Efficacy,prey stage preference and optimum predator–prey ratio of the predatory mite,Neoseiulus longispinosus Evans (Acari: Phytoseiidae) to control the red spider mite,Oligonychus coffeae Nietner (Acari: Tetranychidae) infesting tea

The predatory mite, N. longispinosus preys up on red spider mite, O. coffeae infesting tea in south India. An attempt has been made to determine the predatory potential, prey stage preference and optimum predator–prey ratio of N. longispinosus under laboratory and green house conditions. When 50 adult female O. coffeae were given, the number of adults reduced by eight days along with an increase in the number of predators. The larvae hatched from the eggs laid by O. coffeae were fed by predatory mite. N. longispinosus preyed up on all life stages with a preference to larvae and nymphs of red spider mite. Predator–prey ratios of 1:33 and 1:50 were effective in lab, and 1:25 was found to be effective in green house. These results revealed that N. longispinosus could be used as a successful biocontrol candidate of O. coffeae in tea through augmentation or mass rearing and field release.     

Seasonal Abundance and Predatory Potential of <Emphasis Type="Italic">Stethorus aptus</Emphasis> Kapur (Coleoptera: Coccinellidae): A Biocontrol Agent of Tea Red Spider Mite <Emphasis Type="Italic">Oligonychus coffeae</Emphasis> Nietner (Acarina: Tetranychidae)

The tea red spider mite, Oligonychus coffeae Nietner is one of the major pests of tea plants in North-east India. The ladybird beetle, Stethorus aptus Kapur, is a newly reported predator of O. coffeae. Predatory efficiency study of S. aptus under laboratory conditions revealed that adult of S. aptus consumed significantly more mites than larvae. In free choice condition, the predator consumed within a range of 48–56 adults and 82–90 larvae of O. coffeae whereas the 3rd and 4th instar larvae of S. aptus consumed 20–26 adults and 50–60 larvae of O. coffeae per day respectively. Population dynamics of S. aptus was observed for 1 year under field conditions. The maximum density of the predator was recorded during January to March and it gradually declined from September onwards. Population of S. aptus showed positive correlation with its prey O. coffeae and relative humidity while effect of other factors was insignificant.     

Clove Oil Efficacy on the Red Spider Mite, <Emphasis Type="Italic">Oligonychus coffeae</Emphasis> Nietner (Acari: Tetranychidae) Infesting Tea Plants

The tea red spider mite, Oligonychus coffeae Nietner (Tetranychidae), is an economically important pest of agricultural and ornamental crops and considered one of the major pests of tea plants in North-east India. In view of increasing resistance recorded in insect and mite pests against pesticides, a study was conducted to determine the acaricidal, antiovipositional, repellent and ovicidal activities of clove oil (an essential oil from the clove plant, Syzygium aromaticum L. Merr. & Perry: Myrtaceae) against tea-red-spider-mite. Mortality of O. coffeae varied with the concentrations and the duration of exposure time of the mites after application of oil. Rate of deposition of eggs by mites on treated leaf surfaces as well as the viability rate of eggs decreased significantly. In addition, certain concentrations of clove oil have been proved effective against adult mites.     

Life table and efficacy of Mallada desjardinsi (Chrysopidae: Neuroptera), an important predator of tea red spider mite, Oligonychus coffeae (Acari: Tetranychidae)

Green lacewing, Mallada desjardinsi Navas, is an important predator of red spider mite, Oligonychus coffeae infesting tea. Life history, life table and efficacy of M. desjardinsi were determined using red spider mite as prey under laboratory conditions. Duration of development of M. desjardinsi recorded was 5.1, 13.8 and 13 days for eggs, larvae and pupae respectively, with an average of 31.9 days from egg to adult emergence. After a mean pre oviposition period of 7.1 days, a single female laid an average of 252.6 eggs in its life time. Adult longevity of the male was recorded as 39.6 days while the females lived longer (58.2 days). The life table of M. desjardinsi was characterized by an intrinsic rate of increase (r) of 0.096 day, net reproductive rate (R ₀ ) of 153.19 eggs/female, gross reproduction rate (∑mx) of 167.28 eggs/female, generation time (T) of 52.47 days, doubling time of 7.22 days and finite rate of increase(λ) of 1.1 day. The optimum predator–prey ratios were 1:50 and 1:33 under laboratory conditions however, 1:33 and 1:25 ratios were effective in green house conditions. The results of the study can be considered as a first step towards the utilization of this predator in an IPM program for the management of red spider mite infesting tea.     

The effects of rainfall and shade on the occurrence of three mite pests of tea in Ceylon

Outbreaks of the red spider mite (Oligonychus coffeae Nietn.), the purple mite (Calacarus carinatus Green) and the scarlet mite (Brevipalpus californicus Banks) of tea were closely associated with the monthly rainfall pattern. Peak numbers occurred during the intermonsoonal dry periods. The relationship between mite numbers and the rainfall pattern suggests that control measures should commence at the end of the first month after the dry season begins. More red spider mites, but fewer purple mites, occurred on tea grown under shaded conditions. Observations on the relationship between scarlet mite numbers and shade were inconclusive. It is suggested that, in addition to direct effects of rainfall and shade, mite numbers are determined by certain biochemical processes that take place within the tea leaves.     

Life table and predation of Oligota pygmaea (Coleoptera: Staphylinidae) a major predator of the red spider mite, Oligonychus coffeae (Acarina: Tetranychidae) infesting tea

The staphylinid beetle, Oligota pygmaea (Solier) is an important predator of the red spider mite, Oligonychus coffeae (Nietner) infesting tea. Biology, life table and predatory efficiency of O. pygmaea were studied under laboratory conditions. Duration of developmental stages of O. pygmaea was 3.2, 5.7 and 12.5 d for eggs, larvae and pupae, respectively with an average of 23.0 d from egg to adult emergence. After a mean preovipostion period of 2.9 d, each female laid an average of 400.5 eggs in its life span. Adult O. pygmaea lived for an average of 54.1 d. Adult females lived for a longer period of 58.8 d compared to the longevity of 49.4 d of adult male. Studies revealed that its life table characterized by an intrinsic rate of natural population increase (r) of 0.118 d, net reproductive rates (R_o) of 243.693 eggs/female, gross reproduction rate (Σm_x) of 245.313 eggs/female, generation time (T) of 46.575 d, doubling time (DT) of 5.874 d and finite rate of increase (λ) of 1.125 d. Seasonal abundance of O. pygmaea and its prey, O. coffeae was monitored by sampling 25 tea leaves randomly from each experimental block grown under the prevailing field conditions. O. pygmaea showed a typical pattern of population dynamics with a peak during January to March and low incidence during June to September. Peak in the population of O. pygmaea coincided with the abundance of O. coffeae in the tea fields. Weather factors such as high temperature, low relative humidity and low sunshine hours adversely affected the populations of O. pygmaea. The first to third instar larvae of O. pygmaea consumed 31.0–133.2 eggs of mites per day. Third instar larva of O. pygmaea consumed an average of 133.2 eggs, 46.4 hexapod larvae, 39.6 nymphs and 11.4 adults per day. Adult females consumed more number of red spider mites compared to the males.     

Effectiveness and pesticide susceptibility of the pyrethroid-resistant predatory mite Amblyseius womersleyi in the integrated pest management of tea pests

To prevent the resurgence of the Kanzawa spider mite, Tetranychus kanzawai Kishida, on tea plants caused by the application of synthetic pyrethroid insecticides (SP), an SP-resistant strain of the predatory mite Amblyseius womersleyi Schicha was released onto tea bushes under SP (permethrin) application. The released predators successfully survived and may be able to suppress T. kanzawai. In the plot where A. womersleyi was released, the damage to new leaves was less severe than in the control plot and the predators remained resistant to the permethrin in the bushes. The selective use of pesticides that are harmless against natural enemies is necessary to achieve a program of integrated tea pest management. Although mortality of adult females of the tested strain in response to SP was from 6.5 to 89.3%, and mortality was more than 95% in response to several carbamate and organophosphate insecticides, usefulness of A. womersleyi as an agent of biological control was successfully demonstrated in the present study.     

Codling moth granulosis virus: effects of its use on some other orchard arthropods

In four field trials from 1978 to 1980, sprays of codling moth granulosis virus (CpGV) plus 1·0% skimmed milk powder did not significantly affect damage to fruit by leaf rollers (tortrix moths). In laboratory tests, survival of larvae of the leaf roller Archips podana fed on leaves sprayed with CpGV plus milk was unaffected and they grew faster than on unsprayed leaves, because of the milk deposits. This might increase damage by A. podana if CpGV plus milk were applied during the feeding period of this species. In one field trial an unusual infestation of fruit by larvae of pith moth Blastodacna atra was not affected by CpGV. Azinphos-methyl significantly reduced damage by B. atru and, in one field trial where sprays were correctly timed, that by leaf rollers. CpGV had no consistently significant effects on numbers of fruit tree red spider mite Panonychus ulmi or its predators, whereas azinphos-methyl induced outbreaks of P. ulmi by killing its predators.     

Life table and predation of Neoseiulus longispinosus (Acari: Phytoseiidae) on Oligonychus coffeae (Acari: Tetranychidae) infesting tea

Life table and predation of the predatory mite Neoseiulus longispinosus (Evans) on the red spider mite (RSM), Oligonychus coffeae (Nietner), a major pest of tea in India, were studied in the laboratory. Developmental time from egg to adult varied from 4 to 14 days at 30 to 15 °C, respectively; at 35 °C no larva survived. Survival of immature stages was more than 94 % at all temperatures. Threshold temperature for development of immature stages of females and males was 10 and 9.9 °C, respectively, and thermal constant was 84.03 degree-days for females and 80 for males. Sex ratio was female biased and temperature (20–30 °C) had no clear effect on sex determination. Egg hatchability was 73 % at 35 °C and >97 % at lower temperatures. Average number of eggs laid per female/day was higher at 30 °C than at 20 or 25 °C. The highest net reproductive rate (R ₀) was 40.7, at 20 °C. Mean generation time (T) decreased from 28 to 13 days with temperature increasing from 20 to 30 °C. Weekly multiplication (6.5) and intrinsic rate of natural increase (r _m ) (0.268) were highest at 30 °C. Males lived longer than females at every temperature tested. Longevity was highest at 20 °C (50 days for females and 55 for males). Survival and longevity were adversely affected by temperature above 30 °C. Daily consumption of prey increased with the advancement of predator’s life stages; adult females consumed the highest numbers of prey items, preferably larvae and nymphs.     

Prey stage preference and functional response of the predatory mite Galendromus flumenis to Oligonychus pratensis

The Banks grass mite, Oligonychus pratensis (Banks) (Acari: Tetranychidae), is a serious pest in dates (Phoenix dactylifera L.) in the New World. Currently O. pratensis is managed using the miticide, Savey, and alternative strategies are necessary to remove pressure from a single control method due to the risk of resistance evolution. For this purpose, studies are underway to develop biological control strategies using the predatory mite, Galendromus flumenis (Chant) (Acari: Phytoseiidae). The current study determined the consumption rate of G. flumenis at constant densities of O. pratensis eggs, larvae, protonymphs and deutonymphs, and defined the functional response of predator females. The predator consumed significantly more eggs than other prey stages, and displayed a type II functional response on all prey stages. The highest attack rate and shortest handling time were obtained for predators feeding on prey larvae and eggs, respectively. The proportions of prey consumed by G. flumenis were higher at lower densities for all stages of Banks grass mite, implying that G. flumenis should be more effective at suppressing Banks grass mite populations at lower densities. Therefore, in an augmentative release program, G. flumenis would need to be released early in the infestation.     

Influence of soil applied nitrogen (NPKS 25: 5: 5:5) on Brevipalpus phoenicis Geijskes (Acari: Tenuipalpidae) mite incidence and damage symptoms on tea

Application of nitrogenous fertilisers (NPKS 25: 5: 5:5) for yield of tea and to induce tolerance to the red crevice ( Brevipalpus phoenicis Geijskes) mite was found to be rates between 150 and 200 Kg N ha^-1 yr^-1 rates above 400 Kg N ha^-1 encouraged the build up of mites on tea. Damage symptoms resulting from mite infestation declined with increase in application of nitrogenous fertilisers.
The levels of nitrogen in the leaf tissues increased with soil applied nitrogen and also was related to the mite numbers found on the leaves suggesting a link. The symptoms of the discoloured necrotic leaf base that accompanied mite infestation was significantly ( P ≤ 0.05) and linearly correlated (r = 0.60) to mite numbers in the control plot. The levels of applied nitrogen were negatively correlated to % leaf necrosis suggesting a tolerance leading to reduction in necrotic symptoms with fertiliser applications.     

Life table and predatory efficiency of Stethorus gilvifrons (Coleoptera: Coccinellidae), an important predator of the red spider mite, Oligonychus coffeae (Acari: Tetranychidae), infesting tea

The ladybird beetle, Stethorus gilvifrons, is a major predator of the red spider mite, Oligonychus coffeae, infesting tea. Biology, life table and predatory efficiency of S. gilvifrons were studied under laboratory conditions. Its average developmental period from egg to adult emergence was 19.2 days. After a mean pre-oviposition period of 5.3 days, each female laid an average of 149.3 eggs. Adult females lived for 117.3 days and males for 41.5 days. The life table of the beetle was characterized by an intrinsic rate of increase (r) of 0.066 day⁻¹, net reproductive rate (R ₀) of 72.2 eggs/female, gross reproduction rate (Σm _x ) of 82.3 eggs/female, generation time (T) of 64.9 days, doubling time of 10.5 days and finite rate of increase (λ) of 1.07 day⁻¹. Population dynamics of S. gilvifrons and its prey, O. coffeae, was monitored by sampling 25 tea leaves from each experimental block grown under the prevailing field conditions. Populations of S. gilvifrons reached a peak during January to March and had low incidence during June to November. Peaks in the populations of S. gilvifrons coincided with the abundance of O. coffeae in tea fields. Weather factors such as low temperature, high humidity and heavy rainfall adversely affected the populations of S. gilvifrons. The predatory efficiency of S. gilvifrons increased during the growth of larval instars. An adult female consumed 205.0 eggs, 92.2 larvae, 81.8 nymphs and 52.4 adult mites per day.     

Wild host plants of four spider mite species (Acari: Tetranychidae) infesting fruit crops in Okinawa

To determine the wild host plants of four major spider mite species infesting fruit crops grown in the subtropical Asian region, we collected and identified mites from non-crop plants throughout the islands of Okinawa, southwestern Japan. Although the two mango pests, Oligonychus coffeae and O. biharensis, are polyphagous, they did not share any wild host species in the field, indicating that their source plants are completely separate in Okinawa. Several major wild hosts were determined for Eutetranychus africanus, a pest of papaya and citrus. Its host range partially overlapped with that of O. biharensis. The citrus red mite, Panonychus citri, was very rare on non-crop plants in Okinawa, suggesting that it maintains its population mainly on the citrus trees in the area. These results are of great significance when considering vegetation control as part of the integrated management of these pest mites. During our survey, two non-pest species, Panonychus caglei (new to Japan) and Oligonychus gotohi (new to Okinawa), were also found.     

Neoseiulus paspalivorus,a predator from coconut,as a candidate for controlling dry bulb mites infesting stored tulip bulbs

The dry bulb mite, Aceria tulipae, is the most important pest of stored tulip bulbs in The Netherlands. This tiny, eriophyoid mite hides in the narrow space between scales in the interior of the bulb. To achieve biological control of this hidden pest, candidate predators small enough to move in between the bulb scales are required. Earlier experiments have shown this potential for the phytoseiid mite, Neoseiulus cucumeris, but only after the bulbs were exposed to ethylene, a plant hormone that causes a slight increase in the distance between tulip bulb scales, just sufficient to allow this predator to reach the interior part of the bulb. Applying ethylene, however, is not an option in practice because it causes malformation of tulip flowers. In fact, to prevent this cosmetic damage, bulb growers ventilate rooms where tulip bulbs are stored, thereby removing ethylene produced by the bulbs (e.g. in response to mite or fungus infestation). Recently, studies on the role of predatory mites in controlling another eriophyoid mite on coconuts led to the discovery of an exceptionally small phytoseiid mite, Neoseiulus paspalivorus. This predator is able to move under the perianth of coconuts where coconut mites feed on meristematic tissue of the fruit. This discovery prompted us to test N. paspalivorus for its ability to control A. tulipae on tulip bulbs under storage conditions (ventilated rooms with bulbs in open boxes; 23 °C; storage period June–October). Using destructive sampling we monitored predator and prey populations in two series of replicated experiments, one at a high initial level of dry bulb mite infestation, late in the storage period, and another at a low initial dry bulb mite infestation, halfway the storage period. The first and the second series involved treatment with N. paspalivorus and a control experiment, but the second series had an additional treatment in which the predator N. cucumeris was released. Taking the two series of experiments together we found that N. paspalivorus controlled the populations of dry bulb mites both on the outer scale of the bulbs as well as in the interior part of the bulbs, whereas N. cucumeris significantly reduced the population of dry bulb mites on the outer scale, but not in the interior part of the bulb. Moreover, N. paspalivorus was found predominantly inside the bulb, whereas N. cucumeris was only found on the outer scale, thereby confirming our hypothesis that the small size of N. paspalivorus facilitates access to the interior of the bulbs. We argue that N. paspalivorus is a promising candidate for the biological control of dry bulb mites on tulip bulbs under storage conditions in the Netherlands.     

The predator guild associated withAceria litchii (Acari: Eriophyidae) in Australia and China

Lychees were surveyed in Queensland, Australia and in Guangdong Province and Hainan Island China, for natural enemies of the lychee erinose mite,Aceria litchii (Keifer), one of the most serious pests of lychee in Australia. A guild of seventeen predators, including ten species of phytoseiid mites, was associated with lychee erinose in Queensland. Six other predaceous mite species and a cecidomyiid larva,Arthrocnodax sp. were also part of the complex. Despite the apparent predation of most of the seventeen species recorded in Queensland onA. litchii, the pest continues to cause major problems. In China, whereA. litchii is a relatively minor pest, nine phytoseiid species were collected in lychee orchards. The value of introducing additional predators to Australia, especially from China, is discussed.     

Potential of the predatory mite Phytoseius finitimus (Acari: Phytoseiidae) to feed and reproduce on greenhouse pests

Phytoseiid mites of the genus Phytoseius are natural enemies of tetranychid and eriophyid herbivorous mites mostly found on hairy plants where they feed on prey, as well as on pollen. Nevertheless, the nutritional ecology and the role of these predators in biological pest control are only rarely addressed. In the present study, we evaluated the potential of Phytoseius finitimus to feed and reproduce on three major greenhouse pests, the two-spotted spider mite, the greenhouse whitefly and the western flower thrips. Additionally, we estimated the effect of cattail pollen when provided to the predator alone or in mixed diets with prey. Contrary to thrips larvae, both spider mite larvae and whitefly crawlers sustained the development of P. finitimus. In addition, females consumed more spider mite eggs and larvae, as well as whitefly crawlers than thrips larvae, but laid eggs when feeding on all prey. When provided alone, cattail pollen sustained the development and reproduction of the predator. The addition of pollen in mixed diets with prey reduced prey consumption, though it increased the predator’s egg production. We discuss the implications of our findings for biological pest control.     

Candidate predators for biological control of the poultry red mite Dermanyssus gallinae

The poultry red mite, Dermanyssus gallinae, is currently a significant pest in the poultry industry in Europe. Biological control by the introduction of predatory mites is one of the various options for controlling poultry red mites. Here, we present the first results of an attempt to identify potential predators by surveying the mite fauna of European starling (Sturnus vulgaris) nests, by assessing their ability to feed on poultry red mites and by testing for their inability to extract blood from bird hosts, i.e., newly hatched, young starlings and chickens. Two genuine predators of poultry red mites are identified: Hypoaspis aculeifer and Androlaelaps casalis. A review of the literature shows that some authors suspected the latter species to parasitize on the blood of birds and mammals, but they did not provide experimental evidence for these feeding habits and/or overlooked published evidence showing the reverse. We advocate careful analysis of the trophic structure of arthropods inhabiting bird nests as a basis for identifying candidate predators for control of poultry red mites.     

饲料类型对茶尺蠖幼虫肠道细菌多样性及幼虫存活率的影响

【目的】茶尺蠖是茶园中的重要害虫。研究茶尺蠖寄主食物-肠道菌群-茶尺蠖生长发育三者之间的关系对于茶尺蠖的防治具有重要的理论指导价值。【方法】分析不添加茶叶因子的纯人工饲料和茶树鲜叶对茶尺蠖幼虫的存活影响;用高通量测序技术分析不同饲料饲喂的茶尺蠖幼虫的肠道菌群异同。【结果】取食人工饲料的幼虫死亡率远远高于取食茶树鲜叶的幼虫;取食人工饲料的幼虫肠道细菌多样性和丰富度高于取食茶树鲜叶的幼虫;茶尺蠖幼虫肠道中存在很多促进宿主生长的细菌。【结论】饲料类型影响茶尺蠖幼虫的存活;饲料类型影响茶尺蠖幼虫肠道菌群结构。     

The relationship between the amount of insect-repelling phenolic compounds in pennywort tea and the number of infesting cigarette beetles in the tea bag during one-year storage

Cigarette beetle, Lasioderma serricorne (F.), is a common food-product pest widely found in homes. This paper investigated the relationship between the number of infesting cigarette beetles and the phenolic content of pennywort tea made from young and mature leaves during one-year storage. It was found that cigarette beetles started to appear in tea bags after six months of storage. More adults were found than larvae and pupae. In addition, the number of cigarette beetles infesting pennywort tea made from mature leaves was higher than when it was made from young leaves. The amount of phenolic compounds in pennywort tea was analyzed by Folin–Ciocalteau assay. The results of a regression analysis indicated that the number of adult cigarette beetles correlated negatively with the amount of phenolic compounds in pennywort tea made from young leaves – when the total phenolic content decreased, the number of infesting cigarette beetles increased (r² = 0.80). The number of larvae and pupae showed a weak negative correlation with the amount of phenolic compounds (r² = 0.40 and r² = 0.56, respectively). Similar correlations were found in pennywort tea made from mature leaves, but the number of infesting beetles was higher due to the lower phenolic content of the mature leaves.     

Geotaxis and leaf-surface preferences mitigate negative effects of a predatory mite on an herbivorous mite

Reproductive success and population growth of an herbivorous mite are limited by activities of phytoseiid predators. However, occurrences on upper versus lower leaf surfaces are sometimes mismatched between these prey and predators. The mismatch potentially mitigates predation risk for the prey species. We assessed factors that affect mite distributions on leaf surfaces, testing whether the presence of the phytoseiid mite Phytoseius nipponicus alters the leaf-surface distribution and reproductive success of the herbivorous false spider mite Brevipalpus obovatus. The host plant was Viburnum erosum var. punctatum (Adoxaceae). Leaves were set in natural (TRUE) and reversed (upside down; INVERTED) orientations using experimental devices. Both surfaces were accessible to mites. We detected lower and abaxial leaf-surface preferences in P. nipponicus. In contrast, upper and adaxial surfaces were preferred by B. obovatus. Thus, prey and predatory mites accumulated on different sides of leaves. Presence of the predator also indirectly decreased egg production in B. obovatus. Brevipalpus obovatus females actively avoided leaf surfaces with elevated predator numbers; these females shifted their distributions and changed oviposition sites to leaf surfaces with fewer predators. In consequence, B. obovatus eggs on the upper sides of leaves were less frequently preyed upon than were those on lower sides. We suggest that upper leaf-surface exploitation in this particular herbivorous mite species mitigates predation risk from phytoseiid mites, which prefer lower leaf surfaces.