Feeding and mating behaviour of Chinese citrus fly Bactrocera minax (Diptera,Tephritidae) in the field

The Chinese citrus fly, Bactrocera minax, is a major tephritid fruit fly pest that infests Citrus spp. fruits. The pest was removed from the national quarantine pest list in China in 2009 owing to its wide spread across the country, and it is currently considered a major threat to citrus industry in Asia. The frequent high infestation levels of B. minax in China emphasize the need for a more comprehensive understanding of its biology and ecology so that more efficient control measures can be developed and applied. In the framework of developing a sterile insect technique program against B. minax, we studied the feeding and mating activities of B. minax in situ (Citrus orchards and surrounding habitats) through open field surveys and video recordings. In the pre-oviposition period, sexually immature adults largely foraged for food (e.g. honeydew from aphids, nectar and sooty mould) on non-host plants. Then, sexually mature adult flies shifted to lick sooty moulds, bird faeces and, to a lesser extent, an unknown substance on the Citrus leaves and fruits during the mating and oviposition periods. Finally, during the post-oviposition period, the flies were observed feeding on ooze from grapes. The mating behaviour patterns of B. minax in the field were described as follows: first, the male established its territory close to the potential oviposition substrate (Citrus fruit), second, the female landed on the fruit and began inspection and ovipositor boring behaviour on the fruit surface (no male courtship observed e.g. wing vibration), and third, the male mounted and copulated with the female. The present study shed light on the feeding ecology and mating behaviour of B. minax in the field; this knowledge will facilitate development of better management strategies against this tephritid fly.     

Population dynamics of Dasiops inedulis (Diptera: Lonchaeidae) and its biotic and abiotic mortality factors in Colombian sweet passionfruit orchards

Throughout South America, the lonchaeid flies Dasiops spp. are important herbivores of passionfruit crops. However, little is known on the biology and ecology of these insects, resulting in inadequate pest management schemes. In this study, we describe Dasiops inedulis population dynamics in Colombian sweet passionfruit (SP; Passiflora ligularis Juss.) and elucidate biotic mortality factors at different fly developmental stages. From August 2009 to July 2010, D. inedulis and Dasiops spp. abundance was assessed through monthly McPhail bait trapping and collection of SP flower buds, flowers, and immature fruits. Mortality levels of D. inedulis were determined for early instar larvae by ovary dissection and for late-instar larvae or pupae by prey removal trials. Maximum infestation reached 80 % in fruits and flower buds, and bud infestation correlated with precipitation during the previous month. Two days after oviposition, 8.2 ± 2.3 (mean ± SD) Dasiops sp. eggs were found in SP ovaries and 4.4 ± 1.2 late-instar larvae were recovered from immature fruits at day 14. Upon larval drop on the orchard soil, 74.8 % larvae burrowed within the soil within 9 min, while 12.5 % larvae were attacked by ants. In-field mortality of young pupae amounted to 75.3 ± 7.0 %, with vertebrate predators likely causing 12.1 ± 6.0 % mortality. Late-instar larvae and pupae appear highly vulnerable to natural enemy action, with the ground-foraging predator community mainly composed of ants (80.37 %) and ground beetles (9.17 %). Our findings should help develop integrated pest management (IPM) tactics for SP crops.     

Diapause termination,developmental threshold and thermal requirements of eggs of the maple aphid,<Emphasis Type="Italic">Periphyllus californiensis</Emphasis> Shinji

The lower developmental threshold and thermal requirements for egg hatch of the maple aphid (Periphyllus californiensis) were estimated to be 4.58°C and 94.48 degree-days. Eggs of the maple aphid appear to have obligatory diapause and chilling seems essential for diapause development. No matter whether eggs in diapause were treated with 2°C chilling or placed in the field, at least 35 to 41 days were required for the first egg to terminate diapause. The time of egg hatch lasted for about a month or even longer. This long period of time in egg hatch may be related to the restricted period that food is available in early spring and the long period of budburst of host plants.     

Variation in the date of budburst in <Emphasis Type="Italic">Quercus robur</Emphasis> and <Emphasis Type="Italic">Q. petraea</Emphasis> across a range of provenances grown in Southern England

The widely observed advance in spring budburst across a range of temperate forest species due to climatic warming has received considerable attention. This change in forest phenology has important implications for the choice of species and provenances currently being planted, which need to be suited to both current and future climatic conditions. Using a provenance trial in the south of England, this study assessed variation in the timing of budburst across 23 different European provenances of oak (Quercus robur L. and Q. petraea (Matt.) Liebl.) over 8 years of observations. The order in which the different provenances reached budburst was related to provenance source latitude: the southern provenances were always earlier than those from more northerly latitudes. The statistical technique partial least squares regression was used to identify critical periods of both chilling and warming. A General Linear Model and three-dimensional temperature response surfaces were used to analyse the temporal trends in budburst. There was a negative correlation between the date of budburst and mean daily air temperature in both the chilling and warming periods for all provenances, which was statistically significant for a majority. Spring warming had a larger effect on budburst than winter chilling with a mean spring temperature-driven advance of 3.61 days/°C (standard error = 0.17 days/°C) and mean winter period temperature-driven advance of 0.99 days/°C (standard error = 0.17 days/°C). Surprisingly, there was no statistically significant interaction between mean air temperatures during the chilling and warming phases on the date of budburst.     

Laboratory and field evaluation of the pathogenicity of entomopathogenic nematodes to the red palm weevil, Rhynchophorus ferrugineus (Oliv.) (Col.: Curculionidae)

Ten Egyptian and imported entomopathogenic nematodes were evaluated for their pathogenicity to R. ferrugineus in both the laboratory and the field. In the laboratory, most nematodes were pathogenic to the pest larvae, pupae and adults. Larvae and adults were more susceptible to nematode infection (mostly 100?% mortality) than pupae enclosed in their cocoons. In the field however, the highest insect larval mortality was 66.67?% and most of nematodes failed in controlling the pest. Such failure could be due to hot weather, the tunnelling behaviour of the pest larvae and the too much sap in the infested sites in the trunks of palm trees.     

The thermal constant for timing the emergence of the Red Palm Weevil, <Emphasis Type="Italic">Rhynchophorus ferrugineus</Emphasis> (Oliv.) (Coleoptera,Curculionidae)

The pupal duration of the red palm weevil, Rhynchophorus ferrugineus (Oliv.) at two different temperatures revealed that the thermal threshold is –?2.3?°C, while the thermal constant is 423 degree days. Around 20.7 cycles of weevil emergence per year have been predicted in Egypt. A temperature between 44?–?45?°C was found to be the higher threshold at which the pupae are killed. The heat units required for the pupal development were utilized to predict the dates of adult emergence throughout the year.     

Laboratory rearing of <Emphasis Type="Italic">Halyomorpha halys</Emphasis>: methods to optimize survival and fitness of adults during and after diapause

Laboratory colonies are necessary to conduct year-round research on the invasive brown marmorated stink bug, Halyomorpha halys (Stål), a severe agricultural and nuisance pest in the USA. When adults are collected in the fall to either start or supplement colonies, they require a period of cold storage before they resume sexual development and egg production. There is a lack of understanding of how to collect and store diapause-triggered adults in the laboratory. A series of experiments in 2013–2015 assessed survival and fecundity of stink bugs collected from different locations and stored under different temperatures and durations. We found that a minimum of 7 weeks is necessary to break diapause and that a substantial proportion of adults can survive when stored at constant 9 °C, even for periods longer than needed to terminate diapause. Adults survived significantly better at 6 and 9 °C than at 3 °C in storage for 7 weeks. Longer durations up to 34 weeks in storage reduced adult survival and significantly affected survival rates, timing of first egg laying, and overall fecundity. Location where adults were collected at overwintering sites in the fall had a significant impact on survival in cold storage and colony performance. Adults collected from soybean fields in mid-September and fed in the laboratory for 2 weeks before storage had lower survival than adults collected in October at aggregation sites and stored immediately. The food sources available to H. halys adults at collection locations for nutrition and sequestration of sufficient energy reserves going into diapause are discussed.     

Effect of temperature on the biology of Acyrthosiphon gossypii Mordvilko (Homoptera: Aphididae) on cotton

Acyrthosiphon gossypii is a widespread, major pest of cotton in central Asia. Effects of specific temperatures on A. gossypii development and survival are unknown and would be useful in helping interpret population dynamics and devising management tactics for this pest. In this paper, the effect of temperature on the life table of A. gossypii reared on cotton was evaluated under laboratory conditions using temperatures of 18, 21, 24, 27, and 30 °C. The developmental rate of immatures increased exponentially from 18 to an optimum around 27 °C and then declined. The estimated lower developmental threshold was 8.0 °C, and 107.5 degree days were required for development from the first instar to adult. The percentage survival of immature stages varied from 81 to 91 % within the range of 18-27 °C. Survival declined to 27 % at 30 °C. The average longevity of adult females was 15.7, 11.7, 8.2, 5.2, and 2.8 days, and the average number of offspring produced per female was 46, 38, 20, 14, and 0, at temperatures of 18, 21, 24, 27, and 30 °C, respectively. From 21-27 °C, the intrinsic rate of increase of A. gossypii was significantly higher than at 18 °C, indicating that 21–27 °C was within the optimal range for the growth of A. gossypii, and that 30 °C constant is beyond the upper limit for reproduction. The observations will form the basis of a forecasting system and could account for the decline of the species on cotton in central Asia as well as other regions during hot summer months.     

微红梢斑螟与桃蛀螟蛹期生物学特性研究

以5年生马尾松、湿地松为寄主材料,通过室内饲养和野外观察,对微红梢斑螟与桃蛀螟2种害虫的蛹期生物学特性进行了比较研究.结果表明:2种害虫化蛹的一些行为学特性、蛹的历期和羽化时辰节律存在一定差异,而蛹体长、蛹最宽、翅芽最宽、翅芽最窄等蛹的形态特征无显著差异(P＞0.05);微红梢斑螟羽化高峰期出现在晚上(18:00～24...     

杨小舟蛾成虫和蛹自然发育进度研究

采用灯诱成虫和地面化蛹进度调查的方法,系统监测了1998,1999年杨小舟蛾成虫和2010年成虫及蛹的自然发育进度.结果表明:春季气温变化可显著影响越冬代和第1代成虫羽化高峰期的出现及第1,2代害虫的生长发育速度;降雨量偏多可导致害虫发育历期延长,种群数量显著下降;夏季异常气候会引起害虫种群数量发生显著变化,干旱高温的...     

Factors influencing citrus fruit scarring caused by Pezothrips kellyanus

Kelly’s citrus thrips (KCT) Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) is a recently recorded cosmopolitan citrus pest, causing fruit scarring that results in downgrading of fruit. Due to the detrimental effects caused on fruits by KCT, we wanted to study some of the factors influencing fruit scarring. Specifically, the objectives were: (1) to determine the fruit development stage when citrus fruits are damaged by KCT and the population structure of KCT during this period, (2) to study the influence of temperature on intensity of damage, and finally, (3) to identify alternative host plants. KCT populations on flowers and fruitlets and alternate plant hosts were sampled in four citrus orchards from 2008 to 2010. The percentage of damaged fruits was also recorded. The exotic vine Araujia sericifera (Apocynaceae) was recorded as a new host for KCT. Thrips scarring started to increase at 350–650 degree-days (DD) above 10.2 °C, coinciding with a peak abundance of the second instar larval stages over all 3 years of the study. The maximum percentage of larval stages of KCT was observed in the 3 years at about 500 DD, a period which corresponds to the end of May or early June. Variation in the severity of fruit scarring appeared to be related to air temperature. Temperature likely affects the synchronisation between the peak in abundance of KCT larvae, and the period when fruitlets are susceptible to thrips damage. Temperature can also influence the survival and development of KCT populations in citrus and other host plants in the citrus agro-ecosystem.     

Pathogenicity of three entomopathogenic fungi on pupae and adults of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

The pathogenicity of local isolates of the entomopathogenic fungi (EPF) Beauveria bassiana (Balsamo) Vuillemin, Isaria fumosorosea (Wize) (formerly Paecilomyces fumosoroseus (Wise) Brown & Smith) and Metarhizium anisopliae (Metschnikoff) Sorokin (Ascomycota: Hypocreales) were evaluated under laboratory conditions against pupae and adults of Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) via different routes of exposure. Average mortality of pupae after immersing them into spore suspensions was in general low and ranged from 18.7 to 23.9 % depending on fungal species and dose applied. However, adults obtained from treated pupae appeared to have higher mortality rates compared to control with all fungi and doses tested. Adults’ average mortalities ranged from 41.9 to 88.0 % after exposing them to EPF either by feeding on a mixture of conidial suspension and artificial food or by bodily contact with conidia, depending on fungal species, dose and method of exposure. The proportion of cadavers, pupae or adults, that produced visible signs of mycosis ranged from 40.4 to 73.3 % with the exception of those that were exposed to M. anisopliae. In that case, none of the insects that died after exposure to conidia of M. anisopliae developed visible mycelium on their surface. Moreover, confining treated with untreated adults indicated horizontal conidial transmission in some cases. Our results indicate that EPF might be a promising biological control agent for the Mediterranean fruit fly and could be utilised with different modes of application: soil application against pupae and cover or bait sprays against adults.     

Developmental threshold temperature and effective accumulative temperature of pupae and eggs of <Emphasis Type="Italic">Holcocerus hippophaecolus</Emphasis>

In order to understand the occurrence and the developmental regularity of seabuckthorn carpenterworm (Holcocerus hippophaecolus) and predict its population density, the developmental threshold temperature (C) and effective accumulative temperature (K) of the carpenterworm pupae and eggs were analyzed under the conditions of constant and variable temperatures. The results show that the values of C and K of the carpenterworm pupae are (12.1±0.2) °C and (295.2±4.1) day-degrees at constant temperatures, and (15.5±0.4) °C and (202.4±13.1) day-degrees at variable temperatures. However, the values of C and K of the eggs at variable temperatures are (16.7±0.8) °C and (101.5±12.6) day-degrees. The differences of developmental threshold and effective accumulative temperature under the conditions of constant and variable temperatures of the carpenterworm pupae accord with the developmental regularity of most insects in nature. By comparing five different constant temperatures, the conclusion is that the optimum developmental temperature of the pupae is 21 °C when both the pupation of the mature larvae and the eclosion of the pupae are very accordant. Moreover, the percentage of eclosion is over 90%. The average developmental durations of the carpenterworm pupae and eggs are 31 and 16 d at variable temperatures.     

Phenology,life table analysis and temperature requirements of the invasive brown marmorated stink bug,Halyomorpha halys,in Europe

The invasive Halyomorpha halys was accidentally introduced into Switzerland around 2004 and has recently established in the neighbouring countries of France and Italy. To better understand the population dynamics of this pest in Europe, the phenology, reproductive biology and temperature requirements of Swiss H. halys populations were investigated. Overwintered adults became active in April, but peak oviposition was not observed before early July. Individual females laid on average 79 eggs (maximum of 160). The oviposition period lasted from mid-June to end of September. Eggs laid in August and September did not result in offspring due to the low temperatures in autumn. Under natural fluctuating temperatures, development from egg to adult lasted between 60 and 131 days. The first new generation of adults did not occur before mid-August when the photoperiod was already below 15 h, which likely initiated diapause and suppressed the reproductive activity of new generation adults. Under controlled conditions of 20, 25 and 30 °C, Swiss H. halys populations developed within 75.8, 42.3 and 33.2 days from egg to adult, respectively. No development was possible at or below 15 and at or above 35 °C. The number of degree days required for completion of development from egg to adult was 588.24 DD. Under semi-natural conditions, total mortality of Swiss H. halys populations was 86.7 % with a net reproductive rate of 5.69, indicating growing populations. In Switzerland, H. halys is univoltine, but if it continues to spread into the Mediterranean area two generations per year could be expected.     

Efficacy of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) against the chive gnat, Bradysia odoriphaga

Chive gnat, Bradysia odoriphaga Yang & Zhang (Diptera: Sciaridae), is the most serious pest of Chinese chive, Allium tuberosum. The present study aimed at determining the biocontrol potential of different indigenous entomopathogenic nematode (EPN) isolates for the management of chive gnat in China. The virulence of 145 EPN isolates belonging to 13 species against B. odoriphaga was evaluated in the laboratory, and then the most promising isolates (Steinernema ceratophorum HQA-87; S. hebeiense JY-82; S. feltiae JY-90, JY-17; S. litorale HXY-68; Heterorhabditis indica ZZ-68; H. bacteriophora NY-63, HQ-94; and H. megidis LFS-10) were selected for further experiments. The mortality of fourth instar B. odoriphaga was significantly affected by nematode isolates and concentrations of infective juveniles (IJ). Third and fourth instars of B. odoriphaga were generally more susceptible to the nematodes than first and second instars and pupae. Pot experiments showed no differences in B. odoriphaga population reduction at 50 and 75 IJ/cm² of different isolates; the tested isolates caused a 78–94 % reduction of the chive gnat population at an application rate of 75 IJ/cm². In a field experiment, S. feltiae JY-90 generated the strongest pest suppression 14 days after EPN application, whereas after 28 days pest densities in the plots treated with S. feltiae JY-17 and S. hebeiense JY-82 were similar to those in plots treated with phoxim and yielded significant reductions of the B. odoriphaga populations. Our findings indicate that EPN may have good potential for use in the integrated management of B. odoriphaga populations in Chinese chive.     

<Emphasis Type="Italic">Drosophila suzukii</Emphasis> flight performance reduced by starvation but not affected by humidity

Drosophila suzukii is widely studied because of its status as a global pest of berries and soft fruits. Environmental conditions and access to food resources impact the physiology and fitness of D. suzukii; these factors could also affect dispersal. Flight mills are a convenient tool for measuring and comparing the flight performance of insects. In this study, two experiments examined the effects of diet and humidity on D. suzukii flight performance using custom-built flight mills, and a third experiment compared the energy reserves of D. suzukii flown or not flown on flight mills. Over all flight assays, the median flight distance and duration were 27.16 m and 2.37 min, respectively, and the mean flight velocity was 0.18 m/s. The maximum flight distance and duration by an individual were 1.75 km and 2.35 h, respectively. Drosophila suzukii provisioned with blossoms, fruits, or standard laboratory diets flew farther distances and longer durations than starved flies. While starvation was associated with reduced flight performance, there were no observed differences between diet types. It remains unclear whether D. suzukii consistently use lipids, glycogen, sugar, or another energy source for flight because tethered individuals may not have flown enough to deplete energy reserves. Humidity did not affect flight performance of D. suzukii within a?~?2 h test period. These data indicate that most D. suzukii are likely to remain within limited area (e.g., within a field) but that some individuals can disperse long distances (field to field spread).     

Beobachtungen zur Biologie der Rübsenblattwespe Athalia rosae L. (Hym., Tenthredinidae)

The Relative Growth Rate of the larvac ofA. rosae at a temperature of 20°C amounts to 0.45–0.63 (RGR of Myzus persicae=0.17–0.39) corresponding to a doubling of the body weight within 1.1 to 1.5 days. The daily intake of plant material reached twice the amount of the respective initial body weight. The diapause ofA. rosae is induced by the photoperiod; temperature seems to be of minor importance. The onset of pigment evasion from the larval eye signalizes the termination of diapause. Diapause ended earlier at temperatures of 5°C and 12°C than at 20°C but even at the latter temperature diapausing individuals eventually yielded adults.     

Are kaolin and copper treatments safe to the olive fruit fly parasitoid Psyttalia concolor?

Kaolin particle films and copper-based products can be considered as possible alternatives to traditional agrochemicals used for controlling the dominant pest of olive grove areas of the Mediterranean Basin, the olive fruit fly, Bactrocera oleae (Rossi) (Dip. Tephritidae), to which this pest has already evolved resistance. Psyttalia concolor (Szèpligeti) (Hym. Braconidae) is a koinobiont larval–pupal endoparasitoid of many Tephritidae of economic importance. It has been routinely used in the Mediterranean Basin for augmentative releases against B. oleae. Detailed knowledge of lethal and sublethal effects of these agrochemicals on non target arthropods is required for effective integrated pest management programmes. The aims of this study were to evaluate direct mortality caused by kaolin and copper salts on the parasitoid and the sublethal effects on emergence of adults from treated pupae and on beneficial capacity of females through four different experiments, three at laboratory level and one in semi-field conditions. Dual choice and no-choice experiments in the case of kaolin were also performed to test kaolin oviposition repellence. The results indicated that the tested agrochemicals were not harmful to the parasitoid. No lethal toxicity or effects on beneficial capacity were recorded. The behavioural experiments, however, showed that when females could choose between parasitising through a kaolin-treated surface and a water-treated one, there was a slight reduction in the percentage of parasitised hosts for kaolin. No differences were detected when females were not given a choice.     

Temperature-dependent development of Sesamia nonagrioides

The effect of various constant temperatures on survival, development and adult longevity of Sesamia nonagrioides Lefébvre (Lepidoptera: Noctuidae) was studied under laboratory conditions. The following temperatures were tested: 14, 17, 21, 25 and 31 °C. The percentage of individuals that completed development at each temperature as well as the days needed for the emergence of the pupa and adult eclosion were measured. Adult longevity was estimated under the same conditions. Development time decreased significantly with increasing temperature within the range 14–25 °C. Survival was higher at medium temperatures (17–25 °C) in comparison with that at more extreme temperature regimens (14 and 31 °C). Egg and first larval instars were the stages where S. nonagrioides suffered the highest mortality levels at all temperatures. The highest survival was recorded with experimental individuals aging between the third and fifth larval instar. Thermal requirements of development (developmental thresholds, thermal constant, optimum temperature) of S. nonagrioides were estimated with application of linear and one nonlinear models (Logan I). Upper and lower developmental thresholds ranged between 31.2 and 36.2 and 7.0 and 10.3 °C, respectively. The optimum temperature for development (where maximum rate of development occurs) was estimated at between 28.1 and 30.3 °C. The thermal constant for total development was estimated at 1,000.0 degree-days. Adult longevity was also affected by temperature, as it was significantly reduced at higher temperatures (21–31 °C) compared to the lower ones (14 and 17 °C). This information would be useful in determining the critical temperatures which may affect the distribution of S. nonagrioides concerning potential climate change.     

Effect of different host plants on the development time and parasitization rate of eretmocerus dehachi rose and rosen (hymenoptera: aphelinidae) withparabemisia myricae (Kuwana) (homoptera: aleyrodidae) as insect host

The effect of six citrus and five non-citrus host plants on the developmental time ofEretmocerus dehachi Rose and Rosen (Hymenoptera: Aphelinidae), the parasitoid ofParabemisia myricae (Kuwana) (Homoptera: Aleyrodidae), was studied under laboratory conditions. On citrus host plants, the mean developmental time from egg to adult was shortest on lemon with 14.6 days and longest on trifoliate orange with 26.3 days. On non-citrus host plants the developmental time ranged between 16.3 days on vine and 23.0 days on pomegranate. Among the various host plants tested,E. dehachi preferredP. myricae on sweet orange. A high mortality ofP. myricae due to host feeding and parasitization was observed on sweet orange and grapefruit among citrus host plants and on rose among non-citrus host plants.