THE INFLUENCE OF SOME FUNGICIDES ON THE EFFECTIVENESS OF SPRAYS OF BACILLUS THURINGIENSIS BERLINER

1963 ◽  
Vol 43 (3) ◽  
pp. 301-306 ◽  
Author(s):  
R. P. Jaques

The effect of five common orchard fungicides, captan, dodine, dichlone, glyodin, and a mercuric acetate eradicant, on the activity of a wettable powder preparation of spores of Bacillus thuringiensis Berliner was studied in the laboratory, orchard, and field, using pests of apple and cabbage as test insects. Glyodin was the only one of the fungicides tested in the laboratory that significantly reduced the activity of the spores against larvae of the eastern tent caterpillar, Malacosoma americanum (Fabricius), and the winter moth, Operophthera brumata (Linnaeus). In the orchard and field tests the combining of glyodin or dodine with sprays of the spores reduced mortality of larvae of the winter moth, the imported cabbageworm, Pieris rapae (Linnaeus), and the diamondback moth, Plutella maculipennis (Curtis).

1961 ◽  
Vol 41 (2) ◽  
pp. 428-430 ◽  
Author(s):  
C. J. S. Fox ◽  
R. P. Jaques

At Kentville, Nova Scotia, during 1960, seven spray schedules including a commercial preparation of Bacillus thuringiensis Berliner and DDT were evaluated in the field for control of the imported cabbageworm, Pieris rapae (L.), and larvae of the diamondback moth, Plutella maculipennis (Curt.). Up to three spray treatments were applied at 2-week intervals. Three applications of B. thuringiensis or one application of DDT followed by two of B. thuringiensis gave good control of both insects. In general, DDT and B. thuringiensis were equally effective against imported cabbageworm but DDT was more effective against larvae of the diamondback moth.


1965 ◽  
Vol 97 (8) ◽  
pp. 795-802 ◽  
Author(s):  
R. P. Jaques

AbstractPlots in a bearing apple orchard were sprayed with formulations of Bacillus thuringiensis Berliner on five to seven occasions in each of four consecutive seasons. Larvae of the winter moth, eye-spotted bud moth, orchard tent caterpillar, and fall webworm were less numerous on foliage in plots treated with B. thuringiensis than in the check plot. Numbers of free-living blister mites were reduced by treatment with the bacterium. Other phytophagous mites were not numerous in any of the plots. Injury to fruit by larvae of the codling moth, winter moth, and eye-spotted bud moth and by the mirid Atractotomus mali (Meyer) was lower in plots treated with the bacterium. Only three taxa of predacious arthropods were consistently affected by the application of B. thuringiensis; one was less numerous where the bacterium was applied and two were more numerous.


1982 ◽  
Vol 114 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Stephen P. Wraight ◽  
Daniel Molloy ◽  
Patricia McCoy

AbstractBacillus thuringiensis var. israelensis (serotype H-14) and B. sphaericus strain 1593 were tested against Aedes stimulons larvae in the laboratory and in 38-cm-diam, open-ended cylinders embedded in the bottom detritus of a woodland pool. Estimates of LC50 were lower against fourth instars in the field at a mean temperature of 15.9 °C than in the laboratory at 21.1 °C. The greater efficacy in the field was attributed to high daytime water temperatures (mean 20.5 °C) following treatment and exposure of the larvae to substantially greater amounts of toxic material in a larger volume of water than in the laboratory. The regression of probit on log10 concentration was not linear over the entire range of mortality caused by B. sphaericus, increasing the difficulty of estimation of LC values. Bacillus sphaericus was significantly less active than B. thuringiensis.


2003 ◽  
Vol 135 (3) ◽  
pp. 359-378 ◽  
Author(s):  
Melanie J. Filotas ◽  
Ann E. Hajek ◽  
Richard A. Humber

AbstractFuria gastropachaecomb. nov. (= Furia crustosa MacLeod et Tyrrell) has long been associated with declines in populations of the forest tent caterpillar, Malacosoma disstria Hübner; however, its prevalence and impact on host populations have never been documented. We clarify the nomenclature for this species, which has previously been called F. crustosa, and describe the morphology of F. gastropachae isolates from Maryland and New York. Epizootics of F. gastropachae were studied in M. disstria populations in New York and Maryland, United States of America. Prevalence (mean ± SE) of F. gastropachae in late fifth instar larvae in New York was 25.6 ± 7.8% compared with 22.2 ± 11.3% infection by virus and 23.3 ± 8.4% parasitism. In Maryland, F. gastropachae was not found in early instars and its incidence in fourth and fifth instars was 14.5 ± 7.3 and 21.6 ± 17.6%, respectively. Dipteran parasitoids were also important natural enemies with 38.3 ± 3.0 and 17.9 ± 1.4% parasitism in fourth and fifth instars, respectively. Virus was found in fewer than 5% of larvae collected. Furia gastropachae showed a marked tendency toward resting spore production in infected larvae, with 100% of larvae collected in New York and >80% of larvae collected in Maryland producing resting spores, either alone or in combination with conidia. The appearance of cadavers of larvae dying from fungal and viral infections was similar. Of 13 species of Lepidoptera exposed to F. gastropachae conidia in host-range bioassays, only 3.3% of Danaus plexippus (L.) (Lepidoptera: Danaidae), 5.6% of Pieris rapae (L.) (Lepidoptera: Pieridae), and 3.7% of Manduca sexta (L.) (Lepidoptera: Sphingidae) were successfully infected by this fungus.


1993 ◽  
Vol 71 (8) ◽  
pp. 1511-1515 ◽  
Author(s):  
T. D. Fitzgerald ◽  
F. X. Webster

Behavioral assays show that the steroid 5β-cholestan-3-one, isolated from the abdomen of the larva of the forest tent caterpillar (Malacosoma disstria), constitutes the chemical basis of trail following in this insect. Caterpillars follow artificial trails prepared from solvent dilutions of the compound at rates as low as 10−11 g∙mm−11 of trail, though the true threshold sensitivity is likely to be one or two orders of magnitude lower than this. Fourth-instar caterpillars store an average of 58 ng of the pheromone. Field and laboratory studies indicate that the compound is fully competitive with their authentic trails. The caterpillars are highly sensitive to differences in the concentration of the pheromone, preferring stronger trails to weaker trails. The caterpillars also respond to 5β-cholestane-3,24-dione, a chemical not found in M. disstria but known to be a component of the trail pheromone of the eastern tent caterpillar, Malacosoma americanum.


Sign in / Sign up

Export Citation Format

Share Document