Efficacy of biological control agents, synthetic insecticides, and their combinations to control tobacco budworm [Heliothis virescens (Lepidoptera: Noctuidae)] in pigeon pea

2019 ◽  
Vol 122 ◽  
pp. 175-179
Author(s):  
Diego M. Viteri ◽  
Leidy Sarmiento ◽  
Angela M. Linares ◽  
Irma Cabrera
2019 ◽  
Vol 19 (3) ◽  
Author(s):  
Marisa Nardiello ◽  
Rosanna Salvia ◽  
Andrea Scala ◽  
Carmen Scieuzo ◽  
Sabino Aurelio Bufo ◽  
...  

Abstract Prothoracicotropic hormone (PTTH) is a neuropeptide that triggers a cascade of events within the prothoracic gland (PG) cells, leading to the activation of all the crucial enzymes involved in ecdysone biosynthesis, the main insect steroid hormone. Studies concerning ecdysteroidogenesis predicted PTTH action using brain extract (BE), consisting in a complex mixture in which some components positively or negatively interfere with PTTH-stimulated ecdysteroidogenesis. Consequently, the integration of these opposing factors in steroidogenic tissues leads to a complex secretory pattern. A recombinant form of prothoracicotropic hormone (rPTTH) from the tobacco budworm Heliothis virescens (F.) (Lepidoptera: Noctuidae) was expressed and purified to perform in vitro tests in a standard and repeatable manner. A characterization of rPTTH primary and secondary structures was performed. The ability of rPTTH and H. virescens BE to stimulate ecdysteroidogenesis was investigated on the third day of fifth larval stage. rPTTH activity was compared with the BE mixture by enzyme immunoassay and western blot, revealing that they equally stimulate the production of significant amount of ecdysone, through a transduction cascade that includes the TOR pathway, by the phosphorylation of 4E binding protein (4E-BP) and S6 kinase (S6K), the main targets of TOR protein. The results of these experiments suggest the importance of obtaining a functional pure hormone to perform further studies, not depending on the crude brain extract, composed by different elements and susceptible to different uncontrollable variables.


1995 ◽  
Vol 85 (4) ◽  
pp. 507-513 ◽  
Author(s):  
G.C. Marris ◽  
J.P. Edwards

AbstractThere is a need to identify potential biological control agents for use against noctuid pests in greenhouses. The gregarious ectoparasitoid Eulophus pennicornis (Nees) attacks a limited range of macrolepidopterous larvae, including those of some important horticultural pest species. Laboratory trials designed to investigate the biology of E. pennicornis on larvae of the tomato moth, Lacanobia oleracea Linnaeus, reveal that wasps preferentially parasitize penulitmate (fifth) or final (sixth) instar hosts. More than two-thirds of wasps lay viable eggs, and individual females oviposit on up to four hosts during their lifespan. Wasp fecundity is high, preadult development is rapid, and offspring show a markedly female-biased sex ratio. Parasitized fifth instar L.oleracea hosts do not grow as quickly as unparasitized larvae, and neither do they undergo normal ecdysis to the final larval stadium. Furthermore, the consumption of artificial diet by parasitized fifth instar hosts is greatly reduced in comparison to that of unparasitized larvae (overall feeding-reduction over a 12 day period was 64.7%). Our results suggest that E. pennicornis affects both the developmental and feeding physiology of host larvae, and that inoculative releases of this parasitoid could provide effective biological control for L. oleracea and other greenhouse pests.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
K. Sindhura Bhairavi ◽  
Badal Bhattacharyya ◽  
Gitanjali Devi ◽  
Sudhansu Bhagawati ◽  
Partha Pratim Gyanudoy Das ◽  
...  

Abstract Background Entomopathogenic nematodes (EPNs) are one of the widely studied biological control agents. The present study was conducted to evaluate the efficacy of two EPNs species, Heterorhabditis bacteriophora (Poinar) (Rhabditida: Heterorhabditidae) and Steinernema aciari (Qui, Yan, Zhou, Nguyen and Pang) (Rhabditida: Steinernematidae), isolated locally from soils of Majuli river island, Assam, India against two important subterrenean pests; Odontotermes obesus (Rambur) (Isoptera: Termitidae) and Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) under laboratory conditions. Results In case of O. obesus, mortality percent was recorded by H. bacteriophora after 72 h. at 300 IJs/termite and by S. aciari at 250 and 300 IJs/termite after 96 h. The lowest LD50 and LT50 values obtained for H. bacteriophora were 13.054 IJs/termite and 26.639 h., respectively, while those of S. aciari were 42.040 IJs/termite and 31.761 h., respectively. With respect to A. ipsilon, H. bacteriophora registered a highest mortality rate at 300 IJs/larvae after 144 h. S. aciari showed 100 percent mortality at 300 IJs/larva after 168 h. The lowest values of LD50 and LT50 for H. bacteriophora were 35.711 IJs/larva and 83.050 h., respectively. The lowest values of LD50 and LT50 for S. aciari were 71.192 IJs/larvae and 97.921 h., respectively. Overall, H. bacteriophora displayed more virulence toward O. obesus and A. ipsilon than S. aciari. Conclusion Both native EPNs were found effective against O. obesus and A. ipsilon. However, H. bacteriophora was more virulent toward O. obesus and A. ipsilon than S. aciari under the laboratory conditions.


1988 ◽  
Vol 23 (3) ◽  
pp. 229-233
Author(s):  
J. A. Joyce ◽  
R. J. Ottens ◽  
G. A. Herzog ◽  
M. H. Bass

Laboratory cultures of field-collected larval tobacco budworm, Heliothis virescens (F.), beet army worm, Spodoptera exigua (Hübner), and fall armyworm, S. frugiperda (J. E. Smith) were bioassayed for response to three pyrethroids in combination with piperonyl butoxide (PBO), or MGK-264. The greatest synergistic effects were seen in S. exigua which also displayed the greatest tolerance to pyrethroids without synergists. The highest SR50 (synergist ratio) value for S. exigua was 22.1 with fenvalerate-PBO mixed in a ratio of 1:5, the highest for S. frugiperda was 4.6 with fenvalerate-MGK-264 1:5, and the highest for H. virescens was 1.3 with permethrin-MGK-264 1:5 or with fenvalerate-PBO 1:5.


1989 ◽  
Vol 24 (4) ◽  
pp. 539-544 ◽  
Author(s):  
Abdul K. Mohamed ◽  
Jen-Rong Yang ◽  
Fred R. S. Nelson

Laboratory studies were conducted to determine the response of healthy and cytoplasmic polyhedrosis virus (CPV) infected Heliothis virescens (F.) larvae to LD50 of methomyl and methyl parathion. Methomyl-CPV combination adversely affected pupal weight and fecundity of the female. The effect of this interaction was synergistic. Exposure of CPV infected larvae to LD50 of methomyl resulted in a mean female pupal weight of 243 mg and a fecundity of 382 per female moth. These values were significantly lower than those of all other treatments. In contrast methyl parathion-CPV combinations did not result in a significant reduction in pupal weight as compared to the control. Adult emergence and egg hatch were not affected.


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