Phylogenetic placement and evidence for horizontal transfer of Wolbachia in Plutella xylostella (Lepidoptera: Plutellidae) and its parasitoid, Diadegma insulare (Hymenoptera: Ichneumonidae)

2010 ◽  
Vol 142 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Philip D. Batista ◽  
B. Andrew Keddie ◽  
Lloyd M. Dosdall ◽  
Harriet L. Harris

AbstractThe diamondback moth, Plutella xylostella (L.), is a global pest of cruciferous crops (Brassicaceae). It has developed resistance to virtually all known insecticides, and biological control has become an important management tool. In North America the parasitoid Diadegma insulare (Cresson) has been used successfully to reduce diamondback moth populations. We document the presence of the α-proteobacterial endosymbiont Wolbachia and its associated bacteriophage WO in P. xylostella and D. insulare and examine the phylogenetic relationships of Wolbachia and WO in both host species. Our results suggest that Wolbachia and WO have been horizontally transferred in this insect–parasitoid system in recent evolutionary history. Knowledge of the dynamics of Wolbachia in P. xylostella and D. insulare may be an important factor in future control of this pest in the field.

2004 ◽  
Vol 94 (6) ◽  
pp. 509-516 ◽  
Author(s):  
Jian-hua Lu ◽  
Shu-sheng Liu ◽  
A.M. Shelton

AbstractThe term ‘dead-end trap cropping’ has recently been proposed to identify a plant that is highly attractive for oviposition by an insect pest, but on which offspring of the pest cannot survive. The potential of the wild crucifer Barbarea vulgaris R. Br. to allure and serve as a dead-end trap crop for the diamondback moth Plutella xylostella (L.), an important pest of cruciferous crops worldwide, was examined in laboratory experiments. When P. xylostella adults were provided with a dual-choice of plants of B. vulgaris, and Chinese cabbage Brassica campestris (L.), in one arena, adult moths laid 2.5–6.8 times more eggs on the former than on the latter. When P. xylostella adults were provided with a dual-choice of plants of B. vulgaris and common cabbage Brassica oleracea L., adult moths laid virtually all their eggs on the former and ignored the latter. Nearly all P. xylostella eggs laid on the three species of plants hatched successfully, but nearly all individuals on plants of B. vulgaris died as neonates or early instar larvae, while 87–100% of the larvae on Chinese cabbage and common cabbage survived to pupation. Dual choice tests with a Y-tube olfactometer showed that volatiles from B. vulgaris were much more attractive to P. xylostella adults than those from common cabbage. The results demonstrate that B. vulgaris has a great potential as a dead-end trap crop for improving management of P. xylostella. Factors that may influence the feasibility of using B. vulgaris as a trap crop in the field are discussed, and ways to utilize this plant are proposed.


2003 ◽  
Vol 38 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Travis A. Hill ◽  
Rick E. Foster

The effects of insecticides on the diamondback moth, Plutella xylostella (L)., and its parasitoid, Diadegma insulare (Cresson), were evaluated in the field. Insecticides applied for control of the diamondback moth caused variations in parasitism by D. insulare ranging from 20 to 84%. Permethrin applications were effective at controlling diamondback moth. Applications of spinosad also resulted in low diamondback moth populations; however, percent parasitism was higher than in untreated plots and over 4× higher than in plots treated with permethrin. Selective materials that conserve D. insulare populations and maintain diamondback moth populations below economic thresholds may reduce the frequency of application, thus prolonging the efficacy of these materials.


2019 ◽  
Vol 21 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Marie-Louise Rugholm Simonsen ◽  
Annie Enkegaard ◽  
Camilla Nordborg Bang ◽  
Lene Sigsgaard

Laboratory experimentswere performed with adult female Anthocoris nemorum (Linnaeus) (Heteroptera: Anthocoridae) at 20°C ± 1°C, L16:D8, 60–70% RH to determine voracity and preference on cabbage aphids (Brevicoryne brassicae L.) (Hemiptera: Aphididae), diamondback moth larvae (Plutella xylostella L.) (Lepidoptera: Plutellidae) and Western flower thrips (Frankliniella occidentalis Pergande) (Thysanoptera: Thripidae) (model species for cabbage thrips (Thrips angusticeps Uzel) (Thysanoptera: Thripidae)). When offered individually, A. nemorum readily accepted all three species with no significant differences in consumption. When aphids and moth larvae were offered simultaneously, A. nemorum showed preference for the latter (numbers eaten and biomass consumed). When aphids and thrips were offered together, A. nemorum preferred thrips in terms of numbers eaten but preferred aphids in terms of biomass consumed. The results showed that A. nemorum is a voracious predator of B. brassicae, P. xylostella and F. occidentalis and can therefore be considered as a potential candidate for biological control in cabbage.


2013 ◽  
Vol 127 (3) ◽  
pp. 211 ◽  
Author(s):  
Adamo Young

Parasitism levels by Diadegma insulare (Muesebeck) (Hymenoptera: Ichneumonidae) and Microplitis plutellae (Haliday) (Hymenoptera: Braconidae) at various densities of their host, Plutella xylostella (L.) (Lepidoptera: Plutellidae), were assessed. Cages with densities of 10 hosts, 20 hosts, and 40 hosts were set up, with the cage volume (40 500 cm3) and number of wasps (2 females) remaining constant. The host populations were also exposed to the wasps for two different exposure times: 1 day and 3 days. The study showed that D. insulare was a better parasitoid overall, achieving a level of parasitism equal to or higher than M. plutellae at all densities. Microplitis plutellae performed best at a lower host density (76% ± 9% of 10 hosts vs. 43% ± 3% of 40 hosts). Diadegma insulare performed similarly at all densities tested (75% ± 5% of 10 hosts, 83% ± 4% of 20 hosts, and 79% ± 6% of 40 hosts). This suggests that D. insulare may be the better parasitoid overall and should be applied in severe, large-scale infestations, while M. plutellae may be better for small-scale infestations.


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