Systemic effect of aldicarb,dimethoate and ethiofencarb on mortality and population dynamics of the spirea aphid, Aphis citricola Van der Goot     

Ilan Neubauer  Benjamin Raccah  Nadav Aharonson  Eliahu Swirski  Isaac Ishaaya 《Crop Protection》1983,2(2):211-218

A bioassay using detached citrus leaves, the petioles of which were immersed in solutions containing insecticides, was used to assess the systemic activity of aldicarb, dimethoate and ethiofencarb on the spirea aphid, Aphis citricola Van der Goot (Homoptera: Aphididae). At identical concentrations in the treatment solutions the order of toxicity to insects of these compounds was aldicarb > dimethoate > ethiofencarb. The toxicity of the residue of aldicarb in the leaves (LC₅₀=2·5 μg/g) resembled that of dimethoate (LC₅₀=1·8 μg/g) and both were more potent than ethiofencarb (LC₅₀=30 μg/g). The amount of aldicarb accumulated in the leaves, 3 days after application, was 25±0·5% of that present in the treatment solution, compared with 4±0·4% of dimethoate and 3±0·3% of ethiofencarb. Thus, the more efficient uptake of aldicarb may be the reason for its high toxicity. When sublethal concentrations of aldicarb incorporated in treatment solutions were taken up by detached leaves, a significant reduction in the pre-reproductive development time, and increased longevity and fecundity were observed. This hormoligosis phenomenon was further emphasized by a considerable increase in aphid weight. This effect seems to be plant mediated, as it was not observed when aldicarb was added to a synthetic diet. Dimethoate showed an effect similar to that of aldicarb, but less pronounced and not statistically significant, whereas ethiofencarb had no such effect.  相似文献   

Pyriproxyfen,a novel insect growth regulator for controlling whiteflies: Mechanisms and resistance management     

Isaac Ishaaya  A. Rami Horowitz 《Pest management science》1995,43(3):227-232

Pyriproxyfen, a novel juvenile hormone mimic, is a potent suppressor of embryogenesis and adult formation of the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). Dipping of cotton or tomato seedlings infested with 0 to 1-day-old eggs in 0.1 mg litre^?1 resulted in over 90% suppression of egg hatch of both B. tabaci and T. vaporariorum. Older eggs were affected to a lesser extent. Exposure of whitefly females to cotton or tomato seedlings treated with pyriproxyfen resulted in oviposition of non-viable eggs. The LC90 values for egg viability of B. tabaci and T. vaporariorum exposed to treated plants were 0.05 and 0.2 mg litre^?1, respectively. Treatment of whitefly larvae with 0.04–5 mg litre^?1 resulted in normal development until the pupal stage; however, adult emergence was totally suppressed. Second instars of B. tabaci exposed to 5 mg litre^?1 pyriproxyfen, excreted honeydew at a level similar to the control level until the fourth instar (pupation), after which a strong reduction was observed. Inhibition of egg-hatch on the lower surface of cotton leaves was observed when their upper surface was treated with 1–25 mg litre^?1, indicating a pronounced translaminar effect. These findings indicate that pyriproxyfen is an efficient control agent of both B. tabaci and T. vaporariorum. The compound has been used successfully for controlling whiteflies in Israeli cotton fields since 1991. Adults of B. tabaci collected from a rose greenhouse and from adjacent cotton fields were monitored during 1991–1993 for their susceptibility to pyriproxyfen. A high level of resistance was recorded in whiteflies collected from a greenhouse after three successive applications of pyriproxyfen. Based on LC50 values, the resistance ratio for egg-hatch suppression was 554-fold and, for adult emergence failure, 10-fold. However, a single treatment of pyriproxyfen in cotton fields during the summer season (according to an insecticide resistance management (IRM) strategy) did not alter appreciably the susceptibility of B. tabaci to this compound. In order to prevent development of resistance, an attempt should be made to restrict its use to one treatment per crop season applied during the peak activity of the pest. Pyriproxyfen can be alternated with other novel compounds such as buprofezin and diafenthiuron for controlling whiteflies in cotton, vegetables and ornamentals as part of integrated pest management (IPM) and IRM strategies. In pyriproxyfen- or buprofezin-resistant strains of B. tabaci or T. vaporariorum, no appreciable cross-resistance was observed among pyriproxyfen, buprofezin and diafenthiuron.  相似文献   

Comparative toxicity of chlorfluazuron (IKI-7899) and cypermethrin to Spodoptera littoralis, Lobesia botrana and Drosophila melanogaster     

I. Ishaaya  A. Navon  E. Gurevitz 《Crop Protection》1986,5(6):385-388

Chlorfluazuron sprayed on cotton seedlings was more efficient than cypermethrin against third-instar larvae of the Egyptian cotton leafworm, Spodoptera littoralis. At a concentration of 3·2 x 10⁻⁵% a.i., chlorfluazuron caused 98 ± 2% larval mortality and cypermethrin 35 ± 9%. All larvae in chlorfluazuron assays died during moulting; hence the leaf area consumed during the test instar was not appreciably affected. On the other hand, in cypermethrin assays, larvae died during the intermoult stage. Chlorfluazuron exhibited potency similar to that of cypermethrin on third-instar larvae of the grape berry moth Lobesia botrana, resulting in 90–95% and 33–34% mortality in treatment concentrations of 5 x 10⁻³% and 2 x 10⁻⁴% a.i., respectively. In another grapevine pest, Drosophila melanogaster, cypermethrin suppressed larval and adult formation to a greater extent than chlorfluazuron. The high potency of chlorfluazuron on various insects, together with its low toxicity to man and the environment, renders this compound a potential agent for controlling important agricultural pests.  相似文献   

Iodine test for determining the mortality of the California red scale after treatment with various insecticides     

I. Ishaaya  E. Swirski 《Pest management science》1971,2(1):8-9

An improved iodine test based on the ability of the live scale to react with iodine, yielding reduced iodine products which in turn are unable to give the blue colour reaction with starch, has been used for determining the mortality of the California red scale after treatment with various insecticides. 0.1% monocrotophos, omethoate or methidathion (active material) and 1.4% ethion formulation were found to give good control, while methomyl, mecarbam and azinphos-methyl were less effective. The results obtained by the iodine method resembled those obtained by the visual method, commonly used for determining death in armoured scales.  相似文献   

Triphenyl derivatives of group IV elements as inhibitors of growth and digestive enzymes of Tribolium castaneum larvae     

Isaac Ishaaya  Roy L. Holmstead  John E. Casida 《Pesticide biochemistry and physiology》1977,7(6):573-577

The potency of triphenyl derivatives of group IV elements in inhibiting the growth of first and fourth instar Tribolium castaneum larvae is much greater for Ph₃SnCl and Ph₃PbCl than for Ph₃GeCl, Ph₃SiOH, and Ph₃CCl. Pupated larvae emerge normally, showing that the pupal stage is not affected. The larval growth retardation may result from an antifeeding effect involving digestive enzyme inhibition. Ph₃SnCl and Ph₃PbCl at 500 μmol/kg of diet completely inhibit larval growth (fourth instar larvae) and provide a reduction of 56–59, 29–33, and 2–15% in the in vivo activity of invertase, amylase, and protease, respectively. Under these conditions Ph₃GeCl, Ph₃SiOH, and Ph₃CCl are essentially inactive. High concentrations (5 × 10^?4 and 2 × 10^?3M) of Ph₃SnCl and Ph₃GeCl acting in vitro strongly inhibit invertase, amylase, and protease activities, whereas Ph₃PbCl is moderately inhibitory and Ph₃SiOH and Ph₃CCl are inactive. When both in vivo and in vitro findings are considered, Ph₃SnCl is the most potent inhibitor of larval digestive enzymes.  相似文献   

The toxic effect of diflubenzuron on Spodoptera littoralis eggs and on their respiration     

K. R. Simon Ascher  Nadia E. Nemny  Isaac Ishaaya 《Pest management science》1980,11(1):90-94

The mortality rates of Spodoptera littoralis eggs of different ages when dipped in aqueous dilutions of a liquid diflubenzuron formulation were investigated. Eggs 2-3 days old were less sensitive than younger eggs, 0-1 day old. The respiratory rate of eggs 0-1 day old, 1 or 2 days after treatment, was the same as in the control. Eggs in the control hatched on the next day; on this day, respiration in the treated eggs decreased rapidly, but further decrease was then gradual and the base line was not reached until 11 days after treatment, or 9 days after the maximum respiratory rate had been obtained. The curve with diflubenzuron resembled that obtained with parathion.  相似文献   

The effect of IKI-7899, a new chitin synthesis inhibitor,on larvae ofTribolium castaneum andSpodoptera littoralis     

I. Ishaaya  Nadia E. Nemny  K. R. S. Ascher 《Phytoparasitica》1984,12(3-4):193-197

The effect of IKI-7899 and diflubenzuron on larval development and emergence ofTribolium castaneum and ofSpodoptera littoralis was determined. The LC₅₀ of IKI-7899 at adult emergence ofT. castaneum larvae fed the compound in their diet and the ED₅₀ of S.littoralis larvae treated topically were approximately one-sixth those of diflubenzuron.  相似文献   

Pyrethroid synergism and prevention of emergence inTribolium castaneum andMusca domestica vicina by the insect growth regulator RO 13-5223     

I. Ishaaya  Sara Yablonski  K. R. S. Ascher  J. E. Casida 《Phytoparasitica》1984,12(2):99-108

Ethyl [2-(4-phenoxyphenoxy)ethyl] carbamate (RO 13-5223) at a dietary concentration of 100 mg kg^-1 synergized the toxicity of thetrans- andcis-isomers of permethrin and cypermethrin in inhibiting the growth (measured as gain in larval weight) ofTribolium castaneum andMusca domestica vicina. With both species the synergism factor forcis-cypermethrin with 100 mg kg^-1 synergist was 1.5- to twofold for RO 13-5223 and about fourfold for piperonyl butoxide. Synergism was more pronounced with first instar than with fourth instarT. castaneum larvae. Methoprene was not a pyrethroid synergist withT. castaneum larvae, so the synergistic effect of RO 13-5223 appears to depend on its structural features and not its insect-growth-regulator activity. Joint application of RO 13-5223 and pyrethroids resulted in a dual effect on bothT. castaneum andM. domestica: increased inhibition of larval growth due to pyrethroid synergism, and progeny suppression — expressed by larval and pupal mortality — due to RO 13-5223 juvenilizing activity.  相似文献   

Effect of diflubenzuron on growth and carbohydrate hydrolases ofTribolium castaneum     

I. Ishaaya  K. R. S. Ascher 《Phytoparasitica》1977,5(3):149-158

The potency of diflubenzuron is much greater in inhibiting growth and development of 1st instar larvae ofTribolium castaneum than of 4th instar larvae, as expressed by death at the apolytic stage and retardation of larval development. A dose-dependent decrease in the activity of trehalase, invertase and amylase was obtainedin vivo with the increase in diflubenzuron concentration. At 5 ppm dietary concentration, a reduction of 37 and 27% in invertase and trehalase activity, respectively, was obtained in 4th instar larvae fed for 3 days on treated diet. The amylase activity was affected to a lesser extent. The observed disturbances of trehalase activity might hamper the supply of glucose needed for chitin build-up and those of invertase and amylase activity might affect feeding. Diflubenzuron does not inhibit these enzymesin vitro; hence, thein vivo effect seems to result from general disturbances in carbohydrate metabolism.  相似文献   

Effect of Buprofezin onIcerya Purchasi andPlanococcus Citri     

Z. Mendel  D. Blumberg  I. Ishaaya 《Phytoparasitica》1991,19(2):103-112

The effectiveness of buprofezin (aqueous suspensions from 25% wettable powder) on cumulative nymph mortality and reproduction of two homopterous pests,Icerya purchasi Maskell (Margarodidae) andPlanococcus citri (Risso) (Pseudococcidae), was investigated under laboratory conditions. Buprofezin was very effective against crawlers of both species. Dipping in concentrations of 0.002%, 0.01% and 0.05% (a. i.) resulted in 91–99% nymph mortality ofP. citri, whereas 100% mortality was recorded whenI. purchasi was treated at 0.05% (a. i.); the 3rd-instar nymphs ofI. purchasi were less susceptible to the chemical. Death of the larval stages occurred mainly during the molting process to the 2nd-instar nymphs. At 0.05%, buprofezin sprayed on adults slightly reduced fecundity and decreased egg hatch to 31% forI. purchasi and, depending on the exposure period of the females, to 49-7% forP. citri. Buprofezin at 0.05% exhibited strong ovicidal activity onP. citri, resulting in inhibition of over 80% egg hatch.  相似文献