scholarly journals Is the spider a good biological control agent for Plutella xylostella (Lepidoptera: Plutellidae)?

2018 ◽  
Vol 35 ◽  
pp. 1-8
Author(s):  
Xuan Huang ◽  
Xiaoyu Quan ◽  
Xia Wang ◽  
Yueli Yun ◽  
Yu Peng

Spiders, as predators of insects and other invertebrates, are an important part of the natural enemies, and they are recognized as an important biological control agent. Plutellaxylostella (Linnaeus, 1758), the diamondback moth (DBM), is a well-known and destructive insect pest of brassicaceous crops worldwide. Here, we analyzed the functional responses of four spiders (Araneae) – Ebrechtellatricuspidata (Fabricius, 1775) (Thomisidae), Pardosalaura (Karsch, 1879) (Lycosidae), Pardosaastrigera (Koch, 1878) (Lycosidae), and Pardosapseudoannulata (Bösenberg & Strand, 1906) (Lycosidae) – on P.xylostella larvae. We also analyzed intraspecific disturbances in the predation reaction and the intensity of scrambling competition of the spiders to P.xylostella larvae. Our results demonstrated that the functional responses of four spiders of different genera were in line with the Holling II model. Two Lycosidae spiders (P.astrigera and P.pseudoannulata) had the potential to control P.xylostella, and female and male spiders that belonged to the same species had different functional responses to P.xylostella. The functional responses of female predation of P.astrigena, P.laura, and P.pseudoannulata was stronger than the males, but male E.tricuspidatus had stronger functional responses to predation than females. We used the Hassell model to describe the intraspecific disturbance experiments of four spiders. There were intraspecific disturbances in the predation reactions of spiders, indicating that the predation ratio of spiders decreased in relation to the increase of its density, and with the increase of spider density, the intensity of scrambling competition of the spider increased.

EUGENIA ◽  
2011 ◽  
Vol 17 (3) ◽  
Author(s):  
Christina L. Salaki

ABSTRACT   The research aimed to explore potential entomopathogenic bacteria as biological control agent for insect pest of P. xylostella and Spodoptera sp. in cabbage and broccoli. The indigenous bacteria were explored by taking 103 samples from location around North Sulawesi. Bacteria were selectively isolated by using Ohba and Aizawa method and then identified based on morphology. Subsequently the isolates were screened by their potency to kill test insect of P. xylostella and Spodoptera sp. The isolates were able to kill ≥ 50 % test insect considered  as potential for biological control. The potential isolates were then selected and would be developed  as powder and liquid bio-pesticide through large scale production. The result of the study showed that 145 Bacillus thuringiensis isolates and 202 Bacillus cereus isolates were obtained from 103 samples. The screening of the isolates based on standard test insect for cabbage and broccoli were in progress. The potential isolates would be further selected on the basis of their pathogenicity test. Based on pathogenecity test, chosen isolates will be developed as  bio-pasticide to control insect pest of cabbage and broccoli. Keywords : Exploration, entomopathogenic bacteria, biological control, Plutella xylostella, Spodoptera Sp.


Insects ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 224
Author(s):  
Wang-Peng Shi ◽  
Xiao-Yu Wang ◽  
Yue Yin ◽  
Yu-Xing Zhang ◽  
Um-e-Hani Rizvi ◽  
...  

Substantial harm to ecosystems from the use of chemical pesticides has led to an increasing interest in the use of biopesticides to control grasshoppers in rangelands, including China. One such potential biopesticide for control of grasshoppers is the fungus Paranosema locustae. In this study, the dynamics of aboveground natural enemies of grasshoppers and arthropod diversity 0–9 years after application of P. locustae were investigated in rangeland in Qinghai Plateau, China. We found that the number of species and of individuals of aboveground natural enemies increased by 17–250% and 40–126%, respectively, after spraying P. locustae, and that the main natural enemies showed three peaks after treatment. The conventional indices of species diversity (H’) and evenness (J’) increased by 11–267% and 13–171%, respectively, after treatment with P. locustae. The results showed the positive effects of P. locustae on aboveground natural enemies and biodiversity in an arthropod community in Chinese rangeland. Paranosema locustae is thought to be a safe biological control agent for grasshopper management in Northwestern China.


2008 ◽  
Vol 98 (3) ◽  
pp. 293-302 ◽  
Author(s):  
Z.Q. Yang ◽  
X.Y. Wang ◽  
J.R. Wei ◽  
H.R. Qu ◽  
X.R. Qiao

AbstractThe fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), is an invasive and important pest in China. Investigations on insect natural enemies have been conducted from 1996 to 1999 in five provinces and one municipality of China in order to select effective species for biological control. Two carabid predators (Coleoptera) and 25 parasitoid species were found, among which 23 were parasitic wasps (Hymenoptera), including five hyperparasitic species and two tachinid flies (Diptera). The two carabids preyed on young larvae inside webs, two braconid wasps parasitized larvae, and 18 parasitoid species attacked the fall webworm during the pupal and/or ‘larval-pupal’ stages. Among these parasitoids, there were one genus and nine species that are new to science and four species new to China, which were described and published by the senior author Yang. The average parasitism rates of fall webworm pupae were 25.8% and 16.1% in the overwintering generation and the first generation (summer generation), respectively. These findings reveal that these natural enemies play an important role in the natural control of the pest. Chouioia cunea Yang (Hymenoptera: Eulophidae), a gregarious pupal endo-parasitoid, was recommended as a promising biological control agent against the fall webworm in China.


2017 ◽  
Vol 108 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Q. Li ◽  
S.V. Triapitsyn ◽  
C. Wang ◽  
W. Zhong ◽  
H.-Y. Hu

AbstractThe flee-weevil Orchestes steppensis Korotyaev (Coleoptera: Curculionidae) is a steppe eastern Palaearctic species, notable as a serious pest of elms (Ulmus spp., Ulmaceae), by feeding on the leaves (adults) or mining them heavily (larvae), especially of Ulmus pumila L. in Xinjiang, China. We have corrected the previous misidentifications of this weevil in China as O. alni (L.) or O. mutabilis Boheman and demonstrated that it is likely to be an invasive species in Xinjiang. Prior to this study, natural enemies of O. steppensis were unknown in Xinjiang. Resulting from field investigation and rearing in the laboratory during 2013–2016, seven parasitoid species were found to be primary and solitary, attacking larval and pupal stages of the host weevil. Pteromalus sp. 2 is the dominant species and also is the most competitive among the seven parasitoids, which could considered to be a perspective biological control agent of O. steppensis. Yet, the current control of this pest by the local natural enemies in Xinjiang is still currently inefficient, even though in 2016 parasitism was about 36% on U. pumila in Urumqi, so the potential for a classical biological control program against it needs to be further investigated, including an assessment of its parasitoids and other natural enemies in the native range of O. steppensis. The presented information on the natural enemies of this weevil can be also important for a potential classical biological control program against it in North America (Canada and USA), where it is a highly damaging and rapidly spreading invasive species.


2020 ◽  
Vol 8 (6) ◽  
pp. 730-742
Author(s):  
Manish Dhawan ◽  
◽  
Neelam Joshi ◽  
Samandeep Kaur ◽  
Saroop Sandhu ◽  
...  

Intensive crop production and extensive use of harmful synthetic chemical pesticides create numerous socio-economic problems worldwide. Therefore, sustainable solutions are needed for insect pest control, such as biological control agents. The fungal insect pathogen Beauveria bassiana has shown considerable potential as a biological control agent against a broad range of insects. The insight into the virulence mechanism of B. bassiana is essential to show the robustness of its use. B. bassiana has several determinants of virulence, including the production of cuticle-degrading enzymes (CDEs), such as proteases, chitinases, and lipases. CDEs are essential in the infection process as they hydrolyze the significant components of the insect's cuticle. Moreover, B. bassiana has evolved effective antioxidant mechanisms that include enzyme families that act as reactive oxygen species (ROS) scavengers, e.g., superoxide dismutases, catalases, peroxidases, and thioredoxins. In B. bassiana, the number of CDEs and antioxidant enzymes are characterized in recent years. These enzymes are believed to be crucial player of evolutionary process in this organism and their role in various mechanism of biological control. Recent discoveries have significantly increased our potential understanding on several potentially wanted unknown mechanisms of B. bassiana infection. This review focuses on the progress detailed in the studies of these enzymes and provides an overview of enzymatic activities and their contributions to virulence.


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