Stage-specific antibody response of Mastomys natalensis during the course of Dipetalonema viteae infection

Stage-specific haemagglutinating (HA) and precipitin antibodies (PA) to infective larvae (L3), adult worms and microfilariae (mf) have been demonstrated in sera of Mastomys natalensis during the course of Dipetalonema viteae infection using indirect haemagglutination (IHA) and Ouchterlony's gel-diffusion tests. L3-specific HA antibody titre was shown to be quite low and lasted for shorter period whereas adult-specific antibody response was significantly higher and persisted for longer duration (beyond day 240 post exposure). No precipitin antibody to L3 stage could be detected, however, significant adult-specific antibody was detected which ultimately tapered off by day 210 post exposure (p.e.). In contrast, mf-specific PA which appeared at the beginning of patency, never disappeared even at the late stage of infection. Mf-specific HA antibody appeared at early incubation period (day 15 p.e.) and after exhibiting two peaks, one in the midst of prepatent period (day 30 p.e.) and the other on day 180 p.e. persisted at low level during the late stage of infection when amicrofilaraemia developed.     

Effect of T-activin on the course of experimental infection with Taenia crassiceps (Zeder, 1800) in mice

T-activin--an immunomodulating preparation of polypeptidic character prepared from calf thymus--was used for influencing the course of infection in a model system mouse-Taenia crassiceps. A single s.c. application of 100 micrograms of T-activin at various intervals before and after infection resulted in a marked decrease in the number of cysticerci in peritoneal cavities of experimental mice (by 47.1-93.6%) compared to the controls. After s.c. application of T-activin and i.p. injection of antigen (crude T. crassiceps larvae homogenate from mice) the decrease in the cystricercus number was still more pronounced than in the mouse groups receiving only T-activin or homogenate (by 76.9% in comparison with 65.5% and 17.0%, respectively). A combination of T-activin with crude T. crassiceps homogenate from rats did not produce the same effect in experimental mice. The protective effect of individual combinations of T-activin with the homogenate does not correlate with the antibody level in the serum of infected mice.     

斜纹夜蛾核型多角体病毒与赤眼蜂联用对斜纹夜蛾的室内防治效果

为探索斜纹夜蛾卵及幼虫的长效控制方法,本文探讨了斜纹夜蛾核型多角体病毒（SpltNPV-KY）与松毛虫赤眼蜂和螟黄赤眼蜂联用对斜纹夜蛾卵和幼虫的防治效果,并评估了核型多角体病毒对赤眼蜂的安全性。结果显示,SpltNPV-KY分别与松毛虫赤眼蜂和螟黄赤眼蜂联用处理斜纹夜蛾卵后,卵孵化率比用5%甲醛溶液处理分别降低了46.80百分点和40.80百分点。SpltNPV-KY单独处理对斜纹夜蛾卵的孵化率无明显影响,但对幼虫死亡率及正常发育至成虫的概率有显著的影响。SpltNPV-KY单独处理,或与赤眼蜂联用时幼虫的校正致死率均大于60%,卵和幼虫的总死亡率均大于80%;SpltNPV-KY分别与松毛虫赤眼蜂、螟黄赤眼蜂联用对赤眼蜂的寄生率和出蜂率均无明显影响,SpltNPV-KY对斜纹夜蛾的总致死率分别比单独用赤眼蜂处理高10.80百分点和10.00百分点。研究表明,松毛虫赤眼蜂、螟黄赤眼蜂与核型多角体病毒联用对斜纹夜蛾卵和幼虫均有良好的防治效果,且SpltNPV-KY对赤眼蜂无不良影响。本研究对斜纹夜蛾卵-幼虫期防治具有一定的指导意义。     

Adrenalectomy and the adaptive liver response in mirex-treated rats

Mirex, an organochlorine compound, was administered as a single oral dose (100 mg/kg body wt) to both intact and adrenalectomized juvenile male Sprague-Dawley rats. Both mirex-treated intact and adrenalectomized animals (dosed 24 hr postsurgery) exhibited significant increases in liver weight to body weight ratios compared to controls. However, the liver weight to body weight ratios in mirex-treated intact animals were significantly greater than those observed in mirextreated adrenalectomized animals. Significant increases were observed in liver weight to body weight ratios in adrenalectomized animals treated with mirex 4 days after surgery. However, the 96-hr mortality in mirex-treated adrenalectomized animals increased from 20% (mirex dose given 1 day postadrenalectomy) to 56% (mirex dose given 4 days postadrenalectomy). Mirex treatment of intact and adrenalectomized animals had no significant effect upon either serum or hepatic activities of glutamic oxalacetic transminase, glutamic pyruvic transaminase, sorbitol dehydrogenase, or protein concentrations. Bromsulfophthalein clearance also was not affected by mirex treatment in adrenalectomized animals. Serum glucose concentrations were significantly decreased in both intact and adrenalectomized animals by mirex treatment. Daily corticosterone supplements to adrenalectomized animals restored liver hypertrophy and serum glucose concentrations to levels observed in mirex-treated intact animals. These results suggest that mirex-induced liver enlargement may be mediated by corticosterone.     

Influence of grain type on the insecticidal efficacy of two diatomaceous earth formulations against Rhyzopertha dominica (F) (Coleoptera: Bostrychidae)

Laboratory bioassays were carried out in order to evaluate the effectiveness of two diatomaceous earth (DE) formulations, Insecto and SilicoSec, against adults of Rhyzopertha dominica (F) in eight different grain commodities. The adherence of the two DEs to each grain was also measured. The eight grains tested were wheat, whole barley, peeled barley, oats, rye, triticale, rice and maize. These commodities were treated with the DEs at three rates, 0.75, 1.0 and 1.5 g DE kg(-1) grain. The mortality of R dominica adults was measured after 24 h, 48 h, 7 days and 14 days of exposure in the treated grains at 26 degrees C and 55% RH. After the 14-day mortality count, all adults were removed and the treated grains retained under the same conditions for a further 60 days. The treated grains were subsequently examined for F1 progeny. Significant differences were recorded among the eight grain types as well as between the DE formulations tested. After 14 days of exposure, even at the lowest DE rate for both formulations, adult mortality was high (>90%) in wheat and triticale. In contrast, adult mortality was significantly lower in peeled barley. Increasing the rate improved the efficacy of the DEs significantly in only some of the grains tested. Reproductive capacity in all the treated grains was significantly suppressed when compared with untreated grains. Generally, more F1 individuals of R dominica were noted in the treated peeled barley than in the other commodities. Significant differences in the percentage of DE retention were noted among the eight grains. The highest retention level was noted in rice (>87%) and the lowest in maize (<6%). However, the degree of DE adherence to a given grain was not always indicative of the effectiveness of DE against R dominica.     

台湾苗木根土浸泡药液稳定性及其处理效果*

试验表明,用于台湾带土苗木根土浸泡的混合药液（10%二硫氰基甲烷乳油33.3 μg/mL+50%多菌灵可湿性粉剂500.0 μg/mL）中二硫氰基甲烷的稳定性较好,能够满足浸泡除害处理的要求。配制1次药液可以连续处理带土苗木3批次,其中每批苗木根土的线虫杀灭率均可达到100%。如需连续浸泡第4批苗木,则应至少添加5%～10%的药量。讨论了浸泡药液用后残液与淤泥的无害化处理。建议在气温高、光照强且长的夏季,一池药液最多浸泡处理2批次苗木。     

Susceptibility of lesser mealworm (Coleoptera: Tenebrionidae) adults and larvae exposed to two commercial insecticides on unpainted plywood panels

BACKGROUND: The susceptibilities of adult and larval lesser mealworms, Alphitobius diaperinus (Panzer), to two commercially formulated insecticides, cyfluthrin and tetrachlorvinphos, were examined through exposure on treated plywood panels. Lesser mealworms were collected from four caged-layer poultry farms, three in New York and one in Maine. An additional strain was obtained from an infestation occurring in a cricket colony.RESULTS: In all poultry farm derived strains, a portion of the population (1.8-16.2%) survived cyfluthrin exposure. The Maine and cricket colony strains were tolerant of tetrachlorvinphos exposure as both larvae and adults, with 55-74% mortality, whereas nearly 100% mortality was observed with New York strains. The cricket colony adult beetles were highly susceptible to cyfluthrin, with 100% mortality following exposure, but larvae were considerably less susceptible (87.7%). Pesticide use histories for the poultry farms and their impact on the results are discussed.CONCLUSION: The results document that tetrachlorvinphos, an active ingredient with a long use history, may be losing its effectiveness against lesser mealworms in some poultry operations; however, it is still effective in many others.     

Susceptibility of Mastomys natalensis to Brugia malayi following pretreatment with antifilarials

Mastomys natalensis pretreated with diethylcarbamazine (DEC), levamisole or centperazine were exposed to the standard inoculum of infective larvae of Brugia malayi. Percentage 'take' of infection, duration of prepatent period, course of microfilaraemia and number of adult worms recovered were compared with those of untreated infected Mastomys (control). DEC and centperazine did not alter the 'take' (DEC/centperazine: 100%; control: 88.24%) and the average prepatent period (DEC: 105.44 days; centperazine: 105.18 days, control: 109.20 days). In levamisole pretreated animals on the other hand, the 'take' was much lower (68.18%) with extended prepatent period (125.87 days). However, unlike centperazine and control, the course of microfilaraemia was identical in DEC and levamisole pretreated animals. The average adult worm recovery was significantly high in centperazine pretreated animals being 14.09 as against 8.12, 7.46 and 8.42 in DEC, levamisole pretreated and control animals, respectively.     

The effects on resistant mosquitoes of interrupted exposure to insecticides

In paired tests on batches of malathion- and dieldrin-resistant Anopheles arabiensis, one of each pair received a continuous exposure to either malathion or dieldrin for 16 h or more, while the other received a non-exposed rest phase in the middle of the exposure period. Among dieldrin-resistant mosquitoes, the mortality rate was decreased in the group that experienced the interrupted, as opposed to the continuous exposures; however, the survival rate of malathion-resistant adults was unaffected by interrupted exposure. There was a significant positive correlation between the mortality rate and the adult age for malathion, but the responses to dieldrin were independent of age. Movement of adult mosquitoes to and from malathion deposits in sprayed houses should not impair the efficacy of this insecticide, whereas prolonged absence from contact with dieldrin would require even longer exposures to achieve the same mortality in the insects.     

Persistence and efficacy of two diatomaceous earth formulations and a mixture of diatomaceous earth with natural pyrethrum against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on wheat and maize

Laboratory tests were conducted to assess the insecticidal and residual effects of three diatomaceous earth (DE) formulations, Insecto, PyriSec and SilicoSec, against Tribolium confusum Jacquelin du Val on wheat and maize. Quantities of wheat and maize were treated with the above formulations at 500, 1000 and 1500 mg kg(-1) and stored at 25 degrees C and 55% relative humidity (RH). Samples were taken on the day of storage and every 30 days until completion of a 360 day period of storage. Adults of T. confusum were exposed to these samples at 25 degrees C and 55% RH and the mortality was measured after 24 and 48 h and 7 and 14 days of exposure. Adult mortality was higher on wheat than on maize. At the beginning of the storage period, mortalities after 14 day exposure on maize treated with the highest rate were 60, 63 and 81% for Insecto, PyriSec and SilicoSec respectively, while on wheat the mortality was 100% for all DEs. On the same commodities 360 days after treatment the respective mortality figures for wheat were 99, 98 and 100%, while in the case of maize they did not exceed 7%. Generally, mortality at exposures < or =48 h decreased with increasing storage time. Furthermore, although mortality on wheat increased with dose, the increase in DE dose from 1000 to 1500 mg kg(-1) resulted in only a small increase in mortality. Thus a DE treatment of 1000 mg kg(-1) was shown to provide long-term protection of wheat against T. confusum, although higher DE application rates and exposure intervals are needed for a satisfactory level of protection of maize against this pest.     

短时高温暴露对草地贪夜蛾存活及生殖的影响

本文研究短时高温暴露对草地贪夜蛾存活和生殖的影响,为其夏季的预测预报及综合防治提供技术支持.分别以卵、不同龄期幼虫、蛹、成虫作为研究对象进行不同时间高温暴露处理,研究高温暴露处理后幼虫和成虫的成活率,幼虫的化蛹率、羽化率、蛹重以及成虫的生殖能力.结果 表明.37℃对卵的孵化率无显著影响,40℃暴露4h卵的孵化率显著降低...     

Bt与硫丹、氟铃脲对棉铃虫的联合作用

通过室内和田间试验，研究了Bt与硫丹、氟铃脲对棉铃虫的联合作用。结果表明：(1)Bt与硫丹无论以何种比例相混，对敏感品系和氰戌菊脂中抗品系均增效。(2)Bt与氟铃脲只有以1:60相混才明显增效；Bt中加入少量氟铃脲和氟铃脲中加入少量Bt则明显拮抗。（3）Bt与硫丹和氟铃脲混用，明显加快了2龄幼虫的死亡速度，混剂在处理后第3d，死亡率便明显高于Bt，而与硫丹或氟铃脲单用接近。（4）田间试验中，Bt和硫丹的混剂显著增效，Bt与氟铃脲的混剂在药后4d表现出一定的增效作用，但药后7d明显拮抗。     

Nephrotoxicity induced by dimethoate in adult rats and their suckling pups

The purpose of this study was to investigate the effect of dimethoate (DM), an organophosphorus insecticide, on oxidative stress in kidneys of adult rats and their suckling pups. Female Wistar rats were given daily DM in drinking water 0.2 g/L equivalent to 40 mg/kg bw from day zero until day 10 after delivery. A significant increase was found in relative kidney weights of treated adult rats and their offspring. DM administration affected strongly specific markers of kidney function such as the 24-h urine volume which was higher than in the controls. In test group we have found higher plasma levels and lower urinary levels of creatinine, a specific indicator of glomerular function, and urea than in the controls. Significant increase in creatinine clearance was also found in treated mothers and their suckling pups. These results indicated that DM exposure provoked low glomerular filtration rate in treated group. Interestingly, these biochemical modifications were accompanied by a marked enhancement of lipid peroxidation in kidney indicating significant induction of oxidative damage and alterations of enzymatic antioxidant defences in test group. Impairment of renal function corresponds histologically. In fact, histological changes, seen in the kidney of mothers and their pups treated with DM are characterized by a narrowed Bowman’s space, degenerative of tubular epithelial cells and widened tubular lumen. Moreover in mothers, extensive vascular congestion was observed.We concluded that the effect of DM treatment in lactation period of mothers was fairly reflected in the offspring in all parameters analysed.     

Combined treatments of spinosad and chlorpyrifos-methyl for management of resistant psocid pests (Psocoptera: Liposcelididae) of stored grain

The combined efficacy of spinosad and chlorpyrifos-methyl was determined against four storage psocid pests belonging to genus Liposcelis. This research was undertaken because of the increasing importance of these psocids in stored grain and the problem of finding grain protectants to control resistant strains. Firstly, mortality and reproduction were determined for adults exposed to wheat freshly treated with either spinosad (0.5 and 1 mg kg(-1)) or chlorpyrifos-methyl (2.5, 5 and 10 mg kg(-1)) or combinations of spinosad and chlorpyrifos-methyl at 30 degrees C and 70% RH. There were significant effects of application rate of spinosad and chlorpyrifos-methyl, both individually and in combination, on adult mortality and progeny reduction of all four psocids. Liposcelis bostrychophila Badonnel and L. decolor (Pearman) responded similarly, with incomplete control of adults and progeny at both doses of spinosad but complete control in all chlorpyrifos-methyl and combined treatments. In L. entomophila (Enderlein) and L. paeta Pearman, however, complete control of adults and progeny was only achieved in the combined treatments, with the exception of spinosad 0.5 mg kg(-1) plus chlorpyrifos-methyl 2.5 mg kg(-1) against L. entomophila. Next, combinations of spinosad (0.5 and 1 mg kg(-1)) and chlorpyrifos-methyl (2.5, 5 and 10 mg kg(-1)) in bioassays after 0, 1.5 and 3 months storage of treated wheat were evaluated. The best treatment was 1 mg kg(-1) of spinosad plus 10 mg kg(-1) of chlorpyrifos-methyl, providing up to 3 months of protection against infestations of all four Liposcelis spp. on wheat.     

Natural infection with two genotypes of Cryptosporidium in red squirrels (Sciurus vulgaris) in Italy

We investigated the genotypes of Cryptosporidium infecting red squirrels (Sciurus vulgaris L.) in two areas of the Western Alps in Italy. Examination of 141 faecal samples from 70 red squirrels revealed oocysts of Cryptosporidium in 17 animals (24.3%). Based on 18S rRNA gene sequencing, two genotypes of Cryptosporidium species were found: 15 squirrels were positive for the Cryptosporidium ferret genotype and 2 for the Cryptosporidium chipmunk genotype I. The occurrence and intensity of Cryptosporidium infection did not differ between the study areas or sex. More than 85% of the positive animals were adults; however no difference was found between Cryptosporidium infection in the juvenile and adult age groups. Oocysts of the Cryptosporidium ferret genotype measured 5.5 +/- 0.3 x 5.2 +/- 0.2 microm (shape index 1.06) and the Cryptosporidium chipmunk genotype I 5.8 +/- 0.3 x 5.4 +/- 0.3 microm (shape index 1.07). Neonatal and adult CD1 and BABL/c mice inoculated with 1 x 10(3) fresh oocysts of both genotypes did not produce detectable infection.     

Bioresidual and integrated pest management status of a biorational agent and a novel insecticide against whitefly and its key parasitoids

The effects of continuous exposure of the adult and crawler stages of the whitefly, Trialeurodes vaporariorum, and adult of the parasitoids Encarsia formosa and Eretmocerus eremicus to spray deposits of potassium salts of a fatty acid and diafenthiuron applied at recommended rates were evaluated. French bean, Phaseolus vulgaris Prince, plants were sprayed and the adults confined on them using modified 5 cm Petri dishes. Fresh (4 - 5-h-old) deposits of fatty acids resulted in a 10.7% mortality rate of whitefly adults and 8.0 and 10.7% mortality rates of E. formosa and E. eremicus adults respectively, while fresh deposits of diafenthiuron resulted in a 62.7% mortality rate of whitefly adults and 12.0 and 14.7% mortality rates of E. formosa and E. eremicus respectively. The mortality rate (6.9 and 69.7%) of whitefly crawlers was recorded when exposed to 24-h-old deposits of fatty acids and diafenthiuron respectively. The mortality rate declined as the deposits aged. Adult parasitoid emergence from the treated pupae was unaffected. Spray deposits of diafenthiuron were effective against whitefly for up to 2-3 weeks in comparison with fatty acids, which were effective only when sprayed. Both products were harmless to adults as well as pupae of both parasitoids irrespective of the exposure period (age of deposits) tested (IOBC Class 1). These insecticides can be included in integrated pest management strategies against whitefly with the fatty acids used on horticultural crops.     

化肥基施对水稻田福寿螺的影响

在水稻田中,碳酸氢铵、碳酸氢铵+尿素、尿素和复合肥作基肥能杀伤田间福寿螺成螺和幼螺,成螺死亡率显著高于幼螺;单用碳酸氢铵成、幼螺死亡的高峰时段出现在施肥后1～7 d,而施复合肥、尿素、碳酸氢铵+尿素死亡的高峰时段则在施肥后1～2 d或7～14 d;碳酸氢铵用量越多,成、幼螺死亡率越高,并使当代的产卵量减少,但不影响下一代的产卵能力;成、幼螺死亡率与碳酸氢铵用量的回归关系式分别为：成螺死亡率Y1=0.652X+18.18,幼螺死亡率Y2=0.014 9X2—0.516 7X+5.442。     

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

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.     

Use of oils combined with low doses of insecticide for the control of Myzus persicae and PVY epidemics

Experiments were carried out in the laboratory to assess the insecticidal effect on Myzus persicae Sulzer of different oils applied alone or combined with imidacloprid or pirimicarb. The oils tested were a horticultural mineral oil, a refined rapeseed oil, a refined soya oil and a raw fish oil. When the oils were sprayed alone on pepper plants infested with M. persicae, mineral oil caused the highest mortality of aphids (over 80%). Applied before aphid infestation of pepper leaves and in mixture with low doses of imidacloprid (at one-fifth of the dose recommended by the manufacturer) and pirimicarb (at one-tenth of the dose recommended by the manufacturer), the oils did not significantly increase the toxicity of the insecticides alone. However, sprayed on aphid-infested pepper plants, the mortality rates achieved by imidacloprid/mineral oil and imidacloprid/rapeseed oil mixtures were significantly higher than those achieved by imidacloprid alone at 16 and 24 h. In a field experiment the effect on the incidence of the potato virus (PVY) of the oils in combination with imidacloprid was determined. Mineral oil, rapeseed oil and soya oil were sprayed eight times onto seed potato plants treated with imidacloprid before sowing. Mineral oil reduced PVY-infected plants by 60% and rapeseed oil by 40% compared with plots treated with imidacloprid. The oils applied as 10 ml litre-1 emulsions in water did not cause symptoms of phytotoxicity on the potato plants, and yield was not reduced.     

Immune response in rabbits experimentally infected with Ascaris suum

Immune response of rabbits experimentally infected with Ascaris suum was studied by indirect haemagglutination method. The animals were infected with the doses of 5,000, 10,000 and 20,000 infective eggs per animal. Positive reactions were observed from days 5-11 p.i., maximum reactions on days 11-19 p.i. A reinfection with the same doses (1x or 2x after 35 and 65 days) increased the antibody titre. The strongest individual reaction was recorded on day 19 p.i. in the group infected with the highest dose (titre 1 : 4096). The increased antibody titres persisted til the end of the experiment (82th day p.i.) in all groups.