Factors affecting entomopathogenic nematode infection of Plutella xylostella on a leaf surface

1995 ◽  
Vol 77 (3) ◽  
pp. 239-250 ◽  
Author(s):  
M. E. Baur ◽  
H. K. Kaya ◽  
G. S. Thurston
2019 ◽  
Vol 27 (5) ◽  
pp. 1031-1042 ◽  
Author(s):  
Federico Cappa ◽  
Giulia Torrini ◽  
Giuseppe Mazza ◽  
Alberto Francesco Inghilesi ◽  
Claudia Benvenuti ◽  
...  

2021 ◽  
pp. 107-107
Author(s):  
Xiao-Xia Li ◽  
Dan Tian ◽  
Ji-Huan He

The lotus leaf surface is modified by covering nanofibers to check its wetting property. The well-known lotus effect of the modified surface is greatly weakened, and a hydrophilic property is found. The geometric potential theory is used to explain the phenomenon, it shows that the two adjacent nanofibers can produce a high geometric potential to push water molecules to move along the fibers, as a result, a hydrophilic surface is predicted after surface modification. An experiment is designed to elucidate the main factors affecting the wetting property of the modified surface of lotus leaf.


2020 ◽  
Vol 11 (2) ◽  
pp. 60
Author(s):  
I G.A.A. INDRAYANI ◽  
A. A. AGRA GOTHAMA

<p>ABSTRAK<br />Nematoda  entomopatogen  Steinernema  sp.  telah  banyak<br />dimanfaatkan sebagai agens hayati untuk mengendalikan serangga hama di<br />luar negeri, namun di Indonesia masih terbatas. Tujuan penelitian adalah<br />mengevaluasi efektivitas 3 strain Steinernema sp. lokal terhadap beberapa<br />hama utama tanaman perkebunan dan hortikultura. Penelitian ini dilakukan<br />di Laboratorium Entomologi dan Kebun Percobaan, Balai Penelitian<br />Tanaman Tembakau dan Serat Malang, Jawa Timur, mulai April 2001<br />sampai Mei 2002. Tiga strain nematoda lokal, yaitu BT02, ML07, dan<br />AB05 diuji masing-masing pada konsentrasi 50; 100; 200; 400; dan 800<br />Juvenil infektif (JI)/ml dan satu kontrol (tanpa JI). Sembilan spesies<br />serangga hama yang diuji yaitu Helicoverpa armigera, dan Pectinophora<br />gossypiella (hama kapas), H. assulta dan Myzus persicae (tembakau),<br />Plutella xylostella, dan Crocidolomia binotalis (kubis), Spodoptera exigua<br />(bawang merah), Liriomyza sp. dan S. litura (bunga krisan). Setiap spesies<br />serangga mewakili satu unit pengujian. Setiap perlakuan dalam unit<br />disusun dalam rancangan acak lengkap (RAL) dengan empat ulangan.<br />Aplikasi perlakuan dilakukan dengan metode vial, kultur sel, dan sumuran,<br />tergantung perilaku serangga uji dan menggunakan spray chamber. Di<br />laboratorium, parameter yang diamati adalah sublethal (LC 25 ) dan lethal<br />concentration (LC 50 ), sublethal and lethal time (LT), dan produksi JI. Di<br />lapang, hanya satu perlakuan tunggal yang digunakan yaitu LC 50 dari<br />setiap strain nematoda. Sebanyak masing-masing 20 inang serangga<br />dipajankan daun atau bagian tanaman yang telah disemprot dengan<br />suspensi nematoda di lapang, kemudian serangga uji diamati di<br />laboratorium hingga mati. Hasil penelitian menunjukkan bahwa ketiga<br />strain nematoda menunjukkan efektif membunuh C. binotalis (BT02), P.<br />xylostella, M. persicae (ML07), dan P. gossypiella (AB05), tetapi kurang<br />efektif terhadap H. armigera (AB05), S. exigua dan S. litura (ML07), dan<br />Liriomyza sp. (BT02). Waktu efektif yang diperlukan nematoda untuk<br />membunuh inang (Lethal Time) pada ketiga strain berkisar antara 1-4 hari.<br />Selain efektif membunuh stadia larva, Steinernema sp. juga efektif<br />terhadap prepupa dan pupa.<br />Kata kunci : Tanaman  perkebunan,  hortikultura,  Steinernema  sp.,<br />Helicoverpa armigera, Pectinophora gossypiella, H.<br />assulta, Myzus persicae, Plutella xylostella, Crocidolomia<br />binotalis, Spodoptera exigua, S. litura, Liriomyza sp., juvenil<br />infektif, mortalitas</p><p><br />ABSTRACT<br />Effectiveness of entomopathogenic nematode Steiner-<br />nema sp. against major insect pests of plantation and<br />horticulture<br />Entomopathogenic nematode of family Steinernematidae is a<br />prospective agent for biological control of insect pests. It has been known<br />that many species of insects can be infected by nematode and sometimes<br />showed different levels of infection. Laboratory and field study on the<br />effectiveness of Steinernema sp. against major insect pests of plantation<br />and horticulture was carried out in Laboratory of Entomology and<br />Experimental Station of Indonesian Tobacco and Fiber Crops Research<br />Institute (IToFCRI), Malang, East Java. The objective was to find out the<br />effectiveness of three local strains of Steinernema sp. to any different<br />major of insect pests of plantation and horticulture. Three local strains of<br />nematode tested as BT02, ML07, and AB05 which each consist of five<br />level concentrations of IJ, viz. 50, 100, 200, 400 and 800 IJ/ml and one<br />untreated with IJ as control were tested against nine species of insect, viz.<br />H. armigera, P. gossypiella (cotton), H. assulta and M. persicae (tobacco),<br />P. xylostella and C. binotalis (cabbage), S. exigua (red onion), Liriomyza<br />sp. and S. litura (chrysanthemum). Each species of insect was tested as<br />one unit of test and treated with the same level of concentration. Each<br />treatment in every unit of test was arranged in randomized complete<br />design with four replications. Application method of treatment used were<br />vial, cell culture plate, and well, depends on insect behaviour. Nematode<br />suspension was applied by using spray chamber. Parameters observed<br />were sublethal and lethal concentration, sublethal and lethal time and IJ<br />production. In field study, only one single treatment LC 50 was used to<br />observe the insect mortality. In this study, twenty of insect hosts were fed<br />on treated-sample leaves collected from the field and observed till death.<br />The result showed that all strains of Steinernema sp. were more<br />pathogenic and effective against C. binotallis (BT02), P. xylostella and M.<br />persicae (ML07), and P. gossypiella (AB05), but less pathogenic against<br />H. armigera (AB05), S. exigua and S. litura (ML07), and Liriomyza sp.<br />(BT02). Time needed (LT) to kill the insect host was ranged from one to<br />four days. Strains of nematode tested were not only effective against larvae<br />but also effective to kill prepupae and pupae of insect host.<br />Key words : Estate crops, horticulture, Steinernema sp., H. armigera, P.<br />gossypiella, H. assulta, M. persicae, P. xylostella, C.<br />binotalis, S. exigua, Liriomyza sp, S. litura, infective<br />juvenile, mortality</p>


2021 ◽  
Vol 37 (3) ◽  
pp. 399-409
Author(s):  
Yong He ◽  
Jianjian Wu ◽  
Shupei Xiao ◽  
Hui Fang ◽  
Qishuai Zheng

HighlightsContact angles of spray droplets were positively correlated with their surface tension.Wettability of rape leaves was generally poor for most pesticides.Surface structure and free energy determine the hydrophobicity of rape leaves.The size of the spray droplets had no significant influence on rape leaf wettability.Abstract. In order to improve the deposition and adherence of spray droplets on leaf surfaces, the wettability of rapeseed leaves was investigated. We explored the effect of different pesticides and test surfaces on droplet contact angles, and analyzed the effects of leaf surface properties, droplet sizes and the addition of organosilicone adjuvant on wettability. The results indicated that contact angles of different liquids were positively correlated with their surface tension for rapeseed leaves. The wettability of rapeseed leaves was generally poor using different pesticides, but was highest for a fungicide mixture of difenoconazole and propiconazole. The hydrophobicity of rapeseed leaves is largely determined by the complex microstructure and the low surface free energy of the leaves. The size of the spray droplets had no significant influence on the wettability. Moreover, the addition of an organosilicone adjuvant significantly reduced the surface tension of all spray droplets, with the best result for a 50% procymidone solution. In conclusion, the factors affecting rapeseed leaf surface wettability should be considered comprehensively before selecting the appropriate pesticide, so as to improve its utilization rates. Keywords: Contact angle, Leaf surface, Pesticide application, Spray droplet.


HortScience ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 346-351 ◽  
Author(s):  
Anton Baudoin ◽  
Sarah Finger McDonald ◽  
Tony K. Wolf

Phytotoxicity of horticultural oil, applied shortly before antifungal sulfur, was evaluated for 23 grape cultivars. Oil application significantly reduced accumulation of soluble solids in berries of 9 of 23 cultivars, but there was no relationship with visible foliar injury. Treatment of leaves of Vitis labrusca `Catawba' with 1.5% JMS Stylet-Oil reduced leaf net photosynthesis (Pn) by 50% to 60% and of Vitis vinifera `Chardonnay' by 20% to 30% 1 day after application. Pn was reduced only when the lower (abaxial) leaf surface was treated; treatment of only the adaxial leaf surface had little effect. The Pn depression in `Catawba' persisted 3 to 4 weeks, whereas reductions in `Chardonnay' persisted less than 2 weeks. The Pn-depressing effect of oil was not significantly ameliorated by real or simulated rainfall, and washing the lower leaf surfaces with water and detergent also had only limited effect. There was no significant difference in Pn depression from oil applications made in the middle of the day (stomata open) compared to application in the evening (stomata closed), or from oil applied at higher versus lower application pressure. The greater sensitivity of `Catawba' than `Chardonnay' to Pn depression by oil may be related to the amount of oil retained by the leaves; the pubescent lower leaf surfaces of `Catawba' retained more than twice as much spray emulsion as did the more glabrous leaves of `Chardonnay'. Visible injury was mild in both cultivars, with small water-soaked lesions developing more commonly on `Chardonnay' than on `Catawba' leaves. Spray oil retention data for additional cultivars suggested that differences in retention can explain a portion of the differences in horticultural oil phytotoxicity.


Nematology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Daiana P. Eliceche ◽  
Matias N. Rosales ◽  
María F. Achinelly

Summary The optimum conditions for storage, infectivity and multiplication of the nematode Heterorhabditis bacteriophora SUP strain, isolated from horticultural soils in Argentina, were determined for later use in biocontrol. This strain was able to kill Tenebrio molitor larvae (over 90%) at 16 and 25°C, after 7 and 4 days, respectively, with mortality being significantly higher at 25°C. No infectivity was reported at 4 and 11°C. Higher concentrations (over 150 infective juveniles (IJ) insect−1) produced higher percentages of mortality. However, increasing inoculum density reduced offspring production and increased emergence time. Storage density between 2500 and 7500 IJ ml−1 had no effect on survival of IJ. Survival of IJ maintained at 4 and 16°C was around 80% after 4 weeks storage and 30% after 32 weeks. However, at 25°C, a 60% IJ survival was observed at 4 weeks, decreasing to around 10% after 16 weeks and with no survival at 24 weeks. An overall significant decrease in virulence was observed after 90 and 120 days of storage but this was more pronounced at a storage temperature of 4°C than at 16 and 25°C. IJ stored at 4°C had reduced virulence after 90 and 120 days, but not after 60 days. This study provides useful information about some fundamental environmental conditions influencing important nematode traits of the species H. bacteriophora.


1997 ◽  
Vol 7 (4) ◽  
pp. 513-526 ◽  
Author(s):  
M. E. BAUR ◽  
H. K. KAYA ◽  
R. GAUGLER ◽  
B. TABASHNIK

2017 ◽  
Vol 1 (1) ◽  
pp. 41
Author(s):  
Mardianto Harahap ◽  
Didik Sulistyanto

Local isolates of entomopathogenic nematodes are symbiotically associated with bacteria of the genus Xenorhabdus or Photorhabdus. Symbiont bacteria isolated from local isolates of entomopathogenic nematode (Pujon, Cemoro Lawang and X. nematophilus) were identical with Xenorhabdus spp and isolate of Ngadas was identical with Photorhabdus luminescens. Some isolates, such as Xenorhabdus (isolate of Pujon) and P. luminescens (isolate of Ngadas) has a high virulence when the bacteria was injected into insect haemocoel. High virulence was indicated by Xenorhabdus nematophilus when it was applied orally.


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