Prey density-dependent feeding activity and life history of <Emphasis Type="Italic">Scymnus subvillosus</Emphasis>

The functional response, development time, survival and reproduction of the lady beetle Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae) were evaluated at different densities of the mealy plum aphid Hyalopterus pruni (Geoffroy) (Homoptera: Aphididae). Treatments were carried out at 25 ± 1°C, 60 ± 10% r.h. and 16L:8D photoperiod in a controlled temperature room. The larvae and adults of S. subvillosus were fed with different densities (5, 10, 20, 40 and 80) of H. pruni in petri dishes. The shape of the functional response was determined by logistic regression, and the values of the coefficient of attack rates (α) and handling times (T _h) were estimated by using nonlinear least-squares regression. Behavior of each larval stage and adults matched Holling’s type II functional response. Estimates of α for all stages of S. subvillosus tested were similar, but estimates of T _h varied; it was the shortest for adult females and the longest for third instar larva. Larvae were able to complete their development at each of the five prey densities, but increased prey densities reduced development time and mortality rate. Increased prey consumption did not change longevity, but resulted in a higher intrinsic rate of increase (r), the finite rate of increase (λ), net reproduction rate (R ₀ ), gross reproductive rates (GRR), and shorter mean generation time (T) and doubling time (DT). This research was funded by the Yuzuncu Yil University/foundation of scientific research projects (No. 2002-ZF 044)     

亚致死浓度毒死蜱对小麦禾谷缢管蚜生长和繁殖的影响

为探讨毒死蜱对小麦禾谷缢管蚜Rhopalosiphum padi(Linnaeus)的亚致死效应,采用玻璃管药膜法确定了其亚致死浓度(LC10、LC20和LC30),并研究了该浓度下毒死蜱对小麦禾谷缢管蚜生长和繁殖的影响。结果表明:以LC10、LC20和LC30浓度处理后,禾谷缢管蚜成蚜的寿命分别为(8.60±0.22)、(8.03±0.18)和(6.68±0.18)d,均显著短于对照的(10.36±0.31)d;单雌产仔量分别为(21.88±0.63)、(20.41±0.53)和(16.68±0.35)只,也均显著少于对照的(26.40±0.89)只;产仔历期分别为(7.55±0.22)、(6.69±0.17)和(5.64±0.15)d,均显著短于对照的(9.13±0.31)d;试验浓度药剂处理对下一代若蚜期的影响不显著;LC30浓度处理对下一代成蚜繁殖有显著的抑制作用,可减少单雌产仔量3.74只,缩短产仔历期1.39 d。生命表参数分析表明:LC30浓度毒死蜱处理使小麦禾谷缢管蚜的净增殖率(R0)比对照降低了34.71%,使种群加倍时间(t)比对照延长了17.37%;LC20浓度处理使小麦禾谷缢管蚜的平均世代历期(T)延长了12.59%;LC10浓度处理组各项指标与对照间无显著性差异。研究表明,亚致死浓度毒死蜱能够缩短小麦禾谷缢管蚜成蚜的寿命,降低其繁殖力,该结果对小麦禾谷缢管蚜综合防治策略的制定具有积极意义。     

Q型烟粉虱对不同番茄品种的适生性

为探究烟粉虱对不同番茄品种的适生性差异,于温室条件下采用生态测定和生化方法,研究了Q型烟粉虱在不同番茄品种上的生物学参数及不同番茄品种叶片营养物质和次生物质含量的差异,并利用"Y"型嗅觉仪测定了Q型烟粉虱成虫对不同番茄品种的行为反应。结果表明,Q型烟粉虱在供试5个不同番茄品种上的存活率、产卵量及种群生命表参数均存在显著差异,其存活率、产卵量、净增殖率和内禀增长率均以在绿肩2号上最高,分别为80.43%、314.00、42.21和0.12,在精品淑娇上最低,分别为41.58%、93.33、12.05和-0.10。不同番茄品种的营养物质和次生物质含量差异显著,可溶性蛋白质和叶绿素含量均以绿肩2号最高,分别为4.13、2.50 mg/g,总黄酮和总酚含量以金陵红玉最高,分别为9.60、9.04 mg/g。行为反应结果显示Q型烟粉虱对绿肩2号的选择性较强,与苏红2003相比,选择率为61.5∶38.5;对精品淑娇最弱,与绿肩2号相比,选择率为41.3∶58.7。     

Demography and population projection of <Emphasis Type="Italic">Myzus persicae</Emphasis> (Sulz.) (Hemiptera: Aphididae) on five pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) cultivars

The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a major pest of pepper. In this study, we collected data on the development, survival, fecundity, and proportion of apterous and alate forms of green peach aphid reared on five commercial pepper cultivars (Amiral, Erciyes, Mert, Mertcan, and Naz) at 25?±?1°C, 60?±?5% RH, and a photoperiod of 16:8 (L:D) h. We analyzed the life history raw data by using the age-stage, two-sex life table. The shortest development time (6.66 days) and highest fecundity (62.68 individuals) occurred on the Erciyes cultivar. The highest intrinsic rate of increase (r?=?0.332 d^?1), finite rate of increase (λ?=?1.394 d^?1), net reproductive rate (R₀?=?62.7 offspring) and shortest mean generation time (T?=?12.45 d) also occurred on the Erciyes cultivar; while the lower fitness occurred on the Amiral, Mertcan and Naz cultivars. Our results compared differences in the population growth rate of M. persicae on different pepper cultivars. This information will be useful to individuals working in pest management programs particularly those involving M. persicae.     

Detection ofplum pox virus in ornamentalPrunus cerasifera

Plum pox virus (PPV) is the causal agent of sharka disease. It is a serious threat for temperate fruit, mainly apricots, plums and peaches. In order to study the ability ofPPV to infect wild and ornamentalPrunus species, several wild, native ornamental stone fruits and weeds were analyzed as possible reservoirs ofPPV. Five species of ornamental stone fruits and 24 species of weeds were evaluated between 2000 and 2004. The virus was not found in the weeds but was detected in one species of ornamental stone fruit, purple cherry-plums (Prunus cerasifera Pissardii). ThePPV strain M was identified by DASI-ELISA and confirmed by IC-RT-PCR. Additionally, mealy plum aphid (Hyalopterus pruni) was determined as a vector ofPPV inP. cerasifera. This is the first report on the reservoir potential of ornamental stone fruit trees and weeds forPPV in Turkey. http://www.phytoparasitica.org posting July 19, 2006;     

Effect of apple cultivar and of temperature on the biology and life table parameters of the twospotted spider mite<Emphasis Type="Italic">Tetranychus urticae</Emphasis>

Development duration and reproduction rate of the twospotted spider miteTetranychus urticae Koch (Acarina: Tetranychidae) were studied on five different apple cultivars (‘Amasya’ (local cultivar), ‘Golden Delicious’, ‘Granny Smith’, ‘Starking Delicious’ and ‘Starkrimson Delicious’) at 25°C, 65±10% r.h. and 16:8 L:D. In addition, the same parameters were determined on Golden Delicious leaves at three constant temperatures (20°, 30° and 35°C, 65±10% r.h. and 16:8 L:D) in the laboratory.T. urticae performed better on Granny Smith than on the other cultivars, due mainly to high daily egg production (4.6 eggs/♀/day) and the intrinsic rate of natural increase (r _m , which was 0.243 ♀/♀/day). The lowestr _m was observed on Amasya variety (0.231 ♀/♀/day). Development periods of immature stages ofT. urticae varied from 6.5 to 15.5 days at 35° and 20°C, respectively, for females, and from 5.9 to 14.5 days at 35° and 20°C, respectively, for males. The development thresholds of the eggs and pre-adult stages, respectively, were 10.78° and 8.43°C, and total effective temperatures were 57.80 and 172.41 degree-days. Mean generation time (T _o ) of the population ranged from 9.94 days at 35°C to 25.99 days at 20°C. The net reproduction rate increased from 66.99 ♀/♀ at 20°C to 92.19 ♀/♀ at 25°C, and decreased to 84.34 ♀/♀ at 30°C and to 12.04 ♀/♀ at 35°C. The highest r _m occurred at 30°C (0.302 ♀/♀/day) and the lowest at 20°C (0.161 ♀/♀/day). http://www.phytoparasitica.org posting Dec. 19, 2003.     

Evaluation of peach and nectarine cultivars in Bulgaria for their resistance to plum pox potyvirus

In spring and summer 1989, it was established that plum pox potyvirus (PPV) was present in certain peach cultivars in Bulgaria. At the same time, we started to investigate the distribution of PPV in naturally infected 4–5 year-old peach and nectarine cultivars and hybrids in order to optimize PPV detection. Over 160 peach and nectarine cultivars and hybrids were evaluated. In about 40% of the genotypes, typical plum pox symptoms were observed. The latter were estimated and divided into groups depending on their susceptibility to PPV. Observations were made on the population density of seven aphid species established in the peach orchards. Five proved to be vectors of the virus. Myzus persicae was the vector that played the main role in spreading the virus on peach.     

三种杀螨剂对双尾新小绥螨后代生长发育和繁殖的影响

为明确杀螨剂对双尾新小绥螨Neoseiulus bicaudus后代生长发育及繁殖的影响,采用联苯肼酯、三唑锡和哒螨灵对土耳其斯坦叶螨Tetranychus turkestani的致死中浓度处理双尾新小绥螨雌成螨,测定其后代各发育阶段的存活率、发育历期、寿命、雌性比例及繁殖力,构建亚致死条件下双尾新小绥螨后代的年龄-龄期两性生命表并模拟其种群增长模型,分析不同杀螨剂亚致死效应对捕食螨后代的影响。结果表明,联苯肼酯处理能显著缩短双尾新小绥螨后代的未成熟期（4.81 d）,显著延长双尾新小绥螨后代雌成螨的寿命（45.43 d）,且对存活率、产卵前期、雌性比例和净增殖率无显著影响。三唑锡处理降低了双尾新小绥螨后代雌性比例（0.37）并显著降低了其后代净增殖率（15.91）,对未成熟期、产卵前期和雌雄成螨寿命均无显著影响。哒螨灵处理对双尾新小绥螨后代的未成熟期、存活率、雌成螨寿命、产卵前期、和雌性比例均未产生显著影响,仅显著延长了雌雄成螨寿命（51.22 d和44.23 d）。经所建Timing种群模型模拟,3种杀螨剂处理后双尾新小绥螨后代种群均可以继续增殖,经过60 d无限制增殖后,联苯肼脂处理的双尾新小绥螨后代种群数量是对照的1.62倍,达4 976头;哒螨灵处理（2 101头）和三唑锡处理（983头）的种群数量较对照分别减少了31.43%和67.92%。表明联苯肼脂对双尾新小绥螨后代影响较小,是较为安全的杀螨剂。     

Effect of certainBrassica plants on biology of the cabbage aphidBrevicoryne brassicae under laboratory conditions

The development time, mortality, survivorship and reproduction of the cabbage aphidBrevicoryne brassicae (L.) were evaluated on detached leaves of sixBrassica species (cabbage cv. ‘Yalova 1’, cauliflower cv. ‘Early Snowball’, broccoli cv. ‘Marathon’, turnip cv. ‘Antep’, rapeseed cv. local variety, and wild mustard) at a constant temperature of 20°C. Total development time ofB. brassicae was the shortest (8.9 days) on cauliflower and the longest (10.4 days) on cabbage. Mortality of immature stages varied from 16% on cabbage to 88% on turnip. Longevity of the cabbage aphid was the shortest (6.2 days) on mustard, and the longest (21.8 days) on cauliflower. The net reproductive rate was highest (35.98) on cauliflower, and lowest (1.89) on turnip. The intrinsic rate of increase was 0.2345 on cauliflower, followed by 0.2009 on cabbage, 0.1976 on broccoli, 0.1662 on mustard, 0.1357 on rapeseed, and 0.0465 on turnip. Cabbage, cauliflower and broccoli were susceptible host plants for the cabbage aphid. Rapeseed, turnip and mustard showed resistance to the pest.     

寄主植物对棉蚜乙酰胆碱酯酶的影响

通过生物测定和生化分析研究了5种不同寄主植物上的棉蚜种群对灭多威的敏感性，乙酰胆碱酯酶（AChE)活性及灭多威对AChE的抑制作用，结果发现，取食石榴和花椒的棉蚜AChE活性最高，是冬青上棉蚜（最低）的2．00倍和3．33倍，说明寄主植物可以影响棉蚜AChE的活性，灭多威对不同寄主植物上的棉蚜个体的AChE进行抑制后，发现棉花和冬青上的棉蚜种群中AChE对灭多威不敏感的棉蚜个体多于花椒，木槿和石榴上的棉蚜种群，这与棉花及冬青上的棉蚜对灭多威耐药性较其它三种强的趋势近似，表明AChE敏感度的降低是棉蚜对灭多威产生抗药性的原因之一。     

Seasonal abundance and spatial distribution of the predator<Emphasis Type="Italic">Macrolophus costalis</Emphasis> and its prey<Emphasis Type="Italic">Myzus persicae</Emphasis> on tobacco

Field studies were conducted to assess the population and the spatial dynamics of the predatory bugMacrolophus costalis Fieber (Hemiptera: Miridae) and of its prey, the aphidMyzus persicae (Sulzer) (Hemiptera: Aphidoidea), on tobacco. From an untreated tobacco field in Tithorea (central Greece), tobacco leaves were collected from the upper and the lower half of the plants from June until September, in 1999 and 2000. The numbers ofM. costalis andM. persicae individuals per leaf were counted. Most aphids were observed during July and August (early and mid season), with densities dropping markedly in September. In contrast,M. costalis population densities increased late in the season (September). Significantly higher numbers of aphids were found on the upper half of the plants than on the lower half. In contrast, significantly moreM. costalis individuals were observed on the lower half. Iwao’s Regression Analysis was used in order to characterize the spatial pattern of the two species. According to this model, in both sampling seasons, aphids andM. costalis nymphs displayed an aggregated spatial pattern, whileM. costalis adults were found to be randomly distributed among sampling units. Although moreM. costalis individuals were recorded on leaves with relatively high aphid densities, this species did not react numerically to changes in prey density. In addition, a significant number of bugs were found on leaves with low aphid densities or no aphids at all. http://www.phytoparasitica.org posting Dec. 18, 2002.     

小麦叶片营养物质与抗麦长管蚜的相关性分析

为了阐明小麦叶片营养物质与小麦抗蚜性之间的关系,观察了麦长管蚜Sitobion avenae(F.)在不同小麦品种上的选择趋性,测定其相对日均体重增长率,并采用Branford法和高效液相色谱技术分别测定了不同品种小麦叶片总蛋白、韧皮部中游离氨基酸以及可溶性糖的含量。结果表明,麦长管蚜显著趋向于铭贤169、西农889与西农1376;在铭贤169、西农889和西农1376上的成蚜相对日均体重增长率显著大于中四-有芒、小偃22;西农889叶片的总蛋白含量最高,为2 822.04μg/mL,小偃22叶片韧皮部的可溶性糖含量最高,铭贤169和西农889叶片韧皮部的游离氨基酸总含量相对较高,分别为1 424.3、1 301.1 nmol·L~(-1)·g~(-1)DW;各游离氨基酸在相对抗蚜品种中四-有芒和小偃22中的绝对含量与其抗蚜性无相关性。研究表明,中四-有芒、小偃22对麦长管蚜具有较强的抗性,植物营养在小麦抗蚜性中起到一定作用。     

Natural enemies and seasonal abundance of the blackmargined aphid (Monellia caryella) in pecan orchards in Israel

The blackmargined aphid,Monellia caryella (Fitch), exhibited a seasonal pattern with early and late peaks of the population in pecan orchards at Newe Ya’ar in the Yizre’el Valley. A similar pattern was not observed at Kibbutz Sede Eliyyahu in the Bet She’an Valley, where there was a single peak, late in the season. The occurrence of natural enemies indicated that spiders and lacewing eggs were the predators most commonly associated with population fluctuations of the aphid. In most cases the rate of increase of the blackmargined aphid was highest late in the season.     

Effects of plant chemicals on the Cotton Bollworm,Helicoverpa armigera (Hübner): A multi-generation study

We studied the effects of feeding on different cotton cultivars with different gossypol contents on the development, reproduction and food plant utilization of three successive generations of Cotton Bollworm, Helicoverpa armigera (Hübner). Significantly higher larval survival rates were observed in three successive generations of H. armigera fed on cotton cultivar “ZMS13”compared with cultivars “M9101” and “HZ401”. There was a significant decrease in fecundity in the first generation compared with the second and third generations of cotton bollworms fed on “M9101” and “ZMS13”. Cotton bollworm generation significantly influenced mean relative growth rate, relative growth rate and relative consumption rate. The relative growth rate significantly decreased in three successive generations of H. armigera fed on the high-gossypol cultivar “M9101” compared with those fed on low-gossypol cultivar “ZMS13”. However, a significantly higher relative growth rate was recorded in the third generation than in the first generation fed on “M9101”. Measurements of development and food utilization at the individual and population levels over more than one generation ought to provide a more meaningful prediction of long-term and population dynamics of the cotton bollworm.     

Epidemiology of sharka disease in Spain

PPV was first detected in Spain in 1984 in Japanese plum ( Prunus salicina Lindl) cv. Red Beaut and spread very quickly to other Japanese and European plums and apricot cultivars but left peach cultivars unaffected. In the years following the detection of PPV, the predominant aphid species visiting Prunus orchards in Mediterranean areas were Aphis gossypii followed by Aphis spiraecola , the latter being the main aphid species found at present. Both species are considered to be the main vectors of PPV in Spanish early Prunus growing areas. Spatial analysis of the spread of PPV-D in Japanese plum and apricot trees confirmed the lack of significant association between immediately adjacent trees. The observed spatial pattern of sharka suggests a lack of movement of PPV-viruliferous aphid vectors to immediately adjacent trees and indicates their preferential movement to trees several tree spaces away. PPV-D is the only type currently present in Spain, with the exception of a PPV-M outbreak that was detected in and successfully eradicated from Aragón in 2002. The short-distance spread of PPV-M infection occurred as far as 12 m along the rows of peach trees. However, PPV-D has not been observed to spread through peach cultivars, despite being grown in the vicinity of heavily infected plots of apricot or Japanese plum trees.     

The effect of some cucumber cultivars on the biology of <Emphasis Type="Italic">Aphis gossypii</Emphasis> Glover (Hemiptera: Aphididae)

The development, reproduction, and population growth parameters of cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), were studied on three different Cucumis sativus cultivars (Beith Alpha Bal?kesir, B.T. Bursaalpha, Beith Alpha MR,) under controlled conditions (25?±?1 °C, 65?±?5% RH, and a photoperiod of 16:8 (L:D) h. Life table parameters were estimated according to age-stage, two-sex life table method. Results indicated that the Bt Bal?kesir are favorable hosts for A. gossypii because of the shorter preadult developmental time, lower preadult mortality rate, and higher total fecundity on this cultivar. The intrinsic rate of increase (r?=?0.4214 d^-1), the net reproduction rate (R₀?=?51.80 offspring), and the finite rate of increase (λ?=?1.5242 d^-1) values were higher on the Bt Bal?kesir. The effect of cucumber cultivars on the biology of A. gossypii was determined as significant and it was found that cv. Bt Bal?kesir was the most convenient cucumber cultivar in terms of the life cycle of A. gossypii. For an ecological and economic pest control, against aphids use of resistant or less favourable crop cultivars is considered one of the important components of integrated pest management. Therefore, results acquired might be used in pest management program that will be prepared for this aphid.     

寄主植物对苹果黄蚜药剂敏感性及解毒酶活性的影响

为研究寄主对苹果黄蚜药剂敏感性及体内酶活力的影响,采用生物测定和生化方法分别对取食杏树、李子树、梨树和苹果树的苹果黄蚜种群的药剂敏感性及解毒酶活性进行了测定。供试药剂对杏树、李子树、梨树和苹果树上蚜虫种群的相对毒力指数测定结果表明,吡虫啉为3.53、3.12、2.55和1.00,马拉硫磷为2.42、2.06、1.69和1.00,溴氰菊酯为2.96、1.66、1.43和1.00,灭多威为2.11、1.65、1.37和1.00;对四种药剂的敏感性大小均为杏树种群>李子树种群>梨树种群>苹果树种群。蚜虫的谷胱甘肽-S-转移酶(GST)、乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)、多功能氧化酶(MFO)的离体酶活力顺序均为苹果种群>梨树种群>李子树种群>杏树种群,四个蚜虫种群的GST活力比值分别为2.32、1.73、1.35和1.00,AChE活力比值为2.48、1.73、1.66和1.00,CarE活力比值为1.60、1.27、1.23和1.00,MFO活力比值为2.02、1.31、1.13和1.00。各种群间的四种酶活力差异均达显著水平。说明寄主植物能影响苹果黄蚜药剂敏感性及解毒酶活力水平。     

Note: Survey of seedborne fungi of sudanese cultivars of onion,with new records

Through incubation of onion (Allium cepa L.) seed samples on potato dextrose agar and moist filter papers at 28±2°C, 32 species and four varieties belonging to 19 genera of fungi were determined as seedborne in this crop. Among them, 23 species are new reports to the mycoflora of onion seeds.Aspergillus (11 species and three varieties, ∼42.1% of the total colony count of fungi) was the most prevalent genus:A. niger (∼19.7%) was found at the highest rate in the seeds, followed byA. parasiticus (∼17.3%,A. oryzae (∼17.3%) andA. flavus (∼14.5%). The genusAspergillus was followed byPenicillium (∼12.4%),Sclerotium (∼7.1%),Fennellia, Rhizopus, Chaetomium, Drechslera andAlternaria (∼12.4%),Fusarium, Emericella andByssochlamys (∼7.1%), whereas the remaining eight genera displayed a low level of infection (∼10%). Twenty-seven species, three varieties and 12 genera represent Hyphomycetes; four genera, three species and one variety — Ascomycotina; one genus and one species — Zygomycotina; two genera and two species — other Deuteromycotina; and one genus — Oomycetes. Some species, which are known to cause devastating pre- and postharvest diseases to onion crops, were recovered from the seeds of this crop, suggesting the high possibility of their transmission by seed. http://www.phytoparasitica.org posting July 14, 2004.     

Toxic culture filtrates produced byCalonectria ilicicola, causal agent of red crown rot of soybean

Eleven soybean cultivars with different levels of susceptibility to virulent isolate SG915 ofCalonectria ilicicola were examined for reaction to metabolites produced by the isolate. When the culture filtrate from isolate SG915 was applied to trifoliates from 11 cultivars, cvs. ‘Cajun’ and ‘Asgrow 7986’ exhibited reduced wilting severity. However, there was no correlation between sensitivity to culture filtrate and susceptibility to the fungal isolate. Wilting severity on cv. ‘Riverside 699’ was greatest when trifoliates were treated with culture filtrates from isolates SG915 (highly virulent) and C31 (less virulent). The dilution end-point for culture filtrates of virulent isolate SG915 was determined to be 1:8. Nonautoclaved culture filtrates caused complete wilt of soybean trifoliates after 36 h, but autoclaved culture filtrates demonstrated a reduced ability to wilt leaves. Electrolyte leakage from treated leaf tissues increased over time regardless of the concentrations of culture filtrate tested. The greatest electrolyte losses were observed during the initial 30 min incubation of leaf tissues. The highest concentration of culture filtrate (50%, v/v) induced more electrolyte loss than the low concentration (10%, v/v) or control. These results suggest that toxic metabolites ofC. ilicicola may be involved in disease development with leaf symptom expression.