Parasitoid complex of black scale <Emphasis Type="Italic">Saissetia oleae</Emphasis> on citrus and olives: parasitoid species composition and seasonal trend

The parasitoid complex of black scale Saissetia oleae (Olivier) (Hemiptera: Coccidae) was studied on citrus and olives to determine their relative abundance, seasonal trend, geographical distribution, and their incidence on black scale populations. Branches and leaves of ten citrus and four olive groves infested with black scale were periodically collected over the period March 2003–December 2005 in eastern Spain, covering an area of 10,000 km². Adult parasitoids were also sampled with a portable engine-powered suction device. Black scale females were attacked by Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae), which was found beneath 35.4 ± 7.5% and 22.4 ± 3.5% female scale’s body in citrus and olive groves, respectively. However, S. caerulea attacked the scales when most of their eggs had already hatched. The parasitic mite Pyemotes herfsi (Oudemans) (Prostigmata: Pyemotidae) fed on all development stages of S. caerulea. The gregarious female’s endoparasitoid Metaphycus lounsburyi (Howard) (Hymenoptera: Encyrtidae) was common in citrus and olive trees, but the parasitism rates it reached was low. Second and third instars of black scale were mainly parasitized by the solitary endoparasitoid Metaphycus flavus (Howard), and secondarily by Metaphycus helvolus (Compere) which was much less abundant and limited in distribution. Thus, M. helvolus, introduced 30 years ago, has not displaced M. flavus as in other Mediterranean areas. According to their abundance, distribution and incidence, M. flavus and S. caerulea appeared as the main parasitoids of black scale in eastern Spain, whereas M. helvolus and M. lounsburyi, considered the main parasitoids in other citrus and olive areas of the world, had a limited incidence. Recommendations for improving the level of biological control are discussed.     

The role of augmentative releases of indigenous parasitoid Metaphycus lounsburyi (Hymenoptera: encyrtidae) in enhancing the biological control of Saissetia oleae (Homoptera: coccidae) on olive in Egypt

The Mediterranean black scale, Saissetia oleae (Olivier) (Homoptera: Coccidae) is the most important pest of olive in Egypt. Indigenous parasitoid Metaphycus lounsburyi (Howard) (Hymenoptera: Encyrtidae) from different localities in Egypt, were manipulated, reared and mass produced for classical biological control in Egypt, more than 193130 parasitoids were released. Several releases were made between May 1999 to April 2001. Increases of the parasitism from 17.4 to 42.0 and from 6.4 to 19.2 during the first year (1999–2000) and the second year (2000–2001), respectively in the Northern Coast. This parasitoid became established in some of the release sites in El-Arish and Matruh Governorates.     

Reproductive biology of Fopius ceratitivorus (Hymenoptera: Braconidae), an egg–larval parasitoid of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

The reproductive biology of Fopius ceratitivorus Wharton, a recently discovered African parasitoid, was studied in quarantine in Hawaii to facilitate its mass production for biological control of the Mediterranean fruit fly, Ceratitis capitata. Mean longevity of host-deprived and ovipositing females was 17.3 ± 0.9 d and 16.2 ± 0.5 d, respectively. Ovarian maturation peaked at 61.6 mature eggs per female on the fifth day after eclosion and declined thereafter. Mean number of offspring produced per day by mated females was 5.1 ± 0.4, and realized fecundity expressed as total eggs deposited during the female’s life time was 107.8 ± 12.8. Females were more attracted, to and reproduced significantly more, in fruit substrates containing odors of adult flies and eggs rather than fruit substrates artificially inoculated with fly eggs. Our findings suggest that F. ceratitivorus is a promising new parasitoid for biological control of C. capitata in Hawaii.     

Encapsulation of parasitoid eggs in soft scales (Homoptera: Coccidae)*

Abstract. 1. The Mediterranean black scale Saissetia oleae (Olivier) was the most suitable host for the imported Metaphycus aff. stanleyi Compere and Metaphycus helvolus (Compere) and for the local Metaphycus flavus (Howard). 2. Difficulties were encountered in the mass rearing of the introduced parasitoids, particularly M. aff. stanleyi, on the hemispherical scale Saissetia coffeae (Walker) and on the brown soft scale Coccus hesperidum L., because many of the eggs were encapsulated. 3. Although all the eggs of M.aff.stanleyi were encapsulated shortly after being deposited in S.coffeae, some larvae developed, broke out of the capsule and developed normally. 4. The incidence of parasitized scales containing only encapsulated eggs of any of the three Metaphycus species, increased with the stage of the host.     

Insect natural enemies of coffee green scales [Hemiptera: Coccidae] in Kenya and their potential for biological control ofCoccus celatus andC. viridis in Papua New Guinea

Coffee green scales,Coccus celatus De Lotto andC. viridis (Green), are major pests of coffee in Papua New Guinea (PNG). Surveys for insect natural enemies of coffee green scales were conducted in Kenya to find species suitable for introduction to PNG. Natural enemy communities in Kenya were found to be diverse, particularly those located in the central highlands where 3 primary parasitoids,Metaphycus stanleyi Compere,M. baruensis Noyes andDiversinervus stramineus Compere (Encyrtidae), were dominant onC. celatus andC. alpinus De Lotto. It is suggested that these 3 parasitoids may be potential biological control agents forC. celatus. Several insect predators were found associated withC. celatus in the central highlands but most were only common in ant-free scale populations. An aphelinid primary parasitoid,Coccophagus rusti Compere, was the only natural enemy ofC. viridis located. This species, however, could be of potential as a biological control agent, especially in view of its previous use in biological control against soft scales.      

Superparasitism in mass reared Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae), a parasitoid of fruit flies (Diptera: Tephritidae)

Superparasitism frequency and its effects on the quality of mass-reared Diachasmimorpha longicaudata (Ashmead) parasitoids were investigated under laboratory conditions. Percentage of adult emergence, sex ratio, survival, fecundity and flight ability of adult parasitoids that emerged from Anastrepha ludens (Loew) pupae with different levels of superparasitism were determined. A high prevalence of superparasitism was observed. The number of scars per pupa, produced by insertion of the parasitoid ovipositor, ranged from 1 to 30, with an average (±SD) of 8.3 ± 6.2. Adult parasitoid emergence decreased as the level of superparasitism increased. However, the fraction of females rose with increasing superparasitism and the flight ability was lower in adults emerging from pupae with only one scar, compared with adults emerging from superparasitized hosts. Female longevity and fecundity were not affected by superparasitism. Our results support the hypothesis that superparasitism in D. longicaudata might be adaptive, since adults emerging from hosts with moderate levels of superparasitism showed the highest percentage of emergence and there were no significant differences in the other quality control parameters tested. Our findings are relevant to the mass rearing process, where the ratio of hosts to parasitoids can be optimized as well as the distribution of eggs deposited in host larvae. This contributes to efficient mass rearing methods for augmentative biological control programs.     

Metaphycus anneckei and Metaphycushageni: two discrete speciesparasitic on black scale, Saissetia oleae

Parasitized black scale, Saissetia oleae, were collected from olives(Olea europaea L.) in Spain and from thismaterial an encyrtid parasitoid was reared that istaxonomically similar to Metaphycus anneckeiGuerrieri and Noyes. Differences were noted betweenthe Spanish Metaphycus nr. sp. anneckeiand material described as M. anneckei that isresident to California. Although dissimilar in fewmorphological characters, the ovipositor length andshape of the male genitalia and the antennal club ofboth sexes can be used to discriminate between M.anneckei resident to California and the Spanishmaterial, which was subsequently named Metaphycushageni Daane and Caltagirone. To determine ifmorphological differences correspond to biologicaldifferences, reproductive and oviposition behavioursof Californian M. anneckei and SpanishM. hageni were studied. Mating was not observedbetween individuals of the two types and only maleprogeny were produced in interspecific pairings. Metaphycus anneckei females deposit eggs through thescale's ventral side and were never observed to hostfeed, while M. hageni females oviposit throughthe scale's dorsum and frequently host fed. Thecollective biological evidence agrees withmorphological evidence, indicating that M.anneckei and M. hageni are discrete species. Specimens from recent collections in California andSpain were compared with specimens from earliercollections (1910s to 1980s) in Australia, California,Greece, Hawaii, Italy, Israel, Mexico, and SouthAfrica. With the exception of Greek and Spanishmaterial, all specimens examined were M.anneckei. We discuss the significance of this newinformation with respect to biological control andprovide a key to separate these and other closelyrelated black scale parasitoids.     

Interactions among the entomopathogenic fungus, Beauveria bassiana (Ascomycota: Hypocreales), the parasitoid, Aphidius matricariae (Hymenoptera: Braconidae), and its host, Myzus persicae (Homoptera: Aphididae)

The effect of the entomopathogenic fungus Beauveria bassiana on the biological characteristics and life table of Aphidius matricariae, a parasitoid of the green peach aphid, Myzus persicae, was studied under laboratory conditions. Aphids were first infected with twice the LC₉₅ of B. bassiana for third-instar M. persicae (2 × 10⁸ conidia/ml). Subsequently, at different intervals they were exposed to 1-day-old mated parasitoid females for 24 h. The number of mummies produced per female and the percentage emergence of the F1 generation differed significantly as a function of the time interval between application of the fungus and exposure to the parasitoid. The interference of B. bassiana on parasitoid development was also studied by first exposing the aphid hosts to the parasitoid for 24 h and subsequently applying B. bassiana. The number of mummies produced by a female A. matricariae varied from 11.8 to 24.8 and was significantly different when the aphids were first exposed to the parasitoids and then treated with B. bassiana 24, 48, 72, and 96 h after exposure. There were no significantly different effects of B. bassiana on net reproductive rate (R₀), mean generation time (T), intrinsic rate (r_m) and the finite rate of increase (λ) of A. matricariae as a result of development in hosts exposed to low or high conidial concentrations (1 × 10², 2 × 10⁸ conidia/ml). The parasitoids developed in infected hosts had lower r_m, λ, T and DT (doubling time) values compared with those that developed in uninfected hosts but no differences were observed in R₀ values. With proper timing, A. matricariae and B. bassiana can be used in combination in the successful biological control of M. persicae.     

Seasonal and Scale Size Relationships between Citricola Scale (Homoptera: Coccidae) and Its Parasitoid Complex (Hymenoptera: Chalcidoidea) on San Joaquin Valley Citrus

The phenology of citricola scale, Coccus pseudomagnoliarum (Kuwana), and its associated parasitoid complex were studied on citrus in the San Joaquin Valley of central California over the period April 1995–March 1997. A total of 10,237 parasitoid specimens of 10 species were collected. Two of these species, Marietta mexicana (Howard) and Encyrtus lecaniorum (Mayr), each recovered from individually isolated scales, represent new parasitoid records for citricola scale. A third species, Encarsia citrinus citrinus (Craw), may represent a new parasitoid record, but this requires further confirmation because a single (male) specimen was recovered from individually isolated scales. The three most dominant parasitoid species, Coccophagus lycimnia (Walker), Metaphycus helvolus (Compere), and Metaphycus luteolus (Timberlake), accounted for the majority (>97%) of the specimens recovered. In contrast to the situation on citrus in southern California, where citricola scale is under effective biological control and is very rarely seen, citricola scale on citrus in the San Joaquin Valley is reemerging as a major pest, especially in groves employing integrated pest management with minimal use of broad-spectrum insecticides. Possible reasons uncovered in this study for the lack of effective biological control of citricola scale in the San Joaquin Valley include: (i) reduced presence of Metaphycus spp. because of hyperparasitism by the heteronomous hyperparasitoid C. lycimnia; (ii) absence of alternate hosts for those species of Metaphycus present; and (iii) absence of hosts of suitable size for Metaphycus at critical times of the year. Recommendations for improving the level of biological control in the San Joaquin Valley are discussed.     

Comparison of the suitability of Liriomyza chinensis and L. trifolii (Diptera: Agromyzidae) as hosts for Neochrysocharis okazakii (Hymenoptera: Eulophidae)

Effective parasitoid production or mass-rearing is one of the key components in practicing biological control with parasitoids. Selection of host species for rearing parasitoids is a major approach to improve the production efficiency. The stone leek leafminer Liriomyza chinensis (Kato) is a destructive pest of onion crops in many Asian countries, which is difficult to control with chemicals. The present study examined whether the production of Neochrysocharis okazakii Kamijo, a promising native biological agent of L. chinensis, could be effective if kidney bean-Liriomyza trifolii (Burgess) system was used as an alternative rearing procedure. The suitability of L. chinensis and L. trifolii as hosts of N. okazakii was investigated in the laboratory. Neochrysocharis okazakii completed its development on both two host species, and the total development time was similar on these hosts. Longevity of N. okazakii females provided with L. chinensis was longer than those on L. trifolii. There were no significant differences in fecundity and offspring sex ratio when females had been provided with these two host species. The adult parasitoids emerged from L. chinensis were significantly larger than those from L. trifolii. However, the intrinsic rate of increase was higher, and mean generation time was lower, for L. trifolii than L. chinensis. Thus, mean net reproductive rate (Ro) was higher when L. trifolii was used as host. Although the two host species were equally suitable as host for N. okazakii, our findings suggested that L. trifolii and kidney bean is an ideal system for N. okazakii production.     

Parasitoids as a bioagent to eliminate the insecticides to control the main pests-infested economic crops

Hemipterous insects are one of the important pests that attack different economic plants. A study was conducted to evaluate the biological control potential of these pests by augmentation with parasitoids, such as Microterys flavus (Howard), Metaphycus lounsburyi Howard (Encyrtidae), Encarsia sophia (Girault and Dodd), Coccophagus scutellaris (Dalman), Aphytis melinus DeBach (Aphelinidae) and Aphidius ervi Haliday (Braconidae). All the species were mass reared and monthly releases were made in fields of citrus, olive, tomato, sugar cane, mango and squash during each of 11 consecutive years (1999–2009). About 5,830,000 individuals of M. flavus, M. lounsburyi, E. sophia, C. scutellaris, A. melinus and A. ervi were released in the fields of Gharbiya, Marsa Matrouh, Daqahlyia, Qena, Qalyubiya and Behira governorates in Egypt on citrus, olive, tomato, sugar cane, mango and squash which were naturally infested by Ceroplastes floridensis Comstock, Saissetia oleae (Olivier) (Coccidae), Bemisia tabaci (Gennadius) biotype Q (Aleyrodidae), Pulvinaria tenuivalvata (Newstead) (Coccidae), Aulacaspis tubercularis (Newstead) (Diaspididae) and Aphis craccivora Koch (Aphididae), respectively. Population of the parasitoids and parasitism increased in field plots where releases were made when compared with where no releases were made. The maximum rate of parasitism reached 61.4, 92.1, 45.7, 59, 91 and 55.2% in the field treatment where releases were made, while parasitism peaked at 8.2, 13.5, 6, 2, 16 and 17.5% where no releases were made. The populations of M. flavus, M. lounsburyi, E. sophia, C. scutellaris, A. melinus, A. ervi were significantly correlated with the populations of C. floridensis, S. oleae, B. tabaci, P. tenuivalvata, A. tubercularis and A. craccivora during the field seasons. Additional parasitism was caused by natural infestations of Metaphycus helvolus (Compere) and M. lounsburyi (Howard) (C. floridensis), Scutellista cyanea (Motschulsky) (S. oleae), Encarsia lutea (Masi) and Eretmocerus mundus (Mercet) (B. tabaci biotype Q), Encarsia citrina (Craw) (A. tubercularis) and Aphelinus demyaati Abd-Rabou (A. craccivora). These observations enhance the understanding of the usefulness of these parasitoids after augmentation in the field.     

Survey of brown soft scale Coccus hesperidum L. parasitoids in southern California citrus

The parasitoid complex of brown soft scale, Coccus hesperidum L., a multivoltine soft scale, was determined in southern California citrus over the period February 2004–March 2006. The survey was conducted by placing brown soft scale-infested yucca leaves in the canopy of citrus trees and subsequently rearing individually isolated parasitized scales in the laboratory. A total of 14 species parasitized brown soft scale in the field, the most abundant ones belonging to the genus Metaphycus Mercet (75%). The most abundant parasitoid species was Metaphycus angustifrons Compere (38% parasitism), and this is a new record of establishment for this species in California. Coccophagus species accounted for only 11% parasitism. There were important spatio-temporal differences across the parasitoid complex survey locations. We also found that the five most abundant encyrtid parasitoid species showed preferences for scales of different sizes. Our results have implications for biological control of citricola scale, Coccus pseudomagnoliarum (Kuwana), an important pest of citrus in the San Joaquin Valley of central California. Notably, this species is nearly absent in southern California. Brown soft scale is considered to be an alternate host for parasitoids of citricola scale, a univoltine soft scale, at times when the latter species is unavailable for parasitism.     

Comparative analysis of the reproductive biology of two Peristenus species (Hymenoptera: Braconidae), biological control agents of Lygus plant bugs (Hemiptera: Miridae)

Peristenus digoneutis Loan and Peristenus stygicus Loan, parasitoids of the European tarnished plant bug Lygus rugulipennis Poppius, are established in the United States for biological control of native North American Lygus species, and are being considered for deliberate release in Canada. High lifetime fecundity of parasitoids is considered a desirable attribute of biological control agents and therefore, an understanding of parasitoid reproductive biology is required. In the present study, the potential lifetime fecundity of both agents was compared under laboratory conditions to estimate the potential impact of Peristenus species on Lygus. Synovigenic P. digoneutis and P. stygicus females oviposited most actively in the first two weeks of their lifetime, with a maximum average daily oviposition rate after five days. The maximum number of eggs laid per day was 83 eggs for P. stygicus, and 36 eggs for P. digoneutis. P. digoneutis has an average potential lifetime fecundity of 385 ± 35 SE eggs produced over 22 ± 3 SE days. In contrast, P. stygicus females have a 50% higher mean potential lifetime fecundity reaching 782 ± 65 SE eggs over 28 ± 1 SE days. A positive correlation between lifetime fecundity and body size was found only for P. stygicus, and both species showed a significant relationship between lifetime fecundity and oviposition period. The present study demonstrates that the fecundity of P. digoneutis and P. stygicus is considerably higher than previously reported. Based on these findings, P. stygicus appears to be the most effective biological control agent for Lygus lineolaris (Palisot de Beauvois) when only fecundity is taken into consideration.     

Biological control of the mediterranean black scale,Saissetia oleae (Hom.: Coccidae) in Israel

During the years 1975–1982, the “Israel Cohen” Inst. for Biological Control conducted a biological control project, against the black scale,Saissetia oleae (Olivier) (Homoptera: Coccidae). Seventeen species of natural enemies were introduced into Israel during that period, and their action reduced the populations of the pest to an acceptable level. The major parasitoid responsible for that transition wasMetaphycus bartletti Annecke &; Mynhardt (Hymenoptera: Encyrtidae). This article describes the project and introduces some notes on the biology of the introduced parasitoids.     

白蜡虫及其3种优势寄生蜂的时空生态位

在白蜡虫Ericerus pela (Chavannes)分布特征和寄生蜂调查的基础上,分析了白蜡虫及其3种优势寄生蜂:白蜡虫花翅跳小蜂Microterys ericeri Ishii、中华花翅跳小蜂M.sinicus Jiang和白蜡虫阔柄跳小蜂Metaphycus ericeri Xu et Jiang的时间和空间的一维生态位宽度、生态位重叠和比例相似性。结果表明,白蜡虫及其3种优势寄生蜂的时间生态位宽度:白蜡虫>白蜡虫阔柄跳小蜂>白蜡虫花翅跳小蜂>中华花翅跳小蜂,空间生态位宽度:白蜡虫>白蜡虫花翅跳小蜂>白蜡虫阔柄跳小蜂>中华花翅跳小蜂。3种优势寄生蜂与白蜡虫的生态位重叠度:白蜡虫花翅跳小蜂>中华花翅跳小蜂>白蜡虫阔柄跳小蜂,比例相似性:白蜡虫花翅跳小蜂>白蜡虫阔柄跳小蜂>中华花翅跳小蜂。说明白蜡虫花翅跳小蜂与白蜡虫在资源序列上分布的相似性最大,在时间上的同步性和空间上的同域性较强,资源利用程度最高。白蜡虫花翅跳小蜂与白蜡虫阔柄跳小蜂在时间生态位、空间生态位和时间-空间生态位上均有较大的重叠和比例相似性,在资源利用上存在明显的种间竞争。白蜡虫种群数量大,生长周期长、为多种寄生蜂的繁育提供了丰富、稳定的食物资源。     

Thermal requirements for the embryonic development of Periplaneta americana (L.) (Dictyoptera: Blattidae) with potential application in mass-rearing of egg parasitoids

The embryonic development of oothecae of Periplaneta americana was evaluated under four different constant temperatures (5, 10, 15, 20, 25, 30, and 35 °C) and also at different exposure times at <5 °C. Their suitability as hosts after the treatment for the parasitoids Evania appendigaster and Aprostocetus hagenowii was also assessed. Temperatures of 5, 10, 15, and 35 °C adversely affected the development of the cockroaches, and exposure times to <5 °C longer than 5 days sufficed to kill all the embryos in the oothecae. The lower thermal threshold for complete development of P. americana was estimated to be 6.8 °C, with a required total amount of 900.9 degree-days. Cold-killed oothecae were still fit for the development of parasitoids. Parasitism rates of A. hagenowii were higher than those of E. appendigaster, although with lower emergence rates. Our results can be useful in aiding mass-rearing of these parasitoids for biological control programmes of P. americana, and may help forecast the time of emergence of nymphs of American cockroaches in infested areas.     

Using the literature to evaluate parasitoid host ranges: a case study of Macrocentrus grandii (Hymenoptera: Braconidae) introduced into North America to control Ostrinia nubilalis (Lepidoptera: Crambidae)

We propose a method for using the literature to evaluate host ranges of parasitoids that are candidates for biological control introductions. Data on the parasitoids that attack a given host species can be used as negative evidence concerning the candidate whose host range is being evaluated. By compiling studies for a variety of host species, one can delineate those taxa unlikely to be attacked by the candidate. Using a retrospective case study of a parasitoid introduced into North America, we describe (1) this approach to using the literature to evaluate host range and (2) how well predictions based on such an evaluation match actual host range. Based on the host range of Macrocentrus grandii in Eurasia as reported in the literature, we predicted that the species in the genus Ostrinia are the most likely hosts. Of native North American species, Ostrinia obumbratalis is the only non-target species likely to be attacked by M. grandii. The predicted host range for North America matched the actual host range found in the field. This suggests that a careful literature review could be used as an important source of data on host range of parasitoid species proposed for introduction into a new environment.     

Biology and behavior of Metaphycus angustifrons Compere (Hymenoptera: Encyrtidae), a newly discovered parasitoid of soft scale insects (Hemiptera: Coccidae) in California

Metaphycus angustifrons Compere has recently been found to be the most abundant parasitoid of brown soft scale, Coccus hesperidum L., in southern California. In laboratory experiments we examined several biological parameters of this species. M. angustifrons both oviposits and host feeds in brown soft scale and is a facultatively gregarious endoparasitoid of this soft scale insect. In contrast with other Metaphycus spp., M. angustifrons is a koinobiont parasitoid, allowing its host to grow up to 40% beyond its size at parasitism. Despite its high abundance on brown soft scale in the field, in the laboratory, high rates of parasitoid egg encapsulation are observed; about half of parasitized hosts failed to issue parasitoids. Furthermore, host scales that encapsulated parasitoids eggs showed significant reduction in development. Increased scale size at oviposition influences the size of emerging females but not the size of males. Female M. angustifrons are synovigenic. They emerge from their hosts without mature eggs and begin maturing eggs after they are provided a carbohydrate source. Carbohydrates prolong the life span of both female and male M. angustifrons. The size of female wasps influences egg load but not longevity. Finally, based on laboratory observations, M. angustifrons uses citricola scale almost exclusively for host feeding and not for oviposition. These results suggest that the role of this species in citricola scale’s decline in southern California in the 1950s–1960s was negligible.     

Acceptance and suitability of different host stages of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) and seven other tephritid fruit fly species to Tetrastichus giffardii Silvestri (Hymenoptera: Eulophidae)

Tetrastichus giffardii Silvestri is a gregarious eulophid endoparasitoid of several tephritid fruit fly species. Host stage suitability was studied using nine age groups of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), namely, eggs less than 24 h and between 24 and 48 h old, and 1- to 7-day-old larvae. Life table studies for T. giffardii using C. capitata as host were done at 26 ± 5 °C and 55–60% RH. Egg load in relation to age of the female parasitoid was also assessed as was the effect of host deprivation on adult longevity. Host acceptance and suitability were examined with respect to eight species of tephritids. Potential hosts so tested were five Ceratitis species, the Medfly, C. capitata, the mango fruit fly, Ceratitis cosyra (Walker), the Natal fruit fly, Ceratitis rosa Karsch, Ceratitis fasciventris (Bezzi), and Ceratitis anonae Graham; two Bactrocera species, the melon fruit fly, Bactrocera cucurbitae (Coquillett) and the newly invasive Bactrocera invadens Drew, Tsuruta, and White; and one Dacus species, the lesser pumpkin fly, Dacus ciliatus Loew. No parasitoids were obtained from eggs while all larval stages were suitable though at varying degrees. Parasitism and number of progeny was related to host age in a curvilinear manner with maxima at 4- to 5-day-old larvae. By contrast, development time decreased with age of host larvae while sex ratio was not affected. The intrinsic rate of increase was 0.17 ± 0.01; gross and net reproductive rates were 64.9 ± 4.3 and 44.9 ± 3.8, respectively. Non-ovipositing females lived significantly longer than ovipositing ones. The females accepted all host species tested, but only C. capitata, D. ciliatus and, to a much lesser extent, C. cosyra were suitable. In the remaining host species, most eggs were encapsulated. In C. capitata and D. ciliatus, percent parasitism was similar, but number of progeny was lower and the sex ratio, as the proportion of females, was higher when the parasitoid was reared on D. ciliatus. Progeny per puparium were also similar for the two hosts. In the light of these results it can be concluded that T. giffardii has a narrow host range, but it attacks and successfully develops in larvae representing a wide range of ages.     

A survey of black scale,Saissetia oleae [Hom.: Coccidae] parasitoids [Hym.: Chalcidoidea] in southern California

A survey of black scaleSaissetia oleae (Olivier) parasitoids present in southern California was conducted between September 1987 and September 1989. From 308 collections of black scale-infested citrus, olive, and oleander twigs from 19 sites in southern California, 1,610 specimens were collected. Nine primary and six secondary parasitoid species were identified. Four primary species were abundant in southern California:Metaphycus bartletti Annecke & Mynhardt,M. helvolus (Compere),Scutellista caerulea (Fonscolombe) (=S. cyanea Motschulsky), andDiversinervus elegans Silvestri. The most common secondary parasitoids wereMarietta mexicana (Howard),Cheiloneurus noxius Compere, andTetrastichus minutus (Howard). In the coastal region of southern California,M. bartletti was the most abundant parasitoid, followed in order byD. elegans, S. Caerulea, andM. helvolus. In the intermediate and interior regions,M. helvolus was most abundant.D. elegans was second most abundant in the intermediate region, but was rare in the interior region.M. bartletti was second in abundance in the interior region and third in the intermediate region.