Journal of economic entomology最新文献

Pseudacysta perseae (Heidemann 1908) (Hemiptera: Tingidae), a foliar pest of avocados, was first discovered in urban San Diego County, California U.S. in 2004. In 2017, damaging populations of P. perseae were discovered in commercial Hass avocado groves in San Diego and Riverside Counties. The unexpected and rapid spread of P. perseae raised the question of whether this range expansion was an extension of the original incursion or the result of a second invasion event. Using sequences of the mitochondrial COI gene, we found strong evidence that P. perseae populations in southern San Diego County are comprised almost entirely of the single haplotype (A) that was detected in 2004. In contrast, newly established (2017 onwards) populations of P. perseae infesting commercial orchards consisted exclusively of a second mitochondrial haplotype (G). This haplotype is found in Florida and the Caribbean and is conclusive evidence that California has been invaded a second time. Molecular analyses also confirmed that invasive P. perseae populations in Hawai'i are haplotype G, indicating that California and Hawai'i populations may have originated from the same source area (possibly Florida), or that California may have acted as an invasion bridgehead for the invasion of Hawai'i. Reproductive compatibility of the primary (haplotype A) and secondary (haplotype G) invasive populations in California was confirmed via a series of reciprocal laboratory crosses and results suggest that fertility of hybrid eggs is increased. The potential consequences of this second invasion into California by P. perseae are discussed.

Effectively mass-rearing insects is critical for research, for environmentally friendly technologies like sterile insect technique, producing biological control agents, and enabling novel pest control methods such as those based on genetics or symbionts. While constant temperature conditions are typically used in mass-rearing, at what is considered an optimum value that produces the fittest insects, homeostatic conditions do not reflect the real world. We investigated the performance of mass-reared adult Ceratitis capitata Wiedemann (Diptera: Tephritidae) under constant (24 °C) and oscillating (mean 24 °C with 4 and 10 °C range) temperature regimes. Insect survivorship, flight ability, and female fecundity were assessed across the temperature regimes. Additionally, we compared adult C. capitata performance under environmental chamber and outdoor conditions to determine if temperature and humidity as simulated in the chambers resulted in similar performance outcomes for the insects as being outdoors. Male C. capitata under the 10 °C range treatment had higher survival probability at 55 d postemergence compared to the constant temperature regime, while females showed no significant differences in survivorship among temperature regimes. Flight ability and fecundity were not significantly affected by temperature regimes, though the 10 °C range group showed the highest fecundity. Comparisons between environmental chamber and outdoor conditions revealed minimal differences in performance metrics. Our findings suggest that the field performance of mass-reared male adult C. capitata can be improved by oscillating temperature regimes in mass-rearing facilities.

Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae), is an important pest in cowpea-growing areas of south China. To study control strategies, M. usitatus has been raised for multiple generations in the laboratory. Considering the impact of supplemental nutrients on colony fitness during laboratory rearing is crucial for achieving a significant population of uniformly developed individuals. Here, an age-stage, 2-sex life table for M. usitatus was developed to examine the impacts of F0  M. usitatus adults fed on 3 different supplemental diets (20% sucrose solution, 20% pollen solution, and 20% honey solution) on the development, fecundity, and population growth of F1  M. usitatus. The findings indicated that, compared to thrips fed on water, F0 adult thrips provided with 3 supplementary diets exhibited a reduction in the developmental duration for each instar, an increase in fecundity, and an extension of the lifespan of F1  M. usitatus, with honey yielding the best results. Similarly, the addition of supplemental nutrients resulted in a reduction in the mean generation time (T) and an enhancement of the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) compared to the control group. The effects were highest for honey, followed by pollen, and then sucrose. This study provides favorable evidence concerning the direct impacts of parental nutrition supplementation on the fitness of offspring in insects, and provides information to aid indoor rearing of M. usitatus.

Aphids and numerous other phloem-feeding insects primarily rely on sucrose in the phloem to locate their feeding sites. However, it is still unclear whether this sweet perception process could serve as a target for aphid control. In this study, we investigated the impact of the sweet taste inhibitor sodium salt of 2-(4-methoxyphenoxy)-propionic acid (lactisole), a widely used food additive that binds to sugar receptors, on the feeding behavior and performance of aphids. Our findings indicate that both the green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) and the English grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae) avoided settling on an artificial diet containing lactisole or on host plants treated with lactisole. In addition, these aphid species showed reduced weights when feeding on the artificial diet containing lactisole or on seedlings root drenched by lactisole. Furthermore, data from the electrical penetration graph revealed that S. avenae exhibited a greater number of phloem probes but significantly shorter mean and total phloem ingestion durations when feeding on wheat plants root-drenched by lactisole. It is worth noting, however, that root drenched by lactisole had a significant inhibitory effect on plant growth. These findings suggest that the sweet taste inhibitor lactisole may reduce aphid feeding preference and growth, offering a new avenue for aphid control strategies.

The European earwig, Forficula auricularia L. (sensu lato), has a dual role in temperate tree fruit crops-a pest of stone fruit and a predator of key pests in pome fruit. Some growers trap earwigs in crops where they are pests, subsequently releasing them in pome fruit as an augmentative biological control strategy. Effective earwig monitoring and trapping are critical for understanding their biological control potential in orchards. Traps made of rolled, corrugated cardboard have long been used for earwig monitoring; however, no standardized studies have investigated improvements to them. In a series of trials, we explore options to improve traps by testing different trap materials, sizes, positioning on the tree, and time in the field, in addition to the lures and baits. We found that cardboard traps had higher earwig catch than black or translucent plastic traps. There were diminishing returns in earwig capture for increased trap length, plateauing at ~30 cm. Traps placed on the main trunk captured more earwigs than traps on the base or near the end of branches. Lures and baits mostly did not increase trap efficacy, except fish sauce which inconsistently increased earwig captures. The use of plastic bottles to contain the cardboard traps greatly reduced trap catch. Finally, we found evidence that traps left in the field for longer periods of time can increase earwig capture, possibly due to the accumulation of earwig aggregation pheromone. Overall, the standard unbaited corrugated cardboard trap was the most effective and practical earwig monitoring trap.

Cotton seed bug, Oxycarenus hyalinipennis (Hemiptera: Oxycarenidae), was discovered in southern California in 2019. Surveys have found it within 160 km of cotton producing areas. While often only a minor pest in its native range, there are justified concerns that O. hyalinipennis could become a major pest of US-grown cotton. To proactively prepare for this possibility, 12 US-registered formulations and 1 experimental formulation were assessed in the laboratory for efficacy against O. hyalinipennis, using both contact and ingestion bioassays. Six formulations, consisting of acephate, dinotefuran, flupyradifurone, and imidacloprid with initial efficacy against O. hyalinipennis were used for subsequent dose-response bioassays. These compounds had LC50 values well below maximum labeled rates, although LC99.9 values often exceeded maximum label rates. Results indicate that if O. hyalinipennis infests cotton production regions, both selective and broad-spectrum options will be available for management. These findings establish a baseline for developing an integrated pest management program that can reduce potential damage from O. hyalinipennis, preserve natural enemies, and contribute to resistance management in cotton production areas.

Conservation biological control in agriculture primarily relies on avoiding pesticides that may harm key natural enemies. In temperate tree fruit crops, the European earwig, Forficula auricularia (L.) has only recently become appreciated as an important predator of economic pests, particularly woolly aphids and pear psylla. Therefore, the non-target effects of orchard pesticides on earwigs are largely understudied. This is particularly true for herbicides, which earwigs are likely to be exposed to due to their foraging behavior moving between the canopy and the ground cover. We tested residues of formulated pesticides (8 insecticides and 7 herbicides) commonly used in tree fruit crops for lethal and sublethal (movement, predation rate) effects on adult female earwigs. Two herbicides, paraquat and glufosinate, and one insecticide, spinetoram, were acutely toxic to earwigs within 72 h. No tested pesticides altered earwigs' movement or resting behavior compared to the control. The insecticides spinosad and cyantraniliprole and the herbicides 2,4-D, glufosinate, halosulfuron, rimsulfuron, and oxyfluorfen reduced earwig predation on green peach aphids. Therefore, these pesticides may reduce earwig predation on pests in orchards. Our results suggest that some pesticides are of greater risk, and thus, should be carefully considered or better timed when used in tree fruit orchards where earwigs are considered for conservation or augmentative biological control.

The braconid wasp Microplitis manilae (Hymenoptera: Braconidae) is a solitary, koinobiont endoparasitoid of young Spodoptera litura (Fabricius) larvae and one of its most crucial natural parasitic enemies. The establishment of a stable and sufficient population of M. manilae by rearing them in a laboratory is the cornerstone of field release management. However, when reared in a laboratory, M. manilae is affected by temperature. Here, we attempted to optimize the rearing temperature of M. manilae for parasitizing second-instar S. litura larvae by examining the effects of rearing at 5 temperatures: 16 °C, 20 °C, 24 °C, 28 °C, and 32 °C. Our results suggest that the development of the parasitoid progeny speeded up with shorter durations of the egg-larval, pupal, and preadult stages with the increase in temperature from 16°C to 32 °C. The parasitism rate and fecundity of M. manilae upon parasitizing second-instar S. litura larvae increased with rearing temperature from 16°C to 24 °C, with the peaks at 24 °C reaching 52.90% and 111.70 eggs/female, respectively, and then decreased at 28 °C to 32 °C. At 24 °C, the sex ratio (0.22) was the lowest, whereas the emergence rate (68.54%) did not differ significantly compared with those at other temperatures. Meanwhile, at 28 °C, the parasitism rate, fecundity, and emergence rate approached the levels at 24 °C, whereas the sex ratio was higher (0.29) than at 24 °C. These findings suggest 24 °C to 32 °C is the most appropriate temperature range for M. manilae mass rearing under laboratory conditions.

Long-lasting insecticide-incorporated netting (LLIN) has been used to deliver pyrethroids for management of stored product insect pests in food facilities. However, the development of resistance to pyrethroids in stored product pests is a widespread and urgent problem, which threatens the efficacy of commercially available LLINs. A potential approach for enhancing LLIN efficacy is the use of insecticide synergists to inhibit detoxification enzymes and exacerbate the effects of pyrethroids. Here, we evaluated the synergistic properties of 3 detoxification enzyme inhibitors-piperonyl butoxide (PBO), diethyl maleate (DEM), and triphenyl phosphate (TPP)-with LLIN against the red flour beetle Tribolium castaneum (Herbst), and the lesser grain borer Rhyzopertha dominica (Fabricius). Pre-exposure to PBO resulted in higher mortality after exposure to LLIN for T. castaneum and R. dominica. With pre-exposure to PBO followed by LLIN exposure, there was a trend for lower LT50 values for both species, while the extent of synergistic effects was greater on R. dominica than T. castaneum. In contrast, with pre-exposure to DEM and TPP followed by LLIN exposure, there were no significant reductions in LT50 values for both species. In addition, the presence of food had a significant effect on the recovery and delayed mortality in T. castaneum and R. dominica, reducing the efficacy of synergist and LLIN in combined exposures. This study provides baseline data towards improving the efficacy of LLIN against stored product pests.

The European earwig F. auricularia L. is an omnivore that has only recently been identified as a direct, fruit-feeding pest of citrus. Here, we start to build the basic tools needed for integrated pest management for this species. We introduce a time-efficient sampling method based on small wooden boards placed on the ground, and we use them in a 2-yr survey of 93 commercial citrus blocks in California's San Joaquin Valley. Insecticides were not applied targeting F. auricularia in any of these citrus blocks. We find that F. auricularia populations are very low or undetectable in most blocks, with higher densities occurring only sporadically. To know when control measures should be implemented, we used video-monitoring of citrus tree trunks to characterize the timing of F. auricularia movement from their soil nests into the tree canopy. Movement of earwigs along the tree trunks was observed throughout our sampling period (22 March to 18 June), suggesting that control measures (sticky bands placed on trunks, or insecticides applied to trunks and surrounding soil surface) should be applied early, well before petal fall when fruit are susceptible to F. auricularia herbivory. Sticky barriers effectively reduced the vertical movement of 2 crawling arthropods, F. auricularia and the Fuller rose beetle Napactus godmanni, along citrus trunks. We failed to find any relationship between estimated F. auricularia densities and damage to maturing or harvested fruit. This highlights a set of important and still unresolved questions about the biology of this species, underscoring the need for additional research.