Field Tests of Bacillus thuringiensis and Chemical Insecticides for Control of Earias insulana on Cotton12

1976 ◽  
Vol 69 (3) ◽  
pp. 343-344 ◽  
Author(s):  
Manzoor Hussain ◽  
Ahmad Askari
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.


1971 ◽  
Vol 64 (6) ◽  
pp. 1421-1422 ◽  
Author(s):  
H. T. Dulmage ◽  
D. A. Wolfenbarger ◽  
M. J. Lukefahr ◽  
J. A. Correa

2006 ◽  
Vol 72 (1) ◽  
pp. 437-442 ◽  
Author(s):  
María A. Ibargutxi ◽  
Anna Estela ◽  
Juan Ferré ◽  
Primitivo Caballero

ABSTRACT Thirteen of the most common lepidopteran-specific Cry proteins of Bacillus thuringiensis have been tested for their efficacy against newly hatched larvae of two populations of the spiny bollworm, Earias insulana. At a concentration of 100 μg of toxin per milliliter of artificial diet, six Cry toxins (Cry1Ca, Cry1Ea, Cry1Fa, Cry1Ja, Cry2Aa, and Cry2Ab) were not toxic at all. Cry1Aa, Cry1Ja, and Cry2Aa did not cause mortality but caused significant inhibition of growth. The other Cry toxins (Cry1Ab, Cry1Ac, Cry1Ba, Cry1Da, Cry1Ia, and Cry9Ca) were toxic to E. insulana larvae. The 50% lethal concentration values of these toxins ranged from 0.39 to 21.13 μg/ml (for Cry9Ca and Cry1Ia, respectively) for an E. insulana laboratory colony originating from Egypt and from 0.20 to 4.25 μg/ml (for Cry9Ca and Cry1Da, respectively) for a laboratory colony originating from Spain. The relative potencies of the toxins in the population from Egypt were highest for Cry9Ca and Cry1Ab, and they were both significantly more toxic than Cry1Ac and Cry1Ba, followed by Cry1Da and finally Cry1Ia. In the population from Spain, Cry9Ca was the most toxic, followed in decreasing order by Cry1Ac and Cry1Ba, and the least toxic was Cry1Da. Binding experiments were performed to test whether the toxic Cry proteins shared binding sites in this insect. 125I-labeled Cry1Ac and Cry1Ab and biotinylated Cry1Ba, Cry1Ia, and Cry9Ca showed specific binding to the brush border membrane vesicles from E. insulana. Competition binding experiments among these toxins showed that only Cry1Ab and Cry1Ac competed for the same binding sites, indicating a high possibility that this insect may develop cross-resistance to Cry1Ab upon exposure to Cry1Ac transgenic cotton but not to the other toxins tested.


1978 ◽  
Vol 54 (6) ◽  
pp. 309-312 ◽  
Author(s):  
W.A. Smirnoff

Action of Bacillus thuringiensis (B.t.) on spruce budworm, Choristoneura fumiferana Clem., was found to be attributable to septicemia with some enterotoxicosis. Development of a compact economical B.t. formulation, with addition of the enzyme chitinase, increased its efficiency by accelerating larval mortality. Between 1971 and 1975 field tests were conducted in balsam fir stands with different levels of insect density to select the best formulation and methods of application and to identify the major influencing environmental variables. Variability in the results prior to 1975 is attributable to difficulties with calibration of spray systems. With accurate calibration in 1976 and 1977, good results in terms of larval mortality and foliage protection were obtained, thus confirming the value of B.t. for control of spruce budworm.


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.


1981 ◽  
Vol 27 (9) ◽  
pp. 952-955
Author(s):  
W. A. Smirnoff

Laboratory and field tests revealed that the addition of Erio acid red XB 400 dye (EAR) to Bacillus thuringiensis formulations inhibited spores of the bacillus. In the laboratory, 74% of the spores present in a suspension containing 16 × 109 viable spores/mL, and 0.25 gm/L of EAR, were inhibited after 28 h. Spore inactivation in a physiological solution containing 1 × 107 viable spores/mL was 75% after the same period of exposure to the same EAR concentration. Field tests showed a reduction in the number of viable spores in a suspension exposed to sunlight; a suspension of 75 000 viable spores/mL yielded 2000 and 400 viable spores/mL after 2 and 4 h of exposure to sunlight, while the same suspension added with 2.5 ppm EAR yielded 1000 and 100 viable spores/mL after the same periods of exposure. The photodynamic action of sunlight on the dye provokes a chemical reaction (oxydation) and the inactivation effect of EAR increases with temperature. Consequently, use of EAR is incompatible with B. thuringiensis formulations and methods used for deposit assessment, based on the use of EAR, should be modified accordingly.


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).


1973 ◽  
Vol 105 (7) ◽  
pp. 941-945 ◽  
Author(s):  
H. H. Cheng

AbstractLaboratory tests were conducted to determine the susceptibility of the various larval stages of Euxoa messoria (Harris) in Ontario to four commercial preparations of Bacillus thuringiensis Berliner: Thuricide® 90TS, Thuricide®-HP, Biotrol® BTB 183, and Dipel. A field test was made to determine whether these preparations could be as effective as Dursban® (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) for control of this species when applied on the rye cover crop in spring.In laboratory tests first to third instar larvae that fed on rye leaves treated with all four B. thuringiensis preparations, were found to be susceptible regardless of the rates applied. Mortality of fourth to seventh instar larvae fed treated tobacco leaves was low. Thuricide 90TS and Biotrol BTB 183 as applied in the field for control of E. messoria populations were relatively ineffective as compared with Dursban.


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