不同作物田烟粉虱发生的时空动态

2008～2009年连续2年系统调查了番茄、茄子、棉花、大豆、玉米等寄主植物上烟粉虱种群发生的时间与空间动态。结果表明：不同寄主植物上的烟粉虱成虫及其伪蛹数量有显著性差异,其密度大小依次为：茄子>棉花>番茄>大豆>玉米。其中,在玉米上除了发现极少量的成虫逗留外,没有发现烟粉虱的卵及若虫。在发生的时间序列上,烟粉虱成虫及伪蛹的数量呈现为先逐渐上升后又下降的变化过程,发生高峰期集中在8月5日到8月31日,9月初以后烟粉虱数量慢慢减少。在空间分布上,表现为烟粉虱成虫喜食寄主的上部叶片。统计分析显示,寄主对烟粉虱成虫和伪蛹的数量的影响极显著,而年份对其数量的影响没有显著差异。由此得出的烟粉虱发生和达到高峰的时间,可为烟粉虱预测预报和区域性综合治理提供重要理论依据。     

烟粉虱成虫对黄瓜叶龄的喜好性及与后代发育适合度间的关系

在室内采用笼罩和发育测定方法,研究了烟粉虱成虫对黄瓜叶龄的喜好性及其与后代生长发育、存活之间的关系,同时调查了叶毛密度与成虫喜好性之间的相关关系。结果表明(1)烟粉虱成虫比较喜欢在黄瓜植株的中部叶片取食和产卵。(2)叶龄对烟粉虱的存活率没有显著影响,对烟粉虱的发育历期只在卵期和若虫四龄期表现出显著影响,对其他龄期或整个世代均没有显著影响。(3)叶毛密度随着叶龄的增大而顺次显著减小;在接虫初始阶段,烟粉虱成虫的叶片选择性与叶毛密度成显著负相关关系,但72h后具有中等叶毛密度的叶片上的成虫数量和着卵量均显著高于叶毛密度较大或较小的叶片。研究结果对培育抗烟粉虱的黄瓜品种和改进烟粉虱的防治措施具有一定指导意义。     

辣椒碱对烟粉虱的生物活性及生长发育和生殖力的影响

在实验室条件下研究了辣椒碱对烟粉虱的生物活性及生长发育和生殖力的影响.结果表明:辣椒碱对烟粉虱各虫态均有杀虫活性,且随辣椒碱浓度的增大活性增强;辣椒碱浸叶法/浸虫法处理对烟粉虱成虫、卵和若虫的毒力(LC50分别为3525.79、1603.29和1526.27mg·L-1))均高于内吸法处理(LC50分别为5360.04、2359.19和5897.43 mg.L-1),两种处理方法下辣椒碱对烟粉虱卵的毒力均明显高于对成虫的毒力;2000和4000 mg·L-1浓度辣椒碱对烟粉虱成虫具有明显的拒食作用,烟粉虱在该两种浓度辣椒碱处理过的棉花叶上取食24 h的蜜露分泌量均显著低于取食非处理棉花叶后的蜜露分泌量;辣椒碱各试验浓度对烟粉虱成虫均表现出较强的产卵忌避作用,当辣椒碱处理浓度达4000 mg·L-1时,对烟粉虱的选择性产卵忌避率和非选择性产卵忌避率分别高达94.2％和83.0％.500、1000和2000 mg·L-1辣椒碱浸渍处理对烟粉虱存活卵和若虫的发育历期、成虫羽化率均没有影响,但辣椒碱4000mg·L-1处理明显延长烟粉虱若虫发育历期、降低成虫羽化率.不同浓度辣椒碱处理均明显抑制烟粉虱生殖力,且这种抑制作用随辣椒碱浓度的增大而增强.     

Sublethal effects of imidacloprid on Bemisia tabaci (Hemiptera: Aleyrodidae) under laboratory conditions

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pests in tropical and subtropical agriculture and is a key pest in greenhouse production worldwide. Current management of B. tabaci relies upon frequent applications of insecticides. Insecticide use not only directly affects pest populations through acute toxicity but also has indirect (sublethal) effects on pest physiology or behavior. In this study, we described sublethal effects of imidacloprid on adult feeding, immature development, adult fecundity, and F1 development of B. tabaci. Honeydew excretion of adults feeding on leaves treated with LC20 and LC40 concentration was significantly lower than that on untreated leaf discs. Egg production of B. tabaci adults subject to LC20 and LC40 concentrations also was less than untreated individuals. Upon transfer to untreated leaves, honeydew excretion and egg production recovered well within 24 and 48 h, respectively. Exposure to LC20 and LC40 concentrations significantly affected developmental time of B. tabaci eggs and nymphs, whereas it did not affect adult molting rate. We did not find sublethal effects on longevity and fecundity of B. tabaci adults when exposed to LC90 and LC40 concentrations for 24 h, and on egg hatching rate, nymphal mortality, and molting rate of the subsequent F1 generation. Exposure to imidacloprid at LC40 concentration significantly decreased the number of females in the F1 generation. Imidacloprid negatively affects development and reproduction of exposed individuals, and sex ratio of subsequent (F1) generation of B. tabaci, which probably disrupts B. tabaci population dynamics, slows population increase, and reduces infestation levels. Therefore, it is necessary to consider potential impact from imidacloprid for integrated management of the pest.     

不同邻作作物对番茄田间烟粉虱种群动态的影响

为明确不同邻作模式下番茄田间烟粉虱的种群动态与空间分布格局,于云南省昆明市选取与西葫芦、黄瓜、玫瑰等作物邻作的番茄田及单作番茄田为研究样地,通过五点取样法进行调查,采用四分位法对不同作物邻作的番茄田间烟粉虱种群动态进行分析.结果表明:在烟粉虱的主要发生期,番茄单作田间烟粉虱种群数量最高,雌成虫达26.69头?叶-1,雄...     

Toxicity of sucrose octanoate to egg, nymphal, and adult Bemisia tabaci (Hemiptera: Aleyrodidae) using a novel plant-based bioassay

The sweetpotato whitefly, Bemisia tabaci (Gennadius), B biotype, presents a unique problem for vegetable growers by serving as a vector of plant viruses and by inducing physiological disorders of leaves and fruit. An action threshold of a single whitefly is necessary because of the threat of disease in many areas and growers rely heavily on a single class of insecticides (neonicotinoids) for whitefly control. Additional control methods are needed to manage this pest in commercial vegetables. Extracts of wild tobacco contain natural sugar esters that have previously been shown effective in controlling many soft-bodied insects. We developed a novel tomato leaf bioassay system to assess a synthetic sugar ester derivative, sucrose octanoate, for insecticidal activity against the eggs, nymphs, and adults of B. tabaci. The LC50 values for sucrose octanoate against adults, second instars, and fourth instars of the whitefly were 880, 686, and 1,571 ppm, respectively. The LC50 against whitefly eggs was higher (11,446 ppm) but indicated that some egg mortality occurred at the recommended application rate of 0.8-1.2% (3,200-4,800 ppm [Al]). Toxicity of sugar esters to whitefly eggs has not been reported previously. The tomato leaf bioassay produced reliable and repeatable results for whitefly toxicity studies and predicted that effective nymph and adult whitefly control can be achieved with sucrose octanoate at application rates < or = 1% (4,000 ppm [AI]). Field efficacy studies are warranted to determine whether this biorational pesticide has application in commercial tomato production.     

Distribution and sampling of the whiteflies Aleurothrixus floccosus, Dialeurodes citri, and Parabemisia myricae (Homoptera: Aleyrodidae) in citrus in Spain

From 1993 to 1995 data sets were collected from four citrus groves in Valencia, Spain, to determine the distribution patterns of eggs and nymphs of Aleurothrixus floccosus (Maskell), Dialeurodes citri (Ashmead), and Parabemisia myricae (Kuwana) on leaves, and to develop reliable sampling plans for estimating densities of immature whiteflies. A. floccosus showed higher aggregation than the other two species. The dispersion index b from the Taylor power law did not vary between different developing stages for A. floccosus and D. citri, reaching overall values of 1.70 and 1.53, respectively. In P. myricae, b was 1.60 for eggs and N1, and 1.46 for the remaining nymphs. The minimum number of leaves to estimate the population density with a coefficient of variation of 0.25 for densities above 10 immature whiteflies per leaf was 40 for D. citri and P. myricae, and 250 for A. floccosus. Binomial sampling programs for the three species were rejected for pest management purposes due to the high sample sizes required. The enumerative procedure of counting the number of insects per leaf appears to be the most suitable method for D. citri and P. myricae. For A. floccosus an index of occupation (from 0 to 10) linearly related to the proportion of the leaf undersurface occupied by this insect was found to be reliable and time-saving. Examining 150 leaves with this index achieves the desired relative variation level of 0.25 for most population densities usually found in commercial groves.     

Within-plant distribution of onion thrips (Thysanoptera: Thripidae) in onions

Two aspects of the within-plant distribution of Thrips tabaci Lindeman (Thysanoptera: Thripidae) on onion, Allium cepa L., plants were investigated: 1) diurnal variations in the distribution of adults and larvae between basal and upper sections of onion leaves, and 2) between-leaf and within-leaf distribution of the eggs. The diurnal investigations showed that higher proportions of larvae than of adults congregated at the basal sections of plants, particularly when plants were young and thrips density was low. As plants matured and thrips density increased, the larvae became more dispersed. Regardless of plant size, there were always more adults in the upper than basal plant sections. There were no clear time-windows during the 24-h diurnal cycle when more thrips were in the upper plant parts. T. tabaci eggs were laid everywhere in the plant. Leaves of intermediate ages had more eggs than older or younger leaves. Within leaves, the white leaf sheath received the least eggs and leaf tips received slightly more eggs than leaf sheaths. The highest egg density was found between the green leaf base and the leaf tips. Regardless of plant size, more than half of all eggs were laid above the basal sections. The percentage increased to >95% in mature plants. Except when plants were small the outer leaves were preferred over inner leaves and upper leaf sections preferred over lower leaf sections as egg-laying sites by adults. Implications of the results in the management of T. tabaci are discussed.     

Characterization of resistance, evaluation of the attractiveness of plant odors, and effect of leaf color on different onion cultivars to onion thrips (Thysanoptera: Thripidae)

Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a worldwide pest of onion, Allium cepa L. In field studies on onion resistance conducted in 2007 and 2008 using 49 cultivars, 11 showed low leaf damage by T. tabaci. In laboratory studies, the 11 cultivars, along with two susceptible checks and four additional cultivars, were evaluated to characterize resistance to T. tabaci and to determine if color and/or light reflectance were associated with resistance to T tabaci. No-choice tests were performed with adults and the numbers of eggs and larvae were counted on each cultivar after three and 10 d, respectively. In choice tests in which all cultivars were planted together in a circle in a single pot, 100 adults were released and the number of adults on each plant was evaluated 24 h later. The behavioral response of walking T. tabaci adults to plant odors was studied in a glass Y-tube olfactometer. The reflectance spectrum of leaves was measured using a UV-VIS spectrophotometer. Results indicate that resistant cultivars showed an intermediate-high antibiotic effect to T. tabaci and all of them showed a very strong antixenotic effect. There were no significant preferences in the response of walking T. tabaci adults to plant odors. The two susceptible cultivars had the highest values of leaf reflectance for the first (275-375 nm) and second (310-410 nm) theoretical photopigment-system of T. tabaci, and these values were significantly different from most resistant cultivars. These results suggest a strong response of T. tabaci to onion cultivars with higher reflectance in the ultraviolet range (270-400 nm). Overall, these results appear promising in helping to identify categories of resistance to T. tabaci in onions that can be used in breeding programs.     

Effect of Eugenia winzerlingii Extracts on Bemisia tabaci and Evaluation of its Nursery Propagation

The development of plant-derived products to control Bemisia tabaci Genn. (Hemiptera: Aleyrodidae) is an urgent need for production of horticultural crops. Plant extracts and essential oils of several species of the genus Eugenia (Myrtaceae) have shown insecticidal activity. In southern Mexico, leaf extracts from Eugenia winzerlingii showed nematicidal effect but its insecticidal properties have not been explored. Therefore, the objective of this study was to evaluate the insecticidal effect of aqueous and organic extracts from E. winzerlingii leaves on B. tabaci egg, nymph and adult stages, and else to explore its nursery propagation. Then, extracts of this species were obtained by maceration with different polarity solvents. Bioassays were carried out on Capsicum chinense leaves. Mortality assays showed that aqueous and total crude ethanol (TCE) extracts necrosed the eggs (LC50 = 0.21% w/v and 4.68 mg/mL, respectively), whereas hexane, ethyl acetate (ETA), residual ethanol and TCE extracts affected the nymphs (LC50 = 0.25 - 4.85 mg/mL). In adults, oviposition inhibition by free choice assay indicated that TCE and ETA extracts had major activity (EC50 = 14.62 and 27.86 μg/cm2, respectively). On other hand, the sexual and vegetative propagation of E. winzerlingii showed that this species can be easily cultivated by seeds. In conclusion, extracts of E. winzerlingii leaves are highly effective in controlling B. tabaci. TCE extract, in particular, was toxic to three stages of B. tabaci. This plant could be a potential alternative to develop a novel botanical insecticide to manage this destructive pest.     

Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus

The abundance and spatial dispersion of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) were studied in 34 grapefruit (Citrus paradisi Macfad.) and six sweet orange [Citrus sinensis (L.) Osbeck] orchards from March to August 2006 when the pest is more abundant in southern Texas. Although flush shoot infestation levels did not vary with host plant species, densities of D. citri eggs, nymphs, and adults were significantly higher on sweet orange than on grapefruit. D. citri immatures also were found in significantly higher numbers in the southeastern quadrant of trees than other parts of the canopy. The spatial distribution of D. citri nymphs and adults was analyzed using Iowa's patchiness regression and Taylor's power law. Taylor's power law fitted the data better than Iowa's model. Based on both regression models, the field dispersion patterns of D. citri nymphs and adults were aggregated among flush shoots in individual trees as indicated by the regression slopes that were significantly >1. For the average density of each life stage obtained during our surveys, the minimum number of flush shoots per tree needed to estimate D. citri densities varied from eight for eggs to four flush shoots for adults. Projections indicated that a sampling plan consisting of 10 trees and eight flush shoots per tree would provide density estimates of the three developmental stages of D. citri acceptable enough for population studies and management decisions. A presence-absence sampling plan with a fixed precision level was developed and can be used to provide a quick estimation of D. citri populations in citrus orchards.     

烟粉虱在不同寄主作物上的种群动态及化学防治

20 0 1年在河北省廊坊市研究了烟粉虱Bemisiatabaci(Gennadius)在主要寄主作物棉花、大豆、花生和玉米上的种群动态和化学防治方法。研究结果表明 ,烟粉虱的种群数量在寄主的生育期内持续增长 ,在 8月 2 2日左右达到高峰 ,之后逐渐减少。烟粉虱虽然寄主范围广泛 ,但在每种寄主上的发生量并不一致 ,调查结果表明烟粉虱在 4种不同寄主上的种群数量比较为 :棉花 >大豆 >花生 ,玉米上没有发现烟粉虱的卵及若虫 ,只有极少量的成虫在植株上逗留。在药效试验中 1 0 %吡虫啉WP、2 5 %扑虱灵WP和 1 0 %高效氯氰菊酯LC在厂家推荐浓度下对烟粉虱成虫的防治效果分别为 2 0 0 7%～ 3 3 1 9% ,2 0 62 %～ 44 88%和 4 0 5 %～ 6 78% ;对若虫的防治效果分别为 5 1 91 %～ 64 46% ,5 4 3 0 %～ 63 99%和 1 6 73 %～ 2 6 97%。     

Within-plant distribution and sampling of single and mixed infestations of Bemisia tabaci and Trialeurodes vaporariorum (Homoptera: Aleyrodidae) in winter tomato crops

In several areas of Spain, the greenhouse whitefly, Trialeurodes vaporariorum (Westwood), and the sweet potato whitefly, Bemisia tabaci (Gennadius), coexist in tomato, Lycopersicon esculentum Miller. For integrated pest management decision-making, it is important to know the abundance of each species, because they exhibit different abilities to transmit viruses, are susceptible to different biological control agents, and have different responses to insecticides. This study was conducted to provide information on the vertical distribution of T. vaporariorumn and B. tabaci in tomato plants grown in greenhouses in winter and to determine the optimal sampling unit and the sample size for estimating egg and nymphal densities of both whitefly species. Eggs of T. vaporariorum were mainly located on the top stratum of the plant, whereas B. tabaci eggs were mainly found on the middle stratum. Nymphs of both species mainly concentrated in the bottom stratum of the plant. When pest abundance and low relative variation were considered, the bottom stratum was selected as the most convenient for sampling nymphs of both whitefly species. Conversely, the same two criteria indicated that either the top or the middle strata could be used when sampling T. vaporariorum and B. tabaci eggs. Several different sampling units were compared to optimize the estimation of nymphal and egg densities in terms of cost efficiency. One disk (1.15 cm in diameter) per leaflet collected from the top stratum of the tomato plant was the most efficient sampling unit for simultaneously estimating the egg densities of the two whitefly species.     

Effect of buprofezin on survival of immature stages of Harmonia axyridis, Stethorus punctum picipes (Coleoptera: Coccinellidae), Orius tristicolor (Hemiptera: Anthocoridae), and Geocoris spp. (Hemiptera: Geocoridae)

The effect of buprofezin, a chitin synthesis inhibitor, on development and survival of immature stages of Harmonia axyridis (Pallas), Stethortus punctum picipes Casey, Orius tristicolor (White), Geocoris pallens St?l, and Geocoris punctipes (Say), was examined in a series of laboratory bioassays. Very few H. axyridis larvae (3.1%) treated with buprofezin reached adulthood, although 65% of treated pupae emerged successfully. Buprofezin caused no mortality to eggs of S. punctum picipes but 71.1% of treated early instar larvae failed to complete development. Eighty percent of treated late instars and 92.3% of pupae produced viable adults. Early instar nymphs of O. tristicolor were unaffected by buprofezin, whereas 47.7 and 85% of G. punctipes and G. pallens nymphs, respectively, failed to complete development. Treated eggs of G. pallens hatched successfully. The use of buprofezin in integrated pest management in Washington state wine grapes is discussed.     

Bemisia tabaci (Homoptera: Aleyrodidae) biotype B colonization on okra- and normal-leaf upland cotton strains and cultivars

We compared smooth-leaf okra- and normal-leaf upland cotton (Gossypium hirsutum L.) strains and cultivars for susceptibility to colonization by Bemisia tabaci (Gennadius) biotype B. Experiments were conducted at seven field sites, five at Holtville, CA, and two at Maricopa, AZ, during 1996-2000. Okra-leaf strains and cultivars, as a group, had lower numbers of adults, eggs, and nymphs compared with normal-leaf strains and cultivars indicating the potential of okra-leaf genetic traits for reducing colonization by B. tabaci. Results also suggest that okra-leaf shape may provide less favorable micro-environmental conditions for the habitat of B. tabaci because of more open canopy as evidenced by higher leaf perimeter to leaf area ratio. The okra-leaf cultivar 'Siokra L-23' appears to have genetic traits that should be examined further as a source of B. tabaci resistance.     

Responses of the sweetpotato whitefly, Bemisia tabaci, to the chinaberry tree (Melia azedarach L.) and its extracts

Host preference bioassays for adults of the sweetpotato whitefly were performed with leaves of the chinaberry tree Melia azedarach L., tomato, cucumber and bean. Fruit and leaf extracts of the chinaberry tree were tested against adults of the sweetpotato whitefly. Fruit extracts were tested against eggs, first and second instar nymphs, and pupae of the insect. Treatments included aqueous, methanol, and acetone fruit extracts of 200 mg ml^?1 and serial dilutions of 20.0 and 2.00 mg ml^?1, ether extract, the botanical insecticides Azatin® and Margosan® ‐O and the control, water or water with Triton®. Mortality data was collected at 6, 7, and 8 days after treatment of the eggs, nymphs and pupae, respectively. Results of the host preference bioassays indicated a significantly lower number of live insects on leaves of the chinaberry tree vs leaves of bean, cucumber, and tomato after 24 h. This indicates that M. azedarach is not a good host for the sweetpotato whitefly. Adults of the insect were significantly more repelled from tomato plants treated with the undiluted extracts when compared to the control after 72 h. There were significant differences in percent mortality of nymphal instars when exposed to the undiluted extracts compared to other extracts and the control. However, there was no significant effect of the fruit extracts on the egg and pupa instars. Thus M. azedarach extracts were found to be repellent to the whitefly adults, while the fruit extracts have shown a significant detrimental effect against early nymphal instars. In general, the methanol extracts were more active against B. tabaci than extracts with other solvents.     

Effect of high and low temperatures on the drugstore beetle (Coleoptera: Anobiidae)

The drugstore beetle, Stegobium paniceum (L.) (Coleoptera: Anobiidae), is a pest of stored medicinal and aromatic plants. Generally, mortality of each stage increased with an increase of temperature and exposure time. Heat tolerance for different stages from highest to lowest was young larvae, old larvae, eggs, adult, and pupae. The mortality after 7 h at 42 degrees C for young larvae, old larvae, eggs, adults, and pupae, respectively, was 16 +/- 5, 31 +/- 6, 48 +/- 3, 63 +/- 8, and 86 +/- 2% (mean +/- SEM). Similar trends for stage specific mortality were seen with the lethal time for 90% mortality (LT90) at 42 degrees C; 773, 144, 12, and 11 h for old larvae, eggs, adults, and pupa respectively. Mortality was too low with young larvae to estimate LT90. The LT90 for young larvae at 42, 45, 50, 55, and 60 degrees C was 25, 20, 3.9, 0.18, and 0.08 h, respectively. The cold tolerance of different stages at 0 degree C from highest to lowest was adults, old larvae, young larvae, pupae, and eggs. The LT90 at 0 degrees C was 298, 153, 151, 89, and 53 h, respectively. The LT90 for adults at 5, -5, -10, and -15 degrees C was 792, 58, 2, and 0.8 h, respectively. The supercooling point of adults was -15.2 +/- 2 degrees C; young larvae, -9.0 +/- 0.8 degrees C; old larvae, -6.5 +/- 0.5 degrees C; and pupae, -4.0 +/- 1.4 degrees C. Heat treatments that control young larvae should control all other stages of S. paniceum. Cold treatments that control adults should control all other stages of S. paniceum. Dried plants stored at 5 degrees C for 45 d or 42 degrees C for 30 h and then kept below 18 degrees C throughout the rest of the year, should remain pest-free without any chemical control.     

Economic injury level and sequential sampling plan for Bemisia tabaci in outdoor tomato

Abstract:  This work aimed to determine the economic injury levels and to establish sequential sampling plans for nymphs and adults of the whitefly Bemisia tabaci Genn. (Sternorrhyncha: Aleyrodidae) in tomato fields. Densities of nymphs and adults, as well as crop yield were evaluated in 13 commercial tomato fields to determine the economic injury levels. The whitefly nymphs were sampled by direct counting in a leaf from the lower part of the canopy and the adults were sampled by beating an apical leaf against a white plastic tray. The sequential sampling plan was based on data collected in eight commercial tomato fields. The validation of the sequential sampling plan was carried out based on the curves of operational characteristics and average sample numbers. The decisions reached with the conventional and the sequential sampling plans in 21 commercial fields were compared for the intended validation of the sequential plan. The economic injury levels were four nymphs per leaf and one adult per tray. The decisions taken based on the sequential sampling plan were similar to those obtained through the conventional sampling plan. Most of the decisions taken with the sequential sampling plan were obtained through the minimum number of seven samples per field for nymphs and 11 samples per field for adults, with reductions of 84.44% and 54.17% in the number of samples required to reach a decision with the sequential sampling plan compared with the conventional sampling plan.     

华卵痣木虱的形态特征及其潜在危险性分析

华卵痣木虱Macrohomotoma sinica Yang et Li是2005年首次在上海发现的地区一种新害虫。描述华卵痣木虱各虫态的形态特征。其成虫的产卵或若虫危害期与小叶榕新叶抽出期相吻合。对该虫的潜在危险性进行初步分析。     

PREDATION OF THE LADYBEETLE CHILOCORUS KUWANAE ON THE SCALE UNASPIS YANONENSIS

Abstract The prey consumption of ovipositing female adults of the ladybeetle Chilocorus kuwanae on the scale Unaspis yanonensis was found to be significantly greater than that of the male adults. At 25°C one female adult ladybeetle, on average, would consume 42. 7 female scale adult per day while one male adult only destroyed 22. 3 female scale adults. However, after a deprivation of the prey for 48 h, this difference was eliminated. A C. kuwanae female adult had to prey on at least 15 U. vanonensis female adults in order to lay eggs. The funcional responses of the beetle adults to densities of different stages of the scale followed Holling's type 1. The functional responses to female scale adults indicated that the maximum prey consumption went up with the increase in temperature from 16°C to 35°C, and dropped sharply at 37°C. However, temperature did not alter the type of the functional response. Rased on the predation of C. kuwanae adults on U. yanonensis female adults, the minimum critical, optimal and maximum critical temperatures for their attack were estimated to be 10. 6°C, 31. 5°C and 38. 2°C respectively. The increase in predation space or in predator density could result in a reduction in the attack rat-e, but with the increase of predator density, the effect of predation space became much smaller. C. kuwanae adults preferred male pupae to other stages of the scale, and their preference for various stages of the prey was in the order of male pupae, 2nd-instar male nymphs, 2nd-instar female nymphs, adult females and kinstar nymphs.