Drosophila suzukii
causes economic damage to berry and stone fruit worldwide. Laboratory-generated datasets were standardized and combined on the basis of degree days (DD), using Gompertz and Cauchy ...curves for survival and reproduction. Eggs transitioned to larvae at 20.3 DD; larvae to pupae at 118.1 DD; and pupae to adults at 200 DD. All adults are expected to have died at 610 DD. Oviposition initiates at 210 DD and gradually increases to a maximum of 15 eggs per DD at 410 DD and subsequently decreases to zero at 610 DD. These data were used as the basis for a DD cohort-level population model. Laboratory survival under extreme temperatures when DD did not accumulate was described by a Gompertz curve based on calendar days. We determined that the initiation of the reproductive period of late dormant field-collected female
D. suzukii
ranged from 50 to 800 DD from January 1. This suggests that
D. suzukii
females can reproduce early in the season and are probably limited by availability of early host plants. Finally, we used the DD population model to examine hypothetical stage-specific mortality effects of IPM practices from insecticides and parasitoids at the field level. We found that adulticides applied during the early season will result in the largest comparative population decrease. It is clear from model outputs that parasitism levels comparable to those found in field studies may have a limited effect on population growth. Novel parasitoid guilds could therefore be improved and would be valuable for IPM of
D. suzukii
.
(Stål), or brown marmorated stink bug (BMSB), has become a major pest and nuisance for both agricultural growers and homeowners since its arrival in North America and Europe. The nutritional ecology ...of BMSB is important for understanding its life history and rearing requirements. However, little is known about the nutritional status of wild populations, especially in the U.S. This research monitored the nutrient status of nymphal and adult BMSB collected from English holly in western Oregon. We measured their weight, nutrient index (weight/(prothorax × width)³), lipid, glycogen and sugar levels and egg load from May⁻September/October. First, glycogen and sugar levels of adults were often lowest sometime in June-August with a general increase by September. Meanwhile, their lipid levels varied without a discernible trend. Second, adult females had few eggs in May, with the highest egg load in June and July, and no eggs by September. Lastly, first and second nymphal instars were found in June, and fourth and fifth instars in September. Because nothing is known about the nutrient levels of nymphs, the reported values from this survey can assist future research on physiological responses of BMSB to treatments or environmental impacts in the field.
Drosophila suzukii is a severe economic invasive pest of soft-skinned fruit crops. Management typically requires killing gravid adult female flies with insecticides to prevent damage resulting from ...oviposition and larval development. Fruits from cultivated and uncultivated host plants are used by the flies for reproduction at different times of the year, and knowledge of D. suzukii seasonal host plant use and movement patterns could be better exploited to protect vulnerable crops. Rearing and various marking methodologies for tracking movement patterns of D. suzukii across different landscapes have been used to better understand host use and movement of the pest. In this study, we report on potential to determine larval host for adult D. suzukii using their fatty acid profile or signature, and to use larval diet as an internal marker for adult flies in release-recapture experiments. Fatty acids can pass efficiently through trophic levels unmodified, and insects are constrained in the ability to synthesize fatty acids and may acquire them through diet. In many holometabolous insects, lipids acquired in the larval stage carry over to the adult stage. We tested the ability of a machine learning algorithm to discriminate adult D. suzukii reared from susceptible small fruit crops (blueberry, strawberry, blackberry and raspberry) and laboratory diet based on the fatty acid profile of adult flies. We found that fatty acid components in adult flies were significantly different when flies were reared on different hosts, and the machine learning algorithm was highly successful in correctly classifying flies according to their larval host based on fatty acid profile.
Drosophila suzukii
is widely studied because of its status as a global pest of berries and soft fruits. Environmental conditions and access to food resources impact the physiology and fitness of
D. ...suzukii
; these factors could also affect dispersal. Flight mills are a convenient tool for measuring and comparing the flight performance of insects. In this study, two experiments examined the effects of diet and humidity on
D. suzukii
flight performance using custom-built flight mills, and a third experiment compared the energy reserves of
D. suzukii
flown or not flown on flight mills. Over all flight assays, the median flight distance and duration were 27.16 m and 2.37 min, respectively, and the mean flight velocity was 0.18 m/s. The maximum flight distance and duration by an individual were 1.75 km and 2.35 h, respectively.
Drosophila suzukii
provisioned with blossoms, fruits, or standard laboratory diets flew farther distances and longer durations than starved flies. While starvation was associated with reduced flight performance, there were no observed differences between diet types. It remains unclear whether
D. suzukii
consistently use lipids, glycogen, sugar, or another energy source for flight because tethered individuals may not have flown enough to deplete energy reserves. Humidity did not affect flight performance of
D. suzukii
within a ~ 2 h test period. These data indicate that most
D. suzukii
are likely to remain within limited area (e.g., within a field) but that some individuals can disperse long distances (field to field spread).
Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) and brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), are global economic pests that may co-occur on small ...fruits. We investigated whether fruit recently exposed to H. halys affected subsequent host use by D. suzukii. Laboratory no-choice and choice tests presented D. suzukii with H. halys-fed and unfed raspberries and blueberries immediately or 3 d after H. halys feeding. Resulting D. suzukii eggs, or larvae and pupae, were counted. The number of D. suzukii immatures among fed and unfed fruit was not significantly different in lab studies. There was no relationship between the intensity of H. halys feeding, as estimated by the number of stylet sheaths, and D. suzukii oviposition on blueberry. Lastly, field studies compared D. suzukii infestation between H. halys-fed and unfed raspberries. Raspberries were previously exposed to H. halys for 3 d or simultaneously exposed to both pests for 7 d. Natural infestation by D. suzukii in the field was similar among raspberries previously or simultaneously exposed to H. halys compared to control fruit.
Predatory wasps are one of the few natural enemies to attack late instar pentatomid nymphs and adults. However, there is a substantial lack of information about their flight and nesting behavior, ...making them poorly understood. We report 3 yr of observational data of Astata unicolor Say 1824 foraging behavior and phenology from a residential site in Portland, OR. A. unicolor attacked and paralyzed at least four hemipteran species, and 64% of paralyzed prey were from the invasive Halyomorpha halys (Stål; Hemiptera: Pentatomidae). Peak flight occurred between late July and mid-September. Though unmanaged and solitary, A. unicolor's preference for H. halys demonstrates that native predators contribute to mortality and potentially management of economically important insects. This is one of the few studies to document predatory wasps' potential for biological control of H. halys. Additional work on Astata is necessary to determine whether trap nesting, dispersal, or habitat enhancement, broadens the potential for expanded biological control.
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► The HIPV squalene was found to be highly attractive to male
Chrysopa nigricornis.
► Chrysopa oculata was highly attracted to a lure of iridodial
+
methyl salicylate. ► Squalene ...lures showed
C. nigricornis was a key natural enemy in apple orchards. ► Methyl salicylate by itself was unattractive, but synergized other attractants.
We evaluated five herbivore-induced plant volatiles plus a male-produced pheromone as attractants for adult green lacewings in Washington apple orchards in 2008. We found at least five attractants or combinations of attractants were attractive to the three most abundant green lacewing species in our trials.
Chrysopa nigricornis and
Chrysopa oculata were attracted to the combination of methyl salicylate and iridodial with iridodial alone being the second best attractant.
Chrysoperla plorabunda was found in lower numbers than
C. nigricornis and
C. oculata, but did exhibit a significant attraction to benzaldehyde. In mid-summer, we added the herbivore-induced plant volatile squalene to the study and found it to be exceedingly attractive, but only to male
C. nigricornis. Whether alone or in combination, squalene attracted 4–5-fold more
C. nigricornis than any other compound tested. Our data have revealed
C. nigricornis to be an abundant orchard predator that can be readily monitored with squalene-baited traps. Despite the obvious promise of HIPVs in biological control programs, we urge caution in their deployment as large-scale attractants, at least until further studies have investigated potential disruption of natural enemy population dynamics.
Halyomorpha halys Stål (Hemiptera: Pentatomidae) is an invasive insect that causes severe economic damage to multiple agricultural commodities. Several monitoring tools, including pheromone and ...light-baited black pyramid traps, have been developed to monitor H. halys. Here, we evaluated the attractiveness of these traps baited with only light, only pheromone, or the combination in comparison with unbaited traps throughout the growing season in regions with high and low H. halys population densities. In regions with high population densities in the Mid-Atlantic, all traps baited with pheromone or lights performed better than control traps. During mid-season, traps containing lights captured more H. halys adults, whereas pheromone-baited traps captured greater numbers during the late season. In low density regions in the Pacific Northwest, traps with lights or pheromone captured more H. halys adults than control traps. In addition, we evaluated the influence of competing light sources associated with anthropogenic structures. When light traps were deployed next to these additional light sources, H. halys captures in pyramid traps baited with light were not significantly reduced. Overall, our results indicate that both light and pheromone traps can be used to detect H. halys activity in low and high density populations.
The effect of delaying female mating on population growth in codling moth (
Cydia pomonella
(L.)) was found to act on a physiological time (degree-day) basis and was predictable using a simple ...quadratic equation. When combined with previous work on degree-day based mortality, we were able to evaluate how the magnitude of population reduction and survival varied between sites, years, and generations at locations in California, Michigan, Pennsylvania and Washington states. In general, reductions in population growth associated with females mating 1–3 days after emergence were greater in warmer areas and during warmer times of the year. In any given year and location, the temperature profiles during peak flight were crucial in determining the population reductions, but over an 11-year period, the average seasonal temperature profile was more important. During the overwintering generation, conditions were relatively mild in all locations and only minor differences were observed in population growth rates between locations. Populations experiencing 1–3 days delay in female mating were reduced 8, 19 and 32 % compared to populations experiencing no delay, respectively. During the first summer generation, population reductions doubled compared to those seen in the overwintering generation. During the second summer flight, reductions in population growth rate at the three cooler locations decreased, while they increased in the warmer California location. Overall, the results show delayed mating can help understand how population growth is related to environmental conditions experienced naturally by insect populations and will help guide studies of the mechanisms of mating disruption, a technique used for pest suppression in agricultural and forest systems.
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