Acute and sublethal toxicity of novaluron, a novel chitin synthesis inhibitor, to Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

The acute and sublethal toxicities of novaluron, a novel chitin synthesis inhibitor, to a laboratory-reared insecticide-susceptible strain of Colorado potato beetle, Leptinotarsa decemlineata (Say), were determined. Novaluron exhibited excellent residual (120 h LC(50) = 0.42 mg litre(-1)) and good direct contact (120 h LC(50) = 27 mg litre(-1)) activity against second-instar larvae (L2). Hatch of eggs exposed by direct contact to novaluron solutions > or =100 mg litre(-1) was significantly reduced, as was the ability of emerged first-instar larvae to moult. L2 from eggs exposed to > or =100 mg litre(-1) novaluron weighed significantly less (P < 0.0001) than those from untreated eggs. However, L2 from eggs treated with 1 mg litre(-1) novaluron weighed significantly more (P < or = 0.05) than those from untreated eggs, suggesting novaluron can have a hormetic effect on L decemlineata larval development. Leptinotarsa decemlineata mating pairs fed foliage treated with novaluron at 25 or 75 g AI ha(-1) produced approximately 25% fewer egg masses and eggs per mass. Hatch of eggs on treated foliage was almost completely suppressed, and longevity of male beetles was reduced by approximately 50% when fed foliage treated with novaluron at 75 g AI ha(-1).     

Inhibition of egg development by phosphine in the cosmopolitan pest of stored products Liposcelis bostrychophila (Psocoptera: Liposcelididae)

Phosphine-induced delay in development of eggs was investigated as a mechanism of resistance to this fumigant in Liposcelis bostrychophila Badonnel. One-day-old eggs of a susceptible and a strongly resistant strain of L bostrychophila were exposed to a range of phosphine concentrations for 6days at 30 (+/- 1) degrees C and 70 (+/- 2)% RH. Delay in mean hatching period occurred in both susceptible and resistant eggs, although it was more pronounced in the latter. A maximum delay of 2.65 days was recorded for eggs of the susceptible strain at 0.01 mg litre(-1) (the highest concentration at which eggs survived) and 13.39 days for the resistant strain at 1 mg litre(-1) (the highest concentration tested). Delay in egg development time was positively correlated with increasing phosphine concentration. Our results reveal that the most successful strategy to control resistant L bostrychophila is to apply relatively low concentrations of phosphine for extended exposure times (eg 0.05 mg litre(-1) for 16 days) that allow all eggs to hatch to the much less tolerant nymph stage.     

海洋放线菌M1D14代谢产物对几种重要植物寄生线虫的抑制作用

采用梯度稀释法室内测定了海洋放线菌M1D14发酵液代谢产物对南方根结线虫(Meloidogyne incognita)2龄幼虫及其卵、松材线虫(Bursaphelenchus xylophilus)、大豆孢囊线虫(Heterodera glycines)2龄幼虫的毒力,同时还测定了经过高温高压灭菌和0.22μm微孔滤膜过滤的M1D14发酵液对南方根结线虫的毒力。结果表明,海洋放线菌M1D14发酵液代谢产物对南方根结线虫卵的孵化无明显的抑制作用,对南方根结线虫幼虫毒力最强,对松材线虫幼虫毒力次之,对大豆孢囊线虫幼虫的毒力最弱。经过高温高压灭菌和微孔滤膜过滤的M1D14发酵液对南方根结线虫仍有毒力。M1D14杀线虫谱广、效果好、使用成本低,在生产上具有很好的应用前景。     

Estimation of the viability ofHeterodera schachtii field populations by measuring ATP,ADP and AMP contents of eggs and juveniles using HPLC

An HPLC method has been developed to determine adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in eggs and juveniles ofHeterodera schachtii in cysts extracted from soils. ATP levels in eggs and juveniles were highly correlated with the numbers of hatched juveniles in root diffusate (r=+0.92) in series of soil samples originating from field trials testing different doses of fumigant nematicides. The measured ATP concentrations in the cysts explained 59% of the sugar-yield reduction on these fields, which was similar to the value based on the hatching test. After fumigation, carried out in a laboratory experiment, ATP and the adenylate energy charge, (AEC=ATP + 0.5 * ADP)/(ATP + ADP + AMP), decreased greatly within a few days. In a series of greenhouse trials in whichH. schachtii had been parasitized severely byVerticillium clamydosporium and other antagonists, there were significant correlations between the numbers of hatched juveniles and the ATP content of the cysts (r=+0.85), and between the percentages of hatched juveniles and the AEC (r=+0.75). The HPLC method is faster than conventional methods and can be used to establish the viability ofH. schachtii field populations affected by soil fumigation or egg pathogens.     

Host–parasite relationships of Meloidogyne incognita on spinach

Host–parasite relationships in root-knot disease of spinach caused by Meloidogyne incognita race 1 were studied under glasshouse conditions. Nematode-induced mature galls were large and usually contained one or more females and egg masses with eggs. Feeding sites were characterized by the development of giant cells containing granular cytoplasm and many hypertrophied nuclei. The cytoplasm in these giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density ( P _i) in a series from 0–128 eggs and second-stage juveniles per cm³ soil and growth of spinach cv. Symphony F₁ seedlings was tested under glasshouse conditions. A Seinhorst model [ y = m  + (1 −  m ) z ^P–T ] was fitted to fresh top- and total plant-weight data for inoculated and control plants. Tolerance limits ( T ) of spinach cv. Symphony F₁ to M. incognita race 1 for fresh top and total plant weights were 0·25 and 0·5 eggs and second-stage juveniles per cm³ soil, respectively. The minimum relative values for fresh top and total plant weights were zero in both cases at P _i ≥ 32 eggs and second-stage juveniles per cm³ soil. Root galling was least at low initial population densities and greatest at 16 eggs and second-stage juveniles per cm³ soil. Maximum nematode reproduction rate was 33·1-fold at the lowest P _i.     

Activity of Hydroxamic Acids from Secale cereale Against the Plant-Parasitic Nematodes Meloidogyne incognita and Xiphinema americanum

ABSTRACT Cyclic hydroxamic acids are secondary metabolites found in the family Poaceae and have been implicated in the allelopathy of rye (Secale cereale). The toxicity of these compounds against plant-parasitic nematodes is unknown. DIBOA (2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one), DIMBOA (2,4-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one), and their degradation products BOA (benzoxazolin-2(3H)-one) and MBOA (6-methoxy-benzoxazolin-2(3H)-one) were screened in vitro against Meloidogyne incognita second-stage juveniles (J2) and eggs and mixed-stages of Xiphinema americanum. Xiphinema americanum was more sensitive to DIBOA and DIMBOA than M. incognita J2, with a maximum apparent mortality of 96 and 92% compared to 73 and 72% at 90 mug/ml. Eggs of M. incognita were less sensitive to the hydroxamic acids than J2; only DIBOA resulted in a 50% reduction in egg hatch, with a lethal concentration (LC(50)) of 74 mug/ml compared to 21 mug/ml for J2. When M. incognita J2 were exposed to DIBOA for 48 h and the compound was removed and replaced with water, the LC(50) value increased from 21.0 to 40.7 mug/ml. MBOA was not toxic to X. americanum or M. incognita eggs, but was toxic to M. incognita J2, with LC(50) values of 44 and 20 mug/ml before and after the compound was removed and replaced with water. BOA was the least toxic hydroxamic acid tested; it did not reduce M. incognita egg hatch after 1 week of exposure or increase X. americanum mortality after 24 h of exposure. While in vitro studies provide a valuable starting point in determining the toxicity of the chemical component of rye, the relevance of the data to soil remains to be determined.     

3种药剂对象耳豆根结线虫卵及2龄幼虫的影响

为了筛选对象耳豆根结线虫Meloidogyne enterolobii防治效果好的药剂,本文采用浸虫法分别测试了 3％阿维菌素微乳剂、41.70％氟吡菌酰胺悬浮剂及20％噻唑膦水乳剂不同浓度、不同处理时间对象耳豆根结线虫2龄幼虫的致死作用,以及对卵孵化和卵胚胎发育的影响.结果表明,3％阿维菌素微乳剂对2龄幼虫致死作用最...     

Effect of water, soil temperatures, and exposure times on the survival of the sugar beet cyst nematode, heterodera schachtii

ABSTRACT The effect of different combinations of temperatures and exposure times on the mortality of Heterodera schachtii eggs was assessed in two different experiments under laboratory conditions. In the first experiment, cysts in water were exposed to 25, 35, 37.5, 40, 42.5, 45, 47.5, 50, or 52.5 degrees C for a maximum period of 2 h. In the second experiment, cysts in naturally infested soil were exposed to 25, 32.5, 35, 37.5, 40, 42.5, or 45 degrees C for a minimum period of 2 h to a maximum of 2,048 h. Viability of eggs in cysts was assessed by a hatching test in 3 mM zinc chloride solution. Viability in water was suppressed after 2-h exposure at 50 degrees C and inhibited after 1 to 2 h at 52.5 degrees C. Emergence of juveniles from cysts in soil was greater at the lower temperature x exposure time combinations and suppressed at higher combinations. Egg mortality started after exposure for 256 h at 40 degrees C, 32 h at 42.5 degrees C, and 16 h at 45 degrees C, and 81, 31, and 7 h of exposure were necessary to kill 50% of the nematode egg population at 40, 42.5, and 45 degrees C, respectively. The data fitted the models P(t) = P(0)10(-t/ (q + mT)) and P(T1) = P(T0)10(-T/(z - pt)) for m = -0.0111, q = 0.8238, z = 2.444, and p = -0.23.     

Influence of phosphine on hatching of Cryptolestes ferrugineus (Coleoptera: Cucujidae), Lasioderma serricorne (Coleoptera: Anobiidae) and Oryzaephilus surinamensis (Coleoptera: Silvanidae)

The hatching and mortality response of 0- to 48-h-old eggs of field strains of the stored-product insects Cryptolestes ferrugineus (Stephens), Lasioderma serricorne (F) and Oryzaephilus surinamensis (L) following phosphine fumigation for 24, 48 or 120 h at 27 (+/- 2) degrees C was investigated. Hatching was delayed and reduced in the first few days in a phosphine-resistant strain of C ferrugineus that was treated with 2.0-7.0 mg litre(-1) doses for 48 h (5-80% mortality) and with 1.0-2.0 mg litre(-1) for 120 h (44-84% mortality). In both the exposures there were significant increases in hatching on later days when compared with the corresponding controls. Developmental delay was, however, not evident in susceptible strains of C ferrugineus, L serricorne and O surinamensis that were exposed to phosphine for 24 h.     

禾谷缢管蚜在越冬寄主植物上的行为研究

通过室内饲养观察、田间调查和利用微型昆虫显微摄影技术,研究了禾谷缢管蚜越冬卵在越冬寄主稠李(Prunus padis)上孵化,干母、干雌取食、生长发育和繁殖等行为过程,以及形态和体色变异特点。结果表明,禾谷缢管蚜越冬卵在室内的孵化率为88.68％-92.51％;在德国北部吕贝克附近田间孵化率为24.2％。越冬卵孵化起点温度低于4℃。在室温22℃下卵孵化历期为5-7d,孵化高峰在卵孵化始期后第3-4天。一日内最佳孵化时间在05:00-07:30。在室内饲养条件下,将越冬卵孵化的干母直接移植到麦苗上,蚜虫几乎都不能存活。     

Effects of cyazofamid against Plasmodiophora brassicae Woronin on Chinese cabbage

Cyazofamid (4-chloro-2-cyano-N,N-dimethyl-5-p-tolylimidazole-1-sulfonamide) is a novel fungicide with high levels of activity against Oomycetes fungi and Plasmodiophora brassicae Woronin. The effects of cyazofamid were investigated against P. brassicae, the causal agent of clubroot disease in Chinese cabbage. Cyazofamid at 0.3 mg litre(-1) inhibited resting spore germination of this pathogen by about 80%. Cyazofamid at 3-10 mg litre(-1) exhibited fungicidal activity to resting spores of P. brassicae 1-10 days after treatment. When cyazofamid was applied to infested soil, both root-hair infections and club formation caused by P. brassicae were strongly inhibited at 1-3 mg kg(-1) dry soil. These results suggest that cyazofamid directly inhibits resting spore germination, thereby leading to the inhibition of root-hair infection and club formation. Cyazofamid at 3 mg kg(-1) dry soil also exhibited complete control of clubroot disease. The effect of broadcast soil application using a dust formulation at 2 kg AI ha(-1) (equivalent to 1.3 mg AI kg(-1) dry soil), and plug seedling tray application by a suspension concentrate formulation at 200 and 400 mg AI tray(-1) (30 x 60 x 4 cm3) against P. brassicae was also evaluated. Cyazofamid exhibited good efficacy against the pathogen. The sequential treatment including plug seedling tray application with cyazofamid and pre-plant broadcast soil application with the fungicide fluazinam also exhibited excellent levels of control. These results indicate that cyazofamid has a high potential to be an effective fungicide for the control of clubroot disease.     

温湿度对南方根结线虫卵孵化和二龄幼虫的影响

根结线虫病害是世界上最难防治的蔬菜病害之一,是否可以通过控制生态条件经济有效地防治根结线虫病害值得深入研究。本文利用室内纯培养技术研究了温湿度单因素和双因素对南方根结线虫（Meloidogyne incognita）2龄幼虫(J2)的致死率和卵囊中卵孵化率的影响。试验结果表明,该线虫对温度敏感,40 ℃以上高温和5 ℃以下低温即可抑制J2存活和卵囊中卵孵化,15～30 ℃是线虫的适宜温度;该线虫对湿度不十分敏感,只有干旱（含水量低于1%）和高湿（含水量高于30%）时,对线虫才有一定抑制作用。低温（5 ℃以下低温、含水量5%以上湿度）和高温高湿（35 ℃以上温度和30%含水量）抑制卵囊中卵孵化和J2的存活。本数据的获得将为设施园艺中生态控制南方根结线虫病害提供理论指导和数据支持。     

Dose-response effects of clove oil from Syzygium aromaticum on the root-knot nematode Meloidogyne incognita

BACKGROUND: Clove oil, derived from the plant Syzygium aromaticum (L.) Merr. & Perry, is active against various organisms, and was prepared in a soy lecithin/detergent formulation to determine concentrations active against the root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood. RESULTS: In microwell assays, the mean effective clove oil concentration that reduced egg hatch by 50% (EC(50)) was 0.097% (v/v) clove oil; the EC(50) for second-stage juvenile (J2) viability was 0.145% clove oil (compared with carrier control treatments). Volatiles from 5.0% clove oil reduced nematode egg hatch in water by 30%, and decreased viability of hatched J2 by as much as 100%. Reductions were not as large with nematodes in carrier. In soil trials with J2 recovered from Baermann funnels, the EC(50) = 0.192% clove oil (compared with water controls). CONCLUSION: The results demonstrated that the tested formulation is active against M. incognita eggs and J2, that the EC(50) values for J2 in the microwell studies and the soil recovery tests were similar to each other and that direct contact with the clove oil is needed for optimal management results with this natural product.     

产生几丁质酶的交枝顶孢(Acremonium implicatum)对南方根结线虫生防潜力

 由于化学杀线剂给环境带来了污染问题,寄生线虫的生防真菌成为研究热点。为进一步鉴定和筛选高效食线虫真菌,从山东日照五莲烟草北方根结线虫卵中分离到1株较高应用潜力菌株WLE1。根据形态学和rDNA-ITS序列分析方法鉴定该菌为交枝顶孢Acremonium implicatum。该菌是1株能够产生几丁质酶的食线虫真菌,在第4天几丁质酶活性到达高峰,为18.49 μmol·h^-1·mL^-1 ,直到第16天依然维持较高活性;活性电泳测定其几丁质酶分子量分别为98.0、82.9、70.2和35.9 kDa;交枝顶孢几丁质粗酶液处理南方根结线虫卵,第7天卵的孵化抑制率为80.17%。该菌能够寄生南方根结线虫卵、2龄幼虫和雌虫。第6天卵和2龄幼虫的寄生率分别为82.11%和73.97%。说明具有高效产生几丁质酶特性且能寄生南方根结线虫不同生活史阶段的交枝顶孢WLE1对南方根结线虫具有巨大生防潜力。     

石榴枯萎病菌拮抗放线菌对南方根结线虫的毒力

从云南蒙自万亩石榴园、建水石榴园采集的土样中分离筛选得到对石榴枯萎病菌有较强拮抗活性的放线菌,其中菌株JS1对石榴枯萎病菌的室内抑菌半径为11mm。测定了菌株JS1发酵液对南方根结线虫的抑杀活性,结果表明,50%JS1菌株发酵液处理南方根结线虫卵6d,卵孵化率与对照相比降低了51.67%;50%JS1菌株发酵液处理南方根结线虫2龄幼虫72h,2龄幼虫的校正死亡率增加了88.10%;菌株JS1兼有拮抗石榴枯萎病菌及抑杀南方根结线虫的活性。结合菌株JS1在鉴定培养基上的培养特征、形态学观察及16SrDNA序列分析,将JS1初步鉴定为壮观链霉菌(Streptomyces spectabilis)。     

旱稻孢囊线虫（Heterodera elachista）孵化特性研究

为了解旱稻孢囊线虫的孵化特性,从水稻根系及根系附近土壤分离孢囊,在室内离体条件下研究不同温度及水稻根系分泌物、土壤浸液、水稻根汁等因子对2龄幼虫孵化的影响,并观察不同温度下2龄幼虫的存活能力.结果表明:旱稻孢囊线虫孵化的适宜温度范围为28～32℃,且在该温度范围初孵2龄幼虫的存活率高、存活时间相对较长,35℃下孵化率及初孵2龄幼虫的存活率、存活时间均明显下降,40℃下无线虫孵化,20℃下孢囊线虫孵化率仅为0.9％,4℃下可延长2龄幼虫的存活时间.水稻分泌物、水稻土壤浸液和水稻20倍根汁对旱稻孢囊线虫孵化具有刺激作用,5倍根汁和4 mmol/L氯化锌溶液对线虫的孵化有抑制作用.上述结果可为制定旱稻孢囊线虫防治措施提供依据.     

Management of root-knot disease of tomato by the application of fly ash in soil

The effects of fly ash at different concentrations (0, 10, 20, 30 … 100% vol./vol. in soil) on plant growth and yield were investigated in tomato plants infected or noninfected with root-knot nematode, Meloidogyne incognita (2000 juveniles per plant) in clay pots. An increase in fly ash concentration in the soil correspondingly increased the availability of carbonates, bicarbonates, sulphate, chlorides, B, P, K, Ca, Mg, Mn, Cu and Zn in the soil. The porosity, water-holding capacity, pH, conductivity and cation exchange capacity also increased progressively in the fly ash amended soil. Ash application enhanced plant growth, leaf pigment concentrations, fruit production, weight of fruit/plant and mean fruit weight of both nematode-infected and noninfected tomato plants, being maximum in the soil containing 50 or 60% fly ash. The yield enhancements were 93.6 (infected plants) and 84% (noninfected plants) at 50 and 60% fly ash levels, respectively. Fly ash treatments adversely affected root invasion by juveniles, disease intensity and reproduction of the nematodes. A gradual increase in the ash concentration in soil caused a corresponding decrease in the numbers of invading juveniles, galls and egg masses per root system and eggs/egg mass, being lowest at 100% fly ash i.e. 52, 16, 10 and 81 against 289, 137, 131 and 238 (control), respectively. Linear regression suggested 40% fly ash as the most economic level, enhancing yield of infected plants by 96% and suppressing the nematode disease and reproduction by 63 and 76%, respectively.     

耐多菌灵淡紫拟青霉对线虫的致病力及其在土壤中的存活

在室内条件下,测定了耐多菌灵淡紫拟青霉Paecilomyces lilacinusPL221菌株对拟松材线虫Bursaphelenchus mucronatus的致死率和对南方根结线虫Meloidogyne incognita卵的寄生率,及其在土壤中的存活情况。结果表明：菌株PL221对拟松材线虫的致死率为75.6%,高于出发菌株36-1,两者有极显著差异;菌株PL221对根结线虫卵的寄生率为62.1%,也高于出发菌株36-1,但两者无显著差异。将菌株PL221以孢子液和固体发酵物的形式施入土壤,都可在土壤中存活至少60d,其中以固体发酵物的形式施入土壤中的存活量较高。菌株PL221在土壤中的存活量受降水量影响较大,二者关系呈负相关。     

Solarization of soil in piles for the control of Meloidogyne incognita in olive nurseries in southern Spain

The potential of solarization to control Meloidogyne incognita in piles of soil used at olive nurseries in southern Spain was studied in 1999 and 2000. Kaolin and soil infested with free eggs and egg masses of the nematode in nylon bags were buried 20 and 40 cm deep inside conical piles of soil 80 cm high and with a base diameter of 1 m. Soil piles were solarized for 3 weeks in July and August. The effect of various periods of solarization was assessed by egg hatch bioassays in sterile water, and by infectivity to tomato plants. Maximum soil temperature at 20 cm depth in solarized piles was 47·4°C in 1999 and 48·2°C in 2000, compared with 32·9°C and 31·7°C in nonsolarized piles. Solarization reduced egg hatch by > 95% compared with nonsolarized samples, irrespective of type, burial depth and location of inocula in a soil pile. Egg hatch of egg mass-infested samples buried at 20 cm depth was higher than that of free eggs buried at the same depth. The differential effect associated with burial depth and type of inoculum was not found in solarized piles. In nonsolarized piles, hatch of free eggs from samples buried at 40 cm depth was higher than that from samples buried at 20 cm depth. Egg hatch in samples from solarized piles was lower than that from nonsolarized piles. A bioassay of tomato plants in 2000 confirmed the reduction in infectivity of free eggs buried in solarized soil piles. Under the conditions in southern Spain, solarization of 40 cm-high piles of soil for 3 weeks can therefore be used for the control of root-knot nematodes in potting soil for olive nursery production.     

五种药剂对黏虫卵的室内触杀效果及胚胎发育的影响

为有效防控黏虫Mythimna separata,选用灭多威、苦参·印楝素、苏云金芽胞杆菌Bacillus thuringiensis、甲维盐和高效氯氟氰菊酯5种药剂对其卵进行室内触杀试验,比较这5种药剂对黏虫卵和初孵幼虫的触杀效果及对卵的毒力,测定不同药剂处理后黏虫卵初孵幼虫存活率、发育历期、化蛹率、蛹重和羽化率;并通过冷冻切片技术观察不同药剂处理后黏虫卵的外部形态和胚胎发育情况。室内触杀试验结果表明,苦参·印楝素浓度大于0.1 mg/L时,对产后不同时间黏虫卵的校正死亡率介于42.89%～97.34%之间,苏云金芽胞杆菌浓度为0.01 mg/L时对产后72 h黏虫卵的校正死亡率已达71.99%;各浓度苦参·印楝素和苏云金芽胞杆菌处理产后24、48和72 h黏虫卵后,其初孵幼虫校正死亡率介于39.02%～83.59%之间。苦参·印楝素对产后24、48 h黏虫卵的毒力最大,致死中浓度LC_(50)分别为0.018、0.109 mg/L;苏云金芽胞杆菌对产后72 h黏虫卵的毒力最大,LC_(50)为0.004 mg/L。黏虫卵经5种药剂处理后,幼虫化蛹率、蛹重和羽化率分别介于91.07%～93.64%、0.272～0.284 g和86.60%～87.78%之间,与对照差异不显著,幼虫存活率较对照显著下降43.02%～60.27%,幼虫发育历期较对照延长0.23～0.88 d,其中灭多威、苦参·印楝素、苏云金芽胞杆菌处理的幼虫发育历期较对照显著延长。苦参·印楝素、苏云金芽胞杆菌使胚胎无法形成正常胚带,同时会使已发育的虫体出现蜷缩、腹部皱缩;高效氯氟氰菊酯会延缓胚胎发育时间,使已形成的虫体畸形或使其肠道断裂;甲维盐影响虫体对营养物质的吸收,造成虫体萎缩,使其不能正常孵化。在黏虫卵防治中推荐使用苏云金芽胞杆菌和苦参·印楝素。