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1.
Bacillus thuringiensis Berliner (B.t.) preparations were bioassayed against larvae of the European corn borer,Ostrinia nubilalis Hübner, to determine their potency.B.t. serovar 3a3b,kurstaki (Dipel) was more potent thanB.t. serovar 1,thuringiensis (Bactospeine I);B.t. serovar 3a3b,kurstaki (Toarow CT) — in which the spores are inactive; or serovar 7,aizawai (ABG 6104). Another preparation of 3a3b,kurstaki (Bactospeine III), at concentrations of 0.5 and 1% sprayed on leaves of potted sweet corn seedlings and plants in the field, was active against larvae reared on an artificial diet in the laboratory. The pH of the corn leaf surface ranged from 6.9 to 7.5, before and after application. 相似文献
2.
The effectiveness of a commercial preparation ofBacillus thuringiensis Berliner (Dipel) against eggs and larvae ofBoarmia (Ascotis) selenaria Schiff. of different age was examined in laboratory and in field tests. The mortality rate ofB. selenaria was proportional to the concentration ofB. thuringiensis and inversely related to the age of the treated larvae. In neonate larvae, 100% mortality was obtained even with a low concentration (0.5%). Egg hatch was not affected, but the survival rate of larvae hatched from treated eggs was very low (2.2%). No phytotoxicity of the commercial microbial preparation was observed on fruit or leaves of avocado. High doses ofB. thuringiensis persisted on avocados, probably because of specific conditions:i.e., absence of rainfall, moderate temperatures and limited penetration of sunlight. Tests carried out in large commercial orchards, using motor-guns and helicopters, yielded good results. 相似文献
3.
In the laboratory, low concentrations of Bacillus thuringiensis Berliner (B.t.), as ‘Dipel’ 2X applied (at about the LC5) to cotton leaves enhanced the activity of endosulfan and reduced resistance to endosulfan from approximately seven fold to two fold in neonate larvae of Helicoverpa armigera (Hubner). Low (LC5) concentrations of endosulfan also increased the toxicity of B.t. Both endo-sulfan and B.t. increased the toxicity of the stomach poison cryolite to H. armigera. This increased toxicity was not observed where B.t./endosulfan combinations were applied topically to larvae or where B.t. was combined with organophosphorus or pyrethroid insecticides which are considered primarily to be contact toxicants. Mixtures of B.t. and endosulfan applied at equitoxic concentrations were less toxic than similar concentrations applied alone. 相似文献
4.
CME 134, a new benzoylphenyl urea chitin synthesis inhibitor, was less active than diflubenzuron and BAY SIR 8514, when tested againstSpodoptera littoralis eggs by a dipping method. AgainstS. littoralis larvae the compound was tested by feeding treated alfalfa, topical application and contact with crystalline residues on glass, followed by observation until the adult stage. With both 200–250 and 360–440-mg larvae 100% mortality was obtained by one-day feeding of alfalfa treated with 0.15 ppm a.i. Topical application to 100- and 200-mg larvae showed CME 134 to be about five and nine times more active than BAY SIR 8514 and diflubenzuron, respectively. These differences were even much greater in the contact tests. Cotton field plots were sprayed with either CME 134 or diflubenzuron formulations, leaves were collected at different intervals and fed for one day toS. littoralis larvae in the laboratory. 0.0009% a.i. CME 134 residues gave complete kill of 30–50-mg larvae after 5 and 20 days, and 86% kill after 28 days of aging. With 0.003 and 0.009% a.i., complete kill was obtained in 200–250-mg larvae until 50 days after spraying. 相似文献
5.
The effect of azadirachtin and salannin, two triterpenoids isolated from seeds of neem (Azadirachta indica A. Juss), on the feeding response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae, was investigated. Styropor (foamed polystyrene) lamellae were painted on both sides with a mixture of 5% sucrose with different concentrations of either azadirachtin or salannin dissoled in methanol-water (3∶7). Azadirachtin strongly suppressed feeding inS. littoralis larvae even at 0.001%, whereas salannin showed some antifeedant activity at 0.005% and above. Larvae ofE. insulana were deterred from feeding on azadirachtin-treated lamellae even at 0.005%, whereas salannin was effective only at 0.01% and above. Azadirachtin applied on cotton leaves deterred larvae ofS. littoralis from feeding at all concentrations ranging between 0.001 and 0.02%. 相似文献
6.
K. R. Simon Ascher Manes Wysoki Nadia E. Nemny Leah Gur-Telzak 《Pest management science》1978,9(3):219-224
Small (70 mg) Boarmia selenaria larvae fed for 4 days on avocado leaves or alfalfa dipped in aqueous diflubenzuron suspensions suffered from severe developmental disturbances. Similar results were obtained with leaves sprayed in an avocado orchard, with which, in addition, the considerable persistence of diflubenzuron under field conditions could be demonstrated. The substance was also active by topical application against large (500–600 mg) B. selenaria larvae, whereas by contact it was only moderately toxic. Some other non-conventional control agents, viz., the antifeedant AC-24055 and several juvenile hormone analogues, were of medium and negligible activity, respectively, against this insect. 相似文献
7.
Synergism of mixtures of pyrethroids with organophosphorus (OP) compounds in insects is reviewed, and the toxicity of such combinations againstSpodoptera littoralis (Boisd.) larvae is reported. Mixtures of one of the pyrethroids cypermethrin, fenvalerate or deltamethrin with one of the OP compounds monocrotophos, profenofos, azinphos-methyl or acephate were assayed at different ratios as 24-h-old dipping residues on alfalfa, which was fed toS. littoralis larvae for 48 h. With most of the binary mixtures containing various OP concentrations in excess of those of the pyrethroids, synergism was demonstrated. In the pairs fenvalerate — azinphos-methyl, deltamethrin — azinphos-methyl and deltamethrin — profenofos, however, no synergism was found. In a detailed investigation with pyrethroid concentrations causing 20% mortality and OP concentrations giving a kill of no higher than ;10%, the above findings on synergism were amply confirmed. A cypermethrinmonocrotophos mixture showed synergism also on cotton leaves sprayed in the field. Synergism could not be demonstrated by topical application of pyrethroid — OP mixtures. 相似文献
8.
为明确黑龙江省乔灌木树种对美国白蛾的适生性, 本试验选取水曲柳、白桦、榆叶梅3种林木的叶片于室内饲养美国白蛾4~6龄幼虫, 研究幼虫取食量及生长发育情况。结果表明:取食3种林木叶片的美国白蛾4龄幼虫累计死亡率差异不显著(P>0.05), 5、6龄幼虫累计死亡率由高到低为榆叶梅>白桦、水曲柳(P<0.05); 取食榆叶梅叶片的美国白蛾幼虫发育到6龄时全部死亡, 而取食水曲柳、白桦叶片的幼虫能完成生活史。美国白蛾4龄幼虫取食量由大到小为水曲柳>白桦、榆叶梅(P<0.05), 5龄的为水曲柳>白桦>榆叶梅(P<0.05), 6龄的为水曲柳>白桦(P<0.05)。美国白蛾4、5龄幼虫龄期长短顺序为榆叶梅、白桦>水曲柳(P<0.05), 取食水曲柳和白桦的美国白蛾6龄幼虫龄期长短差异不显著(P>0.05); 成虫期长短顺序为水曲柳>白桦(P<0.05), 而幼虫期和蛹期长短顺序与成虫期相比正相反(P<0.05)。取食水曲柳、白桦叶片的美国白蛾化蛹率、羽化率、产卵量及幼虫生长指数、蛹生长指数差异均不显著(P>0.05)。说明水曲柳和白桦为美国白蛾潜在适生寄主, 榆叶梅不适合其生长; 与白桦相比, 美国白蛾更喜欢取食水曲柳叶片, 且成虫寿命更长。这为预防美国白蛾传入定殖潜在适生树种、有针对性地采取措施保护黑龙江省林木提供理论依据。 相似文献
9.
In both laboratory and field trials, as well as in semicommercial scale applications, the minimum concentration ofBacillus thuringiensis (B.t.) required to secure satisfactory larval mortality ofBoarmia selenaria could be halved, from 0.5% to 0.25%, by addition of 1% of the commercial phagostimulant Coax. Another phagostimulant product, Gustol, was inactive. Coax did not attract caterpillars from a distance. However, individual, Coax-treated spots on the avocado leaf surface were consumed by the larvae to a significantly greater extent than control. The same difference in palatability was recorded when the spots were treated with a mixture of Coax and aB.t. formulation. This explains, at least partially, the aforementioned advantageous effect of Coax in practical control of the looper byB.t. 相似文献
10.
Uwe Pluschkell A. Rami Horowitz Phyllis G. Weintraub Isaac Ishaaya 《Pest management science》1998,54(2):85-90
The effects of DPX-MP062 [methyl 7-chloro-2,3,4a,5-tetrahydro-2-[methoxycarbonyl(4-trifluoromethoxyphenyl)carbamoyl] indeno[1,2-e][1,3,4] oxadiazine-4a-carboxylate] a broad-spectrum insecticide with a novel mode of action, on the Egyptian cotton leafworm, Spodoptera littoralis, were studied in laboratory experiments. Egg hatch was affected by high concentrations (125 mg AI litre-1) of DPX-MP062. Larvae that hatched from treated eggs were significantly affected at concentrations of 12·5 mg AI litre-1 and greater. Larvae were fed castor bean leaves treated with DPX-MP062; 1st-instar larvae were the most susceptible development stage. Pupation and adult formation were determined in assays with 5th-instar larvae. There was strong suppression of adult formation; 65 and 91% at 0·5 and 0·75 mg AI litre-1, respectively. Highly affected larvae died before pupation; slightly affected ones reached pupation 2–4 days later, were smaller than larvae in the untreated control, and were sometimes unable to develop into normal adults. Comparatively high concentrations (50 and 100 mg AI litre-1) of the test compound were necessary to affect adults by ingestion, but no effects from contact application could be determined at a concentration of 100 mg AI litre-1. © 1998 Society of Chemical Industry 相似文献
11.
The effect of Neem on the development ofBoarmia (Ascotis) selenaria Schiff. was investigated. Young leaves of avocado were treated in the laboratory with varying concentrations of Neem seed kernel suspensions or with emulsions of some Neem oil products, and offered to larvae of different size. Furthermore, avocado plants in flower pots were sprayed with Neem suspensions and the residues allowed to age in different locations. Leaves from the different treatments were offered to larvae of various sizes in laboratory tests and the larval weight, pupation rate and mortality were recorded. 0.3% Neem was highly effective on laboratory-treated leaves. A negative correlation was found between the concentration of the Neem suspensions on the one hand and the rate of growth and pupation on the other hand. No activity was found with the emulsion of either Neem extractive or Neem oil obtained from Neem kernels after extraction. In larvae kept for four days on avocado leaves treated with 0.3% Neem suspension, the growth and pupation rate was nearly as low as in larvae fed on treated leaves throughout their life span. The experiment with Neem-sprayed plants kept at different locations indicated the following order of activity of the residues: laboratory ? shade > sun. 相似文献
12.
The residual effect of a dried methanolic extract of neem (Azadirachta indica A. Juss) seed kernels was investigated with larvae of the Egyptian cotton leafworm,Spodoptera littoralis (Boisd.), in field trials. Fodder beet was sprayed with 1% emulsions of the extract. The treated leaves were collected from the field 1, 3, 5 and 9 days after spraying and offered to the larvae for 48 h. Survival and mean weight of the larvae were recorded 2, 4, 6, 9 and 11 days from the start of exposure to the residues, and rate of pupation was calculated. The extract had a strong antifeedant effect and an intense insect growth-regulating (IGR) effect in field-treated leaves, especially with the 1- and 3-day-old residues. A positive correlation was found between the age of the residues and the mean percent of live larvae, larval weight and pupation rate of the larvae. 相似文献
13.
The efficacy of the commercial product Dipel 2X (Bacillus thuringiensis var.kurstaki), was assessed as a biological control means of the cotton leaf wormSpodoptera littoralis attacking clover cultivations (Trifolium alexandrinum) in Egypt. Field experiments using the biological agent were carried out in two localities as compared with the conventional chemical insecticide lannate. The percentage of reduction in the larval population increased at higher doses ofB. t. and the infestation levels reached very low levels, almost similar to those obtained after using lannate. The yield of the first cut of clover was estimated. The data obtained indicate that the yield significantly increased after treatment with eitherB. t. or lannate. In Menoufia, the yield was significantly higher after two successive spray applications withB. t. at 750 g/f compared to that obtained withB. t. when used at 500 g/f. In Giza Governorate, the yield was slightly higher after a single treatment withB. t. at 500 g/f as compared with lannate. 相似文献
14.
The efficacy of the commercial product Dipel 2X (Bacillus thuringiensis var.kurstaki), was assessed as a biological control means of the cotton leaf wormSpodoptera littoralis attacking clover cultivations (Trifolium alexandrinum) in Egypt. Field experiments using the biological agent were carried out in two localities as compared with the conventional
chemical insecticide lannate. The percentage of reduction in the larval population increased at higher doses ofB. t. and the infestation levels reached very low levels, almost similar to those obtained after using lannate.
The yield of the first cut of clover was estimated. The data obtained indicate that the yield significantly increased after
treatment with eitherB. t. or lannate. In Menoufia, the yield was significantly higher after two successive spray applications withB. t. at 750 g/f compared to that obtained withB. t. when used at 500 g/f. In Giza Governorate, the yield was slightly higher after a single treatment withB. t. at 500 g/f as compared with lannate. 相似文献
15.
Fentin acetate (FA) at effective antifeedant concentrations does not have a high, immediate toxicity for 170–190 mg larvae of the Egyptian cotton leafworm (Spodoptera littoralis); the mortality of such larvae exposed to FA residues on leaves is not appreciably higher than that of larvae being starved. The antifeedant effect of FA is also not due to an influence on sensory receptors on the mouth parts. Protease and amylase are inhibited in vivo in larvae feeding on FA-treated leaves; the enzyme inhibition increases with the concentrations of the leaf-dipping suspensions. At 0.05% FA, protease and amylase activity was only about 20 and 30%, respectively, of that of the control larvae and was lower than in starved larvae.Antifeeding and enzymatic inhibition are also obtained by injecting FA into the haemocoel, results which indicate that FA does not inhibit the digestive enzymes directly, but seems to affect the enzyme production in the gut. This interpretation is strengthened by the finding that the addition of massive amounts of FA to the enzyme reaction mixture does not affect the enzyme activity. 相似文献
16.
利用室内饲喂法,以抗Cry1Ac近等基因系棉铃虫为材料,比较转基因棉花33B和SGK321及其对照亲本DP5415和石远321对抗、感棉铃虫生长发育的影响。结果表明,抗性棉铃虫在取食常规棉叶后表现出一定的适合度代价。取食DP5415和石远321两种常规棉花后,抗性品系棉铃虫的幼虫存活率显著低于敏感品系,取食33B和SGK321两种转基因棉花的抗性棉铃虫,不仅其幼虫存活率显著高于敏感品系,而且致死中时间也比敏感品系延长。取食9天后,抗性品系在常规棉花石远321和DP5415上发育到3龄和4龄幼虫的比例显著低于敏感品系,取食33B和SGK321转基因棉花的抗性品系发育到3龄幼虫的比例均显著高于敏感品系。抗性品系在常规棉上的蛹重均显著低于敏感品系,部分取食转基因棉花的抗性品系棉铃虫可以化蛹,而敏感品系不能在转基因棉花上化蛹。 相似文献
17.
F. Mansour 《Phytoparasitica》1987,15(1):31-41
Densities of spiders in sprayed and unsprayed cotton fields were determined during 1981 and 1982. Eighteen families were found in an unsprayed field and 13 in sprayed fields. Species of Clubionidae, Gnaphosidae and Philodromidae comprised more than half of the total number collected. The mean weekly number of spiders per meter of cotton row was 9.1 in the unsprayed field and 5.1–5.6 in sprayed fields. Spider populations fluctuated similarly in sprayed fields in both observation years, with only one peak in July, whereas there were two peaks in the unsprayed field. Spiders played an important role in suppressing pest populations and in delaying pest outbreaks early in the cotton growing season. Thus, early pesticide applications to cotton fields are unnecessary. In a biocontrol experiment, spiders suppressed larvae of the Egyptian cotton leaf worm,Spodoptera littoralis (Boisd.), thereby reducing damage to cotton leaves. 相似文献
18.
The chitin biosynthesis inhibitor diflubenzuron and its analog BAY SIR 8514 are equitoxic for eggs ofSpodoptera littoralis. BAY SIR 8514 residues on alfalfa fed toSpodoptera larvae were more toxic than diflubenzuron residues, whereas BAY SIR 8514 topically applied to these larvae was consistently twice as toxic as diflubenzuron, according to different criteria. 相似文献
19.
A. Ben-Aziz J. Meisner N. Aharonson K.R.S. Ascher 《Pesticide biochemistry and physiology》1976,6(1):58-64
The ingestion and excretion of sublethal doses of phosfolan, monocrotophos, parathion, and leptophos were studied in larvae of the Egyptian cotton leafworm, Spodoptera littoralis Boisd. Styropor (foamed polystyrene) lamellae treated with insecticide-sucrose mixtures were fed to the larvae and recovery of the undecomposed insecticides from the feces could be estimated by gas-liquid chromatography, without any cleanup of the sample. The insecticidal residues on Styropor were found to be stable for 5 days.As regards the percentage of insecticide recovered from the feces, two groups could be distinguished: (a) leptophos, practically complete; parathion, 59–67%; b) phosfolan, 10–23%; monocrotophos, 4–7%. A tentative hypothesis was advanced that both oral toxicity of the four compounds for S. littoralis larvae and their subsequent recovery in the feces were related to water solubility. 相似文献
20.
The value of high gossypol characters of cotton strains, in comparison with the glandless strain Acala 63–74 and the commercial cv. Acala SJ2, in suppressingSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) populations, was demonstrated in unsprayed fields in two regions of Israel. The same held true forE. insulana in sprayed plots. 相似文献