BIOLOGICAL CONTROL- AND PREDATORS Performance Of Psyttalia Humilis (: ) Reared From Irradiated Host on Fruit (Diptera: ) In California

VICTORIA Y. YOKOYAMA,1,2 XIN-GENG WANG,3 ALICIA ALDANA,4 CARLOS E. CA´ CERES,4 HANA A. YOKOYAMA-HATCH,5 PEDRO A. RENDO´ N,4 MARSHALL W. JOHNSON,6 3 AND KENT M. DAANE Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021

Environ. Entomol. 41(3): 497Ð507 (2012); DOI: http://dx.doi.org/10.1603/EN11252 ABSTRACT The Psyttalia humilis (Silvestri) was reared on Mediterranean fruit ßy, (Wiedemann), third instars irradiated at 0Ð70 Gy at the USDA, APHIS, PPQ, Moscamed biological control laboratory in San Miguel Petapa, Guatemala, and shipped to the USDA, ARS, Parlier, CA. Irradiation dose did not affect the parasitoidÕs offspring sex ratio (53Ð62% females), percentage of unemerged adults (12Ð34%), number of progeny produced per female (1.4Ð1.8), and (19Ð24%). Host irradiation dose had no signiÞcant effect on the forewing length of female P. humilis and its parasitism on olive fruit ßy, oleae (Rossi) and offspring sex ratio, but dissection of 1-wk-old female parasitoids reared from hosts irradiated with 70 Gy had a signiÞcantly lower number of mature eggs than females from nonirradiated hosts. Longevity of P. humilis adults decreased with increased temperature from 15 to 35ЊC, regardless of food provisions, gender, and host irradiation dose. Females survived 37Ð49 d at 15ЊC with water and food, and only 1Ð2 d at 35ЊC without food, whereas males lived shorter than females at all temperatures and food combinations tested. Adult P. humilis reared from fertile C. capitata and aspirated for dispensing in cups lived signiÞcantly longer after shipment than those specimens chilled and dispensed by weight. At 21 and 32ЊC, 50% of parasitoids departed release cages after 180 and 30 min, respectively, but none departed at 12ЊC. Thirteen shipments of P. humilis (2,980Ð21,922 parasitoids per shipment) were received between September and December 2009, and seven shipments (7,502Ð22,560 parasitoids per shipment) were received between October and December 2010 from San Miguel Petapa, Guatemala. Daily number of olive fruit ßy adult and percentage female trap captures ranged Ͻ1Ð19 and 8Ð58% in 2009, and Ͻ1Ð11 and 0Ð42% in 2010, respectively. The number of parasitoids released ranged 848Ð12,257 in 2009 and 3,675Ð11,154 in 2010. Percentage parasitism of olive fruit ßy third instars at all locations ranged 0Ð9% in 2009 and 0Ð36% in 2010.

KEY WORDS larval parasitoid, Bactrocera oleae (Rossi), irradiated host, parasitism, longevity

The parasitoid, Psyttalia humilis (Silvestri), imported released for biological control of olive fruit ßy, Bac- from Kenya into Guatemala in 1999, was mass reared trocera oleae (Rossi) (Yokoyama et al. 2008, 2010, 2011; on Mediterranean fruit ßy (Medßy), Ceratitis capitata Wang et al. 2011b). Irradiating Medßy third instars for (Wiedemann), third instars at the USDA-APHIS-PPQ, parasitoid production helps eliminate the risk of a Moscamed, laboratory in San Miguel Petapa, Guate- fertile host in shipments to California. The use of irra- mala for shipment to the USDA-ARS, Parlier, CA, and diation to sterilize hosts before parasitization also im- proves the economics of producing biological control agents such as eliminating unnecessary sorting steps be- This article reports the results of research only. Mention of a fore shipment, and reducing handling costs (Hendrichs proprietary product does not constitute an endorsement or recom- mendation for its use by the USDAÐARS or USDA-APHIS-PPQ. et al. 2009, Steinberg and Cayol 2009). However, the 1 USDAÐARS, San Joaquin Valley Agricultural Sciences Center, technique may affect the survival and vigor of the para- 9611 South Riverbend Ave., Parlier, CA 93648. sitoids reared by this method. A suitable irradiation dose 2 Corresponding author, e-mail: [email protected]. would allow healthy adult parasitoids but not fruit ßy 3 Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720. hosts to emerge, greatly facilitating handling procedures 4 USDA-APHIS-PPQ-CPHST, Guatemala City, Zona 10, Guate- (Cancino et al. 2009c). Thus, the technique has been mala. extensively adopted to produce various biological con- 5 Department of Pathology, University of California, Davis, trol agents (Goettel 2009). CA 95616. 6 Department of Entomology, University of California, Riverside, Fruit ßy parasitoids have been used extensively for CA 92521. classical and augmentative biological control against

0046-225X/12/0497Ð0507$04.00/0 ᭧ 2012 Entomological Society of America 498 ENVIRONMENTAL ENTOMOLOGY Vol. 41, no. 3 pest tephritid fruit ßies worldwide (Wharton 1989, irradiated host in 2008 (Yokoyama et al. 2010) which Purcell 1998, Ovruski et al. 2000, Daane and Johnson resulted in recovery of progeny in some locations. 2010). Many fruit ßy parasitoids, including Diachas- However, in 2009Ð2010 we began searching for olive mimorpha longicaudata (Ashmead) (Sivinski and fruit ßy populations in the California Central Valley Smittle 1990, Cancino et al. 2009a), D. tryoni (Cam- and reservoirs of infestation during the fall when the eron) (Cancino et al. 2009a), Doryctobracon areolatus pest is abundant in . Sites close to areas where (Sze´pligeti) (Palenchar et al. 2009), Fopius arisanus olives are grown for canning and oil were selected to (Sonan) (Cancino et al. 2009b), P. humilis (Yokoyama release the parasitoid and support integrated pest et al. 2010), and P. concolor (Sze´pligeti) (Hepdurgun management (IPM) of olive fruit ßy (Johnson et al. et al. 2009a, 2009b), have been successfully reared on 2006). We collected weather data at these sites and irradiated larvae of factitious hosts including Medßy, evaluated adult and larval hosts in olive trees and fruit Mexican fruit ßy, Anastrepha ludens (Loew), and and calculated rates of parasitism and presence of

other Anastrepha spp. Cancino et al. (2009c) also overwintering populations to determine the efÞcacy Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 reared eight native larval-prepupal and pupal parasi- of the imported parasitoid reared from an irradiated toids on irradiated Anastrepha sp. larvae. These studies host. showed that total suppression of adult emergence of irradiated Medßy larvae could be achieved at a dose Materials and Methods of 60 Gy (Cancino et al. 2009a, Hepdurgun et al. 2009a) or even lower depending on the cohort size of in Laboratory Tests. Medßy third instars the irradiated larvae (Cancino et al. 2009a). were produced in the Moscamed rearing facility in San In previous studies, host irradiation did affect the Miguel Petapa, Guatemala, according to methods pre- Þtness of fruit ßy parasitoids determined by rates of viously described by Caceres (2002). Larvae were adult emergence, longevity or fecundity (Cancino et collected in water to inhibit movement and prevent al. 2009a, Hepdurgun et al. 2009a). While Hepdurgun escape; placed in a sifter to remove excess water; and et al. (2009a) reported that irradiation of Medßy lar- placed in plastic irradiation bag (0.5 liters larvae per vae at doses Ͻ60 Gy had no signiÞcant effect on the bag). The bags of larvae were placed in an irradiation emergence and sex ratio of P. concolor adults or prog- cylinder and irradiated for 3 min at 0, 40, 50, 60, and eny quality, Yokoyama et al. (2010) found that P. 70 Gray (Gy) in a Cesium 137 irradiator (Hussman 521 humilis reared from Medßy larvae irradiated at 70 Gy A Series 006, Isomedix, Whippany, NJ). The irradiated had a low mature egg load compared with females larvae were separated according to irradiation dose; reared from nonirradiated hosts. This observation em- exposed to oviposition by P. humilis in cages made of phasizes the need to reexamine the currently used two nestled plastic rings (10.8 cm inner diameter by irradiation dose of 70 Gy to sterilize Medßy third 1.5 cm high) covered with mesh (625 openings per instars for production of P. humilis and develop suit- cm2) (Yokoyama et al. 2008); placed on top of able irradiation doses for other fruit ßy hosts used for screened cages, and held for pupation and adult para- mass rearing parasitoids. sitoid emergence as described by Yokoyama et al. Our goal was to determine the most suitable irra- (2010). As adult P. humilis emerged, they were col- diation doses for mass rearing P. humilis that would not lected, separated according to host irradiation dose, affect postemergence quality, Þtness, and parasitism of chilled for 3 min at 0ЊC, and dispensed by weight (2 olive fruit ßy. We conducted a detailed study to in- g ϭ 1,000 adults) in a waxed paper cup (Ϸ100 para- vestigate the possible effect of host irradiation dose on sitoids per cup, 50% females), which was provisioned adult P. humilis Þtness, including preshipment repro- with water on a sponge and honey on a cloth lid. The duction and rates of parasitism, and postshipment parasitoids were packed at a low density per cup to body size, fecundity (both realized and potential fe- reduce possible stresses to the parasitoids and damage cundity), and survivorship under different conditions to the wings during air shipments to the USDA, ARS, of temperature and food provisions before Þeld re- San Joaquin Valley Agricultural Sciences Center lease. Temperature and food provisions are well (SJVASC), Parlier, CA (Fig. 1) (Yokoyama et al. known to affect the longevity of P. humilis (Yokoyama 2010). The time from parasitoid collection in Guate- et al. 2010; Wang et al. 2011a,b). Furthermore, we mala to arrival in California was 2 d. Parasitoids were investigated possible interactive host irradiation-re- unpacked in an isolated screened room, where they lated effects on other important parasitoid life history were transferred into aluminum-frame or organdy- traits such as ability to withstand adverse weather screened cages (30.5 cm wide by 30.5 cm long by 30.5 conditions in the presence or absence of suitable food cm high) that were provisioned with honey and pro- resources. vided with water before tests. Finally, the performance of P. humilis reared from A laboratory colony of olive fruit ßy was maintained irradiated Medßy larvae was evaluated in Þeld releases on olive fruit collected from an insecticide-free olive in four different regions in California for biological orchard at the University of California Kearney Agri- control of olive fruit ßy in 2009 and 2010. We studied cultural Research and Extension Center (KARE) as the effect of preshipment dispensing techniques in described by Wang et al. (2009b). The fruit were Guatemala and postshipment release rates at different placed in cloth cages (Bug Dorm2, BioQuip, Rancho temperatures to help maximize parasitoid efÞciency. Dominguez, CA) that were held under controlled We released the Þrst P. humilis adults reared from room conditions (24 Ϯ 2ЊC, 16L: 8D, 40Ð60% RH). June 2012 YOKOYAMA ET AL.: PERFORMANCE OF PARASITOID FROM IRRADIATED HOST 499

parents and the number of Medßy larvae exposed to oviposition in each test to calculate the number of progeny per female parent and percentage parasitism, respectively. The results were compared among the irradiation treatments using an arcsine transforma- tion of percentages, one-way analysis of variance (ANOVA), and TukeyÕs honestly signiÞcant differ- ence (HSD) test (GraphPad Software 2007). The re- sults were reported as the mean Ϯ SEM among the host irradiation doses. The effects of the host irradiation doses on adult female P. humilis body size based on forewing length,

mature egg-load, parasitism of olive fruit ßy and prog- Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 eny sex ratio based on percentage females were stud- ied at KARE under conditions of 24 Ϯ 2ЊC, 16L:8D, and 40Ð60% RH. Female parasitoids used for all tests were 1 wk-old and had been caged with approximately the same number of males after arrival from Guatemala. Thirty females were randomly selected, killed to mea- sure the forewing from the outer edge of the base of the anal cell to the terminal tip of the wing, and dissected to determine the number of mature eggs that were fully developed in the lower egg tubes. Infested olive fruit were collected 8 d after exposure Fig. 1. Locations of olive fruit ßy collection and P. hu- to olive fruit ßy adults in the laboratory to produce two milis releases in California in 2009 and 2010. to three early third instars per fruit (Daane et al. 2008). Five to six fruit were placed in a petri dish (8 cm Each cage had 100Ð200 mature (Ͼ2 wk old) olive fruit diameter) in the middle of an acrylic cylindrical cage ßy females, which were provisioned with honey, wa- (8.5 cm top diameter by 11.5 cm bottom diameter by ter, and protein yeast (FisherBiotech, Fairlawn, NJ). 15 cm high) that had two 5 cm diameter organdy The fruit were left in the cage until each fruit had 3Ð5 covered holes on the sides for ventilation. An im- oviposition punctures. The infested olives were then ported female P. humilis reared from irradiated Medßy removed from the cage and placed on a raised metal larvae was placed in the acrylic cage for 3 d for each screen, held 2 cm above a plastic tray. After 10Ð12 d of two consecutive exposures using new infested fruit, olive fruit ßy larvae exited the fruit and dropped into i.e., additionally measuring 6 d parasitism when pro- the tray, where the pupae were collected and placed vided with unlimited access to host larvae. After each into holding cages for adult emergence. exposure to parasitoids, the exposed olives were Host Irradiation Dose versus Female Parasitoid Fit- placed on cloth raised 2 cm above the bottom of a ness. The effect of host irradiation dose on rate of plastic container (8 cm high by 11 cm wide by 14 cm parasitism by female P. humilis was determined at the long), and covered with an organdy screen. The fruit Moscamed laboratory in San Miguel Petapa, Guate- were held until all olive fruit ßy and parasitoid adults mala. Irradiated Medßy third instars were exposed to emerged. All adults were counted and gender of para- parasitoids in mesh covered, plastic ring cages. A total sitoids recorded. All fruit were dissected and the of 7,000 Medßy third instars, 700 per each of 10 ring noneclosed or dead olive fruit ßy pupae were col- cages per each irradiation dose of 40, 50, 60, or 70 Gy, lected, reconstituted in water for 1Ð2 d, and dissected and a nonirradiated control were placed over a under a microscope to determine unemerged parasi- screened cage containing 4-d-old parasitoid adults toids. Thirty-Þve imported parasitoid females were (1076Ð1907) and Ϸ900 females per cage at 25ЊC using evaluated for each host irradiation dose. previously described procedures (Yokoyama et al. Parasitoid forewing length, mature egg-load, para- 2010). The tests were replicated weekly for four sitism of olive fruit ßy, and percentage female progeny weeks. The exposed Medßy third instars were trans- were compared among the host irradiation doses using ferred to sawdust for pupation. Fourteen days later, a one-way ANOVA and TukeyÕs HSD test (SAS Insti- the pupae were sieved from the sawdust and held for tute 2008). Proportional data were arcsine square-root emergence of parasitoids and hosts. The parasitoids transformed before analysis and results reported as the that emerged were counted by sex and the unemerged mean Ϯ SEM. Medßy pupae were dissected to determine numbers of Host Irradiation Dose versus Parasitoid Longevity. unemerged parasitoids (pharate larvae and adults). The longevity of imported P. humilis adults reared The total number of female parasitoid progeny and from Medßy larvae irradiated at 0, 40, 50, 60, or 70 Gy unemerged parasitoids were divided by the total num- was determined at constant temperatures of 15, 25, Њ ber of F1 parasitoids to calculate percentage females and 35 C, 14L:10D, and 50% RH in environmental (sex ratio) and unemerged adults. The total number of chambers (model E32560, Lab-line, Melrose Park, IL).

F1 parasitoids was divided by the number of female Temperatures and RH in each chamber were moni- 500 ENVIRONMENTAL ENTOMOLOGY Vol. 41, no. 3 tored with a data logger (HOBO Pro v2, Onset Com- were monitored with a data logger to record every puter, Bourne, MA) to record every minute and minute. Comparisons of percentage survival of the changed as needed. Ϸ50 parasitoids with a similar parasitoids between chilled and aspirated treatments number of males and females were placed in a cylin- were performed by survival analysis log-rank test (SAS drical acrylic cage (8.5 cm top diameter by 11.5 cm Institute 2008). bottom diameter by 15 cm high) with no water or food, Rate of parasitoid departure from aluminum-frame water only, or water and honey provided for food. release cages was determined in environmental cham- Water was provided through a cotton wick placed in bers (I-36VL, Percival ScientiÞc, Perry, IA). A 60 cm a water-Þlled 50 ml plastic cup and replenished every wide by 60 cm long by 60 cm high, cloth cage (Bug- 1Ð2 wks. Honey was streaked on the sides of the cage Dorm 2120, MegaView Science, Taichung, Taiwan) wall and replenished every 2Ð3 d. Mortality in each was placed inside each chamber to contain released cage was determined daily in the mornings and after- parasitoids. Each of three chambers was set at 12, 21, Њ noons until all insects were dead. Each test was rep- or 32 C and 50% RH. Thirty parasitoids of equal sex Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 licated three times. Longevity for each parasitoid was ratio were placed in each release cage, and the release calculated and data were pooled from three replicate cage was placed inside the cloth cage inside the cham- tests. The total number of tested individuals ranged ber. The top of the release cage was opened, and the from 25 to 141 for each gender and treatment com- number of parasitoids that departed was observed for bination including host irradiation dose, temperature, 2, 5, 30 min, and every 30 min to 3 h. Each test was and type of provision. Survival was compared among replicated three times for each temperature. The re- irradiation doses, provisions, and gender using a three- sults were compared for each time among the tem- way ANOVA for each temperature (SAS Institute peratures using a one-way ANOVA and TukeyÕs HSD 2008). Results were reported as the mean Ϯ SEM. test (GraphPad Software 2007) and reported as the Prerelease Parasitoids. Parasitoids were mass reared mean Ϯ SEM for the replicates. on third instar Medßy larvae irradiated at 70 Gy in San Field Release and Recovery of P. humilis. Eight sites Miguel Petapa, Guatemala, according to methods de- in 2009 and seven sites in 2010 were selected for Þeld scribed by Yokoyama et al. (2010). Seven thousand releases of P. humilis in California and are collectively irradiated Medßy larvae were placed in mesh covered, shown in Fig. 1. The olive trees in each site were not plastic ring cages and exposed for1htooviposition by sprayed with insecticides or harvested for fruit. Re- P. humilis. The parasitized larvae were placed on corn leases were made from 17 September to 21 December cob diet as described by Caceres (2002), held for 2009 and from 29 October to 18 December 2010, dur- pupation, and transferred to emergence cages. The ing the period when olive fruit can be heavily infested. emerged parasitoids were chilled in the cages in a Cages of parasitoids were opened beneath or in trees room at 0ЊC for 3 min, and2gofadults (Ϸ1,000) were with fruit visibly infested with olive fruit ßy larvae. dispensed into waxed paper cups (0.275 liters) that Parasitoid releases were made either once with a sub- contained water on a sponge, and honey on the lid. sequent postrelease evaluation or repetitively in lo- The cups were packaged and shipped by DHL air cations with high olive fruit ßy infestations and fruit freight and entered the U.S. through Miami, FL. Upon that remained in the trees for an extended period. The arrival at the USDA, ARS, Parlier, CA the cups of number of trees and fruit per tree sampled was based parasitoids were placed into in aluminum-framed, or- on availability of infested fruit, ideally four trees per gandy-screened cages (30.5 cm wide by 30.5 cm long site, and collections of Ͼ100 fruit per tree. Postrelease by 30.5 cm high) (BioQuip Products, Rancho Domin- samples were made from trees receiving parasitoids guez, CA), opened, provided with water and honey, the previous sample date, and typically ranged from 4 allowed to mate, observed for 1Ð2 d, and transported to 8 d after the release. by automobile to release sites. The total number of Data loggers (2Ð3 per site) were used to record parasitoids released was calculated from number of temperature and relative humidity at each parasitoid dead adults counted in the cups and cages after release release site. The data loggers were placed in the can- and subtracted from the number shipped from Gua- opy of sampled trees, and programmed to record every temala. hour. During the 2010 study, temperature loggers Survival after shipment was compared between failed in BakersÞeld 15Ð26 November and Grapevine chilling versus aspirating parasitoids from emergence 5Ð19 November, and the hourly temperatures for both cages to dispense them into cups for shipping from sites were obtained from the California Irrigation Guatemala. Parasitoids were from the same cohort and Management Information System (CIMIS) weather reared from fertile Medßy larvae. Upon arrival at the station No 125, Arvin-Edison (35Њ 12ЈN, 118Њ 46ЈW). SJVASC, Parlier, CA, the parasitoids were transferred Weather data during the period between pre- and to cylindrical acrylic cages and maintained and ob- postreleases were reported as the mean Ϯ SEM high, served in the same manner as parasitoids used in the low and average temperature and % relative humidity. host irradiation, longevity study. Four replicate cages To estimate olive fruit ßy populations, adults were each containing 50Ð65 adults of which 46Ð60 were trapped using four to six yellow panel Pherocon AM females that were chilled, and four replicate cages traps (Tre´ce´ Inc., Adair, OK), with a clear packet (10.5 each containing 14Ð27 adults of which 7Ð22 were fe- cm wide by 10.5 cm high) of ammonium bicarbonate males that were aspirated before shipment were held bait (15Ð20 g), and a plastic dispenser (1.7 cm wide in the laboratory at Ϸ23ЊC. Temperature and humidity by 4.8 cm long) containing pheromone (1,7- June 2012 YOKOYAMA ET AL.: PERFORMANCE OF PARASITOID FROM IRRADIATED HOST 501

Table 1. Mean ؎ SEM percentage females and unemerged of available third instars and reported as the mean Ϯ adult P. humilis, no. of progeny per female, and percentage par- SEM of the replicates. asitism of Medfly larvae irradiated at different doses in San Miguel Petapa, Guatemala

Host % % No. progeny % Results irradiation, Female Unemerged per female Parasitism Gy progeny adults Host Irradiation Dose versus Female Parasitoid Fit- 0 62.3 Ϯ 3.9a 13.5 Ϯ 2.6a 1.85 Ϯ 0.17a 23.8 Ϯ 2.3a ness. Adult P. humilis reared from irradiated Medßy 40 58.2 Ϯ 6.3a 15.4 Ϯ 3.4a 1.74 Ϯ 0.17a 22.3 Ϯ 2.2a larvae showed no differences (one-way ANOVA) in 50 54.0 Ϯ 4.1a 16.4 Ϯ 2.6a 1.45 Ϯ 0.14a 18.8 Ϯ 1.9a emerged percentage females (F ϭ 0.67; df ϭ 4, 15; P ϭ 60 53.3 Ϯ 6.8a 33.6 Ϯ 8.8a 1.48 Ϯ 0.10a 18.9 Ϯ 1.3a ϭ ϭ ϭ Ϯ Ϯ Ϯ Ϯ 0.62), unemerged adults (F 3.03; df 4, 15; P 70 62.3 3.9a 12.4 4.0a 1.59 0.22a 20.6 2.9a 0.052), number of progeny per parasitoid female ϭ ϭ ϭ Means within columns followed by same letters are not signiÞcantly (F 1.02; df 4, 15; P 0.43), and percentage Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 different (P Ͼ 0.05, one-way ANOVA, TukeyÕs HSD test). parasitism (F ϭ 1.01; df ϭ 4, 15; P ϭ 0.44) among the host irradiation doses of 0Ð70 Gy. For parasitoids reared from irradiated host, females ranged 53Ð62%, dioxaspiro[5,5]undecane, 80 mg) supplied by Vioryl, unemerged adults 12Ð34%, number of progeny per Athens, Greece. Traps were placed at mid-canopy female 1.4Ð1.8, and parasitism 19Ð24%, in tests con- height (Ϸ 2.4 m) in a shaded area near fruit, with each ducted in San Miguel Petapa, Guatemala (Table 1). trap in a separate tree and traps spaced one to several Host irradiation dose had no signiÞcant effect on trees apart as described by Yokoyama et al. (2006). At body size of female P. humilis based on forewing the end of the exposure period, the total number of length (F ϭ 0.61; df ϭ 4,145; P ϭ 0.58); parasitism of females and males in each trap were counted, and the olive fruit ßy over a 6Ðd exposure (F ϭ 1.98; df ϭ 4,170; results reported as mean Ϯ SEM adults per day per P ϭ 0.32), or percentage female progeny (F ϭ 0.78; trap and percentage females. df ϭ 4,170; P ϭ 0.54) (Table 2) in tests conducted at To determine parasitism levels, samples of olive the KARE in Parlier, CA. Dissected 1-wk old female fruit were randomly sampled from trees before and parasitoids reared from hosts irradiated with 70 Gy had after parasitoid releases to record emerging numbers a signiÞcantly lower number of mature eggs than fe- of olive fruit ßy pupae and adults or P. humilis adults. males from nonirradiated hosts, but no signiÞcant dif- Fruit samples were weighed, placed in plastic con- ferences were found among females from hosts irra- tainers (22 cm wide by 32 cm long by 13 cm high), diated with 0Ð60 Gy (F ϭ 2.56; df ϭ 4,145; P ϭ 0.04). covered with organdy cloth, and held in the laboratory Host Irradiation Dose versus Parasitoid Longevity. at 23 Ϯ 2ЊC. After all insects had emerged, rates of Mean Ϯ SEM temperatures and % RH in environmen- parasitism were calculated for each site and sample tal chambers were 14.6 Ϯ 0.0ЊC and 80.4 Ϯ 0.01% RH; date, based on previously published procedures 25.8 Ϯ 0.0ЊC and 55.4 Ϯ 0.01% RH; and 34.7 Ϯ 0.01ЊC (Yokoyama et al. 2008, 2010). Parasitism was based on and 54.6 Ϯ 0.03% RH. Longevity of P. humilis adults the olive fruit ßy third instar which is preferred by the decreased with increased temperature, regardless of P. concolor species complex (Sime et al. 2006) and P. food provisions, gender, and host irradiation dose (Ta- humilis (Yokoyama et al. 2008). The number of third ble 3). Longevity at each temperature was affected by instars available to the parasitoids on each release date food provision, gender, and their interaction (Table was calculated from the number of olive fruit ßy larvae 4). At 15ЊC, females survived 6Ð7 d without food, 8Ð9 and pupae that emerged for4dinprerelease fruit d with water, and 37Ð49 d with water and food. At samples. The number of available third instars was 26ЊC, females survived 2 d without food, 3 d with multiplied times the number of fruit in each postre- water, and 20Ð24 d with water and food. At 35ЊC, lease fruit sample, and reported as the mean Ϯ SEM females survived 1Ð2 d without food, 2 d with water, of the replicates. Percentage parasitism was calculated and 5Ð7 d with water and food. At 15ЊC, males survived by dividing the number of parasitoids that emerged in 2Ð4 d without food, 4 d with water, and 8Ð16 d with the postrelease fruit samples by the estimated number water and food. At 26ЊC, males survived 1 d without

Table 2. Mean ؎ SEM size and egg-load of female P. humilis and percentage parasitism of olive fruit fly larvae and female progeny of parasitoids in California that were reared from Medfly larvae irradiated at different doses in San Miguel Petapa, Guatemala

Parasitism and progeny Females (n ϭ 30) Host sex ratio (n ϭ 35) irradiation, Gy Forewing Mature Host % % Female length, mm egg-load density Parasitism progeny 0 3.85 Ϯ 0.04a 48.6 Ϯ 1.8a 24.3 Ϯ 1.3a 74.9 Ϯ 2.9a 59.9 Ϯ 4.7a 40 3.81 Ϯ 0.03a 44.6 Ϯ 1.4ab 28.6 Ϯ 1.5a 79.1 Ϯ 2.1a 54.2 Ϯ 5.2a 50 3.85 Ϯ 0.03a 45.9 Ϯ 1.2ab 25.5 Ϯ 1.4a 79.6 Ϯ 3.2a 52.8 Ϯ 5.3a 60 3.85 Ϯ 0.03a 43.7 Ϯ 1.5ab 24.1 Ϯ 1.4a 75.7 Ϯ 3.2a 56.7 Ϯ 5.4a 70 3.79 Ϯ 0.03a 42.2 Ϯ 1.6b 26.2 Ϯ 1.7a 77.2 Ϯ 2.9a 47.9 Ϯ 5.6a

Means within columns followed by different letters are signiÞcantly different (P Ͻ 0.05, one-way ANOVA, TukeyÕs HSD test). 502 ENVIRONMENTAL ENTOMOLOGY Vol. 41, no. 3

Table 3. Mean ؎ SEM (n) days of longevity for female and male P. humilis reared from Medfly larvae irradiated at different doses and kept under different conditions of temp and food provisions after shipment to California

Temperature, Food Host irradiation, Gy Sex ЊC provision 0 40506070 Female 15 No food 6.3 Ϯ 0.3 (89) 7.2 Ϯ 0.4 (65) 6.8 Ϯ 0.4 (65) 7.1 Ϯ 0.4 (79) 6.9 Ϯ 0.3 (65) Water only 7.9 Ϯ 0.3 (110) 8.3 Ϯ 0.4 (77) 8.3 Ϯ 0.5 (52) 8.8 Ϯ 0.4 (72) 8.1 Ϯ 0.5 (67) Water, honey 48.9 Ϯ 3.4 (90) 47.5 Ϯ 4.1 (76) 37.1 Ϯ 3.9 (59) 45.9 Ϯ 4.2 (73) 48.2 Ϯ 4.0 (78) 26 No food 2.1 Ϯ 0.1 (108) 2.1 Ϯ 0.1 (70) 2.3 Ϯ 0.1 (53) 2.2 Ϯ 0.1 (58) 2.4 Ϯ 0.1 (68) Water, only 2.8 Ϯ 0.2 (97) 2.6 Ϯ 0.1 (69) 2.6 Ϯ 0.2 (42) 2.8 Ϯ 0.2 (48) 2.6 Ϯ 0.1 (66) Water, honey 19.5 Ϯ 2.0 (92) 24.5 Ϯ 2.6 (68) 21.4 Ϯ 2.8 (56) 20.3 Ϯ 2.4 (66) 23.4 Ϯ 2.5 (74) 35 No food 1.3 Ϯ 0.1 (89) 1.3 Ϯ 0.1 (65) 1.5 Ϯ 0.1 (50) 1.4 Ϯ 0.1 (45) 1.6 Ϯ 0.1 (70) Water, only 1.8 Ϯ 0.1 (100) 1.8 Ϯ 0.1 (80) 1.9 Ϯ 0.1 (54) 2.0 Ϯ 0.1 (56) 1.9 Ϯ 0.1 (69) Water, honey 5.6 Ϯ 0.3 (141) 5.2 Ϯ 0.3 (91) 5.3 Ϯ 0.4 (63) 4.6 Ϯ 0.4 (68) 6.6 Ϯ 0.4 (73) Ϯ Ϯ Ϯ Ϯ Ϯ Male 15 No food 3.9 0.2 (38) 4.0 0.4 (47) 2.8 0.3 (38) 2.4 0.3 (25) 2.8 0.3 (43) Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 Water only 3.9 Ϯ 0.3 (47) 3.7 Ϯ 0.3 (40) 3.5 Ϯ 0.3 (38) 3.5 Ϯ 0.3 (36) 4.5 Ϯ 0.4 (42) Water, honey 10.2 Ϯ 2.2 (27) 12.3 Ϯ 2.2 (51) 8.8 Ϯ 1.6 (34) 7.5 Ϯ 1.2 (38) 15.6 Ϯ 2.0 (35) 26 No food 1.1 Ϯ 0.1 (47) 1.2 Ϯ 0.1 (44) 1.2 Ϯ 0.1 (38) 1.3 Ϯ 0.1 (49) 1.4 Ϯ 0.1 (32) Water only 1.4 Ϯ 0.1 (36) 1.3 Ϯ 0.1 (44) 1.0 Ϯ 0.1 (36) 1.2 Ϯ 0.1 (50) 1.3 Ϯ 0.1 (42) Water, honey 3.7 Ϯ 0.9 (31) 4.8 Ϯ 0.9 (30) 3.3 Ϯ 0.6 (34) 3.6 Ϯ 0.6 (47) 3.9 Ϯ 0.7 (24) 35 No food 0.9 Ϯ 0.03 (47) 1.0 Ϯ 0.04 (48) 0.9 Ϯ 0.1 (38) 1.0 Ϯ 0.04 (48) 1.0 Ϯ 0.03 (34) Water only 1.2 Ϯ 0.1 (37) 1.1 Ϯ 0.04 (57) 1.1 Ϯ 0.1 (35) 1.0 Ϯ 0.03 (60) 1.2 Ϯ 0.1 (36) Water, honey 2.9 Ϯ 0.6 (30) 2.4 Ϯ 0.3 (37) 1.7 Ϯ 0.4 (34) 2.6 Ϯ 0.3 (54) 2.8 Ϯ 0.3 (31) food, 1 d with water, and 3Ð5 d with water and food. min, respectively (Table 5). Rates of departure were At 35ЊC, males survived 1 d without food, 1 d with proportional to time and temperature, and signiÞcant water, and 2Ð3 d with water and food (Table 3). At 15 differences were found in departure rates among the and 26ЊC, host irradiation dose did not affect parasitoid temperatures at 30 (F ϭ 16.41; df ϭ 2, 6; P ϭ 0.004), longevity and no interactive effects on longevity were 60 (F ϭ 32.22; df ϭ 2, 6; P ϭ 0.001) and 90 min (F ϭ found among food provisions, host irradiation dose, 39.22; df ϭ 2, 6; P ϭ 0.001). and gender (Table 4). At 35ЊC, host irradiation dose Field Release and Recovery of P. humilis. Thirteen affected parasitoid longevity and an interactive effect shipments of P. humilis (2,980Ð21,922 parasitoids per was found between food provision and host irradiation dose but not between the host irradiation dose and gender (Table 4). Prerelease Parasitoids. Female P. humilis reared from fertile Medßy and aspirated from emergence cages for dispensing in cups lived signiÞcantly longer (␹2 ϭ 47.68, df ϭ 1, P Ͻ 0.001) than those chilled and dispensed by weight after shipment to the ARS, Par- lier, CA, and provided with water and honey and held at a room temperature of 22.8 Ϯ 0.01ЊC and 34.6 Ϯ 0.04% RH (Fig. 2.). Male longevity did not differ whether aspirated (n ϭ 22, 13.6 Ϯ 2.2 d) or chilled (n ϭ 24, 13.6 Ϯ 2.4 d) for shipment (␹2 ϭ 0.001, df ϭ 1, P ϭ 0.97) (Fig. 2). Females lived signiÞcantly longer than males when aspirated (␹2 ϭ 71.5, df ϭ 1, P Ͻ 0.001) or chilled (␹2 ϭ 27.3, df ϭ 1, P Ͻ 0.001). No parasitoids departed release cages at 12ЊC. At 21 and 32ЊC, 50% of the adults departed after 180 and 30

Table 4. Results of three-way ANOVA testing the effects of host irradiation dose, food provision, sex, and their interactions on longevity under different temperatures on imported adult P. hu- milis reared from irradiated Medfly larvae

15ЊC26ЊC35ЊC df FPFPFP Food (F) 2 297.7 Ͻ0.001 199.2 Ͻ0.001 384.5 Ͻ0.001 Irradiation 4 1.5 0.193 0.5 0.794 3.1 0.015 Fig. 2. Comparison of percentage survival of adult female dose (D) (A) and male (B) P. humilis provided with water and honey Gender (G) 1 270.0 Ͻ0.001 179.5 Ͻ0.001 246.9 Ͻ0.001 at 23ЊC and 35% RH in California after aspiration or chilling F ϫ D 8 1.3 0.245 0.6 0.804 2.6 0.009 for dispensing, packaging, and shipment from San Miguel F ϫ G 2 134.2 Ͻ0.001 114.7 Ͻ0.001 80.1 Ͻ0.001 ϫ Petapa, Guatemala. Dispensing method followed by different D G 4 0.6 0.697 0.3 0.903 1.8 0.124 letters in each legend indicates a signiÞcant difference (P Ͻ F ϫ D ϫ G 8 0.5 0.842 0.3 0.977 1.5 0.169 0.05, Survival analysis, log-rank test). June 2012 YOKOYAMA ET AL.: PERFORMANCE OF PARASITOID FROM IRRADIATED HOST 503

Table 5. Mean ؎ SEM percentage P. humilis departing from release cages from 2 to 180 min at three incubator temperatures

Temp., ЊC 2 5 30 60 90 120 150 180 12 0a 0a 0a 0a 0a 0a 0a 0a 21 15.6 Ϯ 7.3a 25.6 Ϯ 12.4ab 33.3 Ϯ 10.2b 36.7 Ϯ 8.4b 41.1 Ϯ 8.0b 43.3 Ϯ 8.8b 44.4 Ϯ 9.9b 51.1 Ϯ 10.9b 32 22.2 Ϯ 6.8a 36.7 Ϯ 10.7b 50.0 Ϯ 3.8b 60.0 Ϯ 3.8c 65.6 Ϯ 4.4c 66.7 Ϯ 5.1b 70.0 Ϯ 7.7b 70.0 Ϯ 7.7b

Means within columns followed by different letters are signiÞcantly different (P Ͻ 0.05, one-way ANOVA, TukeyÕs HSD test). shipment) from San Miguel Petapa, Guatemala, were ifornia will help ensure that fertile hosts will not con- received at the SJVASC, Parlier, CA, between Sep- taminate shipments imported from Guatemala. Host tember and December 2009. Ten of the 2009 ship- irradiation dose did not affect parasitism and repro- ments were used for Þeld releases in olive trees in- duction of P. humilis (Table 1), but female parasitoids fested with olive fruit ßy and three shipments were reared from larvae irradiated at 70 Gy had fewer eggs Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 used to determine the effect of rearing the parasitoids (Table 2). The highest level of irradiation could have on irradiated hosts. Seven shipments were received caused tissue damage to Medßy larvae decreasing the between October and December 2010 (7,502Ð22,560 nutritive value to the developing parasitoids and egg parasitoids per shipment) and used for Þeld releases. production. Although, one-week fecundity was not Table 6 and Table 7 show regions and speciÞc loca- affected by host irradiation dose (Table 2), the fe- tions selected for parasitoid releases, description of males may not have yet used all eggs for reduced egg the olive trees, and fruit sample dates and trees sam- production to be detected. Furthermore, initial egg pled at each release site. In these locations, daily num- load may not provide a good estimate of fecundity in ber of olive fruit ßy and percentage female trap cap- synovigenic parasitoids. In such parasitoids, small dif- tures ranged Ͻ1Ð19 adults and 8Ð58% in 2009 (Table Ͻ ferences in egg load at eclosion quickly disappear 8) and 1Ð11 adults and 0Ð42% in 2010 (Table 9), (Cicero et al. 2011), and may not affect foraging and respectively. Daily mean temperatures and RH ranged parasitism in the Þeld. 6Ð21ЊC and 37Ð82% in 2009 (Table 8) and 8Ð18ЊCin In the Þeld, the actual effect of reduced mature egg 2010 (Table 9). Exeter in 2010 had two cultivars, Mis- load on parasitoid efÞciency would depend on lon- sion and Ascolano, that had medium and large size gevity in relation to food conditions and environmen- fruit infested with olive fruit ßy in which to compare parasitism, and the mean Ϯ SEM size by weight of the tal temperature. Most parasitoids are time-limited or fruit was 3.7 Ϯ 0.2 and 7.9 Ϯ 0.5 g, respectively. dead before all eggs have been deposited (Ellers et al. Parasitoid releases, post release evaluation dates, 2000). Without food provisions, female P. humilis Ϸ Њ prerelease olive fruit ßy larval infestations in olive fruit would only survive 1wkat15C (Table 3) and 1Ð2 including the calculated number of third instars, and d at higher temperatures and are less subject to egg recovery of P. humilis adults and percentage parasit- limitation. When the parasitoid has full access to food ism are shown for all locations in 2009 (Table 10) and sources, e.g., honeydew, longevity in the Þeld would 2010 (Table 11). The number of P. humilis released increase (Wang et al. 2011a). Under these conditions, ranged 848Ð12,257 parasitoids in 2009 and 3,675Ð the parasitoid may deplete its egg supply, and those 11,154 parasitoids in 2010. Percentage parasitism of reared from an irradiated host exposed to the highest olive fruit ßy third instars at all locations ranged 0Ð9% dose could be marginally less productive. Nonethe- in 2009 (Table 10) and 0Ð36% in 2010 (Table 11). less, the dose of 70 Gy should not be used for steril- ization of Medßy larvae for mass production of para- sitoids based on the observation of decreased Discussion parasitoid egg-load if lower doses are also effective for Irradiation of Medßy larvae for production of P. this purpose. Thus, we reconÞrmed a previous report humilis for biological control of olive fruit ßy in Cal- that 70 Gy used for the irradiation of Medßy larvae

Table 6. Region and specific location, description of the olive trees, and fruit sample dates from September to December 2009 in eight release sites for P. humilis in California

GPS No. Tree Sample Trees Region Site Elev. m Cultivar coordinates trees layout date sampled Sacramento Valley Oroville 39Њ 28Ј N, 121Њ 29Ј W 171 Manzanillo Ͼ100 Orchard 22 Nov. 4 North Coast San Jose 37Њ 17Ј N, 121Њ 44Ј W 199 Mission 59 Ornamental 17 Sep. 2 Central Coast San Luis Obispo 35Њ 11Ј N, 120Њ 42Ј W 20 Manzanillo 84 Groves 11 Dec. 4 18 Dec. 4 Solvang 34Њ 37Ј N, 120Њ 06Ј W 207 Mission 9 Windrow 21 Dec. 3 San Joaquin Valley Lodi 38Њ 06Ј N, 121Њ 15Ј W 16 Mission 18 Windrow 10 Oct. 2 27 Nov. 3 4 Dec. 5 Porterville 36Њ 06Ј N, 118Њ 50Ј W 248 Manzanillo 26 Grove 26 Oct. 2 BakersÞeld 35Њ 24Ј N, 118Њ 50Ј W 259 Mission 62 Ornamental 9 Oct. 2 4 Dec. Grapevine 34Њ 56Ј N, 118Њ 55Ј W 459 Mission 5 Ornamental 5 Oct. 1 504 ENVIRONMENTAL ENTOMOLOGY Vol. 41, no. 3

Table 7. Region and specific location, description of the olive trees, and fruit sample dates from October to December 2010 in seven release sites for P. humilis in California

GPS No. Tree Sample Trees Region Site Elev. m Cultivar coordinates trees layout date sampled Sacramento Valley Oroville 39Њ 28Ј N, 121Њ 29Ј W 171 Manzanillo Ͼ100 Orchard 18 Dec. 4 Woodland 38Њ 39Ј N, 121Њ 45Ј W 10 Mission Ͼ100 Windrow 10 Dec. 3 San Joaquin Valley Lodi 38Њ 06Ј N, 121Њ 15Ј W 16 Mission 18 Windrow 12 Nov. 2 Merced 37Њ 20Ј N, 120Њ 30Ј W 53 Mission 8 Windrow 1 Nov. 3 Exeter 36Њ 18Ј N, 119Њ 05Ј W 312 Mission, Ascolano 45 Ornamental 2 Dec. 3 BakersÞeld 35Њ 24Ј N, 118Њ 50Ј W 259 Mission 62 Ornamental 29 Oct. 2 15 Nov. Grapevine 34Њ 56Ј N, 118Њ 55Ј W 459 Mission 5 Ornamental 5 Nov. 1 Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 reduced the mature egg load of P. humilis (Yokoyama nonirradiated larvae and larvae exposed to 40Ð70 Gy et al. 2010). (Table 1). Medßy larvae were exposed to parasitism Irradiation can cause damage to host organs and naked (Table 1) while olive fruit ßy larvae were ex- tissues preventing parasitoid development. Irradiation posed in olive fruit (Table 2). The higher rate of of late third instar Mexican fruit ßy, A. ludens, at 20 Gy parasitism of olive fruit ßy may have resulted from the retarded protein metabolism and arrested develop- higher level of acceptability of fruit ßy larvae in fruit. ment at the transition from cryptocepahlic to phan- Also, the density of Medßy larvae under such artiÞcial erocephalic puparium (Thomas and Hallman 2000). exposure conditions may have limited host accept- The endoparasitic pupal parasitoid, Coptera haywardi ability and resultant parasitism. (Ogloblin), is unable to develop in puparia derived Temperature and food are known to affect the lon- from irradiated larvae or puparia (Menezes et al. gevity of P. humilis and its host, olive fruit ßy 1998), but development of the parasitoid is completed (Yokoyama et al. 2010, Wang et al. 2009a,b, 2011a,b,c). if radiation is applied after pupation (Cancino et al. Temperature had a greater effect than host irradiation 2009c). In addition to retarding host development, dose on parasitoid survival and the adults required irradiation might damage vital structures in the host water and food for longevity (Table 3). The females required by the immature parasitoid. In Mexican fruit lived longer than males and survival decreased with ßy, radiation damages the larval nervous and endo- increasing temperatures regardless of the presence or crine system (Nation et al. 1995). The majority of absence of water and food. The longest lived (48 d) parasitoids use host derived nutrients for reproduction parasitoids were females provided with water and although adult diet may in some cases compensate honey for food at 15ЊC. The shortest lived (1 d) were larval deÞciencies (Visser et al. 2010). For P. humilis, males without water or food at 35ЊC and under the the percentage of unemerged parasitoids from Medßy same conditions the females only lived slightly longer larvae (Table 1) was similar for all host irradiation than 1 d. Temperatures selected for this study reßect doses suggesting that the quality of the irradiated mild conditions in coastal regions and the hot interior larvae was similar for development of immature para- Central Valley of California as described by Johnson sitoids. et al. (2011) where olives are commercially grown. Parasitism at all host irradiation doses by P. humilis Aspirating P. humilis for packaging and shipment ranged 48Ð60% on olive fruit ßy in California (Table from the rearing facility in San Miguel Petapa, Gua- 2) but only 19Ð24% on irradiated Medßy in Guatemala temala to Parlier, CA, improved longevity upon arrival (Table 1). Irradiated Medßy third instars were ob- and females lived as long as 99 d in the laboratory (Fig. served to be acquiescent after exposure which did not 2). However, females that were chilled and weighed affect the acceptability of the larvae to the parasitoid lived as long as 82 d so the technique is still advanta- because percentage parasitism did not differ between geous even with a loss of viability because the proce-

Table 8. Mean ؎ SEM trap captures of olive fruit fly adults, and daily temperature and relative humidity from September to December 2009 at eight release sites for P. humilis in California

No. adults captured Daily temp (ЊC) Site Trap period % Captured females Daily % RH per day per trap Highest Lowest Mean Oroville 22Ð28 Nov. 4.07 Ϯ 0.33 29.8 Ϯ 2.1 17.3 Ϯ 1.4 6.0 Ϯ 0.7 11.2 Ϯ 0.4 68.8 Ϯ 1.6 San Jose 17Ð24 Sep. 18.63 Ϯ 6.35 49.8 Ϯ 8.8 31.8 Ϯ 0.8 14.5 Ϯ 0.5 21.4 Ϯ 0.5 65.9 Ϯ 1.5 San Luis Obispo 11Ð18 Dec. 0.86 Ϯ 0.00 20.8 Ϯ 0.0 18.6 Ϯ 1.2 6.8 Ϯ 1.5 11.9 Ϯ 0.4 78.6 Ϯ 1.4 18Ð31 Dec. 0.18 Ϯ 0.07 44.2 Ϯ 15.1 17.6 Ϯ 0.8 4.4 Ϯ 0.7 10.2 Ϯ 0.3 71.9 Ϯ 1.1 Solvang 21Ð30 Dec. 0.28 Ϯ 0.06 58.3 Ϯ 8.3 16.7 Ϯ 0.8 1.5 Ϯ 0.9 7.8 Ϯ 0.4 72.5 Ϯ 1.3 Lodi 10Ð23 Oct. 18.90 Ϯ 0.50 39.6 Ϯ 1.8 22.3 Ϯ 0.9 12.7 Ϯ 0.8 16.9 Ϯ 0.2 78.6 Ϯ 0.8 27 Nov.Ð4 Dec. 0.33 Ϯ 0.08 8.3 Ϯ 0.0 16.6 Ϯ 0.8 3.3 Ϯ 0.9 9.1 Ϯ 0.4 68.9 Ϯ 1.6 4Ð14 Dec. 0.00 Ϯ 0.00 0.0 Ϯ 0.0 11.1 Ϯ 0.6 2.2 Ϯ 1.6 5.9 Ϯ 0.3 81.9 Ϯ 0.9 Porterville 26 Oct.Ð3 Nov. 1.00 Ϯ 0.00 13.6 Ϯ 0.0 21.5 Ϯ 1.6 6.2 Ϯ 0.7 12.9 Ϯ 0.4 57.3 Ϯ 1.3 BakersÞeld 9Ð15 Oct. 2.79 Ϯ 1.21 20.6 Ϯ 11.5 24.2 Ϯ 1.3 14.3 Ϯ 0.9 18.9 Ϯ 0.3 56.3 Ϯ 1.7 Grapevine 5Ð9 Oct. 0.60 Ϯ 0.00 33.3 Ϯ 0.0 20.5 Ϯ 1.6 11.7 Ϯ 1.0 16.0 Ϯ 0.4 36.6 Ϯ 0.7 June 2012 YOKOYAMA ET AL.: PERFORMANCE OF PARASITOID FROM IRRADIATED HOST 505

Table 9. Mean (؎ SEM) trap captures of olive fruit fly adults, and daily temp and relative humidity from Oct. 2010 to Jan. 2011 at seven release sites for P. humilis in California

No. adults captured % Captured Daily temp (ЊC) Site Trap period Daily % RH per day per trap females Highest Lowest Mean Oroville 18 Dec.Ð2 Jan. 0.02 Ϯ 0.00 0.0 Ϯ 0.0 10.9 Ϯ 0.7 4.9 Ϯ 0.8 7.7 Ϯ 0.2 88.2 Ϯ 0.7 Woodland 10Ð17 Dec. 0.19 Ϯ 0.00 16.7 Ϯ 0.0 14.4 Ϯ 0.9 6.7 Ϯ 1.5 10.3 Ϯ 0.3 90.2 Ϯ 0.5 Lodi 12Ð22 Nov. 5.00 Ϯ 0.72 38.6 Ϯ 3.1 18.2 Ϯ 1.6 6.8 Ϯ 0.4 11.6 Ϯ 0.3 78.8 Ϯ 1.0 Merced 1Ð12 Nov. 2.33 Ϯ 0.34 14.4 Ϯ 2.4 21.6 Ϯ 1.7 8.1 Ϯ 1.0 14.1 Ϯ 0.4 74.4 Ϯ 1.0 Exeter 2Ð6 Dec. 0.25 Ϯ 0.0 18.8 Ϯ 0.0 14.9 Ϯ 1.5 9.3 Ϯ 0.6 11.7 Ϯ 0.2 74.3 Ϯ 0.7 BakersÞeld 29 Oct.Ð8 Nov. 11.10 Ϯ 3.33 36.8 Ϯ 13.4 24.2 Ϯ 1.5 11.7 Ϯ 0.8 17.6 Ϯ 0.4 61.6 Ϯ 1.3 15Ð26 Nov. 1.67 Ϯ 0.21 40.3 Ϯ 8.0 16.2 Ϯ 1.8 3.7 Ϯ 1.0 9.4 Ϯ 1.0 78.1 Ϯ 2.2 Grapevine 5Ð19 Nov. 1.00 Ϯ 0.53 42.2 Ϯ 21.5 20.8 Ϯ 1.5 6.4 Ϯ 0.6 12.8 Ϯ 1.0 73.6 Ϯ 3.3 Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 dure allows faster dispensing and packaging of large most canning olives are grown (Yokoyama 2011). In numbers of parasitoids. Longevity may not affect par- 2009Ð2010 (Tables 8 and 9) we found new reservoirs asitism of olive fruit ßy because the parasitoids can ßy of olive fruit ßy on the eastern edge of the Central for long periods and may leave the release site Valley where cooler climatic conditions were found to (Yokoyama et al. 2010), but for parasitoids that re- be favorable for the adults and above the elevation of main, longevity would increase time for host location 103 m at Parlier, CA. These foothill reservoirs of the in infested orchards. Males did not live as long, Ϸ27Ð36 pest included Oroville in the Sacramento Valley, and d, using either dispensing technique, so holding the Porterville, Exeter, BakersÞeld, and Grapevine in the parasitoids for at least one day after arrival helps en- San Joaquin Valley. Central Valley locations below sure mating before Þeld release. Baeza-Larios et al. 103 m elevation, where olive fruit ßy has been previ- (2002) found that chilling as low as 3.5ЊC for 1 h did ously found, include Lodi and Woodland and in 2010 not affect female longevity of other opine braconid we discovered moderate infestations in Merced. parasitoids used in aerial releases. These infestations are on the valley ßoor but the ma- Rates of P. humilis departure from open cages rine inßuence of the Sacramento Delta helps cool the showed low ambient temperature conditions near regions creating environmental conditions favorable 12ЊC (Table 5) were not conducive to successful re- for olive fruit ßy and biological control by P. humilis. leases. In 2010 at the Oroville location, the highest day We conducted P. humilis releases in coastal sites in temperatures averaged Ϸ11ЊC (Table 9) during a 2009 in addition to inland valley releases (Table 10) parasitoid release in which only 3,675 of a total of but emphasized Central Valley locations in 2010, 14,864 parasitoids departed cages over a 2 wk period. closer to the canned olive growing areas (Table 11). The low Þeld temperatures were probably related to Releases were begun in September in 2009 and in the lack of recovery of the progeny. At 21ЊC the para- October in 2010. Subsequent generations of the para- sitoids were slow to depart the cages and a release sitoid were recovered in most locations Ͻ3 wks after would require Ͼ3 h to complete. Once Þeld temper- release except when fruit and olive fruit ßy larvae atures decrease in the fall when olive fruit ßy larval were scarce such as Porterville in October 2009 or infestations are abundant, parasitoid releases will be- when weather was cold such as at Lodi and Oroville come increasingly more difÞcult and impractical. in December 2009 and 2010, respectively. Olive fruit ßy in California is abundant in olives in Calculation of percentage parasitism (Tables 10Ð the cool and humid coastal regions including San Jose, 11) in our study was based on the number of available San Luis Obispo, and Solvang (Table 8) and found in olive fruit ßy third instars, rather than the total number low numbers in the hot and dry interior valleys where olive fruit ßy larvae present, because eggs and young

Table 10. Number and dates P. humilis released, mean (؎ SEM) number of fruit and olive fruit fly (OLF) emerged, estimated third instars exposed to parasitoids, and percentage parasitism of third instars at eight sites in California from September to December 2009

Pre-release Release No. parasitoids Post-release OLF reared Total % Parasitism of Location No. fruit date released sample date Third instars P. humilis reared OLF third instar Total per fruit Oroville 22 Nov. 2,743 28 Nov. 283 Ϯ 30 69 0.05 Ϯ 0.02 12 4.98 Ϯ 2.69 San Jose 17 Sep. 4,045 24 Sep. 923 Ϯ 125 1,043 0.13 Ϯ 0.03 11 1.56 Ϯ 1.03 San Luis Obispo 11 Dec. 7,841 18 Dec. 230 Ϯ 17 137 0.14 Ϯ 0.02 9 5.40 Ϯ 3.65 18 Dec. 12,257 31 Dec. 294 Ϯ 77 114 0.10 Ϯ 0.04 9 4.25 Ϯ 0.00 Solvang 21 Dec. 4,318 30 Dec. 238 Ϯ 11 178 0.17 Ϯ 0.01 2 0.68 Ϯ 0.00 Lodi 10 Oct. 1,280 23 Oct. 267 Ϯ 20 80 0.11 Ϯ 0.04 0 0 27 Nov. 1,258 4 Dec. 251 Ϯ 24 436 0.55 Ϯ 0.11 2 0.25 Ϯ 0.16 4 Dec. 8,351 14 Dec. 203 Ϯ 20 1,660 0.94 Ϯ 0.05 0 0 Porterville 26 Oct. 4,251 3 Nov. 135 Ϯ 11 1 0 0 0 BakersÞeld 9 Oct. 848 15 Oct. 225 Ϯ 32 19 0.03 Ϯ 0.02 3 9.22 Ϯ 0.00 Grapevine 5 Oct. 1,930 9 Oct. 240 Ϯ 20 87 0.18 Ϯ 0.07 2 1.01 Ϯ 0.00 506 ENVIRONMENTAL ENTOMOLOGY Vol. 41, no. 3

Table 11. Number and dates P. humilis released, mean (؎ SEM) number of fruit and olive fruit fly (OLF) emerged, estimated third instars exposed to parasitoids, and percentage parasitism of third instars at seven sites in California from October 2010 to January 2011

Pre-release Release No. parasitoids Post-release OLF reared Total % Parasitism of Location No. fruit date released sample date Third instars P. humilis reared OLF third instar Total per fruit Oroville 18 Dec. 3,675 2 Jan. 511 Ϯ 51 29 0.02 Ϯ 0.01 0 0 Woodland 10 Dec. 11,154 17 Dec. 368 Ϯ 88 193 0.08 Ϯ 0.02 62 36.16 Ϯ 19.05 Lodi 12 Nov. 6,550 22 Nov. 645 Ϯ 56 1,636 0.62 Ϯ 0.09 52 2.02 Ϯ 0.71 Merced 1 Nov. 3,697 12 Nov. 400 Ϯ 71 555 0.64 Ϯ 0.21 13 1.33 Ϯ 0.22 Exeter 2 Dec. 4,985 13 Dec. 357 Ϯ 35 252 0.14 Ϯ 0.03 6 1.17 Ϯ 0.63 BakersÞeld 29 Oct. 3,889 8 Nov. 367 Ϯ 27 66 0.06 Ϯ 0.01 4 3.72 Ϯ 2.16 15 Nov. 6,656 26 Nov. 309 Ϯ 31 258 0.27 Ϯ 0.07 28 6.42 Ϯ 2.08 Ϯ Ϯ Ϯ Grapevine 5 Nov. 10,688 19 Nov. 405 113 800 0.66 0.41 7 0.52 0.23 Downloaded from https://academic.oup.com/ee/article/41/3/497/359904 by guest on 28 September 2021 instars are unsuitable for oviposition (Sime et al. mass-reared parasitoids (Hymenoptera: Braconidae) of 2006). Additionally, Yokoyama et al. (2008) reported the Mediterranean fruit ßy, Ceratitis capitata (Wiede- that P. humilis caused mortality of the Þrst and second mann) (Diptera: Tephritidae). Biocontrol Sci. Technol. instars. When olive fruit ßy third instars were avail- 12: 205Ð215. able, weather conditions were favorable (Table 8), Caceres, C. 2002. Mass rearing of temperature sensitive ge- and parasitoid progeny were not recovered such as in netic strains in the Mediterranean fruit ßy (Ceratitis capi- tata). Genetica 116: 107Ð116. Lodi in October 2009 (Table 10), the small sample size Cancino, J., L. Ruı´z, P. Lo´pez, and J. Sivinski. 2009a. The of postrelease fruit may have limited the ability to suitability of Anastrepha spp. and Ceratitis capitata larvae detect parasitized larvae. Except for Woodland in 2010 as hosts of Diachasmimorpha longicaudata and Diachas- (Table 11), percentage parasitism was in general low mimorpha tryoni: effects of host age and radiation dose based on our calculations and sampling methods. Low and implications for quality control in mass rearing. Bio- rates of parasitism were not attributed to any effect of control Sci. Technol. 19: 81Ð94. rearing the adults from irradiated Medßy host. Al- Cancino, J., L. Ruı´z, J. Pe´rez, and E. Harris. 2009b. Irradi- though, parasitism of olive fruit ßy larvae in larger size ation of Anastrepha ludens (Diptera: Tephritidae) eggs fruit may be limited by the length of P. for the rearing of the fruit ßy parasitoids, Fopius arisanus and Diachasmimorpha longicaudata (Hymenoptera: Bra- humilis (Wang et al. 2009c,d), parasitoid progeny conidae). Biocontrol Sci. Technol. 19: 167Ð177. were collected from the large size Ascolano fruit in Cancino, J., L. Ruı´z, J. Sivinski, F. O. Ga´lvez, and M. Aluja. Exeter in 2010. 2009c. Rearing of Þve hymenopterous larval-prepupal Releases of P. humilis were made in 2008 (Braconidae, Figitidae) and three pupal (Diapriidae, (Yokoyama et al. 2010) in the same sites in San Jose, Chalcidoidea, ) native parasitoids of the ge- Solvang, and Lodi in 2009. Before 2009 parasitoid re- nus Anastrepha (Diptera: Tephritidae) on irradiated A. leases at these sites, olive fruit ßy infested fruit were ludens larvae and pupae. Biocontrol Sci. Technol. 19: evaluated for new generations of parasitoids that may 193Ð209. have resulted from previous 2008 releases. However, Cicero, L., J. Sivinski, J. Rull, and M. Aluja. 2011. Effect of larval host food substrate on egg load dynamics, egg size over-wintering parasitoids were not recovered. Re- and adult female size in four species of braconid fruit ßy covery of subsequent season parasitoids was also not (Diptera: Tephritidae) parasitoids. J. Physiol. 57: observed between 2009 and 2010 in Oroville, Lodi, 1471Ð1479. BakersÞeld, and Grapevine. However, P. humilis Daane, K. M., and M. W. Johnson. 2010. Olive fruit ßy: reared from irradiated Medßy larvae readily located, managing an ancient pest in modern times. Annu. Rev. parasitized, and reproduced in olive fruit ßy larvae in Entomol. 55: 155Ð169. infested olives within the same season after importa- Daane, K. M., K. R. Sime, X. G. Wang, H. Nadel, M. W. tion from Guatemala. Johnson, and V. M. Walton. 2008. Psyttalia lounsburyi (Hymenoptera: Braconidae), potential biological control agent for the olive fruit ßy in California. Biol. Control 44: Acknowledgments 78Ð89. Ellers, J., L. G. Sevenster, and G. Driessen. 2000. Egg load We are grateful to Julie A. Gagnon, Sean K. Pelham, and evolution in parasitoids. Am. Nat. 156: 650Ð665. Tim De Silva, USDA-ARS, San Joaquin Valley Agricultural Goettel, M. 2009. Use of radiation in biological control. Bio- Sciences Center, Parlier, CA, for assistance with this project, control Sci. Technol. 19: 1Ð2. and to the numerous cooperators who have allowed us to use GraphPad Software. 2007. GraphPad Prism, version 5.00. their olive groves. This research was funded in part by the GraphPad Software, San Diego, CA. California Olive Committee, Fresno, CA; the USDA CSREES Hendrichs, J., K. Bloem, G. Hoch, J. E. Carpenter, P. Greany, Special Grants Program: Pest Management Alternatives; and and A. S. Robinson. 2009. Improving the cost-effective- the Moscamed Program, USA-Mexico-Guatemala. ness, trade and safety of biological control for agricultural insect pests using nuclear techniques. Biocontrol Sci. References Cited Technol. 19: 3Ð22. Hepdurgun, B., T. Turanli, and A. Zu¨ mreog˘lu. 2009a. Par- Baeza-Larios, G., J. Sivinski, T. Holler, and M. 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