Development and life table parameters of the Phytoseius corniger Wainstein (Acari: Phytoseiidae) feeding on the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions

Life history and reproductive parameters of the generalist predatory mite Euseius (Amblyseius) finlandicus (Oudemans) were studied in the laboratory at 25 +/- 1 degrees C, with a 16L:8D photoperiod and 60 +/- 15% RH, to investigate its response to different food sources: an eriophyid mite Aceria sp., tulip pollen Tulipa gesnerana L., and two-spotted spider mite Tetranychus urticae Koch. Total developmental time of the immature stages was the shortest on eriophyid mites, followed by pollen, and then spider mites. Fecundity was highest on pollen (43.69 eggs; 1.63 eggs/female/day), then eriophyid mites (39.73 eggs; 1.37 eggs/female/day) and lowest on spider mites (18.16 eggs; 0.80 eggs/female/day). Intrinsic rate of increase (Rm), net reproductive rate (Ro) and finite rate of increase (lambda) followed the same pattern [pollen (0.168, 27.96 and 1.183, respectively), eriophyid mites (0.153, 20.81 and 1.167), spider mites (0.110, 9.44 and 1.119)]. Mean generation time (days) was the shortest on pollen (19.90), followed by eriophyid mites (20.02), and then spider mites (20.59). Average spider mite larvae consumed by E. finlandicus during immature stages were 9.18 for males and 11.85 for females. Adult E. finlandicus females consumed an average of 166.38 spider mite protonymphs during adult stage compared to an average of 66.55 by males. The number of prey protonymphs consumed per day by females was highest in the oviposition period, lower in the pre-oviposition period and the lowest in the post-oviposition period. The eriophyid mite as a prey recorded the shortest developmental time, while pollen as food recorded the highest oviposition rate in E. finlandicus. The potential of this predator as a biocontrol agent against T. urticae is discussed.

Simple SummaryThe two-spotted spider mite Tetranychus urticae and its interactions with fungi, notably Beauveria bassiana, on common bean plants were the main subjects of this study. The mite’s life cycle on untreated and endophyte-colonized plants was examined using the age-stage, two-sex life table hypothesis. The findings indicated that mites reared on untreated plants had shorter developmental stages and higher fecundity than those on colonized plants. Furthermore, mites on untreated plants displayed a higher intrinsic rate of increase and net reproductive rate. The study also revealed that fungal endophyte colonization negatively affected mite growth, adult lifespan, fecundity, reproductive rate, and the intrinsic rate of increase. The findings point to a possible application of entomopathogenic fungal endophytes in host plant resistance programs for future integrated pest control.Tetranychus urticae is a highly polyphagous and global pest. Spider mites primarily feed on the underside of leaves, resulting in decreased photosynthesis, nutritional loss, and the development of chlorotic patches. We investigated the life tables of the two-spotted spider mite T. urticae on fungal endophyte Beauveria bassiana colonized and untreated plants of the common Phaseolus vulgaris L., a bean plant. Based on the age-stage, two-sex life table theory, data were evaluated. The mites raised on untreated plants had protonymphs, deutonymphs, and total pre-adult stage durations that were considerably shorter (1.76, 2.14, and 9.77 d, respectively) than the mites raised on plants that had been colonized (2.02, 2.45, and 10.49 d, respectively). The fecundity (F) varied from 28.01 eggs per female of colonized plants to 57.67 eggs per female of endophyte-untreated plants. The net reproductive rate (R0) in the plants with and without endophytes was 19.26 and 42.53 brood, respectively. The untreated plants had an intrinsic rate of increase (rm) of 0.245 days as opposed to the colonized plants, which had an r of 0.196 days and a finite rate of increase (λ) (1.27 and 1.21, respectively). Population forecasts based on a two-sex, age-stage life table demonstrated the dynamism and variability of the stage structure. Furthermore, the colonization of B. bassiana had a negative impact on the growth and development of T. urticae. It lowered the adult mite life span, female fecundity, net reproduction rate, and intrinsic growth rate. We propose that future research should better use entomopathogenic fungal endophytes to understand host plant resistance strategies in integrated pest management.

Prey suitability and life table analysis of Amblyseius swirskii and Amblyseius aerialis (Parasitiformes: Phytoseiidae) on Panonychus citri (Acariformes: Tetranychidae) and Phyllocoptruta oleivora (Acariformes: Eriophyidae)

Most terrestrial plants live in symbiosis with arbuscular mycorrhizal (AM) fungi. Studies on the direct interaction between plants and mycorrhizal fungi are numerous whereas studies on the indirect interaction between such fungi and herbivores feeding on aboveground plant parts are scarce. We studied the impact of AM symbiosis on host plant choice and life history of an acarine surface piercing-sucking herbivore, the polyphagous two-spotted spider mite Tetranychus urticae. Experiments were performed on detached leaflets taken from common bean plants (Phaseolus vulgaris) colonized or not colonized by the AM fungus Glomus mosseae. T. urticae females were subjected to choice tests between leaves from mycorrhizal and non-mycorrhizal plants. Juvenile survival and development, adult female survival, oviposition rate and offspring sex ratio were measured in order to estimate the population growth parameters of T. urticae on either substrate. Moreover, we analyzed the macro- and micronutrient concentration of the aboveground plant parts. Adult T. urticae females preferentially resided and oviposited on mycorrhizal versus non-mycorrhizal leaflets. AM symbiosis significantly decreased embryonic development time and increased the overall oviposition rate as well as the proportion of female offspring produced during peak oviposition. Altogether, the improved life history parameters resulted in significant changes in net reproductive rate, intrinsic rate of increase, doubling time and finite rate of increase. Aboveground parts of colonized plants showed higher concentrations of P and K whereas Mn and Zn were both found at lower levels. This is the first study documenting the effect of AM symbiosis on the population growth rates of a herbivore, tracking the changes in life history characteristics throughout the life cycle. We discuss the AM-plant-herbivore interaction in relation to plant quality, herbivore feeding type and site and the evolutionary implications in a multi-trophic context.

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of dates in the Middle East and North Africa, inflicting severe economic damage if not controlled early. As predaceous mites are known to be potential biocontrol agents against several pests, so predation capacity, life table, reproduction, and survival of Amblyseius swirskii Athias-Henriot and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), collected from date palm farms in Qassim Saudi Arabia, were studied under laboratory conditions (25 °C, 30 °C, 35 °C and 50 ± 5% RH) against all motile stages of O. afrasiaticus. For both predators, mean developmental time, oviposition period, and longevity were inversely related to temperature from 25 to 35 °C. Various parameters were studied for A. swirskii and N. cucumeris at 25 °C, 30 °C and 35 °C, i.e. the female developmental time, 9.37, 7.29, 5.56, and 10.67, 8.38, 6.45 d; oviposition period, 19.77, 16.18, 13.94 and 15.90, 13.84, 10.64 d; longevity, 29.39, 24.79, 20.64 and 25.42, 21.94, 17.39 d; fecundity, 31.91, 37.10, 42.16 and 21.75, 26.84, 30.56 eggs per female, respectively. The maximum daily predation rate for both the predators was recorded at 35 °C during the oviposition period. The total predation of A. swirskii and N. cucumeris female was 370.86, 387.54, 405.83, 232.14, 263.32, 248.85 preys at 25 °C, 30 °C and 35 °C respectively. The maximum reproduction rate of A. swirskii and N. cucumeris (3.02, 2.87 eggs/♀/day) was recorded at 35 °C while the minimum (2.00, 1.36 eggs/♀/day) was recorded at 25 °C. The life table parameters were estimated as net reproductive rate (Ro) 21.68, 25.94, 29.52 and 18.95, 20.25, 22.78; the mean generation time (T) 24.92, 21.82, 18.24 and 26.30, 23.60, 20.56 d; the intrinsic rate of increase (rm) 0.181, 0.232, 0.248 and 0.170, 0.185, 0.196; the finite rate of increase (λ) 1.365, 1.551, 1.706 and 1.126, 1.324, 1.428 for A. swirskii and N. cucumeris at 25 °C, 30 °C and 35 °C respectively. The results of this study suggested that the two phytoseiid species are promising biological control agents of O. afrasiaticus at a wide range of temperatures.

The effects of milbemectin and spirodiclofen resistance on Phytoseiulus persimilis A.[sbnd]H. (Acari:Phytoseiidae) life table parameters

Predatory soil-dwelling mites, Gaeolaelaps aculeifer (Canestrini) and Stratiolaelaps scimitus (Womersley) (Mesostigmata: Laelapidae), are essential biocontrol agents of small soil arthropod pests. To understand the population characteristics of these two predatory mites, we investigated their development, survival, and fecundity under laboratory conditions. We used Tyrophagus putrescentiae (Schrank) as a food source and analyzed the data using the age-stage, two-sex life table. The duration from egg to adult for G. aculeifer was longer than that for S. scimitus, but larval duration was similar between the two species. Notably, G. aculeifer laid 74.88 eggs/female in 24.50 days, but S. scimitus laid 28.46 eggs/female in 19.1 days. Several population parameters, such as the intrinsic rate of increase, finite rate of increase, net reproductive rate, and gross reproductive rate of G. aculeifer, were significantly higher than those of S. scimitus. Using the bootstrap technique with 100,000 samples, we demonstrated that the life tables constructed based on the 2.5th and 97.5th percentiles of finite rate of increase (λ) net reproductive rate (R0) may characterize the variability in the survival and fecundity curves, as well as predict population growth uncertainty. These data provide important information for the practical application of predatory soil mites to manage agricultural pests.

The red spider mite, Tetranychus neocaledonicus (Acari: Tetranychidae) can be an important pest on lima bean (Phaseolus lunatus L.). Thus, the objective of this work was to assess the antibiosis and antixenosis effects of lima bean genotypes on T. neocaledonicus, through the evaluation of performance parameters as well as the host preference for food and oviposition. Nine lima bean genotypes from the Active Bank of Germplasm of the Federal University of Piauí – BGP / UFPI were screened. To assess antibiosis parameters, eggs of T. neocaledonicus were individually placed on leaf disks of each genotype. The period and survival of the different stages of development (larvae, protonymph, deutonymph and adult), pre-oviposition, oviposition and post-oviposition period, longevity and fecundity of females were evaluated, and fertility life table parameters were calculated. In choice tests, adult females of T. neocaledonicus were used. The numbers of mites and eggs were counted for each genotype. The protonymph, egg-adult, longevity and oviposition period, fertility life table parameters, as well as the food and oviposition preference were affected by lima bean genotypes. We found that some genotypes reduced adult female longevity, increased the larval and egg-adult period, decreased oviposition period, negatively affected the fertility life table parameters, reducing the net reproductive rate (Ro), the intrinsic rate of increase (rm) and the finite rate of increase (λ), while increasing the population doubling time (DT), exhibiting a reliable antibiosis effect upon T. neocaledonicus. Nevertheless, these same genotypes were the most preferred for food and oviposition. By contrast, some other genotypes reduced the adult female longevity and oviposition period, elongated the larval period and affected fertility life table parameters, demonstrating an antibiosis effect upon T. neocaledonicus. Moreover, these other genotypes were among the less preferred for food and oviposition, exhibiting an additional antixenosis effect. Thus, our results demonstrate that the genotypes of lima bean may present distinct levels of resistance to T. neocaledonicus, and this resistance may be an important tool for Integrated Pest Management. This is one of the first studies aiming to describe mite resistance sources in lima bean.

In this study, the life history and demographic parameters of Histiostoma feroniarum (Defour) on Fusarium graminearum Clade were studied under laboratory condition. The incubation, larval and nymphal periods and longevity of adults were observed to be 1.6, 2.56, 3.09 and 10.48 days, respectively. The sex ratio was 0.65. Pre-oviposition, oviposition and post-oviposition periods lasted 1.8, 8.27 and 0.66 days, respectively. The gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of increase (rm), finite rate of increase (λ), mean generation time (T) and doubling time (DT) were calculated to be 110.56 females/female, 23.54 females/ female, 0.195 day-1, 1.215 day-1, 16.23 days and 3.55 days, respectively. The results of this study reveal high potential of H. feroniarum as a major pest of laboratory cultures.

Knowledge of the impact of acaricides on predatory mites is crucial for integrated pest management programs. The present study evaluated the sublethal effect of fenazaquin (Pride(®) 20% SC, Behavar, Iran) on life table parameters of the subsequent generation of the predatory mite, Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae), fed on Tetranychus urticae Koch under laboratory conditions [26±1°C, 70±3% RH and 16:8 (L:D) h]. The sublethal concentrations including LC10, LC20 and LC30 were determined using a dose-effect assay. The total development time of both sexes enhanced with an increase in concentration. The oviposition period and total fecundity decreased in dose-dependent manner. The intrinsic rate of increase (r) and finite rate of increase (λ) significantly descended with concentration enhancing from LC10 to LC30, compared with the control. The net reproductive rate (R 0) ranged between 2.76 and 7.37 offspring. Overall, the results indicated that fenazaquin had negative effects on development and life table parameters of the subsequent generation of A. swirskii. In conclusion, fenazaquin is not a compatible acaricide with A. swirskii and should not be used with this predatory mite in integrated management of T. urticae.

In this study we evaluate the biotic potential and reproductive parameters of Spodoptera cosmioides (Walker, 1858) under controlled conditions (25 ± 1 °C, 70 ± 10% RH and 14 hour photophase). Females, on average, (14.433 days) did not live significantly longer than their male counterparts (13.100 days). The mean durations of the pre-oviposition, oviposition and post-oviposition periods were 2.767, 10.600 and 1.067 days, respectively. The mean fecundity of females was 5,073.533 eggs and the mean fertility was 5,021.027 larvae. On average, females copulated 1.167 times. Fecundity was positively correlated with the number of copulations (r = 0.583, P <0.001). The number of copulations, however, was negatively correlated whit the duration of the pre-oviposition (r = -0.560, P = 0.007) and oviposition (r = -0.479, P = 0.048) periods, and overall longevity (r = -0.512, P = 0.031). The biotic potential was estimated at 6.547 x 1021 individuals/female/year. The net reproductive rate (Ro) was 2,193.722 times per generation and the mean generation time (T) was 46.407 days. The intrinsic rate of increase (rm) was 0.166, with a finite rate of increase (λ) of 1.180, per week.

Multigenerational hormetic effects of different insecticides on Spodoptera frugiperda (J.E. smith) (Lepidoptera: Noctuidae)

The life table characteristics of the polyphagous mirid Macrolophus caliginosus Wagner (Heteroptera: Miridae) preying on various stages of Tetranychus urticae Koch (Acari: Tetranychidae) with tomato as host plant were described at 22 °C. The following average parameters were obtained: Female longevity: 28.7 days; fecundity: 0.7 eggs/female/day; egg mortality: 2.6%; pre‐oviposition period: 5.5 days; oviposition period: 18.1 days; post‐oviposition period: 3.2 days; juvenile development time: 26.8 days; juvenile mortality: 34.9%; and sex ratio (♀/(♀+♂)) 0.46. Life table parameters were estimated as net reproduction rate (R0): 6.15; intrinsic rate of increase (rm): 0.031 day−1; finite rate of increase (≤): 1.032; mean generation time (Tc): 58.17 days; and doubling time (T2) 22.2 days. The parameters obtained were in accordance with those reported for M. caliginosus fed on another mite species (T. turkestani Ugarov &amp; Nikolski (Acari: Tetranychidae)). However, compared to the performance of M. caliginosus fed on common glasshouse insect pests, a diet consisting of only mites appeared to be inferior. However, being a voracious predator, M. caliginosus may be a valuable addition to existing methods of mite control.

Temperature-dependent development and life history of Oligonychus litchii (Acari: Tetranychidae), on wax apple

The lesser cornstalk borer, Elasmopalpus lignosellus (Zeller) (Lepidoptera: Pyralidae) is an important pest of sugarcane (a complex hybrid of Saccharum spp.) in southern Florida. Reproductive and life table parameters for E. lignosellus were examined at nine constant temperatures from 13 to 36 °C with sugarcane as the larval food source. The pre- and postoviposition periods decreased with increasing temperatures and reached their minimums at 33 and 36 °C, respectively. The oviposition period was longest at 27 °C. The mean fecundity, stage-specific survival, stage-specific fecundity, intrinsic rate of increase, and finite rate of increase were greatest at 30 °C and decreased with increasing or decreasing temperature. The net reproductive rate was greatest at 27 °C. The Logan-6 model best described the relationship between temperature and intrinsic rate of increase. The generation and population doubling times were longest at 13 and shortest at 33 and 30 °C, respectively. The most favorable temperatures for E. lignosellus population growth were between 27 and 33°C. Life table parameters for E. lignosellus reared on sugarcane were greater than for the Mexican rice borer [Eoreuma loftini (Dyar) (Lepidoptera: Crambidae)] reared on an artificial diet at 30 °C. The intrinsic rates of increase for the sugarcane borer [Diatraea saccharalis (F.) (Lepidoptera: Crambidae)] reared on sugarcane or corn were the same as for E. lignosellus reared on sugarcane at 27 °C, but the net reproductive rate was four times higher for the former than the latter borer species.