Potensi Ekstrak Jahe Merah (Zingiber Officinale Var. Rubrum) Sebagai Larvasida Alami Aedes Albopictus

DBD masih merupakan masalah kesehatan masyarakat utama di Indonesia. Upaya pencegahan yang dilakukan saat ini menggunakan insektisida berbahan dasar kimia yang dapat merusak lingkungan juga menimbulkan resistensi. Penggunaan larvasida alami dari tumbuhan dapat menjadi alternatif insektisida, salah satunya adalah jahe merah (Zingiber officinale var. rubrum) yang dapat dijadikan sebagai insektisida alami karena adanya kandungan senyawa aktif. Tujuan penelitian ini adalah untuk mengetahui tingkat kematian, perbedaan rerata kematian larva Aedes albopictus serta mengetahui Lethal Time dan Lethal Concentration. Jenis penelitian ini merupakan penelitian true eksperimental dengan posttest only control group design. Hasil penelitian menunjukkan bahwa kematian larva 100% lebih cepat pada konsenrasi 8% yaitu setelah 6 jam pengujian. Hasil Uji Kruskal Wallis untuk melihat perbedaan rerata kematian larva setiap jam kelompok perlakuan ekstrak jahe merah dengan kelompok kontrol menunjukkan terdapat perbedaan secara signifikan rerata kematian larva (0,000 < 0,05). Hasil uji probit Lethal Time menunjukkan bahwa diperlukan waktu 2,196 jam dalam mematikan 50% larva dan 4,788 jam dalam mematikan 99% larva dengan konsentrasi 8% sedangkan Lethal Concentration menunjukkan bahwa diperlukan konsentrasi sebesar sebesar 0,772% dalam mematikan 50% larva dan 1,973% dalam mematikan 99% larva setelah 9 jam pengukuran. Perlu dilakukan penelitian lebih lanjut untuk mengembangkan ekstrak jahe merah yang aman dan layak pakai namun tidak menghilangkan senyawa yang ada pada ekstrak jahe merah.

Residual toxicity of selected insecticides on Aphis gossypii and their safety limits on honeybees

Evaluation studies were carried out to simulate realistic field exposures of sulfoxaflor and flonicamid against Aphis gossypii at foraging time of Apis mellifera. Semi-field trials of field rates of sulfoxaflor and flonicamid against A. gossypii laboratory strain at 48 h of exposure had equipollent overall mean of mortality of 62.50 and 63.50%, respectively in season of 2020, likewise 60.50 and 62.50%, respectively in season of 2021. Lethal time values (LT1) had ranges of 51.33–32.46 days for sulfoxaflor and 49.00–39.55 days for flonicamid. Laboratory trials on foraging honeybees (∼21 days old) at 5 h of exposure showed an excellence for sulfoxaflor (5.00%) in overall mean of mortality compared to flonicamid (2.75%) in season of 2020. Likewise, sulfoxaflor (4.75%) surpassed flonicamid (2.75%) in season of 2021. The highest LT1s on honeybees for sulfoxaflor and flonicamid reached 27.45 and 10.94 days, respectively. International Organization for Biological Control classified both insecticides to be harmless on honeybees. Survival foraging bees exposed to LD50s of the tested insecticides had malformed digestive tracts gradually vanished along week of exposure. Suggestions for foliar spray stoppages prior to flowering period were mentioned for both insecticides.

UJI BEBERAPA KONSENTRASI EKSTRAK UMBI GADUNG (Dioscorea hispida Dennst) TERHADAP HAMA KEONG MAS (Pomacea canaliculata L.)

Riau is one of a lowland rice producing provinces. One of the pests that can reduce rice productivity is the golden snail (Pomacea canaliculata L.). The solution for controlling the golden snail (P. canaliculata L.). Pest uses environmentally friendly control techniques, namely botanical pesticides of gadung tubers. This study aims to obtain a concentration of the extract of gadung tuber flour (Dioscorea hispida Dennst) which is effective in controlled the attack of golden snails (P. canaliculata L.) in lowland rice plants. This research was conducted experimentally using completely randomized design (CRD) consisting of five treatments and four replications, in order to obtain 20 experimental units. The treatments consisted of concentrations of gadung tubers extract, namely 0 g.l-1, 25 g.l-1, 50 g.l-1, 75 g.l-1, and 100 g.l-1. Observations included the initial dst time to snail death, lethal time 50 (LT 50), daily total mortality, and behavior changes in behavior. The results showed that the application of 100 g.l concentration of gadung tuber extract treatment caused the highest total mortality of golden snails (P. canaliculata L.) of 74.99%, but it was not effective yet in controlling the golden snail pest because it was not able to kill the golden snail above 80%.

The Effectiveness of Bandotan (Ageratum conyzoides L.) Leaf Extract on Mortality of Boophilus microplus In Vitro

The purpose of this research is to find the effectiveness of bandotan’s (Ageratum conyzoides L.) leaf extract on mortality of Boophilus microplus in vitro and also to get of lethal concentration and lethal time. This research used 125 Boophilus microplus. This research used five treatments, namely neguvon suspensionon (K+), ethanol 1% (K-), 1% concentration (P1), 2% concentration (P2) and 3% concentration (P3). The observation of mortality was done every six hours. Boophilus microplus dies when there is no movement. The data were analyzed using one-way ANOVA and followed by Duncan's Multiple Distance Test. The result is said to be significant if p<0.05. Probit analysis of LC50 is 1.63% at the first hour, 0.85% at the second hour, 0.54% at the third hour, 0.34% at the fourth hour, 0.04% at the fifth hour and 0.04% at the sixth hour, LC90 reached by using 5.6%, 2.9%, 1.8%, 1.2%, 0.16 and 0.16% concentration in 1, 2, 3, 4, 5 and 6 hours, respectively. The LT50 of ethanol 1% (K-) was at 10.142 hours, neguvon suspension on (K+) was at 0.747 hours, 1% concentration (P1) was at 2.184 hours, 2% concentration (P2) was at 1.579 hours, 3% concentration (P3) was at 0.923 hours and LT90 was at 23.734, 1.749, 5.110, 3.695 and 2.159 hours. The conclusion of this study was bandotan’s (Ageratum conyzoides L.) leaf extract was effective as an acaricide based on the mortality of Boophilus microplus.

UJI BEBERAPA KONSENTRASI EKSTRAK BIJI PINANG (Areca catechu L.) UNTUK MENGENDALIKAN HAMA ULAT JENGKAL (Chrysodeixis chalcites Esper) PADA TANAMAN KEDELAI (Glycine max L.)

Chrysodeixis chalcites Esper is the main pests in soybean plants cultivation that can cause damage up to 90%. One of controlling was done by using areca nuts (Areca catechu L.) which has a potential as a botanical insecticide. This study aimed to obtain effective concentrations of areca nuts extract to control Chrysodeixis chalcites Esper pests on soybean plants (Glycine max L.). This research was conducted at the Laboratory of Plant Pest and Experimental Farm, Faculty of Agriculture, Riau University, Pekanbaru from August to November 2018. The study was conducted experimentally using a completely randomized design (CRD), which consisted of five treatments and four replications, namely: the concentration areca nuts extract 0 g.l-1 water, 20 g.l-1 water, 40 g.l-1 water, 60 g.l-1 water, and 80 g.l-1 water. The results showed that the concentration of 80 g.l-1 of water was an effective concentration to control Chrysodeixis chalcites pest with an initial death time of 14 hours, lethal time 50 29.25 hours after application, and total mortality of 87.50%.

Influence of heavy metal ions on ecotoxicological indicators of planorbarius corneus (Mollusca, Gastropoda, Pulmonata, Bulinidae)

The influence of different concentrations of ions of copper, zinc, nickel, manganese of the aquatic environment on the ecotoxicological indicators of the wide range and the most numerous species of malacofauna of Ukraine – Planorbarius corneus (Linnaeus, 1758) was studied. According to the level of toxic effect on the coils, the pollutants studied by us belong to the categories of low-toxic (Mn2+), moderately toxic (Ni2+), highly toxic (Zn2+) and highly toxic (Cu2+) substances. The values of subthreshold, sublethal, chronically lethal, and acute lethal concentrations for each of the used toxicants (mg/dm3) were determined according to the peculiarities of behavior and physiological condition of the experimental animals. As the concentrations of metal ions in the medium increase, the values of the latent period in P. corneus increase. The first signs of poisoning in animals are a weakening of motor activity and increased mucus secretion. At lethal concentrations (LC100) of these toxicants in experimental mollusks develops a rapid pathological process. By the end of the experiment, all individuals in this group die. With increasing concentrations of heavy metal ions, lethal time and lethal mean time decrease. The highest lethal time values were observed for manganese (II) ions, and the lowest for copper ions. The reversibility of mollusk poisoning by different concentrations of these metals was studied. Restoration of functions in the studied animals is carried out in reverse order. Under the action of the same concentrations of heavy metal ions, the duration of the lethal mean time is different. The value of the coefficient of endurance under the influence of heavy metals on the horn extract decreases from high to low concentrations. At subthreshold concentrations, this coefficient cannot be established due to the absence of 100 % death of individuals until the end of the acute experiment. The values of the adaptation coefficient are the highest for highly toxic metal (Cu2+) and the lowest for weakly toxic (Mn2+). Under the action of copper ions, the adaptation of animals to the effects of the toxicant is temporary, followed by depression.

Efficacy of soil isolates of entomopathogenic fungi against the bulb mite, Rhizoglyphus robini (Acari: Acaridae)

The bulb mite, Rhizoglyphus robini, is a serious pest of garlic, onion and other crops. The mite is usually found in association with dangerous fungal pathogens such as Fusarium spp. Control of this pest has relied upon the use of synthetic acaricides but chemical control of the bulb mite is difficult because it is able to develop resistance quickly. Thus, alternative control methods, e.g. biological control, need to be developed and implemented. The aim of this study was to assess efficacy of selected strains of entomopathogenic fungi (EPF) against adult females of R. robini under laboratory conditions. New EPF strains were isolated from soil samples collected in onion and garlic fields in the Czech Republic and Israel using soil elution and cultivation on selective media. Fungal species were determined using macroscopic, microscopic and molecular markers. The efficacy against R. robini females was tested in 17 isolated and 3 reference strains of EPF. Results revealed high variability among species and strains. The highest efficacy against R. robini mites was found in strains of Metarhizium anisopliae isolated from soil samples collected in the Czech Republic which caused mortality up to 99.3%, and a Metarhizium indigoticum strain from Israel causing 98.3% mortality after four days of bioassay. Isaria fumosorosea strains did not caused mortality higher than 40%. The lowest virulence was found in Beauveria spp. strains causing mortality of mites between 5 and 25%. Median lethal time (LT50) and median lethal concentration (LC50) in the three most virulent strains ranged between 2 and 4 days and between 1.01×104 and 2.36×105 spores/ml, respectively. The concentration-response models indicated that the M. indigoticum strain is more lethal than M. anisopliae strains. The present study showed that some strains of entomopathogenic fungi, especially from the genus Metarhizium, could be perspective biocontrol agents against R. robini.

Larvicidal toxicity and parasporal inclusion of native Bacillus thuringiensis BK5.2 against Aedes aegypti

Objectives Native Bacillus thuringiensis BK5.2, isolated from soil of Baluran National Park, East Java, Indonesia, has been shown to be toxic against Aedes aegypti larvae. This study aims to determine the strength and the speed of the toxicity of B. thuringiensis BK5.2 against A. aegypti larvae in lethal concentration (LC) and lethal time (LT), as well as detection of toxin structure and parasporal inclusion. Methods LC values were determined by the mortality of A. aegypti third instar larvae after 24 and 48 h exposure to five various concentrations of B. thuringiensis BK5.2, while LT values were determined based on the mortality of A. aegypti third instar larvae due to exposure to LC90 concentration at 0; 0.5; 1; 2; 4; 8; 10; 20; 24; and 48 h. Larvicidal toxicity was determined based on value of LC50 and LC90 (CFU/mL), as well as LT50 and LT90 (hours) analysed ​​with Probit analysis. Parasporal inclusion was detected using transmission electron microscope (TEM) and scanning electron microscope (SEM). Results Based on bioassay, LC50 and LC90 values ​​were 11.6 × 106 and 22.7 × 106 CFU/mL, respectively, at 24 h exposure, as well as 8.3 × 106 and 15.4 × 106 CFU/mL, respectively, at 48 h exposure, while the value of LT50 and LT90 were 19.0 and 26.6 h, respectively. Morphological observation of the dead larvae showed there was damage on abdomen and thorax region. Detection by TEM and SEM showed there was cuboidal parasporal inclusion. Conclusions Native B. thuringiensis BK5.2 has high toxicity against A. aegypti larvae and detected flatcuboidal toxin in parasporal inclusion.

Transcription Activator Swi6 Interacts with Mbp1 in MluI Cell Cycle Box-Binding Complex and Regulates Hyphal Differentiation and Virulence in Beauveria bassiana

Mbp1 protein acts as a DNA-binding protein in MluI cell cycle box-binding complex (MBF) and plays an essential role in filamentous myco-pathogen Beauveria bassiana.In the current study, BbSwi6 (a homologue of yeast Swi6) was functionally characterized in B.bassiana. Both BbSwi6 and BbMbp1 localize in the nucleus and display a direct interaction relationship which is indicated by a yeast two-hybrid assay. BbSwi6 significantly contributes to hyphal growth, asexual sporulation and virulence. On the aerial surface, ΔBbSwi6 grew slower on various nutrients and displayed abnormal conidia-producing structures, which hardly produced conidia. In liquid media, BbSwi6 loss led to 90% reduction in blastospore yield. Finally, the virulence of the ΔBbSwi6 mutant was modestly weakened with a reduction of 20% in median lethal time. Comparative transcriptomics revealed that BbSwi6 mediated different transcriptomes during fungal development into conidia and blastospores. Notably, under the indicated condition, the BbSwi6-mediated transcriptome significantly differed to that mediated by BbMbp1. Our results demonstrate that, in addition to their roles as the interactive components in MBF, BbSwi6 and BbMbp1 mediate divergent genetic pathways during morphological transitions in B. bassiana.

Combination of Modified Atmosphere and Irradiation for the Phytosanitary Disinfestation of Trogoderma granarium Everts (Coleoptera: Dermestidae)

The khapra beetle, Trogoderma granarium Everts, is defined as one of the most important quarantine pests globally, and fumigation with methyl bromide, an ozone-depleting substance, is a common phytosanitary measure currently used. The modified atmosphere (MA), irradiation, and their combination treatments of T. granarium larvae and adults were performed at room temperature (24–26 ℃) to develop an ecofriendly phytosanitary disinfestation measure and to shorten the exposure time and overcome treatment disadvantages of irradiation. Late-stage larvae are determined as the most tolerant stage resulted in large LT99.9968 values of 32.6 (29.2–37.5) and 38.0 (35.1–41.7) days treated under 1% and 2% O2 (with N2 balance) atmosphere, respectively. Ionizing radiation was used to enhance the effect of MA and the mortality was highly significantly affected by all the interaction effects, indicating that the synergistic effects present in all the combined treatments. The synergistic ratios, which is defined as the estimated lethal time for MA treatment (LD90, LD99, and LD99.9968), divided by that of combined treatment, were between 1.47 and 2.47. In the confirmatory tests, no individuals recovered from a sum of 111,366 late-stage larvae treated under 1% O2 atmosphere for 14- or 15-d after 200 Gy irradiation, which resulted in validating the probit estimations and achieving an efficacy of 99.9973% mortality at 95% confidence level. Therefore, these treatment schedules are recommended to disinfest T. granarium infecting commodities for phytosanitary purposes under the warehouse, MA packaging, or in combination with international transportation by train or sea container.