Bio-efficacy of two bacterial insecticide strains ofBacillus thuringiensis as a biological control agent in comparison with a nematicide, nemacur, on certain parasitic nematoda

AbstractPhymastichus coffea LaSalle (Hymenoptera:Eulophidae) is an adult endoparasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera:Curculionidae:Scolytinae), which has been introduced in many coffee producing countries as a biological control agent. To determine the effectiveness of P. coffea against H. hampei and environmental safety for release in Hawaii, we investigated the host selection and parasitism response of adult females to 43 different species of Coleoptera, including 23 Scolytinae (six Hypothenemus species and 17 others), and four additional Curculionidae. Non-target testing included Hawaiian endemic, exotic and beneficial coleopteran species. Using a no-choice laboratory bioassay, we demonstrated that P. coffea was only able to parasitize the target host H. hampei and four other adventive species of Hypothenemus: H. obscurus, H. seriatus, H. birmanus and H. crudiae. Hypothenemus hampei had the highest parasitism rate and shortest parasitoid development time of the five parasitized Hypothenemus spp. Parasitism and parasitoid emergence decreased with decreasing phylogenetic relatedness of the Hypothenemus spp. to H. hampei, and the most distantly related species, H. eruditus, was not parasitized. These results suggest that the risk of harmful non-target impacts is low because there are no native species of Hypothenemus in Hawaii, and P. coffea could be safely introduced for classical biological control of H. hampei in Hawaii.

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Pathogenicity of Pakistani isolates of Steinernema bifurcatum and S. affine (Rhabditida: Steinernematidae) in management of stored grain pests Lasioderma serricorne and Tribolium castaneum (Coleoptera: Ptinidae, Tenebrionidae)

Egyptian Journal of Biological Pest Control ◽

10.1186/s41938-021-00418-1 ◽

2021 ◽

Vol 31 (1) ◽

Author(s):

Tabassum Ara Khanum ◽

Salma Javed

Keyword(s):

Biological Control ◽

Tribolium Castaneum ◽

Biological Control Agent ◽

Economic Loss ◽

Research Area ◽

Control Agent ◽

Lasioderma Serricorne ◽

Stored Grain ◽

Insect Infestations ◽

Stored Grain Pests

Abstract Background Stored grain products suffer a considerable economic loss due to insect infestations. The resistance of pests to insecticide, and residues on crops are produced by the application of insecticide. Nowadays, incremental necessity has been occurred to find out alternatives to chemicals. As biological control agents, entomopathogenic nematodes (EPNs) attract attention increasingly in the research area recently. Results The aim of the study was to evaluate the pathogenicity of Pakistani isolates Steinernema bifurcatum and S. affine against the stored grain pests, Tribolium castaneum and Lasioderma serricorne, under laboratory conditions. Suspensions of nematodes were applied at 4 different concentrations 0, 50, 100, and 200 IJs/ml and 3 variable temperatures 15, 30, and 45°C. Pathogenicity rate was recorded after 48 h of application. The larval stage is found more susceptible than the adult. At 200 IJs, S. bifurcatum showed high mortality of L. serricorne larva (92%) and T. castaneum larva (93%), whereas S. affine showed 90 and 95% mortality of L. serricorne and T. castaneum larva, respectively, at 200 IJs. The results revealed that both species of EPN were able to control and reproduce on L. serricorne and T. castaneum. Maximum mortality was recorded at 45 °C from S. bifurcatum whereas S. affine at 15 °C. Conclusions Therefore, S. bifurcatum and S. affine could be suggested as a biological control agent for hot and cold climatic zones, respectively.

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Biology of an Adventive Population of the Armored Scale Rhizaspidiotus donacis, a Biological Control Agent of Arundo donax in California

Insects ◽

10.3390/insects12070588 ◽

2021 ◽

Vol 12 (7) ◽

pp. 588

Author(s):

Charles A. Braman ◽

Adam M. Lambert ◽

A. Zeynep Özsoy ◽

Ellen N. Hollstien ◽

Kirsten A. Sheehy ◽

...

Keyword(s):

Biological Control ◽

Biological Control Agent ◽

Control Agent ◽

Arundo Donax ◽

Giant Reed ◽

Aphytis Melinus ◽

Adult Females ◽

Armored Scale ◽

Riparian Systems

Arundo donax (giant reed) is invasive in Mediterranean, sub-, and tropical riparian systems worldwide. The armored scale Rhizaspidiotus donacis is approved for biocontrol in North America, but an adventive population was recently discovered in southern California. We documented this population’s distribution, phylogeny, phenology, potential host spillover to Phragmites spp., and potential for parasitism by a common biocontrol parasitoid of citrus scale. The adventive scale was found within a single watershed and is genetically closest to Iberian scale genotypes. Rhizaspidiotus donacis developed on Phragmites haplotypes but at much lower densities than Arundo. The adventive population is univoltine, producing crawlers from March-June. Aphytis melinus parasitoids exhibited sustained interest in R. donacis during choice and no-choice trials and oviposition resulted in a small second generation. Rhizaspidiotus donacis appears limited in distribution by its univoltinism and sessile adult females. This presents challenges for broad biocontrol implementation but allows for targeted application. The genetic differentiation between imported biocontrol samples and adventive populations presents an opportunity for exploring benefits of hybrids and/or alternative genotypes where establishment has been difficult. While unlikely to occur in situ, spillover to vulnerable endemic Phragmites or deleterious parasitoid effects on scale biocontrol agents warrants consideration when planning use of R. donacis.

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