Pedro A. Rendón

Psyttalia cf. concolor (Hymenoptera: Braconidae) for biological control of olive fruit fly (Diptera: Tephritidae) in California.

Abstract The larval parasitoid, Psyttalia cf. concolor (Szépligeti), reared on Mediterranean fruit fly, Ceratitis capitata (Weidemann), by the USDA–APHIS–PPQ, Guatemala City, Guatemala, was imported into California for biological control of olive fruit fly, Bactrocera oleae (Gmelin), in olives, Olea europaea L. Mean percentage parasitism of olive fruit fly third instars infesting fruit in field cages ranged from 7.0 in Grapevine to 59.7 in Santa Barbara and in free releases ranged from 0 in Grapevine to 10.6 in Santa Barbara after 4- to 6-d exposures. In the laboratory, more parasitoids developed to adults in olive fruit fly larvae that were 11–13 d old than in larvae 8–10 d old. Adult parasitoids lived significantly longer when provided with water than adults without water in environmental chambers at 5°C, 85% RH; 15°C, 65% RH; 25°C, 25% RH; and 35°C, 25% RH. Adult parasitoids lived for 48 d with honey for food and water and 32 d with food and sugar solution at 15°C and 65% RH. Survival of adult parasitoids without food and water in greenhouse tests was ≈4 d in a simulated coastal climate and 1 d in a simulated inland valley climate and was significantly increased by providing food and water. The parasitoid did not develop in the beneficial seedhead fly, Chaetorellia succinea (Costa), in yellow star thistle. The rate of parasitism of walnut husk fly, Rhagoletis completa Cresson, larvae in green walnut husks was 28.4% in laboratory no-choice tests. In choice tests, the rate of parasitism of walnut husk fly versus olive fruit fly larvae in olives was 11.5 and 24.2%, respectively.

COLONIZATION OF FOPIUS CERATITIVORUS, A NEWLY DISCOVERED AFRICAN EGG-PUPAL PARASITOID (HYMENOPTERA: BRACONIDAE) OF CERATITIS CAPITATA (DIPTERA: TEPHRITIDAE)

Abstract Fopius ceratitivorus Wharton is a recently discovered braconid parasitoid of the Mediterranean fruit fly (= medfly), Ceratitis capitata (Wied.). Unlike other parasitoids previously used in medfly biological control, F. ceratitivorus was originally collected from medfly in its purported region of origin, east Africa. Shipments of Ceratitis spp. pupae from Kenya to a newly constructed quarantine facility in Guatemala yielded both F. ceratitivorus and its congener F. caudatus (Szèpligeti). Only the former species was successfully colonized through the use of medfly infested coffee berries. In the process of colonization it was determined that F. ceratitivorus oviposited into the eggs and recently hatched larvae of medflies and completed development in the hosts’ puparia. This is a relatively rare behavior among fruit fly parasitoids and, because tephritid eggs near the surface of fruits are particularly vulnerable to attack, one that might contribute to its success as a biological control agent.

CAPTURE OF ANASTREPHA SPECIES (DIPTERA: TEPHRITIDAE) WITH MULTILURE TRAPS AND BIOLURE ATTRACTANTS IN GUATEMALA

Abstract Two trapping systems were compared in a study in Guatemala during the wet season, May through Dec 2001. Trap/lure combinations consisting of green or yellow-based plastic McPhail-like traps baited with a synthetic 2-component lure (putrescine and ammonium acetate) and 300 mL of propylene glycol antifreeze as a preservative were compared to the traditional glass McPhail baited with torula yeast/borax and 300 mL of water. Both systems captured several key Anastrepha species including Anastrepha ludens Loew, A. obliqua, Macquart, A. serpentina Weidemann, A. striata Schiner, A. distincta Greene, A. fraterculus Weidemann as well as Ceratitis capitata Weidemann. Additionally, 13 other Anastrepha spp. were captured with the synthetic lure. The plastic traps captured more key flies than the McPhail trap except for A. distincta where there were no significant differences between the yellow-based plastic trap and the McPhail trap and no significant differences between any trap and lure for trapping A. fraterculus. The synthetic lure lasted 10 weeks. The sex ratio was female-biased for almost all captured key species in both systems. Moreover, there were significant numbers of captured nontarget insects in all traps; however, the captured flies in those traps with the synthetic lure were not adversely affected by these insects. Propylene glycol-based antifreeze was a superior preservative when compared to borax/water.

The sterile insect technique and the Mediterranean fruit fly: assessing the utility of aromatherapy in large field enclosures

The sterile insect technique (SIT) is widely used in integrated programs against tephritid fruit flies, particularly the Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae). Unfortunately, the mass‐rearing procedures inherent to the SIT often lead to a reduction in the male mating competitiveness. One potential solution involves the prerelease exposure of males to particular attractants. In particular, male exposure to ginger root oil [Zingiber officinale Roscoe (Zingiberaceae); hereafter GRO], has been shown to increase mating success dramatically in field cage trials. To evaluate more rigorously the effectiveness of GRO exposure, we here describe two projects that compared levels of egg sterility or pupal yield, respectively, following the release of wild flies and either GRO‐exposed (treated) sterile males or GRO‐deprived (control) sterile males in large field enclosures. In both projects, sterile males from a genetic sexing strain were exposed as adults to GRO for 24 h while held in large storage boxes. In Hawaii, we dissected eggs from fruits to determine the percentage of egg hatch at four overflooding ratios, ranging from 5 : 1 to 60 : 1 (sterile : wild males), and found that, at all four ratios, the proportion of unhatched (sterile) eggs was significantly greater in enclosures containing GRO‐exposed males than control males. In Guatemala, we allowed larvae to develop in fruits and counted the number of pupae produced. At the only overflooding ratio tested (25 : 1), pupal yield was approximately 25% lower for enclosures containing GRO‐exposed males than control males, although this difference was not statistically significant. An explanation for the differing outcomes is proposed, and the implications of these findings for the SIT are discussed.

Performance Of Psyttalia Humilis (Hymenoptera: Braconidae) Reared From Irradiated Host on Olive Fruit Fly (Diptera: Tephritidae) In California

ABSTRACT The parasitoid Psyttalia humilis (Silvestri) was reared on Mediterranean fruit fly, Ceratitis capitata (Wiedemann), third instars irradiated at 0–70 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 parasitoids offspring sex ratio (53–62% females), percentage of unemerged adults (12–34%), number of progeny produced per female (1.4–1.8), and parasitism (19–24%). Host irradiation dose had no significant effect on the forewing length of female P. humilis and its parasitism on olive fruit fly, Bactrocera oleae (Rossi) and offspring sex ratio, but dissection of 1-wk-old female parasitoids reared from hosts irradiated with 70 Gy had a significantly lower number of mature eggs than females from nonirradiated hosts. Longevity of P. humilis adults decreased with increased temperature from 15 to 35°C, regardless of food provisions, gender, and host irradiation dose. Females survived 37–49 d at 15°C with water and food, and only 1–2 d at 35°C 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 significantly longer after shipment than those specimens chilled and dispensed by weight. At 21 and 32°C, 50% of parasitoids departed release cages after 180 and 30 min, respectively, but none departed at 12°C. Thirteen shipments of P. humilis (2,980–21,922 parasitoids per shipment) were received between September and December 2009, and seven shipments (7,502–22,560 parasitoids per shipment) were received between October and December 2010 from San Miguel Petapa, Guatemala. Daily number of olive fruit fly adult and percentage female trap captures ranged <1–19 and 8–58% in 2009, and <1–11 and 0–42% in 2010, respectively. The number of parasitoids released ranged 848–12,257 in 2009 and 3,675–11,154 in 2010. Percentage parasitism of olive fruit fly third instars at all locations ranged 0–9% in 2009 and 0–36% in 2010.

Response of Psyttalia humilis (Hymenoptera: Braconidae) to Olive Fruit Fly (Diptera: Tephritidae) and Conditions in California Olive Orchards

ABSTRACT The larval parasitoid, Psyttalia humilis (Silvestri), reared on Mediterranean fruit fly, Ceratitis capitata (Weidemann), by USD A-APHIS-PPQ, San Miguel Petapa, Guatemala was imported into California for biological control of olive fruit fly, Bactrocera oleae (Rossi). This study reports the results of field releases and recovery of P. humilis in California, and laboratory investigations to determine the effects of food provision, high temperature, and insecticidal bait spray on the parasitoids survival and fecundity. Parasitoids (3,613–7,823) were released in Orland, San Juan Bautista, Cayucos, Sylmar, Santa Barbara, and San Diego during October through December 2006. Mean daily temperatures at the release sites ranged from 10.7°C in Orland to 20.9°C in San Juan Bautista. The lowest (0.5) and highest (29.7) mean number of adult B. oleae per day per trap was captured in Orland and Sylmar, while the lowest (0.01) and highest (2.21) number of third instar larvae per fruit was collected on 11 December in Orland and on 5 October in San Diego in prerelease samples, respectively. Parasitoids were recovered from all release sites, the lowest (0.3%) and highest (100%) parasitism occurred on 25 January in Sylmar and on 26 October in Cayucos, respectively. At 24°C, parasitoids reared from B. oleae larvae survived 36 d on honey, 31 d on orange juice, and 28 d on honeydew, which was significantly longer than on cut olive fruit (8 d) or without food (11 d), but was similar to those reared from C. capitata larvae under the same food conditions. Under a high diurnal temperature regime (18.3–35°C) reflecting the summer olive growing conditions in the California Central Valley, the parasitoids survived <5 d when no food or only water was provided. Its longevity and life-time fecundity significantly increased by provision of honey or honeydew. There was no difference in the parasitoids longevity between females and males or between food and sexes. Percent mortality of parasitoid adults was not significantly affected by the exposure to insecticidal fruit fly bait (GF-120) in four different types of choice tests with artificial honeydew and GF-120.

Efficacy of Wax Matrix Bait Stations for Mediterranean Fruit Flies (Diptera: Tephritidae)

ABSTRACT Tests were conducted that evaluated efficacy of wax matrix bait stations for Ceratitis capitata (Wiedemann) adults in Guatemala. Bait stations were exposed to outdoor conditions to determine effect of weathering on longevity as indicated by bait station age. Results of laboratory tests found that bait stations with spinosad and ammonium acetate remained effective for at least 31 d compared with pesticide-free controls, although there was some loss of efficacy over time. Percentage mortality for bait station strips with 2% spinosad and 1% ammonium acetate decreased from 100 ± 0.0% on day 0 to 70 ± 7.1% after 31 d. Ammonia concentration had little effect on percentage mortality although there was some indication that ammonia concentration affected number of flies observed on the bait stations. Bait station strips (one per cage) were more effective than controls for 6–8 wk when tests were conducted in field cages (3 m diameter × 2 m), but only 2–3 wk when tests were conducted in large (2.5 m high and 6.0 m wide and 7.5 m long) field cages. Longevity was restored when multiple bait stations (3, 6, or 12) were deployed per cage. Bait stations containing methomyl were used for field tests of efficacy for wild flies. Dipped lure bait stations, which were made by coating two edges of commercial ammonium acetate and trimethylamine lures, killed six times more flies than corn cob bait stations dipped into a Nulure/malathion solution. They also killed more flies than pesticide-free controls for 8 wk.

Inheritance of Fifteen Microsatellite Loci in Ceratitis capitata (Diptera: Tephritidae)

Abstract Molecular methods that rely on microsatellite markers have been developed for population genetic studies and diagnostics of tephritid pest species such as the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Whereas many of these markers are tested to see if they are within the Hardy—Weinberg equilibrium, very few markers developed for pest species are tested to ensure the selected alleles behave according to the laws of Mendelian inheritance. Fifteen previously developed microsatellite markers were examined for Mendelian inheritance. Nine parental groups consisting of a laboratory reared parent and a wild type parent and their respective progeny were examined. In total, 174 flies, consisting of 90 males and 84 females, were analyzed. Seventy-seven segregation ratio tests were performed to determine if any departures from expected Mendelian inheritance occurred. Representatives from each of the observed alleles were cloned and sequenced. Troubleshooting was performed on loci that did not conform to expected Mendelian inheritance ratios to confirm the cause and improve laboratory procedures. Issues observed included incomplete adenylation at the 5′ end in Ccmic3, the presence of artifactual bands leading to false calls in Ccmic25, and monomorphic alleles in Ccmic7. Only 1 locus, Ccmic25, deviated from Mendelian expectations after protocol optimization in the form of a detected transmission ratio distortion leading to excessive heterozygosity. Finally, 1 locus, Ccmic9, showed evidence of allelic homoplasy.