Field Studies on the Effect of Pesticides on the Diamondback Moth (Lepidoptera: Plutellidae) and Parasitism by Diadegma insulare (Hymenoptera: Ichneumonidae)

1993 ◽  
Vol 86 (4) ◽  
pp. 1196-1202 ◽  
Author(s):  
A. B. Idris ◽  
E. Grafius
Keyword(s):  
Diamondback Moth ◽  
Field Studies ◽  
Diadegma Insulare

Influence of Selected Insecticides on the Population Dynamics of Diamondback Moth (Lepidoptera: Plutellidae) and Its Parasitoid, Diadegma insulare (Hymenoptera: Ichneumonidae), in Cabbage

2003 ◽  
Vol 38 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Travis A. Hill ◽  
Rick E. Foster
Keyword(s):  
Population Dynamics ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Diadegma Insulare ◽  
Economic Thresholds ◽  
Percent Parasitism

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.

Parasitism of Diamondback Moth (Lepidoptera: Plutellidae) Larvae by Cotesia plutellae (Hymenoptera: Braconidae) and Diadegma insulare (Hymenoptera: Ichneumonidae) in Cabbage Fields after Inundative Releases of C. plutellae2

1999 ◽  
Vol 34 (1) ◽  
pp. 101-112 ◽  
Author(s):  
E. R. Mitchell ◽  
G. Y. Hu ◽  
J. S. Okine ◽  
J. E. Carpenter
Keyword(s):  
Brassica Oleracea ◽  
Diamondback Moth ◽  
Release Site ◽  
Cotesia Plutellae ◽  
Diadegma Insulare ◽  
Cabbage Plant ◽  
Sentinel Plants ◽  
Release Area ◽  
Total Parasitism ◽  
Inundative Releases

Cocoons of Cotesia plutellae (Kurdjumov) were released for nine consecutive wk along the margins of two commercial cabbage (Brassica oleracea var. bravo L.) fields near Bunnell, Flagler Co., FL, in spring 1996. The larval parasitism of diamondback moth, Plutella xylostella (L.), by C. plutellae and by the native parasitoid Diadegma insulare (Cresson) was evaluated in release fields and in nearby cabbage fields using two methods-sentinel collard (Brassica oleracea var. acephala L.) or sentinel cabbage plants and non-sentinel plants. Total parasitism of diamondback moth larvae on sentinel plants in the release and adjacent fields was 35.7%. There were no significant differences in the level of parasitism by C. plutellae among sentinel plant locations within the release fields. In non-release fields, parasitoids spread as far as 1,500 m from the nearest release site during the release period, but parasitism of larvae on sentinel plants decreased as the distance from the release area increased. Parasitism of diamondback moth larvae by D. insulare was 8.3% in C. plutellae release and adjacent fields, but 14.6% in the nearby fields. Sampling of non-sentinel cabbage plants for diamondback moth larvae demonstrated a total of 37.4% larval parasitism by C. plutellae in the release and adjacent fields, similar to that recorded on sentinel plants. However, C. plutellae were detected only as far as 800 m from the release site on non-sentinel cabbage plants, and total parasitism in the dispersal fields also was very low. Diadegma insulare contributed only 1.1% parasitism of larvae sampled from non-sentinel plants in all cabbage fields. Cotesia plutellae was more effective than D. insulare in attacking diamondback moth larvae in this study where field populations of diamondback moth were low (<0.1 larva per cabbage plant).

Interrelationship of Bacillus thuringiensis Berliner to the Diamondback Moth (Lepidoptera: Noctuidae) and its Primary Parasitoid, Diadegma insulare (Hymenoptera: Ichneumonidae)

1996 ◽  
Vol 31 (4) ◽  
pp. 371-377 ◽  
Author(s):  
S. Ulpah ◽  
L. T. Kok
Keyword(s):  
Bacillus Thuringiensis ◽  
Diamondback Moth ◽  
Parallel Line ◽  
Primary Parasitoid ◽  
Diadegma Insulare ◽  
Significant Difference ◽  
Laboratory Colonies ◽  
The Mean ◽  
Lepidoptera Noctuidae ◽  
Lc50 And Lc90

The interrelationship of Bacillus thuringiensis Berliner var. kurstaki to the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), and its primary parasitoid, Diadegma insulare Cress. (Hymenoptera: Ichneumonidae), was investigated using laboratory colonies of the insects. The differential response of third-instar diamondback moth, parasitized and unparasitized, to B. thuringiensis (Bt), and the ability of D. insulare to oviposit in Bt-stressed hosts were determined. No significant difference (P > 0.05) was found between the mean mortality of parasitized and unparasitized larvae at each of three concentrations (154, 334, and 2,237 IU/ml) of Bt endotoxin. The three concentrations were equivalent to the LC30, LC50, and LC90 of Bt potency based on preliminary tests. Parallel line assay analysis, however, revealed that the linear dose-response regressions of parasitized and unparasitized larvae were highly significant (P = 0.0001). The LC50s of parasitized versus unparasitized larvae were 373 and 175 IU/ml Bt endotoxin, respectively, indicating that parasitized larvae were less susceptible to Bt. Female D. insulare oviposited in Bt-stressed hosts. The percentage of D. insulare females emerging from Bt-treated larvae (41.4%) was not significantly different from that of untreated larvae (32.0%).

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