed that the sensitivities of shoots and roots were different between the test species, and the inhibition of seedling elongation significantly increased with increasing concentration of leaf extracts of <em>C. manghas</em> for all the test species. The IC₅₀ (50% inhibitory concentration) values showed that 8.50–32.30 and 4.26–34.67 mg dry weight equivalent extract mL⁻¹ of <em>C. manghas</em> inhibited seedling elongation by 50%, for shoots and roots respectively. Isolation and identification of the phytotoxic substances from <em>C. manghas</em> are suggested for future investigation.

Anredera cordifolia (Tenore) Steenis is widely planted as an ornamental and medicinal plant in Indonesia. On the other hand, in some other countries this plant is classified as a noxious weed. As a harmful weed, A. cordifolia is reported to have the ability to smother all native vegetation, collapse canopies of tall trees, cultivate as a ground cover and disrupt native seedling development. There is no available information about the involvement of any allelochemicals from A. cordifolia related to these issues. The present study evaluated the allelopathic effect by isolating and identifying the allelopathic substance from A. cordifolia leaf extract. The allelopathic potency of A. cordifolia was determined by a series of bioassays of shoot and root growth on some selected test plants. Separation and purification of the active substances was achieved through several chromatography processes. Finally, the substances with allelopathic activity were identified through high-resolution electrospray ionization mass spectrometry (HRESIMS) analysis and determined by the specific rotation of compound, proton and carbon NMR spectroscopies. The results show that A. cordifolia possesses allelopathic properties which affect other plant species. The isolated compound from the plant material, 3-hydroxy-alpha-ionone, may contribute to the allelopathic effects of A. cordifolia.

Nerium oleander historically has been known worldwide as a poisonous plant that can be used to control pests. However, studies on the effects of oleander leaves against Rattus argentiventer as a major agricultural rodent pest are limited. This research aimed to probe the potency of oleander leaves extracted in methanol as a rice-field rat repellent. The experiments involved a choice test (T-maze arena) and a no-choice test (metabolic cage) that were analyzed by the T-test using three replications for 6 days. The results showed that the rats on the T-maze avoided consuming food and water near the oleander treatment. The same results occurred in the metabolic cage, which was indicated by a decrease in the average of food and feces, and also by an increase in the average of water and urine. Additionally, the treatment also caused a disruption in daily activity patterns, which was significantly indicated by an increase of 22.84% in average time for resting activities and a decrease in time for locomotion and nesting activities (by 9.71% and 13.13%, respectively). Overall, oleander leaves have the potential to provide a repellent effect against rice-field rats, especially in the choice test.

The chrysanthemum plant (Chrysanthemum morifolium Ramat.) contains many secondary metabolites such as flavonoids and various volatile compounds that can be utilized as drugs. Tissue culture can be an alternative to enhance the production of certain secondary metabolite. The study aimed to determine the types of secondary metabolites that contained in shoot culture, callus and field plants of C. morifolium. The research method was exploration in the laboratory to analyze and compare the content of secondary metabolite from shoot culture, callus and field plants of C. morifolium. Callus was induced by explants of C. morifolium plantlet stems and leaves respectively on MS medium with an addition of 3 ppm 2,4-D + 2 ppm kinetin and 4 ppm 2,4-D. For shoot culture, single nodule explants with one leaf were planted on MS media with the addition of 1 ppm BAP. The secondary metabolite compouds were analized and identified by GC-MS (Gas Chromatography-Mass Spectrometry). The results showed that various types of secondary metabolites contained in shoot culture, callus and field plants of C. morifolium. In callus culture from leaf explants, four compounds from groups of alcohol, acetic acid and organosilicon were identified, whereas in callus culture from stem explants were identified eight compounds from aldehydes, esters, alkanes, and carboxylic acids group. In the shoot culture, nine compounds of alcohol, ketone, aldehyde, cycloalkane and organosilicon group were identified, while in the field plants five compounds were identified from the cycloalkanes, ketones, organoborones and organosilicon group. Some detected compounds have a potential as precursors of alkaloid, phenolic, and flavonoid.Keywords: chrysanthemum, culture, shoots, callus, secondary metabolites.

Burung bondol jawa (Lonchura leucogastroides) merupakan salah satu hama pada tanaman padi ketika memasuki fase generatif. Petani seringkali menjaga sawah selama sehari penuh untuk mengendalikan hama burung. Cara tersebut kurang efektif karena banyak waktu petani yang terbuang hanya untuk mengendalikan burung. Penelitian ini bertujuan untuk mengetahui tingkat kematangan padi yang disukai bondol jawa dan mengetahui kelimpahan kunjungan tertinggi burung bondol jawa di sawah. Penelitian dilakukan pada bulan Maret hingga bulan Mei 2020 bertempat di lahan sawah milik petani di Desa Cileles, Jatinangor dan Laboratorium Vertebrata, Fakultas Pertanian, Universitas Padjadjaran. Metode uji kelimpahan kunjungan tertinggi dilakukan dengan menghitung jumlah burung yang berkunjung pada lahan penelitian. Sementara itu, metode uji preferensi pada bondol jawa dilakukan dengan membandingkan bagaimana cara makan bondol jawa ketika diberi pakan padi yang matang susu dan padi yang sudah matang penuh. Hasil penelitian menunjukkan bahwa bondol jawa menyerang sepanjang pengamatan, yaitu 11 MST-14 MST. Tingkat kematangan padi yang disukai bondol jawa adalah saat matang susu. Kelimpahan bondol jawa mengunjungi sawah adalah saat sore hari, yaitu mulai dari jam 14.00 hingga jam 17.00. Hal ini menunjukkan bahwa masa tersebut dapat digunakan petani untuk mengendalikan hama burung di sawah.