Effect of host plants on developmental time and life table parameters of <Emphasis Type="Italic">Amphitetranychus viennensis</Emphasis> (Acari: Tetranychidae)

The effect of host plant species including black cherry (Prunus serotina cv. Irani), cherry (Prunus avium cv. siahe Mashhad) and apple (Malus domestica cv. shafi Abadi) was studied on biological parameters of Amphitetranychus viennensis (Zacher) in the laboratory at 25 ± 1°C, 70 ± 10% RH and 16L: 8D photoperiod. Duration of each life stage, longevity, reproduction rate, the intrinsic rate of natural increase (r _m ), net reproductive rate (R ₀ ), mean generation time (T), doubling time (DT), and finite rate of increase (λ) of the hawthorn spider mite on the three host plants were calculated. Differences in fertility life table parameters of the spider mite among host plants were analyzed using pseudo-values, which were produced by jackknife re-sampling. The results indicated that black cherry might be the most suitable plant for hawthorn spider mite due to the shorter developmental period (10.6 days), longer adult longevity (25.5 days), higher reproduction (65.6 eggs), and intrinsic rate of natural increase (0.194 females/female/day). Cherry was the least suitable host plant. To determine the effect of host shifts, the mite was transferred from black cherry onto cherry and apple. In the first generation after shifting to apple, the developmental period, reproduction and life table parameters were negatively influenced. However, population growth parameters in the first generation on cherry were actually better than after three generations on this new host. This underscores the relevance of the mites’ recent breeding history for life table studies.     

Life history of western flower thrips, Frankliniella occidentalis (Thysan., Thripae), on five different vegetable leaves

Biological characteristics of western flower thrips, Frankliniella occidentalis (Pergande) (Thysan., Thripae), were investigated on excised leaves of five vegetables: cabbage (Brassica oleracea L. var. Jingfeng 1), cucumber (Cucumis sativus L. var. Zhongnong 8), capsicum (Capsicum annuum L. var. Zhongjiao 5), kidney bean (Phaseolus vulgaris L. var. Gonggeizhe) and tomato (Lycopersicon esculentum M. var. zhongza 9). The developmental time from egg to adult on the cucumber, cabbage, bean, capsicum and tomato leaf was 9.22 ± 0.13, 10.19 ± 0.08, 10.42 ± 0.06, 12.15 ± 0.07 and 12.91 ± 0.04 days, respectively. Survivorship of immatures on cucumber, cabbage and tomato was high (75–80%) but low on capsicum (50%). The total number of first instars produced was highest on cabbage (76.62 ± 11.79), while the daily first instar production was highest on cucumber (6.12 ± 1.81), whereas the total and daily first instar production rates were lowest on capsicum (7.67 ± 3.35 and 1.89 ± 0.91). F. occidentalis had the highest intrinsic rate of increase (r_m) on cucumber (0.208), followed by cabbage (0.184), bean (0.164), tomato (0.100) and capsicum (0.017). The results indicate that cucumber was the most suitable host plant for F. occidentalis, whereas capsicum was the least suitable.     

Effect of floral and extrafloral resources on predation of Aphis spiraecola by Harmonia axyridis on Apple

Flowering companion plants and plants producing extrafloral nectar are being proposed to enhance biological control in apple (Malus domestica Borkh.) orchards. This experiment evaluated the impact of floral and extrafloral resources on predation of spirea aphid (Aphis spiraecola Patch) on apple by adult Harmonia axyridis (Pallas) under greenhouse conditions. Predation of spirea aphids was not affected by the presence of flowering buckwheat (Fagopyrum esculentum) as compared with either buckwheat with flowers removed or an uninfested apple shoot. However, there was a significant reduction in predation of spirea aphids on an apple shoot in the presence of a peach shoot with extrafloral nectar glands compared with either a peach shoot of the same cultivar without nectar glands or an uninfested apple shoot. These findings demonstrate that alternative food resources potentially could interfere with rates of biological control and, therefore, need to be carefully evaluated before incorporating in an orchard design. More studies are needed to adequately gauge the net effects of adding floral or extrafloral resources in orchards for conservation biological control.     

橘大实蝇对三种寄主植物的偏好比较

比较取食3种不同寄主植物脐橙、杂柑、蜜橘对橘大实蝇Bactrocera(Tetradacus)minax(Enderlein)的蛹特征、卵量及为害率的影响,研究橘大实蝇对寄主植物的选择性。结果表明,取食蜜橘的橘大实蝇其蛹长及蛹宽显著大于取食脐橙的;取食杂柑的与取食脐橙的无显著差异。三者之间蛹重差异显著。取食蜜橘的雌成虫卵量显著大于取食脐橙的,取食杂柑的雌成虫卵量与取食脐橙的其无显著差异。对寄主植物的为害率顺序为:脐橙>杂柑>蜜橘。     

Life History of Kampimodromus aberrans as a predator of Phytoptus avellanae (Acari: Phytoseiidae, Phytoptidae)

The biology of Kampimodromus aberrans (Oudemans), a predator of the big bud mite, Phytoptus avellanae Nalepa, was studied under laboratory conditions. All experiments were conducted on hazelnut leaf discs in an incubator at 25 ± 1 °C, with 16:8 h L:D, at an average daily relative air humidity of 76%. Observations were made twice daily for the immature stages and daily for the adults to determine developmental time, survival and fecundity. The mean developmental time for females was 6.90 days and for males was 7.10 days, and mean adult longevity for females was 11.67 days. The mean total and daily egg production were 12.67 and 1.85 eggs, respectively. The net reproduction rate (R₀) was 7.09 females/female, intrinsic rate of increase (r_m) was 0.153 female/female/day and mean generation time (T₀) was 12.80 days. The mortality rate of immature stages was 0.66% and the sex ratio was 0.51 female.     

Influence of prey on developmental performance, reproduction and prey consumption of Neoseiulus californicus (Acari: Phytoseiidae)

The Spical strain of the predatory mite Neoseiulus californicus (McGregor) is used as a biological control agent, but little is known about its preferred prey and host plants in Japan. Here we studied the development, reproduction and prey consumption of the Spical strain when fed on eggs of five different spider mite species deposited on both their laboratory-rearing plant and cherry, on which all five spider mite species developed well. The developmental periods of immature N. californicus females and males were significantly affected by the prey species they fed on, but not by the plants. No difference was found between males and females. The developmental period was shorter on eggs of two Tetranychus species than on eggs of Panonychus ulmi. Immature females had a higher predation rate than immature males. Preoviposition period, oviposition period and the number of eggs laid per female were not significantly affected by either the plants or the type of prey eggs. The postoviposition period and total adult longevity were shorter on eggs of P. ulmi than of the other four prey species, but there was no effect of plant substrate. The postoviposition period of the Spical strain was much longer than that of other N. californicus strains or other predatory mite species: the postoviposition period of the Spical strain was more than three times longer than the oviposition period, accounting for more than 75% of the total adult longevity. This suggests that the females need multiple mating to reach full egg load, but this remains to be tested. Total consumption by N. californicus adults was lower for eggs of P. ulmi than for eggs of the other four species, apparently because of the shorter postoviposition period when fed on eggs of P. ulmi. The intrinsic rates of natural increase (r _m) on the rearing plant did not differ among prey species, whereas those on cherry were significantly different: the value was higher on Tetranychus urticae eggs than on eggs of other species. Only when N. californicus fed on T. urticae eggs, the r _m-values were significantly different between the rearing plant and cherry (higher on cherry). Thus, the Spical strain of N. californicus could feed on eggs of all five spider mite species, deposited on a variety of plants with similar r _m-values, suggesting that it could be successfully used to control spider mites in orchards and various crop fields of Japan.     

Biology and fertility life table of the greenbug,Schizaphis graminum (Hemiptera: Aphididae) on the resistant winter wheat cultivar (Pishgam) in Iran

The greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae) has been known as a major pest of small grains, particularly wheat, worldwide. In this study, the effect of new wheat cultivar (Pishgam) for cold regions on biological characteristics of greenbug was investigated in a greenhouse at 25 ± 2 °C, 55 ± 10% relative humidity and a photoperiod of 16:8 h (L:D). The raw data were analysed based on the age-stage, two-sex life table. The intrinsic rate of increase (r), the finite rate of increase (λ), the net reproduction rate (R₀) and the mean generation time (T) of greenbug were 0.313 ± 0.0019, 1.36 ± 0.0027 females/female/day, 83.33 ± 0.331 females/female and 14.11 ± 0.09 days, respectively. The life expectancy of a nymph is 43.57 days. The maximum reproductive value of females is on the 16th day which coincides with the total pre-reproduction period counted from birth. Hence, the present results may provide helpful information for comprehensive IPM programme of greenbug on this variety in cold regions of Iran. Result revealed that nymphal survival rate of the aphid was 100% on studied cultivar like that on sensitive host plant cultivar.     

Effects of mixed prey on the development and demographic attributes of a generalist predator,Coccinella septempunctata (Coleoptera: Coccinellidae)

Coccinella septempunctata Linnaeus, 1758 (Coleoptera: Coccinellidae) is an aphidophagous ladybird beetle species with cosmopolitan distribution. However, it may also thrive on arthropods other than aphids, when the latter are not readily available. Certain life history traits and demographic attributes of C. septempunctata were determined using seven different diets with different alternations and proportions of an aphid, Lipaphis erysimi (Kaltenbach,1843) and a mite, Tetranychus urticae Koch, 1836, in the laboratory (at 25±0.5°C, 65±5% RH and a photoperiod of 16 h L:8 h D).The larval duration was longest (12.61±6.17 days) when fed an alternating diet of two days aphid/two days mite. Adult longevity was longest (78.65±1.09 days) when fed aphids only and shortest (3.17±1.25 days) when fed mites only. Life expectancy (e_x) was highest (111 days) when adults were fed only aphids and lowest (11.3 days) when fed only mites. Survival rates of ladybird beetles were positively related to an increasing ratio of aphids in their diet. Their ability to prey on both aphids and mites indicates the effectiveness of C. septempunctata as a biological control agent on plants infested with these two pests.     

Importance of early arrival of adult <Emphasis Type="Italic">Harmonia axyridis</Emphasis> for control of <Emphasis Type="Italic">Aphis spiraecola</Emphasis> on apple

The biological control of aphid populations may only be possible when natural enemies arrive soon after aphid colonization. This study was done to identify how quickly adult Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) need to arrive at newly established spirea aphid [Aphis spiraecola Patch (Homoptera: Aphididae)] colonies on apple (Malus domestica Borkh.) to provide population control. A total of 100 newly established spirea aphid colonies were caged in an experimental apple orchard in West Virginia, USA. A single adult H. axyridis was added to each of ten caged colonies at day 0, 5, 10, 15 and 20 days after caging. An additional ten caged colonies were opened for exposure to natural levels of predation at each of the treatment intervals as a control. The single H. axyridis eliminated the aphid colonies significantly more quickly than natural predation for up to ten days after colony establishment. The probability of an aphid colony producing alates was significantly lower in the presence of a single H. axyridis adult than when exposed to natural predation for the first ten days. Adult H. axyridis beetles are capable of completely controlling individual spirea aphid colonies on apple only if they are abundant enough to find colonies within one week of colony establishment.     

Rearing method and life-table data for the cocoa mirid bug Sahlbergella singularis Haglund (Hemiptera: Miridae)

The mirid bug Sahlbergella singularis feeds on cocoa pods and shoots, causing considerable crop losses. As laboratory experimentation requires numerous insects, this study aimed at improving available rearing method of S. singularis for Cameroon. Fifty second to fifth nymphal stages were collected at a cocoa farm and reared to the adult stage on cocoa pods in an insectary (T = 24.7 ± 0.9°C, RH = 84.5 ± 6.8%, photoperiod: 12 : 12 L : D). Newly emerged females were confined for 5–6 days on cocoa twigs for sexual maturation and each female paired with a male for 24 h. The pairs were returned to the field and enclosed in mousseline sleeves on attached cocoa pods, for egg laying. After 16 days (expected egg lifetime), the sleeve cages were checked daily to detect newly hatched nymphs. Then, the pods were collected and brought to the insectary, where nymphs continued to emerge and develop into adults. Our method allowed the production of 14.6 ± 6.7 nymphs per female per generation, for 15 consecutive generations. Nymphal survival was calculated to be 68.2% and the mean duration of the nymphal development was measured at 22.7 ± 3.1 days. The rearing performance was evaluated using life‐table calculations. The net reproductive rate (R₀) was 6.59; the intrinsic rate of increase (r) was 0.037 per female per day with a population doubling time (T_d) of 18.9 days. On average each female contributed 9.70 individuals to the population given a mean generation time (T_c) of 52.1 days. The percentage of reproductive females and the mean number of nymphs per female were significantly different between generations, with 86.8% and 18.1% in generation G7 as compared to 45.8% and 8.4% for generation G5, respectively. As rainfall showed concordant variations during the period of investigation, we discuss the impact of this factor on mirid fecundity.     

The life cycle of Hyalomma rufipes (Acari: Ixodidae) under laboratory conditions

Biological characteristics of Hyalomma rufipes parasitising on rabbits and sheep were compared under laboratory conditions in Gansu, China. Mature ticks could parasitize both rabbits and sheep, while immature ticks only fed on rabbits successfully. Adults sucked blood on sheep significantly longer than on rabbits (16 and 13 days, respectively). Other adult parasite characteristics fed on the two hosts were similar, including the weight of engorged adult, female daily oviposition, and the weight and amount of the egg mass laid. Those indicated that this tick species showed little host specificity between sheep and rabbits during its adult stage. In total, the life cycle of H. rufipes was completed in an average period of 179 days. The average developmental periods were 59 days for egg incubation, 3 and 21 days for immature tick prefeeding and feeding, 2, 12 and 40 days for adult prefeeding, female preoviposition and oviposition. The longer female fed for engorgement, the shorter preoviposition period of engorged female needed, although when the feeding period was less than 15 days, this relationship was not obvious. The results confirmed the correlation between the weight of the engorged female and the number of eggs laid (r = 0.909). The reproductive efficiency index (REI) and reproductive fitness index (RFI) in females was 10.63 and 7.22, respectively. Engorged nymphs moulting to females were significantly heavier (27.6 ± 0.89 mg) than those moulting to males (22.3 ± 0.52 mg). Males outnumbered females by 1.4:1.     

Semi-field demographic performance of the invasive planthopper,Orosanga japonica (Hemiptera: Ricaniidae) on two host plants

Orosanga japonica Melichar (Hemiptera: Ricaniidae) is an invasive polyphagous pest in Iran. The planthopper damaged host plants by sap-sucking and egg laying on new twigs. This study aimed to determine the life table parameters of O. japonica on Rubus ulmifolius Schoot (elm leaf blackberry) and Melia azedarach L. (chinaberry) under field conditions in Rudsar (North of Iran) during 2019–2020. The collected life history data were analyzed based on age-stage, two-sex life table theory. The results showed that the incubation period of O. japonica was too long (≈ 270 days) on both host plants. The nymphs emerged from mid-May 2020. The planthopper had five nymphal stages under field conditions. The nymphal duration was 41.39 ± 0.56 days and 38.13 ± 0.62 days on R. ulmifolius and M. azedarach, respectively. The total preadult survival rates were 53.2% and 51.7% on R. ulmifolius and M. azedarach, respectively. Based on the results, a significant shorter total developmental time was observed on M. azedarach. When adults emerged in late July, they laid eggs after 26.05 days and 26.75 days on R. ulmifolius and M. azedarach, respectively. The fecundity on M. azedarach (131.69 egg/female) was significantly higher than that on R. ulmifolius. However, the life table parameters were all not significantly different on the two host plants. The intrinsic rate of increase (r) were 0.0097 ± 0.0005 day⁻¹ and 0.0105 ± 0.0006 day⁻¹ on R. ulmifolius and M. azedarach, respectively. Generally, these findings could be helpful to establish an efficient management strategy for this exotic pest.     

Biology of the House Fly Predator <Emphasis Type="Italic">Carcinops pumilio</Emphasis> (Erichson) (Coleoptera: Histeridae)

Two larval instars of Carcinops pumilio (Erichson) were identified from a frequency distribution of the head capsule measurements. The total developmental time from egg to adult emergence averaged 20.5 ± 0.1 days at 30 °C. The 2nd instar was the longest, accounting for 39% of the total development time. The 1st instar larvae sustained the highest mortality of 26% whilst there was no mortality in the pupal stage. The immature stages sustained about 50% mortality before adult emergence. The adult females of C. pumilio can live for 140 days and the rate of survival was high in the young adults but decreased as the beetles aged. Newly emerged adults survived for 25.5 ± 0.4 days without feeding. The sex ratio was 0.48 females: 0.52 males. The intrinsic rate of natural increase (r_m) was 0.065, the generation time (T) was 50.019 days and the net reproduction rate (R_o) was 20.191.     

Life table of Gaeolaelaps aculeifer (Acari: Laelapidae) feeding on larvae of Lycoriella auripila (Diptera: Sciaridae) with stage-specific estimates of consumption

Gaeolaelaps aculeifer (Canestrini, 1883) is a soil-dwelling predatory mite with potential for use as a biological control agent of fungus gnats (Diptera: Sciaridae) in mushroom production. The life table, predation rate and population growth rate of G. aculeifer on a diet of larvae of the sciarid fly, Lycoriella auripila, at 23?±?1°C, 60?±?5% RH and a photoperiod of 0:24 (L:D)?h was investigated. The results revealed that the duration of egg, larva, protonymph, deutonymph, females and males of G. aculeifer were 3.8?±?0.1, 1.4?±?0.1, 3.9?±?0.1, 4.1?±?0.1, 67.7?±?2.8 and 60.3?±?3.1 days, respectively. Net reproductive rate (R₀) was 54.8?±?7.1 offspring, intrinsic rate of increase (r) was 0.12?±?0.01 offspring day^?1, finite rate of increase (λ) was 1.13?±?0.01 day^?1and mean generation time (T) was 32.3?±?0.6 days. The predator consumed a mean of 0.08?±?0.05, 1.73?±?0.18, 3.16?±?0.28 and 75.9?±?7.1 third instar L. auripila larvae during the larval (1.3?±?0.1 days), protonymph (3.9?±?0.1 days), deutonymph (4.1?±?0.1 days) and adult (52.6?±?2.2 days) stages. Population parameters and consumption rates suggest that G. aculeifer has good potential as a biological control agent of L. auripila in mushroom production.     

Demography of greenbug,Schizaphis graminum (Rondani) (Hemiptera: Aphididae) on six barley cultivars

The greenbugs, Schizaphis graminum (Rondani) were collected from the barley fields in Isfahan region of Iran. The aphid colonies were maintained on each of six barley cultivars including Karoon, Kavir, Zarjoo, Nosrat, Afzal and Rihane. All the experiments were done on the mentioned barley varieties at 26 ± 1°C, 60 ± 5% relative humidity (RH) and at a photoperiod of 16:8 (L:D) h. The shortest and longest developmental times were obtained on Nosrat 6.35 ± 0.11 and Rihane 6.75 ± 0.07 days, respectively. The survivorship of immature stages varied from 71.95% on Nosrat to 82.14% on Zarjoo. The total number of offsprings were 71.05 and 63.22 nymphs per female on Kavir and Karoon. The highest and lowest r _m values were observed on Kavir (0.336 ± 0.005) and Rihane (0.299 ± 0.008), respectively. The statistical analysis of jackknife did not show a significant influence of the tested barley varieties for the mean generation time and a similar procedure of difference for λ and r _m was estimated.     

Life table parameters of the tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae) on different tomato cultivars

The tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato plants originating from South America. In this study, the effect of three tomato cultivars on the life table parameters of T. absoluta was investigated. Data were analysed based on age‐stage, two‐sex life table theory. The net reproduction rate (R₀) of T. absoluta on Falkato, Isabella and Grandella cultivars was determined as 15.73 ± 3.35, 17.66 ± 3.33 and 10.03 ± 4.10 eggs, respectively. The intrinsic rate of increase (r) value on those cultivars was 0.09 ± 0.007, 0.095 ± 0.006 and 0.074 ± 0.017 day^?1, respectively. Finite population rates of increase (λ) were 1.095 ± 0.008, 1.099 ± 0.007 and 1.076 ± 0.018 day^?1, and mean generation times (T) on the three cultivars were 30.09 ± 0.29, 30.22 ± 0.27 and 31.12 ± 0.65 days, respectively. The egg incubation period, pre‐adult duration and fecundity on these tomato cultivars was also calculated. The results showed no significant differences between r, R₀, and T on the three tested tomato cultivars. These findings can be useful for developing an integrated pest management strategy against this noxious pest.     

Biological Cycle of Lorryia formosa (Acari, Tydeidae) on Rubber Tree Leaves: A Case of Thelytoky

Lorryia formosa Cooreman has been collected on many different host plants around the world. The biological cycle of this species was studied at 28 °C with mites collected from a rubber tree crop. The life table was constructed based on sixty individuals. The average lifetime was 37.43 ± 20.23 (SE) days, and the r_m was 0.08. The sex ratio was totally female biased, and unfertilized eggs developed into females. This is the first record of thelytoky in Tydeoidea proved by rearing.     

Physiological and morphological development of Anagyrus ananatis at constant temperatures

The lower developmental temperature threshold (T ₀) and the Degree Days (DD) required for the encyrtid endoparasitoid Anagyrus ananatis Gahan to develop from egg to adult on the pink pineapple mealybug (PPM), Dysmicoccus brevipes (Cockerell) (Hemiptera: Pseudococcidae), were determined. The T ₀ was estimated to be about 12.65 °C for both females and males. In contrast, females and males required about 275 and 265 DD, respectively, to complete development from egg to adult. Temperatures from 19 to 29 °C were optimal for mass rearing of A. ananatis, with the optimal temperature being around 24 °C. At this temperature, A. ananatis could complete almost two generations in the time it takes PPM to complete only one generation. Although A. ananatis is a koinobiont, the mealybug host was killed within a few (6–8) days after parasitization. The developmental stages of A. ananatis were described (e.g., appearance, size, color) and their time periods quantified when reared on PPM at 23.5 ± 0.5°C. Encyrtiform eggs were inserted through the dorsal surface of the PPM and were attached to the host via a slender stalk. This immature parasitoid remained attached to the host cuticle via the stalk until entering the prepupal stage. The host mealybug mummified during the parasitoid’s prepupal stage. First adult eclosion occurred at 24 days post-parasitization.     

Effect of African nightshade species (Solanaceae) on developmental time and life table parameters of <Emphasis Type="Italic">Tetranychus evansi</Emphasis> (Acari: Tetranychidae)

The effect of five African nightshade (Solanum sp.) species on the biological and demographic parameters of the tomato spider mite, Tetranychus evansi Baker and Pritchard, was examined in the laboratory at 25 ± 1°C, 70–80% RH and 12L:12D photoperiod. Duration of each development stage, reproduction rate, longevity, intrinsic rate of natural increase (r _m), and doubling time (DT) of the tomato spider mite on the five nightshade species were calculated. The results indicated that S. villosum, S. scabrum, S. tarderemotum and S. americanum are more suitable for T. evansi due to a shorter developmental period, longer adult longevity, higher reproduction and intrinsic rate of natural increase ranging between 0.180 and 0.196 females/female/day compared with S. sarrachoides which cannot support T. evansi populations as the r _m (−0.063 females/female/day) and DT were negative on this host. Differences in developmental time and life table parameters among the other host plants were not significant.     

Biological parameters of Elasmus nudus (Hymenoptera,Eulophidae), a parasitoid of the pistachio fruit hull borer moth,Arimania komaroffi (Lepidoptera,Pyralidae)

Elasmus nudus (Nees) is known as a synovigenic, gregarious ectoparasitoid of the pistachio fruit hull borer moth, Arimania komaroffi Ragonot in pistachio plantations in southern Iran. The biological parameters of this parasitoid were studied using the Mediterranean flour moth, Ephestia kuehniella Zeller as a host and the resulting data were compared with that of its native host, A. komaroffi. The parasitoid developed successfully from egg to adult over a temperature range of 17–35°C. The developmental times of the parasitoid on A. komaroffi and E. kuehniella were not significantly different. The threshold value at which the development rate of E. nudus was zero was estimated to be 9.2°C and the estimated number of degree days (°D) for development from egg to adult was 238 above this threshold. The reproductive potential of E. nudus was similar on both hosts at 30°C. The intrinsic rate of natural increase (r _m ) for E. nudus did not vary much between 25°C and 32.5°C. In addition, the clutch size of the parasitoid on the two hosts was not statistically different. The present study provides some basic information on the biological characteristics of E. nudus.