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The diet of adult parasitoid wasps is vital for their survival and reproduction. However, the availability of food resources, such as plant nectar, can vary widely in cropping systems, potentially affecting parasitoid fitness and thereby biological control of pests. The egg parasitoid Hadronotus pennsylvanicus(Ashmead) (Hymenoptera: Scelionidae) is a potential biological control agent of the pistachio pest Leptoglossus zonatus(Dallas) (Heteroptera: Coreidae). While H. pennsylvanicusis known to attack L. zonatuseggs in California, USA, parasitism rates in orchards are highly variable. Floral resource provisioning has the potential to enhance parasitoid longevity and thus improve parasitism rates, leading to reduced pest densities. Here, a combination of field and laboratory studies was used to assess the influence of flowering groundcovers on the reproductive fitness of H. pennsylvanicusand the abundance of L. zonatus. Evaluated groundcovers included oat (Avena sativaL.), cowpea (Vigna unguiculataL.), white mustard (Sinapis albaL.), and buckwheat (Fagopyrum esculentumMoench). Under laboratory conditions, buckwheat and mustard provided the greatest benefit to female H. pennsylvanicuslongevity. However, females provided a buckwheat diet produced the greatest number of offspring over the course of their lifetime. In field trials, flowering groundcovers did not influence the abundance of H. pennsylvanicusnor parasitism rates on L. zonatus. While the availability of floral resources can improve the reproductive fitness of H. pennsylvanicus, the use of groundcovers in pistachio did not enhance biological control of L. zonatus.

The mealybug, Ferrisia gilliGullan, attacks important crops such as almonds, grapes, and pistachios in California. In pistachios, F. gillihas 3 generations per year, and a single insecticide application timed to the presence of first instars of the first or second generation provided sufficient control. This strategy has, recently, become less effective, and here we tested the possible explanation that F. gillilife stages are smeared, with different life stages present concurrently, reducing the efficacy of a single pesticide application. We monitored F. gillipopulations and their natural enemies in central California pistachio orchards from 2021 through 2022. We found the first generation of F. gilliwas synchronous, but occurred 3 wk earlier than previously reported. Subsequent generations were smeared. Increased yearly temperatures are a likely explanation for the changes observed in phenology. Almost all natural enemies found were lacewings (n> 10,000). Parasitoids were recovered from pistachios in 2021 (n= 4) and 2022 (n= 164), most were hyperparasitoids. Based on these studies, recommendations are made to monitor F. gilliin early May rather than late May to better target insecticide applications for the first instars.

Agricultural systems are often lacking in resources for natural enemies. Providing alternative prey can help natural enemies persist through periods of low pest abundance, although this approach has been rarely commercially implemented in open field crops. In this study, we tested the potential of eight plant species to provide alternative prey to natural enemies in lettuce fields over a 2-yr period. Results showed that the tested plants would not act as sources of the lettuce aphid Nasonovia ribisnigriMosley (Hemiptera: Aphididae), the primary lettuce pest. Of the banker plants tested, barley contained high numbers of non-lettuce aphids and appeared to provide reliable habitat for hoverfly larvae. However, lettuce aphids were present on lettuce early in the season, and may have dwarfed any effects of nonlettuce aphids on natural enemy populations. Numbers of hoverfly larvae were also high in lettuce, but did not appear to track numbers of non-lettuce aphids on banker plants. In contrast, numbers of lacewing larvae were highest on plants containing high numbers of non-lettuce aphids, and predatory hemipterans appeared to be associated with numbers of thrips on banker plants. Although barley showed promise as a source of alternative aphids, it did not appear to improve pest control in the adjacent crop.

The leaffooted bugs Leptoglossus zonatusand L. occidentalis(Hemiptera: Coreidae) cause substantial damage in tree nut crops in North America and pine seed orchards in North America and Europe, respectively. Sexually mature males of both species produce a number of aldehydes, esters, and sesquiterpenes, which are hypothesized to constitute an aggregation pheromone attractive to both sexes. Among the volatiles produced by males of both species, we identified a unique sesquiterpene hydrocarbon, given the common name “leptotriene” (5), which elicited strong responses from antennae of both sexes in electroantennogram assays. Here, we report its structure and its synthesis from (−)-(E)-β-caryophyllene (1).

We provide recommendations for sampling and identification of introduced larval parasitoids of spotted-wing drosophila, Drosophila suzukii(Matsumura) (Diptera: Drosophilidae). These parasitoids are either under consideration for importation (aka classical) biological control introductions, or their adventive (presumed to have been accidentally introduced) populations have recently been discovered in North America and Europe. Within the context of the ecology of D. suzukiiand its parasitoids, we discuss advantages and disadvantages of estimating larval parasitism levels using different methods, including naturally collected fruit samples and sentinel baits. For most situations, we recommend repeated sampling of naturally occurring fruit rather than using sentinel baits to monitor seasonal dynamics of host plant–Drosophila–parasitoid associations. We describe how to separate Drosophilidae puparia from host fruit material in order to accurately estimate parasitism levels and establish host–parasitoid associations. We provide instructions for identification of emerging parasitoids and include a key to the common families of parasitoids of D. suzukii. We anticipate that the guidelines for methodology and interpretation of results that we provide here will form the basis for a large, multi-research team sampling effort in the coming years to characterize the biological control and nontarget impacts of accidentally and intentionally introduced larval parasitoids of D. suzukiiin several regions of the world.

The mealybug, Planococcus ficus(Signoret), is a primary vineyard pest in California and other grape-growing regions throughout the World. Mating disruption programs are commercially available to manage Pl. ficus, but widespread adoption has been limited, in part, by high costs compared with insecticide programs. To improve mating disruption economic effectiveness, different deployment technologies (passive, aerosol, and microencapsulated formulations) were individually examined. Adult male Pl. ficuscaptures in pheromone traps and categorical ratings of vine infestation or crop damage suggest that all deployment strategies lowered mealybug densities or damage. Using passive dispensers, deployment rates of 310 and 465 per ha lowered Pl. ficuscrop damage similar to 615 per ha, a rate commonly used in commercial operations; reduced rates would lower product and deployment costs. Meso dispensers, containing more a.i., deployed at 35 per ha did not have a treatment impact, but a microencapsulated formulation and aerosol canisters lowered male flight captures and/or crop damage. Male mealybug flight activity was greatest from 0500–1100 hr, which coincided with temperatures >16° and <32°C. These restricted times and temperatures suggest programable dispensers might allow pheromone deployment to coincide only with flight patterns. A large field trial using passive dispensers found greater treatment separation after 3 yr of pheromone deployment. Discrepancies in results among vineyards may be related to Pl. ficusdensity, but combined results from all trials suggest that different deployment technologies can be used to impact Pl. ficusdensities and damage, even at reduced rates, especially with continued use over multiple seasons.

Drosophila suzukii(Matsumura) (Diptera: Drosophilidae) also known as spotted-wing drosophila (SWD), is a pest native to Southeast Asia. In the last few decades, the pest has expanded its range to affect all major European and American fruit production regions. SWD is a highly adaptive insect that is able to disperse, survive, and flourish under a range of environmental conditions. Infestation by SWD generates both direct and indirect economic impacts through yield losses, shorter shelf life of infested fruit, and increased production costs. Fresh markets, frozen berries, and fruit export programs have been impacted by the pest due to zero tolerance for fruit infestation. As SWD control programs rely heavily on insecticides, exceedance of maximum residue levels (MRLs) has also resulted in crop rejections. The economic impact of SWD has been particularly severe for organic operations, mainly due to the limited availability of effective insecticides. Integrated pest management (IPM) of SWD could significantly reduce chemical inputs but would require substantial changes to horticultural management practices. This review evaluates the most promising methods studied as part of an IPM strategy against SWD across the world. For each of the considered techniques, the effectiveness, impact, sustainability, and stage of development are discussed.Graphical Abstract

Grapevine red blotch virus (GRBV) is the causal agent of grapevine red blotch disease, which affects wine grapes and leads to reduced crop yield and quality. The pathogen-plant-vector relationship of GRBV is not well understood; however, some possible vectors have been identified: Caladonus coquilletti(Van Duzee; Hemiptera: Cicadellidae), Colladonus reductus(Van Duzee; Hemiptera: Cicadellidae), Erythroneuraspp., Melanoliarussp. (Hemiptera: Cixiidae), Osbornellus borealisDeLong. & Mohr (Hemiptera: Cicadellidae), Scaphytopius granticus(Ball; Hemiptera: Cicadellidae), Spissistilus festinus(Say). Of these species, S. festinushas been shown to transmit the virus to uninfected grapevines, making it of particular interest. Since the pathogen-plant-vector relationship of GRBV is not yet completely understood, pesticide use is not necessarily the best way to manage these possible vectors. Here we test if ground cover removal, by discing in spring, could reduce the activity of potential GRBV vectors. We show that S. festinuspresence in the canopy was reduced in disc rows compared to just mowing the ground vegetation, whereas there were no differences in presence in the canopy between disc and mow rows of the other possible insect vectors. Erythroneura elegantula(Osborn; Hemiptera: Cicadellidae), a common pest of grapevines but not a candidate GRBV vector, was found to have higher densities in the canopy in disc rows compared to mow rows, an effect possibly mediated by changes in vine vigor associated with ground covers. We conclude that if S. festinusis a primary vector of GRBV, discing ground covers in early spring may be a viable way to reduce their presence in the vine canopy.

To assess the potential of Asobara japonica Belokobylskij (Hymenoptera: Braconidae) as a biological control agent for the invasive Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), key biological traits were evaluated: preference and suitability of different host ages, relative performance on two host species (D. suzukii and Drosophila melanogaster Meigen), female life-time fecundity and egg maturation on the two host species, and parasitism levels on D. suzukii larvae infesting different host fruits (blackberry, cherry and strawberry). Asobara japonica preferred young over old hosts, and although host age did not affect offspring survival, parasitoid offspring developed faster in older than younger hosts but had a reduced body size. There was higher A. japonica offspring survival, longer developmental time, and larger body when reared from D. suzukii than D. melanogaster. Female wasps emerged with around one third of their lifetime egg load and matured eggs rapidly with mature egg load reaching a peak 2–3 d post-emergence. Large females (typically reared from D. suzukii) contained more mature eggs than small females (typically from D. melanogaster). During their lifetime, A. japonica females produced 117.4 and 92.5 progeny on D. suzukii and D. melanogaster, respectively, with a corresponding intrinsic rate of increase of 0.217 and 0.210, respectively. Progeny were strongly female-biased (> 90% females), regardless of host age or species. This larval parasitoid was able to develop from D. suzukii infesting cherry, blackberry or strawberry. This information may help improve protocols for the rearing and future evaluations of this parasitoid for a potential biological control program against D. suzukii.

Grapevine red blotch virus (GRBV) is the causal agent of grapevine red blotch disease, which affects wine grapes and leads to reduced crop yield and quality. While some virus spread can be attributed to the propagation of infected plant material, a greenhouse assay recently demonstrated that the threecornered alfalfa hopper (Membracidae: Spissistilus festinusSay) can transmit GRBV between grapevines. While S. festinusis not considered an economic pest of wine grapes, this species is present in California vineyards and their feeding can cause petiole girdling. Recent surveys have noted a correlation between S. festinuspopulations and GRBV-positive vines in vineyard areas adjacent to riparian habitat. Here, S. festinuspopulations were monitored over a 2-yr period at multiple vineyard sites adjacent to riparian habitats. At each site, insects were sampled from ground covers and the vine canopy at the vineyard edge and interior, and vines in both locations were evaluated for petiole girdling. Results indicate that there was no difference in abundance of S. festinusat the vineyard edge and interior. Populations in the vine canopy were highest in the late spring and early summer, and this was followed by the appearance of petiole girdling, indicating a key period of potential GRBV transmission. Furthermore, activity in the vine canopy appears to be amplified when the quality of ground covers is reduced as the season progresses. That said, overall populations of S. festinuswere relatively low and additional work is needed to characterize the timing and efficiency of transmission under field conditions.

Drosophila suzukiihas become a key invasive pest of soft- and thin-skinned fruit crops in its invaded regions in Europe and Americas, where naturally occurring natural enemies are generally not effective for the suppression of this pest or largely absent such as larval-attacking parasitoids. As a part of systematic evaluations of candidate agents for classical biological control of this invasive pest, we evaluated the functional responses of three Asian-native larval hymenopteran parasitoids, Asobara japonica(Braconidae), Ganaspis brasiliensis, and Leptopilina japonica(both Figitidae) to D. suzukiior Drosophila melanogaster(A. japonicaonly) larvae. Host larval densities were 5, 10, 15, 20, 25, 30, 35, or 40 larvae per test for A. japonicaand 3, 6, 9, 12, 18, 24, 30, 36, or 42 larvae per test for G. brasiliensisor L. japonica. Host larvae were provided in standard artificial diet in tubes for a 24-h exposure to individual female parasitoids under the quarantine conditions (23°C). All three parasitoids showed a linear (type I) functional response to the tested host densities. Host species (for A. japonicaonly) did not affect the number of hosts parasitized or the functional response. Asobara japonicawas more efficient than either figitid in terms of the searching efficiency while L. japonicapreformed slightly better than G. brasiliensisunder the tested conditions. The results are discussed with respect to the selection of parasitoid species to be released in North America and Europe to suppress D. suzukii.

Reliable monitoring of the invasive Halyomorpha halysabundance, phenology and geographic distribution is critical for its management. Halyomorpha halysadult and nymphal captures on clear sticky traps and in black pyramid traps were compared in 18 states across the Great Lakes, Mid-Atlantic, Southeast, Pacific Northwest and Western regions of the United States. Traps were baited with commercial lures containing the H. halyspheromone and synergist, and deployed at field sites bordering agricultural or urban locations with H. halyshost plants. Nymphal and adult captures in pyramid traps were greater than those on sticky traps, but captures were positively correlated between the two trap types within each region and during the early-, mid- and late season across all sites. Sites were further classified as having a low, moderate or high relative H. halysdensity and again showed positive correlations between captures for the two trap types for nymphs and adults. Among regions, the greatest adult captures were recorded in the Southeast and Mid-Atlantic on pyramid and sticky traps, respectively, with lowest captures recorded in the West. Nymphal captures, while lower than adult captures, were greatest in the Southeast and lowest in the West. Nymphal and adult captures were, generally, greatest during July–August and September–October, respectively. Trapping data were compared with available phenological models showing comparable population peaks at most locations. Results demonstrated that sticky traps offer a simpler alternative to pyramid traps, but both can be reliable tools to monitor H. halysin different geographical locations with varying population densities throughout the season.

Pachycrepoideus vindemiae(Rondani) and Trichopria drosophilae(Perkins) are among a few indigenous parasitoids attacking the invasive Drosophila suzukii(Matsumura) (Diptera: Drosophilidae) in North America. Both parasitoid species occur in California, whereas only P. vindemiaehas been reported from Oregon. We compared the thermal performance of the California populations of P. vindemiaeand T. drosophilae, and the Oregon population of P. vindemiaeat eight constant temperatures (12.6–32.8°C). Both P. vindemiaepopulations could develop at all tested temperatures. T. drosophilaefailed to develop at or above 29.6°C. This species was, however, able to develop at a diurnal temperature regime of 15–32°C, and survival was higher in older developmental stages. T. drosophilaewas less tolerant to both low and high temperatures than P. vindemiae, whereas the Oregon P. vindemiaepopulation was more cold-tolerant but less heat-tolerant than the California population in terms of offspring survival, development, and reproduction. To develop storage strategies for mass-cultured parasitoids, we compared the cold tolerance of immature P. vindemiaeand T. drosophilaeof the California populations at 12°C for 1, 2, or 3 mo, followed by a 23°C holding period. Successful development to the adult stage decreased as cold storage duration increased. Successful development, however, increased when cold storage was initiated during the older developmental stages for 1-mo exposure for both parasitoid species. The results are discussed with regards to parasitoid thermal adaptation and the potential use of P. vindemiaeand T. drosophilaefor biological control of spotted-wing drosophila.

Abstract: A series of laboratory experiments was conducted on a colony of Bracon celer Szépligeti (Hymenoptera: Braconidae) reared on the olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae). Female B. celer preferentially probe and oviposit into olives containing late third-instar fly larvae. The parasitoid develops as a solitary, ectoparasitic idiobiont. Mean development time (oviposition to adult eclosion) at 22 °C was, for females, 36±1 (SE) days, and for males, 34±1 days. The mean longevity of adult female wasps when provided honey and water was significantly greater than when they were provided water alone, or nothing. The females produced an average of 9.7±7.2 progeny during their lifetimes, but production levels in the insectary colony suggested that this level of fecundity was artificially low and could be improved. The discrepancy may be a consequence of constraints on oviposition behavior imposed by the experimental design. The results are discussed with respect to insectary production methods and the potential use of B. celer as a biological control agent for olive fly in California.

The sex pheromone of the obscure mealybug, Pseudococcus viburni, consists of (1R*,2R*,3S*)-(2,3,4,4-tetramethylcyclopentyl)methyl acetate, the first example of a new monoterpenoid structural motif in which the two isoprene units forming the carbon skeleton are joined by 2′–2 and 3′–4 connections rather than the usual 1′–4, head-to-tail connections. This highly irregular terpenoid structure, and the irregular terpenoid structures of related mealybug species, suggest that these insects may have unique terpenoid biosynthetic pathways.

New techniques are presented on the use of 15Nto mark insects. 15N, a stable isotope of nitrogen, was enriched above natural abundance in plant and insect tissues. Two laboratory studies demonstrated that enriched 15N‐concentrations could be tracked from plant to insect using mass spectrometry. In the first study, adult Cotesia plutellae(Kurdjimov) (Hymenoptera: Braconidae) and Hippodamia convergensGuérin‐Méneville (Coleoptera: Coccinellidae) were allowed to feed at the flowers of rapid‐cycling Chinese cabbage plants that had been fertilized with 15N‐enriched potassium nitrate (KNO3‐15NO3). Both insect groups were found to have significantly elevated 15Nlevels after visiting the flowers of the 15N‐enriched plants for 48 hours. In the second study, 15N‐enriched bean plant (Phaseolus vulgarisL.) tissue was incorporated into an insect diet and fed to navel orangeworms, Amyelois transitella(Walker) (Lepidoptera: Pyralidae). When the navel orangeworm larvae were 4th instars, they were removed from the diet and exposed to the parasitoid, Goniozus legneriGordh (Hymenoptera: Bethylidae). Results indicated that the enriched 15N‐concentration of the bean plants was transferred to the navel orangeworms and, subsequently, to the parasitoids. This work may provide useful techniques to help establish whether agriculturally important entomophaga visiting 15N‐enriched flowers or parasitizing enriched sentinel larvae in the field can be effectively marked with 15N.

The overwintering survival and development of Drosophila suzukii Matsumura were investigated in California’s San Joaquin Valley. Drosophila suzukii were exposed to overwintering conditions in cages hung in a citrus orchard, and the pupae were buried in the soil. Eggs exposed from late November to January did not survive; a low percentage (<3%) of larvae and pupae developed into adults. Survival of pupae was significantly higher when buried in the soil than on the citrus tree. From late January to March, all life stages developed into adults and overwintered adult female D. suzukii produced eggs when provided with 10% honey-water and sliced oranges. Adult survival varied among fruit juice provision treatments and overwintering exposure periods, ranging from 3.4 ± 0.9 d (water) to 44.1 ± 3.0 d (10% honey-water). Fruit juices of apple, cherry, grape, orange, and pomegranate were tested as adult food sources; results showed that adult female and male D. suzukii lived only 2 d with water only, whereas adults survived from 14.2 to 34.8 d with fruit juice treatments and the 10% honey-water control. An unexpected event was the oviposition and immature development of D. suzukii with the fruit juice. In a follow-up laboratory trial, when 10% honey-water or orange juice were provided along with an artificial diet for oviposition and immature development, female D. suzukii survived for 21.6 ± 2.4 or 21.6 ± 1.5 d, and produced 106.8 ± 14.1 or 98.5 ± 13.1 offspring, respectively. We discuss factors potentially influencing overwintering survival of D. suzukii.

Anagrus erythroneurae S. Trjapitzin & Chiappini and Anagrus daanei Triapitsyn are the key parasitoids of the western grape leafhopper (Erythroneura elegantula Osborn) in northern California vineyards. Erythroneura elegantula overwinters as an adult in reproductive diapause. To successfully overwinter, Anagrus spp. must locate an alternate leafhopper host that overwinters in an egg stage that they can parasitize. These alternate leafhopper hosts are thought to be primarily located in the natural habitats surrounding vineyards. This study identifies the noncrop host plants utilized by Anagrus spp. not only during the overwintering period but throughout the entire year, as well as the leafhopper species associated with these host plants. Over a 2-yr period, Anagrus spp. and leafhoppers were sampled from numerous plants in natural and cultivated habitats surrounding vineyards. Results from this study confirm previously known Anagrus spp. host plants, but also identify new host plant species. Some of the host plants harbored Anagrus spp. year-round while others were utilized only during certain periods of the year. Leafhoppers associated with Anagrus spp. host plants may potentially serve as the alternate host utilized by Anagrus spp. on these plants, but this was not confirmed in the current study. Records of E. elegantula demonstrate their cyclical movement between the vineyard floor (winter), temporary noncrop hosts (spring/fall), and the grape vine canopy (summer).

The recent availability of sex pheromone lures for the navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), improves options for monitoring this key pest in conventionally managed almonds. These lures are, however, minimally effective in the presence of mating disruption. Experiments were conducted to determine if phenyl propionate (PPO), an attractant for the navel orangeworm, acts in an additive or synergistic manner when presented together with the pheromone. In the absence of mating disruption, traps baited with PPO captured significantly fewer adults than traps baited with a sex pheromone lure. There was no difference in the number of adults captured in traps with both attractants when mating disruption was not used. In the presence of mating disruption, pheromone traps were completely suppressed, yet traps with both pheromone and PPO captured significantly more adults than traps baited with only PPO. Traps with only PPO captured equal numbers of both sexes, whereas traps with both attractants had significantly more males. These findings demonstrate that PPO is likely to be useful for monitoring navel orangeworm in fields treated with mating disruption.

The postrelease impact of weed biological control agents on their target weeds is rarely assessed. This study focuses on the impacts of the univoltine broom psyllid Arytainilla spartiophila Forster on the growth of its target weed, the invasive shrub Scotch broom, Cytisus scoparius (L.) Link (Fabaceae), in California. Arytainilla spartiophila is an adventive species that has been present in North America for several decades. In a greenhouse experiment, plant growth as measured by both height and total stem length (height + length of all branches) was reduced on plants that received psyllids, and psyllid densities were negatively correlated to proportional change in plant height. There were no effects on number of leaves, however. Furthermore, the psyllid had no statistically detectable impacts on plant growth parameters in a field experiment, underscoring how results obtained under controlled conditions may not fully predict the performance of biological control agents in the field. The high psyllid mortality that occurred at higher psyllid densities in both the greenhouse and the field suggests that the impacts of A. spartiophila may be moderated by intraspecific competition.

Olive fruit fly, Bactrocera oleae Rossi, is a worldwide pest of olives. To discover new parasitoids for a biological control program in California, olives were collected from various locations in the Himalayan foothills (China, Nepal, India, Pakistan) as part of a comprehensive search for B. oleae throughout its range. Wild olives, Olea europaea ssp. cuspidata, were sparsely distributed and B. oleae-infested olives were scarce. Wild olives were most widespread in Pakistan where fly infestation reached 30%. Infested olives in southwestern China were rare, reaching only 5%. Flies were identified morphologically as B. oleae, the first record from China. No B. oleae were recovered from India or Nepal. Mitochondrial gene sequences from NADH dehydrogenase (ND1), cytochrome oxidase subunit 1 (COX1), and 16S rRNA were obtained from flies and compared with B. oleae sequences in GenBank. A single mitochondrial haplotype was found in Chinese flies. Chinese B. oleae represent a maternal lineage based on ND1 and COX1 that is highly divergent from other B. oleae. Phylogenetic analysis by maximum likelihood and Bayesian inference based on the concatenated dataset of B. oleae sequences with sequences of two close subcongeners, Bactrocera biguttula (Bezzi) and Bactrocera munroi White, and analysis of delineation of species boundaries using the genealogical sorting index, supported the idea that Chinese flies share recent common ancestry with B. oleae. Flies were parasitized by braconid wasps, Psyttalia ponerophaga (Silvestri) in Pakistan, and a Diachasmimorpha species in China. Our survey reinforces the possibility of finding new biocontrol agents of olive fruit fly in the Himalayan region.

Ferrisia gilli Gullan (Hemiptera: Pseudococcidae) is a new pest in California pistachios, Pistacea vera L. We conducted a 3-yr field study to determine the type and amount of damage caused by F. gilli. Using pesticides, we established gradients of F. gilli densities in a commercial pistachio orchard near Tipton, CA, from 2005 to 2007. Each year, mealybug densities on pistachio clusters were recorded from May through September and cumulative mealybug-days were determined. At harvest time, nut yield per tree (5% dried weight) was determined, and subsamples of nuts were evaluated for market quality. Linear regression analysis of cumulative mealybug-days against fruit yield and nut quality measurements showed no relationships in 2005 and 2006, when mealybug densities were moderate. However, in 2007, when mealybug densities were very high, there was a negative correlation with yield (for every 1,000 mealybug-days, there was a decrease in total dry weight per tree of 0.105 kg) and percentage of split unstained nuts (for every 1,000 mealybug-days, there was a decrease in the percentage of split unstained of 0.560%), and a positive correlation between the percentage of closed kernel and closed blank nuts (for every 1,000 mealybug-days, there is an increase in the percentage of closed kernel and closed blank of 0.176 and 0.283%, respectively). The data were used to determine economic injury levels, showing that for each mealybug per cluster in May there was a 4.73% reduction in crop value associated with quality and a 0.866 kg reduction in yield per tree (4.75%).

The spotted wing drosophila, Drosophila suzukii Matsumura, has widely established in North America and become an economic concern for a variety of fruit crops. To better understand fruit susceptibility, we evaluated peach surface characteristics on the pest's oviposition success. The number of D. suzukii eggs laid into the fruit flesh was tested on 1) peaches with or without indumenta (commonly referred to as peach fuzz), 2) peaches physically damaged by harvest operations, 3) peaches damaged by the peach twig borer Anarsia lineatella Zeller or the forktailed bush katydid, Scudderia furcata Brunner von Wattenwyl, and 4) peaches with punctures that simulated stink bug damage. Female D. suzukii did not lay eggs in intact fuzzy sections of the fruit or into small punctures (0.3 or 0.5 mm), but readily laid eggs in sections without fuzz, with insect damage, and with large punctures (1 mm). The number of eggs per treatment was positively related to the area of the damaged section; the overall fruit firmness and sugar content was not related to the number of eggs laid in treated or damaged spots. Direct observations of D. suzukii oviposition confirmed that peach fuzz appeared to be an obstacle for the fly's oviposition success, and female flies ceased ovipositional attempts on fuzzy peach sections after a short period of time. Successful oviposition times were associated with substrate firmness, with shorter oviposition time in damaged spots than in cherry fruit or shaved spots of the peach. The results indicate that intact, preharvest peach fruit are unlikely to be infested by the fly, but any surface damage could render the fruit susceptible to the fly.

The encyrtid parasitoids Coccidoxenoides perminutus Girault and Anagyrus nr. sp. pseudococci (Girault) were compared in the laboratory as parasitoids of the mealybug Planococcus ficus (Signoret). Female C. perminutus preferred second-instar P. ficus for oviposition, and produced more adult offspring (149.3 per female) than A. nr. sp. pseudococci (54.1 per female). The development time, from egg to adult emergence, of C. perminutus decreased with increasing constant temperatures between 18.5 and 30.1°C; at lower (12.0 and 15.0°C) and higher (31.1, 32.7, and 34.2°C) temperatures, the parasitoid did not develop. The lower threshold was calculated by linear methods to be 10.97°C, and the thermal constant was calculated to be 507.98 degree-days. The development times of C. perminutus were longer than those of A. nr. sp. pseudococci, and C. perminutus had narrower temperature tolerances than P. ficus or A. pseudococci. Argentine ants (Linepithema humile (Mayr)) reduced the amount of time C. perminutus foraged on mealybug-infested squash, but did not affect the number of oviposition attempts or offspring produced, whereas Argentine ants reduced A. nr. sp. pseudococci foraging time, oviposition attempts, and number of offspring obtained. Overall, the results suggest that under certain conditions, including optimal conditions of temperature and host-stage availability, C. perminutus outperforms A. nr. sp. pseudococci, and may be an effective augmentative control agent even when ants are tending the hosts. However, temperature limitations and host-stage selection behaviors would reduce C. perminutus performance in the field, and in the absence of ants, other parasitoids may be favored.

Life history parameters were established under controlled laboratory conditions for the green stink bug, Chinavia hilaris (Say) (=Acrosternum hilare), to improve pest control in pistachios in California. Parameters measured and calculated included survival and development at seven constant temperatures (ranging from 15 to 35°C), development time, upper and lower development thresholds, thermal constants, fecundity, generation time, net reproductive rate, and intrinsic rate of increase. C. hilaris did not complete development at 15 and 35°C. Within the range of 20–27.5°C, development time decreased linearly with temperature; it increased again at 30°C. The lower threshold was calculated by linear methods to be 12.3°C, and the thermal constant was calculated to be 588 degree days. Fastest development was recorded at 27.5°C, whereas greatest survival was observed at 22.5°C. At 27.5°C, mean fecundity was 53.5 eggs per female, mean generation time was 74.4 d, net reproductive rate was 20.09, and intrinsic rate of increase was 0.04. Use of a nonlinear model yielded estimates of 13.2, 28.4, and 33.4°C, for the lower threshold, optimum temperature, and upper threshold, respectively. Results were compared with similar studies and interpreted in the light of pest management needs in pistachio. Increased emphasis on monitoring and management of overwintering sites and early-season migration are recommended.

The mealybug Ferrisia gilli Gullan is an emerging pest of wine grapes grown in California's Sierra foothills. A relatively new species, it had previously been recorded as a pest of pistachio, almond, and ornamentals. It was first reported on grape in El Dorado County in 2003 and has since established and spread. Nondestructive monitoring of grape vine sections was conducted in untreated vineyard plots and compared with destructive sampling conducted in grower-treated plots in 2008 and 2009 to determine F. gilli life stage seasonal presence, number of generations, location on the vine during the season, and damage potential to fruit clusters. Two generations were observed to be completed during the season. F. gilli overwintered under the bark at the base of the trunk, trunk, and cordon as second and third instars. Adults were found at the base of emerging shoots (spring) or on and under bark of old and new spurs. Live crawlers were born in June (first generation) and late August to September (second generation), and migrated to leaves to feed before moving to protected locations under bark or into fruit clusters. Lower mealybug densities and fruit damage were recorded on vines with than without insecticide treatment(s). Parasitized mealybugs were collected in low numbers and an Acerophagus sp. was the dominant parasitoid.

Pediobius ni Peck (Hymenoptera: Eulophidae) is a eulophid parasitoid indigenous to North America that was found attacking the invasive light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), in California. We investigated host age suitability, fecundity, and temperature-dependent developmental time for P. ni as a parasitoid of E. postvittana. Parasitoid offspring survival was higher on E. postvittana presented as prepupa or young pupa (<3 d old) than older pupa (>3 d old), and P. ni would not attack mature E. postvittana larva. Parasitoid developmental time increased with advanced host age. At 24°C, P. ni parasitized 6.8 ± 0.7 hosts, and produced 119.5 ± 16.8 offspring during a 21.5 ± 3.0 d adult lifetime when provided food and host pupae. The developmental rate of P. ni was a positive linear relationship between 15-28°C, but it failed to develop at constant temperatures >29°C. The estimated lower developmental threshold is 13.0°C, and degree-day requirements (DD) are 278 DD. As a comparison of host species suitability, P. ni was tested with obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae); navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae); omnivorous leafroller, Platynota stultana Walsingham (Lepidoptera: Tortricidae); orange tortrix, Argyrotaenia franciscana (Walsingham) (Lepidoptera: Tortricidae); and peach twig borer, Anarsia lineatella Zeller (Lepidoptera: Gelechiidae). The parasitoid readily attacked all tested host species; percentage parasitism was lower on A. lineatella than on A. transitella, P. sultana, and C. rosaceana, but similar among the other tested species. Clutch size generally increased with host size, but percentage adult emergence and sex ratio was not affected by host species. Exposure of hosts to multiple P. ni increased the numbers of emerged wasps per parasitized host without obvious costs to offspring fitness.

Habrobracon gelechiae Ashmead (Hymenoptera: Braconidae) was studied as a parasitoid of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) in California pistachio (Pistacia vera L.) orchards. Ovipositional behavior, adult longevity and fecundity, and the effects of temperature on developmental time and survival were determined. Habrobracon gelechiae develops as a gregarious, ectoparasitic idiobiont on late-instar C. rosaceana larvae. At 25°C, adult female wasps survived longer when provided honey and water (35.4 ± 4.9 d) or honey, water, and host larvae (34.4 ± 2.4 d) than when provided water (8.9 ± 1.1 d) or no food (5.9 ± 0.8 d). Over the adult lifespan, females parasitized 20.6 ± 2.1 hosts and deposited 228.8 ± 24.6 eggs. The intrinsic rate of increase was 0.24, the mean generation time was 18.15 d, and the double time 2.88 d. At constant temperatures, H. gelechiae successfully developed (egg to adult) from 15 to 35°C. The developmental rate was fit to a nonlinear model, providing estimates of the parasitoid's lower (10.5°C), upper (36.0°C), and optimal (33.3°C) development temperatures. Based on a linear model, 155 degree days were estimated for egg to adult eclosion. Temperature-dependent nonlinear model of survival showed similar shape with the model of development rate. The wasp developed under two diurnal temperature regimes, with 31.0 ± 13.3% survival at low (4-15°C) and 63.0 ± 11.4% survival at high (15-35°C) temperature regimes. The results are discussed with respect to H. gelechiae potential as a parasitoid of C. rosaceana in California's San Joaquin Valley.

The mealybug Ferrisia gilli Gullan is a serious new pest of pistachios in California. It was first found near the town of Tulare in the late 1990s and has since spread to orchards in most pistachio-producing regions of the state. The seasonal phenology of F. gilli was evaluated in a commercial pistachio orchard in Tulare County during 2005 and 2006. During both seasons F. gilli overwintered as small nymphs and had three complete generations per year. Mealybug population densities were low and remained as immatures in March and April; by late May adult females formed and averaged (±SE) 1.3 ± 0.3 and 1.2 ± 0.3 per 0.75 m of sample branch in 2005 and 2006, respectively. The first in-season generation occurred from early June through mid-July, with mealybug densities ranging from 17.6 ± 5.6–26.4 ± 6.2 mealybugs per 0.75 m sample branch. The second in-season generation occurred from late July through September and had peak densities of 408.6 ± 93.9 and 182.0 ± 34.2 mealybugs per branch. In March and April mealybugs were located primarily on the buds and branch wood; in May the population was on branch wood as well as the rachis; from June through September the population was located primarily in the pistachio cluster. F. gilli's seasonal phenology described herein was used to develop a management program.

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 parasitoid's 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.

The light brown apple moth, Epiphyas postvittana (Walker), an Australia native tortricid, was found in California in 2006. A field survey of host plants used by E. postvittana was conducted in an urban region of the San Francisco Bay Area. An inspection of 152 plant species (66 families), within a 23-ha residential community, found E. postvittana on 75 species (36 families). Most (69 species) host plants were not Australian natives, but had a wide geographic origin; 34 species were new host records for E. postvittana. Heavily infested species were the ornamental shrubs Myrtus communis L., Pittosporum tobira (Thunb.) W.T. Aiton, Euonymus japonicus Thunb., and Sollya heterophylla Lindl. To survey for parasitoids, four urban locations were sampled, with E. postvittana collected from five commonly infested plants [M. communis, P. tobira, E. japonicus, Rosmarinus officinalis L., and Genista monspessulana (L.) L.A.S. Johnson]. Twelve primary parasitoid species and two hyperparasitoids were reared; the most common were the egg parasitoid Trichogramma fasciatum (Perkins), the larval parasitoids Meteorus ictericus Nees, and Enytus eureka (Ashmead), and the pupal parasitoid Pediobius ni Peck. Meteorus ictericus accounted for >80% of the larval parasitoids, and was recovered from larvae collected on 39 plant species. Across all samples, mean parasitism was 84.4% for eggs, 43.6% for larvae, and 57.5% for pupae. The results are discussed with respect to the potential for resident parasitoid species to suppress E. postvittana populations.

A simple molecular tool was developed and tested to identify seven mealybug species found in North American vineyards: Pseudococcus maritimus Ehrhorn, Pseudococcus viburni (Signoret), Pseudococcus longispinus (Targioni-Tozzeti), Pseudococcus calceolariae (Maskell), Planococcus ficus (Signoret), Planococcus citri (Risso), and Ferrisia gilli Gullan. The developed multiplex PCR is based on the mitochondrial cytochrome c oxidase subunit one gene. In tests, this single-step multiplex PCR correctly identified 95 of 95 mealybug samples, representing all seven species and collected from diverse geographic regions. To test the sensitivity, single specimen samples with different Pl. ficus developmental stages (egg to adult female and adult male) were processed PCR and the resulting output provided consistent positive identification. To test the utility of this protocol for adult males caught in sex baited pheromone traps, Pl. ficus adult males were placed in pheromone traps, aged at a constant temperature of 26 ± 2°C, and processed with the multiplex each day thereafter for 8 d. Results showed consistent positive identification for up to 6 d (range, 6-8 d). Results are discussed with respect to the usefulness of this molecular tool for the identification of mealybugs in pest management programs and biosecurity of invasive mealybugs.

Many biotic and abiotic factors affect the transmission efficiency of vector-borne plant pathogens. Insect vector within-plant distribution and host tissue preference are known to affect pathogen acquisition and inoculation rates. In this study, we first investigated whether feeding tissue affects the transmission of Grapevine leafroll-associated virus 3 by Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) and the effect of mealybug within-plant distribution on virus transmission under greenhouse conditions. Results showed no significant effect on transmission efficiency after insect confinement on leaf blades, petioles or stems of virus source or healthy test plants for either acquisition or inoculation trials. Transmission efficiency of a single mealybug varied from 4 to 25% in those trials. Second, we tested whether leaf position affected transmission efficiency due to potentially variable virus populations within acquisition plant tissues. No significant differences of transmission rate among acquisition leaf position were observed, probably because there were no differences in the virus population within source tissues. Finally, we examined the seasonality of the virus in field-collected samples and found that GLRaV-3 prevalence varied along a growing season, such that GLRaV-3 translocated along expanding shoots to leaves. Similarly, mealybug populations are known to increase in spring, and then mealybugs spread to cordons and leaves. This coordination of spatial and temporal dynamics of the virus and its vector may increase the risk of GLRaV-3 transmission during late spring and early summer. Further integration of information about pathogen populations in plants, vector feeding behavior and vector population seasonality could lead to more effective management practices.

The larval parasitoid, Psyttalia humilis (Silvestri), reared on Mediterranean fruit fly, Ceratitis capitata (Weidemann), by USDA-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 parasitoid's 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 parasitoid's 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.

Almond leaf scorch (ALS) disease is caused by the bacterium Xylella fastidiosa and transmitted by xylem-feeding insects. Reports of increased incidence of ALS-diseased trees in California prompted surveys in three almond [Prunus dulcis (Mill.) D.A.Webb]-growing regions, from June 2003 to September 2005, to determine insect vector species composition and abundance. For comparison, sampling in and near vineyards in the San Joaquin Valley, California, also was completed. Sampling in or near almond orchards collected >42,000 Cicadomorpha of which 4.8% were xylem feeders, including 1,912 grass sharpshooter, Draeculacephala minerva Ball; five Xyphon fulgida Nottingham; and a single spittlebug, Philaenus spumarius L. The most abundant vector was D. minerva. Season-long sampling indicated that D. minerva was a year-round resident in and/or near almonds in the Sacramento Valley, but not in the San Joaquin Valley. Similarly, D. minerva was rare in vineyards in the San Joaquin Valley, but was abundant in irrigated pastures near vineyards. D. minerva was most frequently collected along orchard margins, and peak densities were observed in summer, the period of time when bacterial titers are reported to increase in infected trees. Screening of D. minerva for presence of X. fastidiosa found that 1.1% of insects collected near almond orchards and 4.5% of insects collected from pastures tested positive. The X. fastidiosa subspecies and genotype detected in insects collected from orchards matched those collected from ALS-diseased almond trees in the same orchard. Of the few X. fulgida and P. spumarius collected, none tested positive for X. fastidiosa. Results are discussed with respect to X. fastidiosa vector control and detection methods.

Eucalyptus spp., native to Australia, have been introduced into many parts of the world as important timber and ornamental trees. Although the trees have important silvicultural qualities, they also have generated intense dissatisfaction, particularly among groups of individuals in California. The trees have benefited from the lack of insect pests and diseases in their adventive ranges but that has changed over the past four decades. In California, two species of insect herbivores were introduced between the time trees were first introduced to the state in the middle of the 19th century and 1983. Between 1983 and 2008, an additional 16 Australian insect pests of eucalyptus have become established in the state. The modes or routes of introduction have never been established. However, examinations of different temporal and spatial patterns suggest that the introductions were nonrandom processes. It is possible that they occurred because of increased trade or movement of people, but the hypothesis that there were intentional introductions also must be considered. The rapid accumulation of introduced herbivores on an ornamental plant system in a single state is a cautionary example of what could happen if a major food or fiber crop were intentionally targeted.

Homalodisca vitripennis (Germar) and Spissistilus festinus (Say) populations were surveyed bimonthly for 14 mo in Kern County, CA, at five agricultural sites made up of a variety of potential host plants. In addition, S. festinus populations were surveyed in four alfalfa, Medicago sativa L., fields in Kern and Tulare counties. Insects were collected by beats-sweeps and sticky traps. Data on host plant condition and phenology, and ground cover presence and composition were collected at the five agricultural sites, whereas data on mowing and insecticide use were collected at the four alfalfa sites. Populations of both insects persisted at the five agricultural locations despite insecticide applications applied as part of a H. vitripennis areawide management program and standard commercial operations. Plants colonized by H. vitripennis included eucalyptus (Eucalyptus L’Hér.), jojoba [Simmondsia chinensis (Link) C. K. Schneid.], and citrus (Citrus spp.). Populations of S. festinus were much greater in collections from alfalfa fields than from the five agricultural sites. Insects collected from the five mixed agricultural sites were negative for presence of X. fastidiosa. In laboratory tests, S. festinus did not acquire or transmit X. fastidiosa in tests with infected grape (Vitis spp.) as an acquisition source and grape, almond [Prunus dulcis (Mill.) D.A.Webb], and alfalfa as inoculation hosts. Recommendations for vector control, vegetation management, and targeted monitoring to reduce insect populations and inoculum potential are discussed.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), vectors the bacterium Xylella fastidiosa that induces Pierce’s disease of grape. This study determined the effect of temperature on the feeding activity of H. vitripennis adults and the resulting production of excreta. The Logan type I model described a nonlinear pattern that showed excreta production increased up to an optimal temperature (33.1°C), followed by an abrupt decline near an estimated upper threshold (36.4°C). A temperature threshold for feeding, at or below which adults cease feeding, was estimated to be 10°C using a linear regression model based on the percentage of adults producing excreta over a range of constant temperatures. A simulated winter-temperature experiment using fluctuating thermal cycles confirmed that a time period above the temperature threshold for feeding was a critical factor in determining adult survival. Using data from the simulated temperature study, a predictive model was constructed by quantifying the relationship between cumulative mortality and cooling degree-hours. In field validation experiments, the model accurately predicted the temporal pattern of overwintering mortality of H. vitripennis adults held under winter temperatures simulating conditions in Bakersfield and Riverside, California, in 2006–2007. Model prediction using winter temperature data from a Riverside weather station indicated that H. vitripennis adults would experience an average of 92% overwintering mortality before reproduction in the spring, but levels of mortality varied depending on winter temperatures. The potential for temperature-based indices to predict temporal and spatial dynamics of H. vitripennis overwintering is discussed.

We evaluated the relationships between plant water status and leaf temperature, and between leaf temperature and spider mite (Acari: Tetranychidae) and predatory mite (Acari: Phytoseiidae) populations in eight vineyards in California in 2006 and 2007. Temperature of south-facing leaves increased significantly by 0.8°C for every 1.0°C increase in ambient air temperature, and by 5.3°C for every one MPa drop in leaf water potential. Peak population densities of Pacific spider mite, Tetranychus pacificus McGregor, increased significantly with increasing frequency of leaf temperatures above 31°C. In contrast, peak population densities of Willamette spider mite, Eotetranychus willamettei (McGregor), showed no relationship with the frequency of leaf temperatures above 31°C. This differential relationship between the two mite species and high leaf temperatures is consistent with their upper thresholds for development, which are 40°C for T. pacificus and 31°C for E. willamettei, as identified in a previous study. Predatory mite population densities showed no relationship with peak population densities of either spider mite species during the analysis period, but decreased with the frequency of leaf temperatures above 31°C. In addition, predatory mite population densities were significantly higher on south-facing than interior leaves after adjusting for the effect of leaf temperature. These results help to explain why outbreaks of T. pacificus occur in warmer or water-stressed vineyards, whereas E. willamettei develops higher populations in cooler or well-irrigated vineyards. In addition, these results suggest that regulated deficit irrigation should be implemented with caution, especially in those vineyards with a high risk of T. pacificus outbreaks.

Peganum harmala L. (Zygophyllaceae) is an herb native to arid and semiarid regions of Central Asian deserts. This study investigated the effects of ethanol extracts of P. harmala seeds on the olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), i.e., adult repellency, reproductive activity, and larval growth, as well as parasitism levels by Psyttalia concolor (Szépligeti). Olive fruit treated with 2% extract reduced B. oleae oviposition. In choice tests, female B. oleae spent >99% of their time foraging on untreated fruit rather than P. harmala-treated fruit. These changes in ovipositional behavior resulted in a nearly 30-fold decrease in oviposition marks on treated fruit compared with untreated fruit during a 48 h exposure period. When female B. oleae were fed liquid diet containing 0.2% P. harmala extract, there was no effect on the number of ovipositional marks on exposed fruit, but up to 21.4% of the deposited eggs were deformed. SDS-polyacrylamide gel electrophoresis analyses of deformed eggs revealed that some protein bands were missing. Consequently, the number of offspring produced by treated females was lower than by untreated females. Neither the sex ratio nor body size of the fly’s offspring were affected by adults fed diet containing 0.2% P. harmala extract. However, there was a slightly prolonged developmental time from egg to adult. Parasitism of larval B. oleae by P. concolor was not affected by infested fruit treatment with 2% P. harmala extract. P. harmala extracts as a potential control for insect pest species are discussed.

The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is an invasive pest in California. Identifying environmental constraints that affect the geographic distribution and abundance of any invasive insect pest is fundamental to its effective management. California’s Central Valley, where most commercial olives are grown, is extremely hot during the summer, with maximum daily temperatures consistently >35.0°C. This study examined the effects of two diurnal temperature regimens (low 18.3°C, high 35.0 or 37.8°C) reflecting summer conditions in the valley, and one control temperature regimen (low 18.3°C, high 23.9°C) on the fly’s survival and reproductive success in the laboratory. The temperature regimen of 18.3–35.0°C resulted in delayed egg maturation and reduced production of mature eggs compared with the control temperature regimen. Egg maturation was possible at the higher temperature regimen when females were provided with water and food, and egg-laying occurred during the cold phase of the temperature cycle. Access to olive fruit and oviposition itself further promoted egg maturation. Under exposure to the 18.3–35.0°C temperature regimen, ≈50% of eggs died, and the remainder that hatched died as first instars. No egg hatch occurred at the temperature treatment of 18.3–37.8°C. We confirmed these laboratory results through field cage studies with adult B. oleae, conducted in the summer of 2007 and 2008. Under ambient summer temperatures, adult B. oleae survived for 1–2 wk, and females readily laid eggs when provided water and food. No offspring developed in midsummer of 2007, and <2% of the offspring developed to adults in summer 2008 trials. These results suggest that high summer temperatures limit the fly’s abundance in California’s Central Valley.

Survival of the glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), was studied under various constant temperatures and feeding conditions. When provided a host plant (Citrus limon L. Burm. f.) to feed on during a 21-d trial, 100% mortality occurred at 0.1, 3.2, and 40.1°C, whereas an average of 74–76% of adults survived in the 13.2–24.5°C range. When individually confined with moist cotton, adult longevity was greatest (16.3 d) at 13.3°C, but it was <3 d at -2.4 and 36.2°C. In a companion study comparing the presence versus absence of a host plant, the presence of a host plant was not a significant factor influencing survival at temperatures =7.8°C but was at temperatures =18.9°C. The relationship between temperature and survival was described by a nonlinear function that estimated the optimum temperature in each feeding regimen: no host plant or moist cotton (5.5°C), moist cotton (9.9°C), and accessible host plant (25.1°C). The model quantitatively predicted that H. vitripennis would survive longer periods at a wider temperature regimen when provided with a host plant than when provided with water alone (moist cotton) or when provided with neither plant host nor water. Our results suggest that continuous exposure to either low (<5°C) or high (>30°C) temperatures are detrimental for adult survival. Specifically, low temperatures caused early mortality because of inhibition of feeding activity and presumably this threshold lies between 7.8 and 13.2°C. Furthermore, this study clearly shows that temperature may influence the survival of H. vitripennis adults regardless of feeding regimens, and its implications for population dynamics are discussed.

The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is a newly invasive pest of olives, Olea europaea L., in California. The table olive industry is located in California's Central Valley, where daily high summer temperatures can be >35.0°C. This study investigated the effects of high temperatures (heat stress) and food conditions on the flight performance of B. oleae in laboratory flight mill tests. Flies were provided food (honey and hydrolyzed yeast) and water for a 1-wk preconditioning period and then subjected to 24-h preflight exposure to diurnal temperature regimes (low-high temperatures of 18.3—35.0°C and 18—37.8°C) and deprivation of food. Flies with the preflight stress conditions had significantly lower flight performance (1,305 m and 0.989 h at 18.3—35.0°C and 1,152 m and 0.966 h at 18.3—37.8°C) than control files that were held under no-stress preflight conditions (constant 23.9°C, food, and water) and flew 1,982 m for 1.54 h. Flight distance and duration were further reduced when no water was provided during the 24-h preflight exposure to high temperature stress. Flight distance and duration also were decreased when the preflight exposure period was increased to 2 and 3 d. When flies were deprived of food and water during the preconditioning period, there was significant adult mortality and flight performance was poor (<;50 m and <2 min) after 24-h preflight exposure to either the 18.3—35.0°C or the 18.3—37.8°C temperature regime and deprivation of food. Heat stress and food deprivation also reduced postflight fecundity and adult longevity. The results are discussed with respect to the ability of B. oleae to survive summer heat and food deprivation by dispersing to refuges with food, water, and shelter.