Involvement of Epidermis Cell Proliferation in Defense Against Beauveria bassiana Infection

Entomopathogenic fungi Beauveria bassiana can infect many species of insects and is used as a biological pesticide world-wide. Before reaching the hemocoel, B. bassiana has to penetrate the integument which is composed of a thick chitin layer and epidermal cells. Some chitinase, protease and lipase secreted by B. bassiana are probably involved in the fungal penetration of the integument. While microscopic proof is needed, it is difficult to locate the precise infection sites following the traditional method of immersion infection. Consequently, we developed a new method to inoculate conidia solution into a single fixed-site on the back of one segment. This fixed-site infection method is pathogenic but it is also dose dependent. Using the fixed-site infection protocol, it is also very convenient to track hyphae inside the cuticle layer by light and transmission electron microscopy. The fact that few hyphae were detected inside the chitin layer after fixed-site infection with mutant ΔBPS8, a protease secreted during fungi germination, indicates that this method is suitable for screening genes involved in penetrating the integument in large scale. We also found that melanization occurs before new hyphae penetrate the chitin layer. Most importantly, we discovered that fungal infection can induce epidermal cell proliferation through DNA duplication and cell division, which is essential for the host to defend against fungal infection. Taken together the fixed-site infection method may be helpful to determine the mechanism of fungal and host interaction in the integument so as to effectively exert fungal biological virulence.

Distribution of Culturable Myxobacteria in Central Inner Mongolia and their Activity against Phytophthora infestans

Myxobacteria can produce rich and varied biological active substances against bacteria, fungi and viruses, which have great development and research value in medicine and agriculture. In this study, the diversity of culturable myxobacteria in central Inner Mongolia in China was studied and the effects of soil utilization mode, soil type and environmental parameters on the distribution of myxobacteria in this region were analyzed. Furthermore, the activities of myxobacteria against potato late blight pathogen were tested. The results showed that Myxococcus, Corallococcus, Pyxidicoccus, Cystobacter, Archangium and Mellittangium were the dominant genera of myxobacteria in this region. Soil utilization mode and soil types have obvious influence on the distribution of myxobacteria. The populations of myxobacteria were abundant in grassland and cultivated land samples, but few in woodland and unused land samples. The diversity of myxobacteria in the soil samples from fuvo-aquic soils, grey-cinnamon soils, castanozems, and bog soils was relatively rich, while the richness of myxobacteria in aeolian soils, solonetzs, skeletol soils and castano-cinnamon soils was poor. There was no significant correlation between myxobacteria distribution and soil environmental parameters (including the water content, pH value, content of organic matter, content of available phosphorus, content of hydrolytic nitrogen and content of available potassium). Most of the myxobacterial strains isolated in this area (83%) showed the activity against P. infestans, among which the proportion of the disease-resistant strains belonging to Myxococcus and Corallococcus was high, the proportion of the strains belonging to Cystobacter and Mellittangium in the medium, and the proportion of the strains belonging to Pyxidicoccus and Archangium low. The completion of this work will enrich the myxobacteria resource bank in Inner Mongolia and lay a foundation for the further study on myxobacteria and the development of biological pesticide against potato late blight. © 2021 Friends Science Publishers

Study on the off-season shallot seed storage using biological pesticides in Kretek district, Bantul regency, Yogyakarta special region

Farmers in the Samiran village use chemical pesticides to store their shallots. The purpose of this study was to examine the storage of shallot seeds from the off-season crops using biological pesticides. The research was conducted in March 2018 in the Ngudi Makmur farmer group. The research materials used were red onion varieties and biological pesticide of neem. The experimental design used was a completely randomized design with 3 factors with 2 replications. The factors were the type of biological pesticide (liquid and powder), storage treatment (hanging and in the basket), and the shallot varieties (Bimo, Crok Kuning, and Tajuk). The parameters observed were weight loss, damage level, growth capacity, and chemical composition. The results showed that the lowest weight loss was the storage of shallot off-season in the bucket with liquid pesticides on the Crok Kuning variety, while the high growth power test results were hanging. The treatment of biological pesticides can reduce the percentage of onion weight loss, while the use of powdered neem leaves can affect the weight loss, but it is not too high compared to the control. Hanging storage is better than basket storage because yield loss due to weight loss in basket is higher.

The Feasibility of Conventional and Environmentally Friendly Shallot Farming at Selopamioro Village Bantul Regency

Yogyakarta Special Region did not include the production center of shallots in Indonesia, but farmers in Selopamioro Village, Imogiri District, Bantul Regency have used biological pesticide input. This study determines the costs, benefits, and feasibility of environmentally friendly and conventional shallot farming in Selopamioro Village, Bantul Regency. The research location is in Nawungan Hamlet as a shallot center that uses biological pesticide input. Respondents, each as many as 35 farmers taken by census on environmentally friendly shallot farmers, and simple random from conventional shallot farmers. Descriptive analysis was used to determine the cost, benefits, and feasibility of farming. The results showed that the production per hectare was 13.8% lower in environmentally friendly shallots, namely 7,876 tons/ha. The environmentally friendly shallot farming costs are 30.54% lower than the conventional shallot farming costs, but the profits obtained are 12.39 % higher. Both farms are feasible, but land, capital, labor, and R/C values are higher in environmentally friendly shallot farming.

Effect of biopesticides against stem borer (Lophobaris piperis) and Thrips sp. on pepper (Piper nigrum)

One of the pepper crop production obstacles is the presence of pests. Several pests that often attack pepper plants in the Sukamulya Experimental Station is pepper stem borer (Lophobaris piperis) and Thrips sp. We studied the effect of biopesticides of botanical pesticides and biological pesticides at the Sukamulya Experimental Station, Sukabumi – West Java in 2020 against the pepper stem borer L. piperis and Thrips sp. in pepper plantation. The research was designed in a randomized block with three treatments, namely (1) botanical pesticides, (2) biological pesticides and (3) control (water), and nine replications. The treatment application is carried out once a month, done immediately after observing the intensity of the pest attack. The results showed that the attack of pepper stem borer was low (below 10%), so the effect of the treatment could not be seen significantly. The Thrips attack was high enough, it was seen that there was the ability of botanical pesticides to reduce the intensity of the attack. Meanwhile, the biological pesticide had not yet shown its ability to reduce the intensity of Thrips sp.

VIABILITAS DAN EFEKTIVITAS FORMULA NEMATODA Steinernema sp. TERHADAP HAMA PENGGEREK BUAH KAPAS Helicoverpa armigera HUBNER

<p>ABSTRAK<br />Entomopatogen dari genus Steinernema berpotensi digunakan<br />sebagai pengendali berbagai serangga hama, terutama ordo Lepidoptera,<br />seperti Helicoverpa armigera. Penggunaan Steinernema untuk<br />pengendalian H. armigera akan menguntungkan karena aman terhadap<br />lingkungan, mudah diproduksi massal, toleran terhadap berbagai macam<br />pestisida, dapat aktif mencari serangga sasaran, tidak menyebabkan<br />resisten dan resurjensi, serta dapat diaplikasikan dengan alat semprot<br />standar. Namun, formula pestisida hayati mengandung Steinernema masih<br />sangat terbatas. Tujuan penelitian adalah membuat formula Steinernema<br />sp. yang efektif terhadap hama penggerek buah kapas (H. armigera).<br />Penelitian dilaksanakan di laboratorium Patologi Serangga, Balai<br />Penelitian Tanaman Pemanis dan Serat, Malang mulai bulan Mei-Juli<br />2010. Larva instar III Steinernema sp. dibuat dalam 6 macam formula<br />perlakuan dengan bahan pembawa (carrier) berbeda-beda, yaitu (1)<br />suspensi (akuades + sukrosa), (2) pellet-2 (sekam padi), (3) pellet-1<br />(tanah liat + arang), (4) agar + spon, (5) kapsul (Ca-alginat), dan (6)<br />kontrol (akuades). Setiap formula diinokulasikan 10 6 juvenil infektif (JI).<br />Masing-masing perlakuan disusun dalam rancangan acak lengkap (RAL)<br />dengan tiga kali ulangan. Penurunan jumlah juvenil infektif (JI) pada<br />setiap formula yang diamati per minggu selama ± 4 minggu. Isolat yang<br />digunakan untuk penelitian ini berasal dari Asembagus. Untuk<br />mengevaluasi efektivitas formula, larva H. armigera diperlakukan dengan<br />JI yang berasal dari masing-masing formula setiap minggu selama empat<br />minggu. Perlakuan ini menggunakan rancangan acak lengkap dengan<br />empat ulangan. Jumlah penurunan JI setiap minggu selama empat minggu<br />setelah perlakuan. Persentase JI yang hidup pada pellet-1, suspensi, pellet-<br />2, agar + spon, kapsul, dan kontrol berturut-turut sebesar 53; 12,4; 44;<br />63,8; 17,6; dan 5%. Pada minggu pertama sampai minggu keempat setelah<br />perlakuan terlihat bahwa formula yang paling baik mempertahankan JI<br />adalah agar + spon dan kemudian berturut-turut diikuti oleh pellet-1,<br />pellet-2, kapsul, suspensi. Steinernema sp. yang disimpan selama empat<br />minggu dalam berbagai bentuk formula terhadap H. armigera berkisar<br />antara 80-99%. Formula agar dan spon paling baik untuk menyimpan<br />Steinernema sp. selama empat minggu, karena formula ini memberikan<br />tingkat viabilitas dan efektivitas Steinernema sp. paling tinggi.<br />Kata kunci : efektivitas, formula, Helicoverpa armigera, Steinernema sp.,<br />viabilitas</p><p>ABSTRACT<br />Entomopathogenic nematodes genus Steinernema for are potential<br />to be used as a control for various insect pests, especially ordo<br />Lepidoptera, such as Helicoverpa armigera. The use of Steinernema to<br />control H. armigera is beneficial because it is environmentally friendly,<br />easy to produce, tolerant to several pesticides, actively search the target<br />insect, does not cause resistance and resurgence, and can be applied by<br />using standard sprayer. Unfortunately, biological pesticide containing<br />Steinernema is still limited. The study was aimed at formulating a<br />biological agen containing Steinernema sp. to control the cotton bollworm<br />weevil (H. armigera). The experiment was conducted at insect pathology<br />laboratory, Indonesian Sweetener and Fiber Crops Research Institute,<br />Malang from May to July 2010. Steinernema sp. instar III larvae was<br />formulated in six different forms such as Pellet-1 (clay+carbon),<br />suspension (distilled water+sucrose), Pellet-2 (rice husk), agar+sponge,<br />capsule (Ca-alginate), and control (distilled water). Each formulation was<br />inoculated with 10 6 Infective Juvenile (IJ). Each treatment was arranged in<br />completely randomized design (CRD) with three replicates. Each<br />formulation observed showed decrease in IJ number every week for + 4<br />weeks. Isolates used for this research were originated from Asembagus<br />experimental station. For evaluation of the formulation effectiveness, H.<br />armigera larvae was treated using IJ from the formula weekly for four<br />weeks. On the first week after treatment, the percentages of living IJ in<br />Pellet-1, suspension, Pellet-2, agar+sponge, capsule, and control were 53;<br />12.4; 44; 63.8; 17.6; and 5%, respectively. Effectiveness of Steinernema<br />sp. stored for four weeks in various formulations against H. armigera<br />ranged from 80-99%. The best formula of Steinernema sp for storage was<br />agar+sponge because of its ability to viability and effectiveness of<br />Steinernema sp.<br />Key words: effectiveness, formulation, Helicoverpa armigera, viability,<br />Steinernema sp.,</p>

Bees Occurring in Corn Production Fields Treated with Atoxigenic Aspergillus flavus (Texas, USA)

A saprophytic soil fungus, Aspergillus flavus, produces aflatoxin (toxigenic strains) in the kernels of corn (Zea mays L.) and seeds of many other crops. Many strains of A. flavus do not produce toxigenic aflatoxin, and soil application of these atoxigenic strains is a suppressive control tactic to assist in controlling toxigenic conspecifics. Effects of atoxigenic A. flavus applications on honey bees (Apis mellifera L.) and other bees are unknown, and basic information on bee occurrences in corn fields treated with and without this biological pesticide is needed to inform integrated pest management in corn. Fields with atoxigenic A. flavus applications were compared to nearby control fields in three counties in corn production regions in eastern Texas. In each corn field, twenty bee bowl traps were deployed along four equal transects located between corn rows, with contents of the bowls (i.e. bees) retrieved after 24 hours. Eleven bee genera from four families were collected from corn fields, with only two honey bees collected and zero honey bees observed in transects. The sweat bee genus Agapostemon (primarily composed of the Texas-striped sweat bee A. texanus) was most abundant in corn fields (44% of the total number of bees collected) followed by long-horned bees (Melissodes spp., 24%). The southernmost county (i.e. San Patricio) produced over 80% of the total number of bees collected. Bee communities occurring in corn production fields with applications of atoxigenic A. flavus applications were not significantly different from nearby control fields. While little is known of bee resource use in corn production systems in Texas, the abundant yet variable bee communities across latitudes in this study suggests a need to investigate the influence of farming practices on bee resources in regional corn production systems.

Genome Sequence of Bacillus thuringiensis Strain MW, a Freshwater Isolate

Bacillus thuringiensis is an agriculturally significant bacterium and common biological pesticide. B. thuringiensis strain MW was isolated from a freshwater stream in Mont Vernon, NH, and sequenced. A draft genome assembly of 5,935,630 bp with a G+C content of 34.86% and an N 50 value of 1,154,949 bp was generated.

Abamectin Efficacy on the Potato Cyst Nematode Globodera pallida

The potato cyst nematode Globodera pallida is a major pest of the potato crop. Abamectin is a biological pesticide showing high nematicide activity, but its efficacy to control G. pallida has not been investigated to date. In this study, combination of different abamectin concentrations ranging from 1.125 to 36 µg/mL x exposure times from 24 to 384 h were tested on the nematode in a hatching test. Abamectin induced mortality with LD50 value in the range of 13.23 (after 24 h) to 2.90 µg/mL (after 384 h). A glasshouse experiment was also performed in pots filled with soil infected with G. pallida in the presence of sprouted potato tubers cultivar “Spunta”. Abamectin at 4.5, 9.0, 18.0 and 36.0 µg/mL was used in comparison with nematicide fosthiazate. The doses of 18 and 36 µg/mL significantly reduced number of eggs, juveniles, cyst/g soil and reproduction rate in comparison to both untreated control and fosthiazate treatment. Soil applications of abamectin provided significant G. pallida control with LD50 and LD99.9 of 14.4 and 131.3 µg/mL, respectively. These results indicate the efficacy of abamectin to control G. pallida on potato crops and its potential use in organic agriculture or in an integrated pest management program.