scholarly journals Toxicity of insecticides to predators of rice brown planthopper: Wolf spider and carabid beetle.

Author(s):  
Md. Jahangir Alam ◽  
Gopal Das

Field toxicity two insect growth regulators (IGR) viz. Award 40 SC (Buprofezin) and Haron 5 EC (Lufenuron) and one newer Thiacloprid viz. Calypso 280 SC against wolf spider, Lycosa pseudoannulata and carabid beetle, Ophionea indica, the predators of rice brown planthopper (BPH) was examined in the Entomology field laboratory, Bangladesh Agricultural University, Mymensingh. Effectiveness of insecticides was assessed on the basis of populations of wolf spider and carabid beetle under field condition at 1, 2, 3, 5 & 7 days after treatment. The abundances of wolf spider and carabid beetle were not changed significantly even when rice plants were treated with either Award or Haron. In contrast, Calypso 280 SC had significantly reduced wolf spiders (about 78%) and carabid beetle (about 57%) populations compared to the control. Therefore it is concluded from the present study that Award 40 SC @ 0.75 ml/L or Haron 5 EC @ 1.00 ml/L would be applied as the protector of predators of BPH in rice-ecosystem. On the other hand, Calypso 280 SC has adverse effects on the populations of wolf spider and carabid beetle in rice-ecosystem as well as other environmental components.

2020 ◽  
Vol 30 (3) ◽  
pp. 275-281
Author(s):  
M Sardar ◽  
MR Khatun ◽  
KS Islam ◽  
MT Haque ◽  
G Das

Experiments were conducted at the net house and laboratory of the Entomology Division of Bangladesh Institute of Nuclear Agriculture (BINA) to determine the effectiveness of four light sources for light trapping, and performance of three predators for controlling brown plant hopper, Nilaparvata lugens (Stal.).The light intensity and sources were 30-50 lux (candle light), 80-100 lux (kerosene lamp), 180-200 lux (bulb) and 380-400 lux (energy saving lamp). The predators, ladybird beetle, carabid beetle and wolf spider, Light traps of 380-400 lux from energy saving lamp showed maximum effect in reducing the pest brown planthopper. Other light sources had little effect on brown planthopper. Light source of 30-200 lux reduced only a few brown planthopper. The predator wolf spider, Lycosa pseudoannulata consumed all the prey individuals of Nilaparvata lugens in three days exposure period indicating its high predation potentiality. Performance of ladybird beetle, Micraspis discolor was moderate and the carabid beetle, Ophionea indica was poor in controlling brown planthopper. The findings of these experiments indicate that light trapping with a source of 380-400 lux, predation by Lycosa pseudoannulata are the promising options in reducing brown planthopper population successfully and it could be an important part of IPM that is essential for the sustainable management of this deleterious brown planthopper in rice cultivation. Progressive Agriculture 30 (3): 275-281, 2019


2007 ◽  
Vol 42 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Isabelle Lauzière ◽  
Gary Elzen

Eleven insecticides were tested using a bioassay of foliar insecticide residue to evaluate their impact on Homalodisca vitripennis nymphs and adults and on Gonatocerus ashmeadi parasitoid pupae and newly-emerged adults. Most compounds caused 100% mortality of H. vitripennis nymphs and adults within the first 24 h following exposure. Dimethoate was significantly less toxic to the nymphs than the other compounds. The insect growth regulators buprofezin and pyriproxifen caused high mortality levels at the end of the 72-h period of observation. They were efficacious against both the H. vitripennis nymphs and adults. Thiamethoxam, acetamiprid, cyfluthrin, fenpropathrin and endosulfan severely affected the immatures and newly-emerged adults of the parasitoid G. ashmeadi with total percent mortality exceeding 65%. Piriproxifen, methomyl, imidacloprid and carbaryl were moderately toxic to the parasitoid pupae and young adults (34–55% total mortality); whereas treatments using buprofezin or dimethoate allowed >89% survival of the parasitoids. These results may help predict the reliability of these compounds in the field and risks to natural enemies associated with their use. It is possible, however, to choose insecticides that are more selective in toxicity to the glassy-winged sharpshooter than to its natural enemies.


1998 ◽  
Vol 38 (5) ◽  
pp. 441 ◽  
Author(s):  
N. J. Campbell ◽  
P. D. Hanrahan ◽  
I. M. Russell ◽  
G. S. Roberts ◽  
B. J. Horton

Summary. A model has been fitted to results from experimental application of organophosphates, synthetic pyrethroids and insect growth regulators to sheep mostly in long wool. The model relates the rate of breakdown of pesticide to the chemical used, the method of application and the length of wool at the time of treatment. A genetic algorithm was used to combine a range of experimental results for each chemical group to determine the rate of breakdown, and also the effect of application method and length of wool on breakdown. Organophosphates break down very quickly when applied to the surface of the wool (initial half-lives of 9–12 days), but the rate of breakdown gradually slows as the proportion of pesticide near the surface of the wool decreases. When the pesticide is applied deep into the wool by hand jetting or dipping, the rate of breakdown is slower (average half-lives of 27–42 days) and more uniform. Synthetic pyrethroids applied by hand jetting or backliner to sheep with 6–9 months wool growth initially break down with half-lives of 32–39 days, but the rate of breakdown decreases to 59–215 days giving average half-lives of 48–103 days over the 3–6 months between application and shearing. Cyromazine applied by hand jetting to sheep with 6–8 months wool growth has an average half-life of 79–96 days, but less if applied by automatic jetting race. The other insect growth regulators have longer half-lives: triflumuron, off-shears backliner, 119 days; and diflubenzuron, long wool jetting on to 7–9 months wool, >119 days. The model allows for different breakdown rates due to the method of application and length of wool and for changes in the rate of breakdown between application and shearing. It can be used to estimate the expected residue on wool at any time after a specified treatment, provided the amount of chemical applied is known. Conversely, the amount applied can be estimated from the residue and treatment details.


2011 ◽  
pp. 88-99
Author(s):  
Khanh Vinh ◽  
Ngoc Doanh Pham ◽  
Van Huy Tran

Objectives: Gastric ulcer is a chronis disease with a lot of dangerous complications and H. pylori is a major cause of gastric ulcer. Eradicating H. pylori helps reducing ulcer relapse and preventing cancer. The aim of study: to evaluate the rate of H. pylori infection in gastric ulcer and efficacy of quadruple therapy RACM for 5 days in patients with gastric ulcer with H. pylori positive. Materials and methods: Total 98 patients with gastric ulcer have been performed the endoscopy and CLO-Test, treated with quadruple therapy RACM for 5 days and evaluate efficacy 4 weeks after ending treatment. Results: The rate of H. pylori in gastric ulcer is 82.65%. The rate of H. pylori eradication is 88.71%. The effect of reducing pain of therapy is 90.32%; and the rate of reducing pain: 96.37% in successfully H. pylori-eradicated group and in the other group 42.85% (p < 0.05). The effect of healing ulcer of therapy is 77.41%; and the rate of healing gastric ulcer: 83.63% in successfully H. pylori-eradicated group and in the other group 28.57% (p < 0.05). The adverse effects of therapy included tiredness: 11.29%, lose appetite: 8.06% and diarrhea: 6.45%. Conclutions: Quadruple therapy RACM for 5 days showed an effective, safe and simple regime for eradicating H. pylori and should be considered to apply as the first lines treatment for H. pylori.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Longqing Shi ◽  
Junian Zhang ◽  
Liangmiao Qiu ◽  
Zhaowei Jiang ◽  
Zhenxing Xie ◽  
...  

Abstract Background Melatonin has been proved to exist and play importance roles in rice plant, such as biosynthesis and resistance. However, little is known about the function of melatonin in its monophagous pest, the brown planthopper. Methods In this study, we examined the effects of melatonin on the copulatory and locomotor behaviors of brachypterous and macropterous adult planthoppers by exposing them to melatonin, luzindole (a melatonin receptor antagonist), or a combination of melatonin and luzindole. Results A total of 68.7% of copulation events occurred at night in the control, while 31.2% occurred at night in the melatonin treatment, which led to a decrease in offspring. Brachypterous males were involved in mating events in the melatonin treatment but not in the other two treatments or the control. The daily locomotor pattern in the melatonin treatment was markedly different from that in the luzindole and melatonin and luzindole treatments. The total locomotor activities of the macropterous and brachypterous males exposed with melatonin were suppressed compared to those in the control. Melatonin significantly decreased the daytime and nighttime locomotor activities of macropterous females. In comparison, the activity of brachypterous females decreased slightly in the daytime but was more than double that of the control females at night. Conclusions Our results reveal that melatonin plays a role in the behaviors of brown planthoppers.


Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 542
Author(s):  
Dariusz Kulus ◽  
Natalia Miler

Lamprocapnos spectabilis (L.) Fukuhara (bleeding heart) is valued both in the horticultural and pharmaceutical markets. Despite its great popularity, information on the in vitro tissue culture technology in this species is limited. There is also little knowledge on the application of plant extracts in the tissue culture systems of plants other than orchids. The aim of this study is to compare the utility of traditional plant growth regulators (PGRs) and natural extracts—obtained from the coconut shreds, as well as oat, rice, and sesame seeds—in the micropropagation and cryopreservation of L. spectabilis ‘Gold Heart’ and ‘White Gold’. The biochemical analysis of extracts composition is also included. In the first experiment related to micropropagation via axillary buds activation, the single-node explants were cultured for a 10-week-long propagation cycle in the modified Murashige and Skoog medium fortified either with 1.11 µM benzyladenine (BA) and 1.23 µM indole-3-butritic acid (IBA) or with 10% (v/v) plant extracts. A PGRs- and extract-free control was also considered. In the cryopreservation experiment, the same 10% (v/v) extracts were added into the medium during a seven-day preculture in the encapsulation-vitrification cryopreservation protocol. It was found that the impact of natural additives was cultivar- and trait-specific. In the first experiment, the addition of coconut extract favoured the proliferation of shoots and propagation ratio in bleeding heart ‘Gold Heart’. Rice extract, on the other hand, promoted callus formation in ‘White Gold’ cultivar and was more effective in increasing the propagation ratio in this cultivar than the conventional plant growth regulators (4.1 and 2.6, respectively). Sesame extract suppressed the development of the explants in both cultivars analysed, probably due to the high content of polyphenols. As for the second experiment, the addition of plant extracts into the preculture medium did not increase the survival level of the cryopreserved shoot tips (sesame and oat extracts even decreased this parameter). On the other hand, coconut extract, abundant in simple sugars and endogenous cytokinins, stimulated a more intensive proliferation and growth of shoots after rewarming of samples. Analysing the synergistic effect of conventional plant growth regulators and natural extracts should be considered in future studies related to L. spectabilis.


1976 ◽  
Vol 24 (5) ◽  
pp. 1065-1068 ◽  
Author(s):  
James E. Oliver ◽  
Albert B. DeMilo ◽  
Charles F. Cohen ◽  
Thomas J. Shortino ◽  
William E. Robbins

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